Late Cretaceous crocodile remains from Naskal (India): comparisons and biogeographic affinities

Late Cretaceous crocodile remains from Naskal(India): comparisons and biogeographic affinities

Guntupalli V.R. Prasada, France de Lapparent de Broinb,*aDepartment of Geology, University of Jammu, Jammu – 180 006, India

bLaboratoire de paléontologie, UMR 8569 du CNRS, Muséum national d’histoire naturelle,8, rue Buffon, 75005 Paris, France

Received 15 October 2001; accepted 21 December 2001

Abstract

Crocodile teeth from the Maastrichtian inter-trappean beds of Naskal (peninsular India) aredescribed here. Because of isolated denticles visible on sufficiently preserved carinae, the presenceof a strong heterodonty (in size and shape), and by comparison to crocodile teeth from various taxa,they are considered as representing a ziphodont form with a heterodont dentition. The differencebetween ziphodont, “false ziphodont” and non-ziphodont dentitions is evaluated. With the help ofscanning electron microscope photographs, it is shown that only precise characteristics of thedenticles and not the tooth shape, allow to distinguish the three categories. These three categoriesdo not correspond to monophyletic groups. It is also shown that the “alligatorid” heterodonty,meso- or eusuchian in grade, exists in each category. Although the ziphodont dentition is notsufficient to allow a taxonomical definition, the peculiarities that it often presents, depending on thetaxa as well as the teeth shape, enable systematic approaches. An examination of previous workson the possible ziphodont crocodiles from the Tertiary deposits of the Indian subcontinent and onNaskal teeth demonstrate that the latter are closer to those of some Gondwanan crocodiles ofmesosuchian grade, known from the early Cretaceous of Africa and possibly a form from the lateCretaceous of Madagascar. They are excluded from eusuchian Laurasiatic as well as Paleogeneforms of the Indian subcontinent, either ziphodont or not. Contrary to the earlier works on theinter-trappean crocodiles, the present study removes this group as one of the evidences in supportof an early (late Cretaceous-early Tertiary) India/Asia collision model. In fact, it provides anadditional support for the existence of possible Cretaceous biogeographic links between India,Madagascar, Africa, and South America. © 2002 E´ditions scientifiques et médicales Elsevier SAS.All rights reserved.

* Corresponding author.E-mail addresses: [email protected] (G.V.R. Prasad), [email protected] (F. de Lapparent deBroin).

Annales de Paléontologie 88 (2002) 19−71www.elsevier.nl/locate/annpal

© 2002 Éditions scientifiques et médicales Elsevier SAS. All rights reserved.PII: S 0 7 5 3 - 3 9 6 9 ( 0 2 ) 0 1 0 3 6 - 4

Résumé

Restes de crocodiles du Crétacé supérieur de Naskal (Inde) : comparaisons et affinitésbiogéographiques. Des dents de crocodile, provenant des couches inter-trappéennes de Naskal(Inde centrale) et datées du Maastrichtien supérieur, sont décrites. La présence de dentelures bienisolées visibles sur les carènes suffisamment préservées et d’une forte hétérodontie (en taille et enforme) amène leur comparaison avec les dents de divers crocodiles, soit considérés commeziphodontes, soit simplement à denture hétérodonte. La distinction entre dentures ziphodonte,« faussement ziphodonte » et non ziphodonte est étudiée. Il est montré, à l’aide de photographiesprises au microscope électronique à balayage, que seules les caractéristiques précises desdentelures permettent de distinguer ces catégories mais non la forme des dents. Les trois « caté-gories » ne correspondent pas à des groupes monophylétiques. Il est aussi montré que l’hétéro-dontie dite « alligatorienne » existe dans les trois catégories, qu’elles soient de grade méso- oueusuchien. La ziphodontie de la denture ne permet pas à elle-seule une détermination taxonomiquemais les particularités qu’elle peut présenter en fonction des taxons, outre la forme des dents,permettent des rapprochements systématiques. Après l’examen des études précédentes sur leséventuels crocodiles ziphodontes du Tertiaire du sous-continent indien et d’un travail concernantaussi des dents provenant de Naskal, les dents de cette localité sont rapprochées de celles decertains crocodiles de grade mésosuchien du domaine gondwanien : Crétacé inférieur d’Afrique etéventuellement une forme du Crétacé supérieur de Madagascar. Sont particulièrement écartées lesformes eusuchiennes de Laurasie et celles du Paléogène du sous-continent indien, ziphodontes ounon. La présente étude démontre que, contrairement aux oeuvres précédentes sur les crocodiles del’ Inter-trappéen, le groupe auquel appartiennent les dents de Naskal n’est pas un témoin de lacollison précoce qui aurait eu lieu entre l’ Inde et l’Asie au Crétacé terminal-base du Tertiaire. Cesdents renforcent au contraire l’hypothèse de l’existence de relations étroites entre l’ Inde,Madagascar, l’Afrique et l’Amérique du Sud avant la séparation de ces continents consécutive àleur dérive. © 2002 Editions scientifiques et médicales Elsevier SAS. Tous droits réservés.

Keywords: Teeth; Crocodiles; Late Cretaceous; India; Ziphodonty; Heterodonty; Palaeogeography

Mots clés: Dents; Crocodiles; Crétacé supérieur; Inde; Ziphodontie; Hétérodontie; Paléogéographie

1. Introduction

The Deccan flood basalts occupy an area of about of 500,000 km2 in peninsular India.At many places thin sedimentary beds occur in association with these volcanic flows.Generally the initial volcanic flows are underlain by a thick sequence of sedimentarybeds which has been formally designated as Lameta Formation or informally asinfra-trappean beds. During the dormant stages of volcanism, at several sites the volcanicflows were covered by large continuous as well as small discontinuous lacustrine basinsthat supported rich plant and animal life. These lacustrine basins were invariably shallowin nature without exceeding a thickness of five meters and are commonly known asDeccan inter-trappean beds in the Indian stratigraphy. Although sedimentary beds areknown to occur above the youngest Deccan lava flows (supra-trappean beds) insubsurface sections, no such beds have been delineated in the outcrops.

20 G.V.R. Prasad, F. de Lapparent de Broin / Annales de Paléontologie 88 (2002) 19–71

Ever since the early report by Hislop (1860), the Deccan infra- and inter-trappean bedshave remained a source of diversified fossil groups, such as vertebrates, invertebrates,and plants (Khajuria et al., 1994; Prasad, Khajuria, 1995). All the early works favoureda Turonian age for the infra-trappean beds and an upper Cretaceous to early Eocene orearly Oligocene age for the inter-trappean beds and thus a total duration of about30-50 m.y. for Deccan volcanism.

The Deccan Traps and the intercalated sedimentary beds attracted considerableattention in recent years because of the hypothesis linking the demise of dinosaurs andmany other groups of organisms at the Cretaceous-Tertiary boundary to Deccanvolcanism (Officer et al., 1987; McClean, 1985; Courtillot, 1990). Latest palaeomagneticand geochronological works suggested that Deccan volcanism was a short-lived eventcovering a period of about 3-5 m.y. rather than 30-50 m.y. (Bakshi, 1987; Courtillot,1990; Courtillot et al., 1986, 1988; Duncan, Pyle, 1988; Pande et al., 1988; Venkatesanet al., 1996).

Renewed interest in the Deccan infra- and inter-trappean biota has been generated byrecent palaeobiogeographic models favouring a late Cretaceous-early Palaeocene faunaldispersal route between the Indian plate and the Asian mainland (Bhatia, Rana, 1984;Sahni, 1984; Sahni et al., 1982). The presence of Laurasian biota in the northwarddrifting Indian plate has subsequently been explained by invoking an early India/Asiacollision event near the Cretaceous-Tertiary boundary (Jaeger et al., 1989), well beforethe long held Middle Eocene age. As a consequence, a plethora of works have beenpublished on the vertebrate fauna of Deccan infra- and inter-trappean beds (Bajpai et al.,1990; Khajuria et al., 1994; Prasad et al., 1995; Prasad, Khajuria, 1995). These workscovered fossil fishes, amphibians, snakes, lizards, turtles, crocodiles, and dinosaurs.Based on ostracodes, foraminifers (from subsurface sections), fishes, dinosaurs, palyno-fossils, recent palaeomagnetic and geochronological data (see Khajuria et al., 1994 forreferences), the Deccan infra- and inter-trappean beds are now considered as Maastrich-tian in age.

Among all the inter-trappean vertebrate groups, the crocodiles are the least studied andare known by fragmentary vertebrae (Prasad, Singh, 1991; Rana, 1987) and teeth(Prasad, Khajuria, 1990; Rana, 1990). Rana, 1987 reported an isolated vertebra from theinfra-trappean beds of Auspalli, Rangareddi District and referred it to Dyrosauridae,crocodiles of mesosuchian grade. A similar vertebra recovered from the infra-trappeanbeds of Marepalli was also assigned to Dyrosauridae (Prasad, Singh, 1991). Subse-quently, Rana (1990) recorded the presence of isolated crocodilian teeth in theinter-trappean beds of Rangapur (Fig. 1A), Rangareddi District, Andhra Pradesh (State)and placed them under the Subfamily Alligatorinae. Prasad and Khajuria (1990)documented a diversified microvertebrate assemblage that included crocodile teethsimilar to those reported by Rana, 1990 from an inter-trappean section exposed 2 kmnortheast of Naskal village, Rangareddi District, Andhra Pradesh (Fig. 1A). Theinter-trappean beds of Naskal have been assigned a Maastrichtian age based onostracodes and palynofossils (Khajuria, Prasad, 1998; Sahni et al., 1996). Following thework of Rana (1990) Prasad and Khajuria (1990) preferred to place the crocodilian teethfrom these inter-trappean beds in alligatorids, crocodiles of eusuchian grade, until adetailed study is carried out. All other previous reports on inter-trappean crocodiles were

G.V.R. Prasad, F. de Lapparent de Broin / Annales de Paléontologie 88 (2002) 19–71 21

based on isolated teeth which have often been referred to Crocodylus sp. without givingsupportive evidence for such an assignment (Prasad, Sahni, 1987; Rana, 1984).

The Deccan inter-trappean crocodiles are one of the fossil groups among a number ofothers that have been cited in support of biotic links between India and Laurasia in the

Fig. 1. Location map of the studied area. (A) Geographical position of the fossiliferous locality with respect toNaskal village. (B) Map of India showing the distribution of Deccan volcanic flows and the position of Naskalinter-trappean beds within the Deccan volcanic province.Fig. 1. Carte géographique de la zone étudiée. (A) Carte de l’ Inde montrant la distribution des couléesvolcaniques du Deccan et la position des couches inter-trappéennes de Naskal dans la province volcanique duDeccan.


late Cretaceous (Rana, 1990; Rana,Sati, 2000). Since such a conclusionhas serious implications for the lateCretaceous biogeography of the Indiansubcontinent, an attempt is made hereto describe isolated heterodont croco-dilian teeth (numbering about 1200) ofthe Naskal inter-trappean beds in detailand evaluate their taxonomic status inthe light of comparisons made with avariety of taxa from the lower Creta-ceous of Africa, lower Cretaceous-lower Tertiary deposits of SouthAmerica, upper Cretaceous-lower Ter-tiary strata of Europe and NorthAmerica and certain living taxa. Anattempt is also made to review a fewearly reports of ziphodont crocodileteeth from the Indian subcontinent.

The fossiliferous inter-trappean sec-tion is exposed 2 km northeast ofNaskal village (17°13’ ; 77°52’ ;Fig. 1A-B), Rangareddi District,Andhra Pradesh (India). The inter-trappean section of Naskal occurssandwiched between volcanic flowsNos. 4 and 5 (Fig. 2) (Dutt, 1975). Thebasal unit of this inter-trappean sectionbegins with a greenish-grey colouredgleyed mudstone unconformably over-lying the volcanic flow No. 4. In thelower part, this unit shows low anglecross-beds and in the upper part thincrossed laminations and a few calcar-eous rhizoliths. This bed yieldedscarce freshwater ostracodes andcrushed gastropod shells. The gleyedmudstone unit gradually changes toyellow mudstone, which is character-ised by horizontally laid rhizoliths andwhite mottling. The basal part of thisbed is harder and more calcareous thanthe upper part and has been designatedas calcareous inseptisol based on vari-ous lithological parameters (Prasad,

Fig. 2. Stratigraphical column of Naskal inter-trappeansection.Fig. 2. Colonne stratigraphique de la coupe des couchesinter-trappéennes de Naskal.


Khajuria, 1990). The yellow mudstone has yielded freshwater ostracodes. An erosionalsurface separates the yellow mudstone from the overlying hard, grey-coloured marlstone.In the lower part, the marlstone is thinly laminated and shows desiccation cracks andburrows on the topmost surface. Yellowish-white rhizoliths occur throughout this unit.The marlstone is rich in ostracodes, gastropods, charophytes, and fragmentary remains offish. The marlstone is followed upwards unconformably by an impure marlstone whichcontains calcareous rhizoliths at places. The impure marlstone is overlain by agreyish-black chert with an erosional contact. The basal part of the chert is banded andcontains ostracodes, gastropods, and charophytes. This grades upwards into massive,dark grey, compact chert yielding no microfossils. The crocodilian teeth described in thispaper come from a calcareous mudstone unit which occurs immediately beneath thevolcanic flow No. 5 (Fig. 2). This mudstone with white and yellow mottling is soft,friable and contains calcareous nodules, rhizoliths, calcretes, and coprolites. The basalpart of this mudstone is pinkish-white in color (because of the abundance of pulmonategastropods of this color) and yielded a rich vertebrate assemblage consisting ofmicroremains of fish: Lepisosteus, Osteoglossidae gen. et sp. indet., Pycnodontidae gen.et sp. indet., Igdabatis; amphibians: Discoglossidae gen. et sp. indet., ? Hylidae gen. etsp. indet.; snakes: Indophis sahnii Rage & Prasad, 1992, Serpentes indet.; lizards:Anguidae gen. et sp. indet. (see Prasad, Khajuria, 1990; Prasad, Rage, 1991, 1995; Rage,Prasad, 1992), and mammals: Deccanolestes hislopi Prasad & Sahni, 1988, Deccano-lestes cf. D. hislopi, D. robustus Prasad et al., 1994 (Godinot, Prasad, 1994; Prasad,Godinot, 1994), Sudamericidae gen. et sp. indet. (Das Sarma et al., 1995; Krause et al.,1997). Besides these, freshwater ostracodes, pulmonate gastropods and charophytes havealso been recovered from this level. The upper part of calcareous mudstone lacks anyfossils and is capped by spheroidally weathered basalt of volcanic flow 5.

Abbreviations: MNHN, Muséum national d’histoire naturelle; AC, Anatomie Com-parée; P, Paléontologie; MP, Mammal Paleogene ages; USTL, Université des Sciences etTechniques du Languedoc, Montpellier II, laboratoire de paléontologie; VLP/JU/IR,Vertebrate Palaeontology Laboratory, Jammu University, inter-trappean reptiles.

2. Systematics

Order: CROCODYLIA GMELIN, 1788FAM., GEN., SP. INCERTAE SEDIS

2.1. Referred material

Vertebrate fossil collections of the Department of Geology, University of Jammu.Isolated teeth, VPL/JU/IR/100-150, and about 1150 unnumbered specimens.

2.2. Horizon and locality

Calcareous mudstone of Deccan inter-trappean section exposed 2 km northeast ofNaskal village, Rangareddi District, Andhra Pradesh, India.


2.3. Description

All the teeth, except the immature ones and those from young individuals(Plate II, Fig. f) are eroded. The surface is strongly pitted, but the lateral crests andenamel ridges are clearly visible. Khajuria and Prasad (1998) attributed the surfacepittting on Naskal microvertebrates to the effects of plants toxicants either at the time ofinitial burial or during exhumation and weathering of fossil material. The anterior toposterior position of the teeth on the maxillary or mandibular series (here undefined) isestimated by comparison with the dentition series of two extant Crocodylidae fromAfrica, Osteolaemus tetraspis (MNHN AC, 1931-45, Plate I), and Crocodylus niloticus(MNHN, Plate II, Figs. a,b). These two forms present the generalized heterodonty inshape and size of most of the extant crocodiles, eusuchian Crocodylidae and Alligatori-dae. Within these families, variations exist in length and shape according to the diet orto the size and shape of the rostrum: teeth are higher as a whole in a longirostrine formsuch as Tomistoma, and very posterior teeth are apically flattened and button-shaped insome short-snouted forms. Among both figured forms, Osteolaemus, a very short snoutedform, is the more differentiated and closer to the heterodonty of the Naskal type by theshortened, bulbous and apically flattened posterior teeth. The Naskal teeth are more orless worn during the life of the animal. The worn teeth show that in spite of their reducedsize, they are not dentary buds, replacement teeth still in the alveoli below the functionalteeth.

2.3.1. Morphotype IThe teeth are high and straight, conical in outline with acutely pointed apices

(VPL/JU/IR/104, 102; Plate II, Fig. d,e). In many teeth, the tip is worn rounded (Plate II,Fig. e). Both labial and lingual faces of the teeth are convex. A sharp crest descends fromeither side of the apex to the broken bases of the crown. Since the base is broken, it isnot known whether there was a constriction between the crown and root. The surface ishighly pitted but appears to have fine longitudinal striations. In some specimens,(VPL/JU/IR/103, Plate II, Fig. g), the central part of the crown is coarsely fluted on oneside (?lingual). The anterior and posterior crests are highly worn, but appear to lackserrations such as those which are present in the other teeth from the locality. Theabsence of serrations might be an artifact of severe etching of the crown surface, becauseone fragmentary specimen belonging to this morphotype bears worn serrations on itsmargins (VPL/JU/IR/124). However a new true ziphodont crocodile from the earlyCretaceous of Morocco (to be defined) do not bear serrations on anterior teeth but onlyon posterior ones. The teeth of the morphotype I have subcircular cross section(Fig. 3b,c,e) VPL/JU/IR/104 (Plate II, Fig. d) differs from VPL/JU/IR/102 and 103 inhaving a posteriorly recurved and slightly lingually tilted apex and convex anterior andconcave posterior faces. Thus the presumed labial face is convex and the lingual face isslightly concave. Otherwise, it is similar to the latter teeth in the presence of finelystriated crown surface and subcircular cross section. All these teeth might belong to theanteriormost series.


2.3.2. Morphotype IIVPL/JU/ IR/100 (Plate II, Fig. c) is the largest of all the teeth, conical in outline,

laterally compressed, acutely pointed, posteromedially recurved with a convex anteriorand slightly concave posterior face. The apex of the tooth is slightly lingually bent.Because of this lingual inclination of the tooth, the labial face is convex whereas thelingual face is concave. The crown has two longitudinal crests, one posteriorly and oneanteriorly, extending from the tip towards the base and terminating well before the baseof the crown. The tooth appears to have had serrations on the anterior and posteriorcarinae, but we are not certain of this as the tooth is heavily pitted. But wherever theenamel is preserved, the middle part of the crown between these carinae shows finelongitudinal striations. In cross section, the tooth has an elliptical outline (Fig. 3a).VPL/JU/IR/100 is probably a caniniform tooth.

In a few of the high, slightly labiolingually flattened teeth (VPL/JU/IR/101), thecrown is not posteriorly recurved, but is slightly lingually tilted. The posterior andanterior crests are convex. The preservation of enamel and surface ornamentation (finelongitudinal striations) is similar to that of VPL/JU/IR/100. The labial face of the teethis convex as in VPL/JU/IR/100, but the lingual surface, particularly the middle part, isslightly convex and both labial and lingual faces are coarsely fluted (1 labial and 2 lingualflutings). The anterior and posterior margins of the teeth are produced into flange-likecrests as the raised central part is separated from the margins by broad, shallow grooves.This is particularly evident on the supposed lingual face. The preservation of anterior andposterior carinae is similar to that of VPL/JU/IR/100 and they appear to lack trueserrations. In cross section, the tooth has an elliptical outline.

Fig. 3. Cross sectional views (at the crown base) of most of the studied crocodile teeth. (a-p) Crocodylia indet.,Naskal, India, late Cretaceous, teeth from the Plates II-VIII, coll. VPL/JU/IR: (a) n° 100; (b) n° 104; (c) n° 102;(d) n° 123; (e) n° 103; (f) n° 105; (g) n° 107; (h) n° 108; (i) n° 111; (j) n° 118; (k) n° 109; (l) n° 120; (m) n° 110;(n) n° 119; (o) n° 122; (p) n° 121. (q) Hamadasuchus rebouli, Erfoud area, Guir, Morocco, early Cretaceous,MNHN (P) MRS 3103, Plate X. (r,s) Pristichampsus rollinati: (r) Argenton-sur-Creuse, France, Lutetian, MP11, MNHN (P) AG 20, syntype, Plates XI, b, XIII, c, XIV, c; (s) Grauves, France, Cuisian, MP 10, MNHN (P)GR 17293, Plates XI, c-d, XIII, b. (t) Sebecus sp., Miocene, Colombia, MNHN (P) VIV 69, Plates XIII, f, XIV,b. (u) cf. Iberosuchus sp., Robiac, France, Bartonian, MP16, MNHN (P) ERH 1001, Plates XIII, e, XIV, a.(v-w) Trematochampsa taqueti, Ibeceten, Niger, Senonian, MNHN (P) IBC 1657, 1656, Plates XV, a-b, XVI.(x-y) Asiatosuchus sp., Mont-Berru, France, Thanetian, MP 6, MNHN (P) BR 12084, Plate XVII, BR15203,Plate XV, a. Magnitude: a-c, e-s and x: x 3; t-v and y, z: x 1.Fig. 3. Section à la base de la couronne de la plupart des dents de crocodiles étudiées. (a-p) Crocodylia indet.,Naskal, Inde, Crétacé supérieur, dents figurées Planches II-VIII, coll. VPL/JU/IR : (a) n° 100 ; (b) n° 104 ; (c)n° 102 ; (d) n° 123 ; (e) n° 103 ; (f) n° 105 ; (g) n° 107 ; (h) n° 108 ; (i) n° 111 ; (j) n° 118 ; (k) n° 109 ; (l)n° 120 ; (m) n° 110 ; (n) n° 119 ; (o) n° 122 ; (p), n° 121. (q) Hamadasuchus rebouli, région d’Erfoud, Guir,Maroc, Crétacé inférieur, MNHN (P) MRS 3103, Planche X. (r,s) Pristichampsus rollinati : (r) Argenton-sur-Creuse, France, Lutétien, MP 11, MNHN (P) AG 20, syntype, Planches XI, b, XIII, c, XIV, c; (s) Grauves,France, Cuisien, MP 10, MNHN (P) GR 17293 Planches XI, c-d, XIII, b. (t) Sebecus sp., Miocène, Colombie,MNHN (P) VIV 69, Planches XIII, f, XIV, b. (u) cf. Iberosuchus sp., Robiac, France, Bartonien, MP 16, MNHN(P) ERH 1001, Planches XIII, e, XIV, a. (v-x) Trematochampsa taqueti, Ibeceten, Niger, Sénonien, MNHN (P)IBC 1657, 1656, Planches XV, b-c, XVI. (y-z) Asiatosuchus sp., Mont-Berru, France, Thanétien, MP 6, MNHN(P) BR 12084, Planche XVII, BR15203, Planche XV, a. Grossissement : a-c, e-s et x : x 3 ; t-v et y, z : x 1.



Plate I. Osteolaemus tetraspis, Africa, Extant, MNHN (AC) 1931-45, (a,b) dentary part of the lower jaw, dorsaland right lateral views. Scale bar: 1 cm.Planche I. Osteolaemus tetraspis, Afrique, Actuel, MNHN (AC) 1931-45, (a,b) partie dentaire de la mandibule,vues dorsale et latérale droite. Echelle: 1 cm.


2.3.3. Morphotype IIIThe crown of these teeth is relatively higher than that of posterior teeth and lower than

that of anterior ones (VPL/JU/IR/105-106, 108; Plate II, Fig. h,j,k). The teeth haveroughly triangular outline in lateral view with an acutely pointed apex, concave posteriorand convex anterior crests. The apex is slightly posteriorly recurved and slightlylingually bent, and the labial and lingual faces are slightly convex and concave,respectively. The crown surface is traversed by fine longitudinal and parallel striations.The crowns are higher than their basal length. The base of the crown is swollen and thejunction between the crown and root is marked by a constriction. The teeth have wornanterior and posterior carinae. Since pitting along lateral crests is very heavy, it is difficultto identify any serrations on them. They have an elliptical cross section (Fig. 3g).VPL/JU/IR/107 (Plate II, Fig. i; Fig. 3g) has a similar morphology, but differs in havingcoarse longitudinal ridges and grooves on the labial as well as lingual surface. Theseflutings are restricted to the raised central part of the crown surface leaving a shallow butbroad groove between the central part and the anterior and posterior carinae. The flutingsgradually become broader towards the base. These teeth appear to be intermediatebetween the anterior and anteriormost posterior teeth.

2.3.4. Morphotype IVThese teeth are relatively short, nearly as high as long (VPL/JU/IR/109-117; Plates III,

IV) or slightly higher than long (VPL/JU/IR/110, Plate VII, Figs. a-b). Unlike those ofmorphotype III, these teeth are not recurved posteriorly, but the apex of the crown isslightly lingually bent. As in the anterior teeth, the apex is still acutely pointed, but thebase is elongated anteroposteriorly. The crowns are labiolingually compressed. Thelingual face is separated from the labial face both anteriorly and posteriorly by sharpcrests descending from the apex to the base of the crown near to the crown-rootconstriction. In majority of the teeth, the surface is ornamented with fine parallel ridgesand grooves which terminate at the constriction basally. In cross section, the teeth areelliptical to strongly elliptical in outline. The lingual face is flat or slightly convex. Thelabial face of the crown is more convex than the lingual face. The teeth which are notstrongly etched exhibit serrations on the anterior and posterior carinae (Plates III, IV;Plate VII, Figs. a-b). In VPL/JU/IR/113-117, the apex is less pointed and anteroposte-riorly longer than that of VPL/JU/IR/109 and 110 (Plate IV; Plate VII, Figs. a-b). Thevariation in the length of apex is attributed to the position of the teeth on the jaws. Themore anterior ones have acutely pointed apices and the posterior ones bear less acuteapices. These teeth possibly represent the anteriormost posterior series.

2.3.5. Morphotype VThese teeth are globular to sub-globular in shape in unworn condition

(VPL/JU/IR/118-119, Plate V, Fig. a; Plate VII, Fig. c). In worn condition, the crown isrectangular in shape (VPL/JU/IR/120, 122; Plate VI, Fig. c; Plate VII, Fig. d). The apexof these teeth is much longer anteroposteriorly than in any other teeth of the presentcollection. In these teeth, the anteroposterior length is greater than the height. Some ofthese teeth are bulbous (VPL/JU/IR/119, Plate VII, Fig. c), being convex both linguallyand labially, whereas others are labiolingually flattened (VPL/JU/IR/120, Plate VI,


Fig. c). A marked constriction is present at the base of the crown. The surface of thecrown is ornamented with medium to coarse ridges and grooves of broadly parallelorientation. The anterior and posterior carinae are worn and show no serrations (see PlateVI, Fig. a) as in morphothype III; since pitting along lateral crests is very heavy, it isdifficult to identify any serrations on them. When strongly worn, the apex also appearsflat and elliptical in outline (VPL/JU/IR/121-122, Plate VIII; Plate VII, Fig. d). All theseteeth have elliptical cross sections (Fig. 3n-p). These teeth can be attributed to theposteriormost series.

2.3.6. Juvenile teethThere is a considerable number of small teeth with a constricted base and rounded

cross section (VPL/JU/IR/123, Plate II, Figs. f,d). The tip of these teeth is slightlyposteriorly recurved and lingually tilted. In some of these teeth, the apex is partially wornand the tooth was possibly completely grown and was derived from a young individual.Other unworn specimens were probably replacement teeth which were still in the base ofthe alveoli of older individuals. In all the posterior teeth described above, the crowns arelaterally compressed and the basal section is elliptical. Because of their rounded section,the present teeth can be referred to the anterior teeth series. Since no dentary or maxillais available from the same site, no comparison with the alveoli is possible.

2.4. Comparisons

2.4.1. Living crocodilesThe living crocodiles are characterised by a relatively uniform dental morphology of

simple, non-serrated conical teeth with a constriction at the base of the crown (but hardlyin gavial). In both figured (Plate I; Plate II, Figs. a,b) extant taxa, Crocodylus andOsteolaemus, the anterior teeth are conical, acutely pointed and the crown surface bearslongitudinal ridges; they are lingually more recurved than the posterior ones; theintermediate teeth are triangular to lanceolate in outline and have more accentuatedlongitudinal ridges. The posterior teeth are triangular to lanceolate in outline inCrocodylus. In Osteolaemus, the posterior teeth are shorter and blunt having horizontal

Plate II. Crocodylus niloticus, Africa, Extant, MNHN: (a) anterior part of the skull, right view; (b) dentary partof the lower jaw, left lateral view. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous: (c-k)teeth, most of them without root, coll. VPL/JU/IR/: (c) n° 100, caniniform tooth, morphotype II, lingual view;(d) n° 104, morphotype I, lingual view; (e) n° 102, morphotype I, lingual view; (f) n° 123, morphotype“ juveniles” , distolabial view; (g) n° 103, morphotype I, labial view; (h) 105, morphotype III, lingual view; (i),n° 107, morphotype III, lingual view; (j), n° 106, morphotype III, lingual view. (k) n° 108, morphotype III,lingual view. a-b, x 1; c-e and g-k, x 3: f, x 20.Planche II. Crocodylus niloticus, Afrique, Actuel, MNHN : (a) partie antérieure dentaire du crâne, vue latéraledroite ; (b) partie dentaire de la mandibule, vue latérale gauche. Crocodylia indet., Naskal, Inde, couchesinter-trappéennes, Crétacé supérieur : (c-k) dents, la plupart sans racine, coll.VPL/JU/IR/ : (c) n° 100, dentcaniniforme, morphotype II, vue linguale ; (d) n° 104, morphotype I, vue linguale ; (e) n° 102, morphotype I,vue linguale ; (f) n° 123, morphotype “ juvéniles” , vue distolabiale ; (g) n° 103, morphotype I, vue labiale ; (h)n° 105, morphotype III, vue linguale ; (i) n° 107, morphotype III, vue linguale ; (j), n° 106, morphotype III, vuelinguale ; (k), n° 108, morphotype III, vue linguale. a-b, x 1; c-e et g-k, x 3: f, x 20.



Plate III. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous, VPL/JU/IR/111, morphotypeIV, posterior (not the posteriormost) tooth; (a) complete unworn tooth, lingual view, x 15; (b), magnified viewof the serrations of the carina, x 70, to be compared with Plates IV, VII and IX-XIV.Planche III. Crocodylia indet., Naskal, Inde, couches inter-trappéennes, Crétacé supérieur, VPL/JU/IR/111,morphotype IV, dent postérieure (pas la plus postérieure) ; (a) dent complète non usée, vue linguale, x 15 ; (b)détail des festons d’une des deux carènes, x 70, à comparer aux Planches IV, VII et IX-XIV.


Plate IV. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous, VPL/JU/IR/109, morphotype IV, posterior (not the posteriormost) tooth; (a) completeunworn tooth, lingual view, x 9; (b) magnified view of the serrations of the carina, x 70, to be compared with Plates III, VII and IX-XIV.Planche IV. Crocodylia indet., Naskal, Inde, couches inter-trappéennes, Crétacé supérieur, VPL/JU/IR/109, morphotype IV, dent postérieure (pas la plus postérieure) ;(a) dent complète, non usée, vue linguale, x 9 ; (b), détail des festons d’une des deux carènes, x 70, à comparer aux Planches III, VII et IX-XIV.

G.V.R

.Prasad,F.de

Lapparent

deB

roin/

Annales

deP

aléontologie88

(2002)19–71

33

Plate V. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous, VPL/JU/IR/118, morphotype V,posterior tooth, nearly unworn; (a) complete tooth, labial or lingual view, x 15; (b) magnified view of thestriations at the slightly worn apex, x 45.Planche V. Crocodylia indet., Naskal, Inde, couches inter-trappéennes, Crétacé supérieur, VPL/JU/IR/118,morphotype V, dent postérieure, à peine usée ; (a) dent entière, vue labiale ou linguale, x 15 ; (b) détail sur lesstriations à l’apex, légèrement usé, x 45.


or rounded apex (button-shaped teeth) and bear fine, parallel, longitudinal ridges thatconverge at the apex, as in the posterior teeth of Naskal (see living crocodiles inWermuth, Mertens, 1961). There is some variability in size, basal cross section and shapeof tooth crowns, according to the position on the upper or lower series and depending onthe taxa they represent. Fluted and/or striated teeth may or not be present in livingcrocodile forms. In a species, they may always be present, variably present or completelyabsent in a series, depending on the individual. Flutings and striations, when present,may be very marked on the maxillary and less on the dentary teeth (figured Crocodylus,Plate II, Figs. a,b). Fluted teeth are more often present in the anterior part of the seriesbut it is not always necessary. Striations may happen all along the series or only in theposterior part. In newly grown, uneroded and unworn teeth of Crocodylidae, the enamelsurface may be ornamented with a network of interwoven irregular ridges that are moreaccentuated at the apex, and the anterior and posterior carinae are crenulated as in “ falseziphodont” crocodiles described below (Plate XV, Fig. a).

The variability in shape and size along the series shown by the two Crocodylidae ofthe Plates I and II, gives an idea of the variability in most of the extant forms but alsoin fossil forms. Longirostrine crocodiles have higher teeth as a whole, for example theCrocodylidae Tomistoma, but the difference in shape shown by Crocodylus teeth in thedental series also exists in the extant species with shorter and slightly lanceolatedposterior teeth. The highly piscivorous Gavialidae Gavialis shows little variation inshape of the teeth. Its teeth are long and acute as a whole, recurved and hardly constrictedat the base of the crown, but show heterodonty in size, some teeth being much taller thanothers. In contrast, some very short-snouted forms of Alligatoridae, such as Melanosu-chus, for example, have shorter teeth with blunt and even completely apically flattened(button-shaped) posteriormost teeth as in Crocodylidae Osteolaemus (Plate I).

2.4.2. Fossil crocodile dentitionIn marked contrast to the extant forms, the fossils exhibit a wider range of tooth

morphology. In some early crocodiles such as Protosuchus Brown, 1934 (see Colbert,1951), from the early Jurassic of Canada, the teeth seem to be relatively lessdifferentiated. They are high, acutely pointed, and non-serrated and apparently onlydifferentiated in height (higher caniniform teeth).

This condition is similar to that of Brillanceausuchus Michard et al., 1990, from theearly Cretaceous of Cameroon in which some teeth are also fluted. In Jurassic times, theEuropean Atoposauridae had already undergone differentiation with more acute anteriorand more lanceolated posterior teeth (Wellnhofer, 1971, Fig. 5).

Recent discoveries indicate a high variety of extraordinary dietary adaptations inMesozoic crocodiles (Buckley et al., 2000; Carvalho, 1993, 1994; Carvalho, Campos,1988; Clark et al., 1989; Gomani, 1997; Larsson, Sidor, 1999; Wu et al., 1995).

2.4.2.1. True ziphodont and false ziphodont dentitions. Besides the above described cat-egories, these two types of dentitions are very common in fossil crocodiles. Even thesetwo broad groups (ziphodonts and false ziphodonts) exhibit considerable variation intheir dental morphology. They are not monophyletic groups. Some have homodontdentition in shape, while others have heterodont dentition in shape, both having


heterodonty in relative size. Those showing homodonty in shape have normally highacutely pointed and low acutely pointed teeth, rounded or compressed, with or withoutconstriction at the base of the crown. Dentitions with heterodonty both in size and shapegenerally have high acutely pointed teeth in the anterior part, (rounded or laterallycompressed), low intermediate lanceolated and low posterior teeth with horizontal apexor rounded button-shaped teeth, generally with a constriction at the base of the crown.

As in extant forms, same individual may show remarkable variation in surfaceornamentation, serrations on the anterior and posterior carinae, and cross sectionaloutline. On the same jaw, anterior teeth may have rounded cross section, while theposterior ones have flat, lensoidal or elliptical cross sections. Some teeth may be smooth,some may have flutings on their surface, others may have fine (or coarse) parallel ridgesor anastomising irregular ridges. Serrations, if present, are usually found on all teeth, butin some forms they are confined to the posterior teeth only, such as in Naskal teeth andin an undescribed new form from the early Cretaceous (late Albian) of Morocco (MNHNcoll.). Because of the great variation in tooth morphology in the same species or sameindividual, isolated teeth of crocodiles are very difficult to assign a taxonomic status atgeneric and even at family level. We can make only a broad grouping of the teeth.

As defined by Langston (1975), true ziphodonts are those with teeth having laterallycompressed crowns with posteriorly recurved apex, anterior and posterior carinaebearing a number of isolated festoon-like denticles (Plates IX-XIV). In comparison tothis, in false ziphodont teeth, the anterior and posterior carinae are relatively coarse andbear crenulations generally formed by anastomising, irregular ridges issued from themain body of the crown (Plates XV-XVII). These crenulations are not isolated from eachother in the true sense (Legasa et al., 1994): the true denticulations are clearly not theprolongation of the enamel ridges, while the false denticulations generally are. But on themargin of anterior and posterior carinae, the false denticulations may appear isolated(Brinkmann, 1992, Fig. 2D) much more clearly than in the figured false ziphodont of thePlates XV-XVII, depending on the taxa. It is difficult to distinguish true and falseziphodont dentition in the absence of sufficiently magnified views of the teeth. Theboundary between the two morphotypes is sometimes thin.

True ziphodont crocodiles. We can enlarge the notion of ziphodont crocodiles andinclude crocodiles such as the form to which the Naskal teeth belonged in this category(Plates III-VIII) and accordingly the definition can be modified. If we consider that aziphodont crocodile is a form which bears clearly individualized denticles on the lateralcrests of teeth, which are not the result of prolongation of the enamel ridges, we have tonotice the variable possibilities which accompany the serrations.

Plate VI. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous, VPL/JU/IR/120, morphotype V,complete unworn crown; posteriormost tooth; (a) magnified view of the the carina, x 45; (b) details of thestriations at the apex, x 45; (c) complete tooth, dorso-lateral view, x 15.Planche VI. Crocodylia indet., Naskal, Inde, couches inter-trappéennes, Crétacé supérieur, VPL/JU/IR/120,morphotype V, couronne complète non usée, position la plus postérieure ; (a) détail de l’une des deux carènes,x 45 ; (b) détail des striations à l’apex, x 45 ; (c) dent complète, vue dorso-latérale, x 15.



. Smooth, ridged, striated, fluted teeth. Ziphodont crocodiles may have a smooth, or astriated (fine striations) or ridged enamel (coarse striations) or a mixed ornament(smooth, striated and ridged enamel, fluted or not), as in non-ziphodont crocodiles.

The teeth are clearly fluted in Pristichampsus rollinati (Gray, 1831) from Eocene ofArgenton-sur-Creuse and Grauves (Plate XI; Cuvier, 1824, pl. 10; Antunes, 1986). Someof the teeth of P. rollinati from Rouzillac, Eocene of France (isolated teeth and a rightdentary; Labarrère and Vidalenc collections) and some teeth from Robiac, Eocene ofFrance, possibly belonging to cf. Iberosuchus are fluted. One tooth of S. icaeorhinusSimpson 1937 (see Colbert, 1946) from the Eocene of Argentina, is possibly fluted butfaintly. The enamel surface is not fluted in the teeth from the Eocene of Spain and fromthe Eocene of Portugal attributed to Iberosuchus Antunes, 1975 (Jiménez Fuentes, 1985;Jiménez Fuentes, Jambrina Leal, 1984; Martín de Jesús, Jiménez-Fuentes, Fincias et al.,1987; Martín de Jesús, Jiménez-Fuentes, Mulas-Alonso, 1987; Ortega, Buscalioni,1992), at least in some of the teeth from the Eocene of France attributed toPristichampsus (Antunes, 1986) but probably belonging to Iberosuchus, in teeth from theEocene of France belonging probably to Iberosuchus (Buffetaut, 1986; Ortega et al.,1996) and in one tooth preserved in the lower jaw of Pristichampsus from Rouzillac.

The teeth of the ziphodont crocodiles may have striations, more or less regular, as inmost of Naskal teeth, preserved teeth of “Araripesuchus” wegeneri Buffetaut, 1981 fromthe late Aptian of Niger, “aff. Araripesuchus” from the early Cretaceous of MayoDjarendi, locality KB6, Koum Basin, Cameroon (Brunet et al., 1990), Hamadasuchusrebouli Buffetaut, 1994 from the late Albian-early Cenomanian of Morocco, andMahajangasuchus Buckley and Brochu, 1999 from the upper Cretaceous of theMaevarano Formation, Mahajanga Basin, northwest Madagascar (if it is a true ziphodontform), or no striations as in Sebecus, Pristichampsus (from France at least), Iberosuchusand others.

. Variability in shape along the series. The teeth of ziphodont crocodiles may have, allalong the series, exactly the same variability in shape than in the non-ziphodontcrocodiles such as in eusuchian non-ziphodont Crocodylidae figured here (Plates I-II)(except for the greater compression of teeth in many ziphodont forms). Similarvariability is present in Naskal teeth. Depending on the taxa, they may be either nearlyhomodont in shape (not in size), or clearly heterodont in shape, together acute and

Plate VII. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous, VPL/JU/IR/: n° 110,morphotype IV, posterior (not the posteriormost) tooth: (a) complete unworn tooth, labial view, x 10 and (b)magnified view of the serrations of the carina, x 70, to be compared with Plates III, IV and IX-XIV; (c) n° 119,posteriormost tooth, slightly worn at the apex and n° 121 (in the background; see Plate VIII), posteriormosttooth, completely worn x 9; (d) n° 122, the posteriormost tooth, completely worn, dorsolateral view, x 9.Planche VII. Crocodylia indet., Naskal, Inde, couches inter-trappéennes, Crétacé supérieur, VPL/JU/IR/ : n°110, morphotype IV, dent postérieure (pas la plus postérieure) : (a) dent complète, non usée, vue labiale, x 10et (b) détail des festons d’une des deux carènes, x 70, à comparer avec les Planches III, IV et IX-XIV ; (c) n°119, dent des plus postérieures, légèrement usée à l’apex, et n° 121 (en arrière-plan ; voir Planche VIII) dentdes plus postérieures, complètement usée, x 9 ; (d) n° 122, dent la plus postérieure complètement usée vuedorso-latérale, x 9.



Plate VIII. Crocodylia indet., Naskal, India, inter-trappean beds, late Cretaceous, VPL/JU/IR/121, morphotype V, posteriormost tooth, completely worn tooth; (a)dorso-lateral view, x 15; (b), showing the growth lines on the left border and the section of the striations of the surface, x 45.Planche VIII. Crocodylia indet., Naskal, Inde, couches inter-trappéennes, Crétacé supérieur, VPL/JU/IR/121, morphotype V, dent des plus postérieures, dent complèteusée ; (a) vue dorso-latérale, x 15 ; (b) montrant les lignes de croissance sur le bord latéral et la coupe des striations de la surface, x 45.

40G

.V.R.P

rasad,F.deL

apparentde

Broin

/A

nnalesde

Paléontologie

88(2002)

19–71

lanceolated teeth or together acute, lanceolated and very blunt teeth, with all theaccompanying characters seen above. There is a high variability of size, shape and basalsection of the crown. Besides conical high teeth (more anterior), they may havelanceolated teeth with a marked constriction at the base of the crown and blunt teeth(posterior) such as in South-American forms of mesosuchian grade: sebecosuchian indet.from the Miocene of Colombia (Langston, 1965, pl. I, c), Peirosaurus Price, 1955 fromthe upper Cretaceous of Brazil and Lomasuchus Gasparini et al., 1991 from the upperCretaceous of Argentina and Brazil (two Peirosauridae), and the eusuchian Pristi-champsidae Quinkaninae Quinkana Molnar, 1981 (see Megirian, 1994; Rossmann, 1998)from the Miocene-Pleistocene of Australia.

. Compressed teeth. Crocodiles bearing true serrations have compressed teeth, morecompressed than in non-ziphodont crocodiles. But the degree of compression varieswithin the ziphodont forms and the distinction between the species is not easy on theshape and basal section of the teeth. For example, less compressed teeth are present inSebecus sp. of mesosuchian grade from the Miocene of Colombia (Langston, 1965; PlateIc) and the presumed sebecosuchian Iberosuchus Antunes, 1975 from the Eocene ofPortugal. Many crocodile remains from the Eocene of Spain and France have beenreferred to the latter genus (Antunes, 1986; Ortega et al., 1992; Rossmann, 1998). Herewe approximate new specimens from the Eocene localities of France to Iberosuchus(Plate XI, Fig. a; Plate XII; Plate XIII, Figs. d,e; Plate XIV, Fig. a) as did by Antunes(1986). The figured tooth from the Robiac locality (Plate XIV, Fig. a), a relatively largerounded tooth, has denticles conforming to those of the iberoccitanian crocodile figuredin Legasa et al. (1994, Fig. 4b) (see the serration section below). Besides compressedteeth, Iberosuchus has clearly more rounded ones (Fig. 3t; Legasa et al., 1994: Fig. 5),in particular the caniniform tooth, than the corresponding tooth in contemporaneousziphodont eusuchian Pristichampsus Gervais, 1853) from the Eocene of France (PlateXI, Figs. b-d; Plate XIII, Figs. b,c; Plate XIV, Fig. c), Germany (Berg, 1966; Rossmann,1998, 2000) and Italy (Rossmann, 1998). But the distinction between the two crocodilesis not easy for the small flattened teeth. Besides, Rossmann (1998) was of the opinionthat Pristichampsus vorax (Troxell, 1925) (see Langston, 1975) from the Eocene ofNorth America has more rounded teeth as evident from the anteromedial alveoli than theEuropean, Australian and Chinese forms.

. Recurved apex, abruptly shortened apex. The ziphodont crocodiles do not alwayspresent a clearly posteriorly recurved apex on the acute teeth: see S. icaeorhinus and asebecosuchian indet., in Langston (1965, Plate I). Recurved posterior teeth from theEocene of Robiac that we have examined for this study (USTL and MNHN coll.)correspond to teeth attributed either to cf. Iberosuchus or to Pristichampsus by Rossmann(1998) but they are certainly referable to the teeth of cf. Iberosuchus from Laure(France), and Caenes (Spain) figured in Ortega (1996) and not to the preserved syntypeof Pristichampsus teeth and other teeth from the type locality. In contrast, some others,similarly serrated and with a similar rounded surface as those attributed to cf.Iberosuchus, are hardly recurved (as the teeth from Chéry-Chartreuve, Plate XI, Fig. aand from Robiac, Plate XII), rather they are as straight as some Pristichampsus teeth. The


teeth from Robiac attributed to Pristichampsus by Antunes (1986) are possibly of cf.Iberosuchus, at least some (these teeth have not been found in the MNHN collections).

There is apparently more differentiation in the relative size of the teeth all along theseries in Iberosuchus and Sebecus (both with short and more lanceolated posterior teeth)than in the known teeth of Pristichampsus. Unfortunately, the complete dentition ofPristichampsus, possibly better known from Messel, Germany, has never been figured.As far as the French type species P. rollinati is concerned, there are 13 isolated teethremaining from the material observed by Cuvier (1824) (MNHN, Rollinat coll.) and 15other teeth (MNHN, de Vibraye coll.) from the type locality Argenton-sur-Creuse. Gray(1831) mentioned only the figured Cuvier’s specimens (Cuvier, 1824, Plate X, Figs. 14,24) which become the syntypes, including three teeth, Figs. 14, 15, 16. The larger toothis much smaller in size than the larger Iberian teeth. On the other hand, in Pristichamp-sus, no tooth ends so abruptly at the apex, no one is as long antero-posteriorly (“width”between the two crests), and no one is as much recurved posteriorly, than in the FrenchEocene crocodile “Atacisaurus crassiproratus” Astre, 1931, from Laure, the Spanishspecimen from the Lutetian of the Escarpes del Tormes, attributed to cf. Iberosuchus(Ortega et al., 1996, Figs. 2, 4; Ortega, Buscalioni, 1992, Fig. 7), and in some small teethfrom Robiac (sample of several tens of isolated teeth, USTL and MNHN coll., and teethobserved by Antunes (1986). We may attribute the latter to cf. Iberosuchus even if theyare as small as the Pristichampsus teeth and bear the same number of denticles permillimeter. The smaller and straighter teeth from Robiac, with a lower number ofdenticles per millimiter, have been considered as belonging to Pristichampsus (Antunes,1986) but this is not prooved: some flattened and fluted teeth from Robiac, attributed toPristichampsus, exhibit exactly the same denticle shape and width as the teeth clearlyattributable to cf. Iberosuchus (Plate XIV, Fig. a) (see below). This difficulty todistinguish the two taxa shows that the presence of separated denticles and the shape ofthe tooth alone are not sufficient to define an isolated tooth as a pristichampsine or asebecosuchian form, for example, or any other undefined taxon.

Plate IX. Aff. Hamadasuchus wegeneri, Gadoufaoua, Niger, early Cretaceous, MNHN (P) GDF 700, holotype;(a) right maxillary border with teeth 4 to 6, lateral view, x 10. Hamadasuchus rebouli, Erfoud area, Guir,Morocco, early Cretaceous, MNHN (P) MRS 3104; (b) replacement tooth, 6th of right maxillary, x 15; cf.Hamadasuchus sp., Cameroon, Koum (Mayo Rey) Basin, early Cretaceous, cast KB6 205, juvenile tooth: (c)complete crown x 15 and (d) details of the serrations on the carina, x 70.Planche IX. Aff. Hamadasuchus wegeneri, Gadoufaoua, Niger, Crétacé inférieur, Aptien supérieur, MNHN (P)GDF 700, holotype ; (a) bord maxillaire droit avec dents 4 à 6, vue latérale, x 10. Hamadasuchus rebouli,région d’Erfoud, Guir, Maroc, Crétacé inférieur, MNHN (P) MRS 3104 ; (b) dent de remplacement, 6e dumaxillaire droit, x 15 ; cf. Hamadasuchus sp., Cameroun, bassin de Koum (Mayo Rey), Crétacé inférieur,moulage KB6 205 : (c) couronne dentaire complète, x 15 et (d) détail des festons d’une des deux carènes,x 70.



. Serrations of the ziphodont crocodiles. As presented here on the plates, the teeth of theziphodont crocodiles show a wide variability: length of each denticle from inner to outerside of the tooth (width), their antero-posterior length, their inclination all along the crest(same or varying along the entire length of the crest, their size relative to the crownlength and their number along the crest).

There is also variability within the species and the individuals, according to their ageor to the growth stage of the tooth (replacement tooth, definitive tooth, young individual,adult individual). It has been shown that the denticles of Iberosuchus were larger and lessnumerous per millimeter than those of Pristichampsus (Antunes, 1975: Table 1). Thisassertion is based on the comparison of small teeth from the French type-series ofPristichampsus, principally with Iberian larger ones attributed to Iberosuchus. But in theabsence of a complete series of teeth for each genus, young and adult, it is difficult toascertain this. Anyway, there is a large number of teeth of all sizes in the Robiac sampleand they surely include young teeth of Iberosuchus. It is presumed that the dinosaur-liketeeth from Robiac - longer antero-posteriorly with respect to their height, posterior teethwith a short and recurved apex as well as the nearly straight teeth, all of them withoutflat facets but with a rounded surface up to the apex (compare Plate XI, Figs. a-c and seefigures in Antunes, 1975, 1986) – belong to cf. Iberosuchus. This is confirmed by anexamination of the denticles under scanning electron microscope (Plate XIII, Fig. e)which shows the same relative length and inclination of the denticles in the small teethpresumed to represent Iberosuchus as in the adults (despite a greater width of thedenticles in adults).

As the section of the caniniform teeth of Iberosuchus is more rounded-ovale (Fig. 3u),the largest tooth from Argenton (MNHN (P) AG 1 of the syntype series (Cuvier, 1824,Fig. 16), a tooth with a more flattened rhombic section, may be considered as acaniniform tooth of Pristichampsus despite its low number of denticles per millimeter asin Iberosuchus (Table 1). In any case, the teeth from P. rollinati from Argenton-sur-Creuse which have the same size as the teeth attributed to cf. Iberosuchus showsometimes approximately same number of denticles per millimeter or a number slightlylower than that of Iberosuchus (Table 1).

If we consider the denticles of the three forms: cf. Iberosuchus from Robiac, Sebecussp. from Colombia and P. rollinati from Argenton-sur-Creuse (Plate XIV), we cannotattribute a taxonomic value, at the level of a group of taxa, to the shape and number ofdenticles. Iberosuchus is presumed to be a sebecosuchian as Sebecus. Both haveplatycoelous vertebrae; but we do not know if Iberosuchus had the basioccipital elevatedrelative to the basisphenoid and pterygoid as in South American sebecosuchians-Peirosauridae and (by convergence) in eusuchians (Laurasiatic in origin). The latter havein contrast procoelous vertebrae, and Pristichampsus is clearly a eusuchian close to theCrocodylidae and Alligatoridae (cf. Brochu, 1999). Yet, the denticles of Sebecus, lessinclined (probably the primitive condition of ziphodonty) look more similar to those ofPristichampsus and small teeth of cf. Iberosuchus than to the larger teeth of the latter. Asfar as those of Naskal teeth are concerned, with their irregularity and divergence (PlateIII, Fig. b; Plate IV, Fig. b), acompanying a more foliaceous shape of the teeth, they areparticularly more similar to those of “aff. Araripesuchus” from Cameroon (Brunet et al.,1990), Hamadasuchus from Morocco and “Araripesuchus” wegeneri Buffetaut, 1981,


Table 1Comparative number of denticles/mm in some ziphodont crocodiles.Comparaison du nombre de denticules par millimètre chez quelques crocodiles ziphodontes.


from Niger, all from the early Cretaceous deposits (see below), and there is a possibilityof synapomorphic relationship. But as observed above, the denticles are not sufficient toestablish a relationship and all the characters of the teeth and jaw series have to beintegrated.

Other ziphodont crocodiles. Besides the above mentionned ziphodont crocodiles, manyothers are known from various parts of the world or were attributed to ziphodont forms.Among them:

• Platyognathus Wu & Sues, 1996, from the ealy Jurassic of Yunnan, China. Serratedteeth are known to occur in this form but they are not figured.

• Hamadasuchus rebouli Buffetaut, 1994 presented as ziphodont without sufficientfigures from the late Albian of Morocco. Teeth attributed to this species have beenbeautifully figured and enlarged in Larsson and Sidor (1999). MNHN collectionposseses now several parts of dentaries (conforming to the holotype), premaxillaryand maxillae with teeth, from the same area. The new material confirms theattribution of Hamadasuchus rebouli to a true ziphodont crocodile, although it wasplaced under the family Trematochampsidae, the type genus-species of which(Trematochampsa taqueti Buffetaut, 1974, Senonian of Niger), is not a ziphodont(see Plates XV, XVI). The teeth present a basal constriction between the crown androot. All the teeth are denticulated and compressed, although some at each jaw waveare slightly more rounded. The anterior dentary and premaxillary teeth have morerounded or oval alveoli. The dentition is heterodont in tooth size: some teeth arestronger: 4 premaxillary teeth, 3 to 9 maxillary and 11 to 14 dentary. The caninetooth is high, conical with acutely pointed and posteriorly recurved apex andlingually inclined tip, and a smooth crown surface (very finely striated, only visibleunder the microscope). Posterior to the canine tooth, the teeth are less recurved andelliptical in cross section. Further posterior to this, the teeth are sub-triangular orlanceolate in shape, laterally compressed with an acutely pointed apex and ellipticalbase. The most posterior teeth are low and blunt. In these teeth, posterior to thecanine, the surface is ornamented with roughly parallel longitudinal ridges which aremore or less confluent at the apex, although previously described one (Larsson,Sider, 1999) seem to be smooth. The individual denticles on the carinae are orientedoblique to the long axis towards the apex, then perpendicular to the border and theninclined towards the base in the lower part of the crown. The variation in shape andsize of the teeth (more or less acute or lanceolated or foliated teeth according to theposition on the series and the age, dentary bud or grown tooth) shown by this form,is similar in several characters but not identical to that from Naskal. Two of theseteeth are figured (Plate IX Fig. b; Plate X; Plate XIII, Fig. a).

Plate X. Hamadasuchus rebouli, Erfoud area, Guir, Morocco, early Cretaceous, MNHN (P) MRS 3103: (a)apex of the right dentary tooth 13, x 15; (b) lateral part of the carina, x 15; (c,d) details of the serrations of thecarina, x 70 and x 100.Planche X. Hamadasuchus rebouli, région d’Erfoud, Guir, Maroc, Crétacé inférieur, MNHN (P) MRS 3103 :(a) apex de la dent dentaire 13 droite x 15 ; (b) partie latérale de la carène x 15 ; (c,d) détails des festons d’unedes deux carènes, x 70 et x 100.



• Other early Cretaceous forms from Africa. These new discoveries of Hamadasuchusare further supplemented by two forms: “aff. Araripesuchus” from Mayo Djarendi,locality KB6, Koum Basin of Cameroon (Brunet et al., 1990), which is clearly closeto Hamadasuchus rebouli (Plate IX, Fig. c) and “Araripesuchus” wegeneriBuffetaut, 1981, from Niger (Plate IX, Fig. a). They were attributed to Araripesu-chus Price, 1959, a genus from the early Cretaceous of Araripe, Brazil and Argentina(Ortega et al., 2000; Price, 1959) which is not a ziphodont. One of us (Broin inKellner, 1987; Michard et al., 1990) had previously the opportunity to notice thatthese two African forms are ziphodont at variance from the Brazilian form. Now,their relationship to Hamadasuchus is evident: the Cameroon form has the samecompressed medio-posterior teeth, which are low and anteroposteriorly long andfoliaceous in aspect as in some teeth of Hamadasuchus. We can consider that thethree African forms, and eventually Caririsuchus Kellner, 1987, another ziphodontfrom Araripe, Brazil, belong to the same new family but surely not to theTrematochampsidae. The latter family is too poorly defined, particularly on thedistribution of teeth on the dentary, the kind of which is also present in many otherGondwanan crocodiles, and may be symplesiomorphic. The three African forms,Hamadasuchus, the species wegeneri and the Cameroon form share the relative sizeof the denticles on the rounded crest border, more strongly diminishing towards theapex and towards the base (Plates IX, X) than in other forms and in the inclinationof the denticles, diverging anteriorly and posteriorly (Plate IX, Fig. a, middle toothof the three, c and Plate X, Fig. a). The medio-posterior teeth from Naskal (PlatesIII, IV) also show a partly similar divergence of the denticulation as in Hamada-suchus group. Only the posterior teeth of aff. Hamadasuchus wegeneri (as we cannow provisionnally name it) are known and they are compressed and denticulated.But the more anterior maxillary (third) and premaxillary (fourth out of five) alsoshow more rounded and stronger section at the base of the missing crowns, at themaximum expansion of the jaw waves. Unlike the teeth of Trematochampsa taqueti(Plates XIV, XV), all these teeth lack the anastomising ridges, and denticles occurin the place of crenulations on the anterior and posterior carinae of Trematochampsataqueti. The form from Niger is clearly less closer to the other two, with lesslanceolated and more oblong teeth. The premaxillary and maxillary alveoli from 1to 3 are rounded, the fourth premaxillary, out of 5, and the third maxillary, out of 12,are much enlarged. The shape of the preserved and figured maxillary teeth from 4

Plate XI. Comparison of caniniform crowns of cf. Iberosuchus and Pristichampsus, Eocene, France. (a) cf.Iberosuchus sp., Chéry-Chartreuve, France, Bartonian, MP 16, Landréat coll., nearly complete crown, x 15; P.rollinati: (b) Argenton-sur-Creuse, France, Lutetian, MP 11, MNHN (P) AG 20, syntype, complete crown, x 3;(c,d) Grauves, France, Cuisian, MP 10, MNHN (P) GR 17293, (c) complete crown x 15 and (d) GR 17 294,details of the serrations on the posterior carina, viewed slightly from below, x 70.Planche XI. Comparaison de couronnes de dents caniniformes de cf. Iberosuchus et de Pristichampsus, Eocène,France ; (a) cf. Iberosuchus sp., Chéry-Chartreuve, France, Bartonien, MP 16, collection Landréat, couronnepresque complète x 15 ; P. rollinati : (b) Argenton-sur-Creuse, France, Lutétien, MP 11, MNHN (P) AG 20,syntype, couronne complète x 3 ; (c,d) Grauves, France, Cuisien, MP 10, MNHN (P) GR 17293, (c) couronnecomplète x 15 et (d) GR 17 294, détail des festons de la carène postérieure, vue légèrement de dessous, x 70.



to 6 (Plate IX, Fig. a) are rather similar to the figured teeth of Caririsuchus, whichare oblong and flat. But this is a more long-snouted genus than the undescribedgenus of the species wegeneri.

• Other ziphodont crocodiles, from Brazil and Australia. The figures of some fossilcrocodiles presented as ziphodont are not enough enlarged (Quinkana Molnar, 1981)or the teeth are not figured (upper Cretaceous Baurusuchus, Price, 1945 from Brazil,a form with more rounded teeth than in Sebecus), but we may have to rely on theauthors with regard to the descriptions. Sometimes, it is difficult to be sure of theirziphodonty (possibly confused with a false ziphodonty) and to see if , besides, theteeth are smooth, fluted or striated.

• Mahajangasuchus Buckley & Brochu, 1999 from Madagascar. Lanceolated, com-pressed and striated teeth similar to the pre-posterior teeth from the Naskal series arepresent. They are said to be denticulated, which is probable but not visible on thefigures. If they are truly denticulated, they represent the closest form to the Naskaltaxon.

• Eremosuchus Buffetaut, 1989 from the Eocene of Algeria. It is apparently aziphodont form, with acute, semi-acute and blunt posterior teeth, but the possibilityof a false ziphodonty is not completely ruled out as the figures do not show thedenticulation. A true ziphodonty is very possible with the enamel appearing smoothand without ridges that prolong into false denticulations of anterior and posteriorcarinae.

Questionnable ziphodont crocodiles. Teeth from the Eocene (Lutetian) Subathu Forma-tion of India (Sahni et al., 1978), Eocene of Pakistan (Buffetaut, 1978) and an isolatedtooth from the Eocene of South Nepal (Sah, Schleich, 1990) were attributed toPristichampsinae. The ziphodonty has to be prooved with better enlarged views of thedenticles. At least some of these teeth may have true serrations, while others clearlybelong to a false ziphodont form (see below, Indian subcontinent crocodiles section).

Therefore, ziphodonty is a derived character extremely homoplastic within tetrapods(mammal-like reptiles, phytosaurs, squamata including mosasaurs, dinosaurs, crocodiles(Buffetaut, 1978; Currie, 1987; Currie et al., 1990; Farlow et al., 1991; Gasparini et al.,1991; Prasad et al., 1994; Rossmann, 2000). It is also highly homoplastic withincrocodiles themselves and appeared early in the group. The multiplicity of morphologiesof the serrations and of all the characters of the dentition (size, shapes, section, flutations,striations etc.) prooves this convergency. That is to say that it appeared independentlyand in many different ways in many groups. But at some grade in a lineage, it maybecome a symplesiomorph character: we cannot substantiate it in the absence of otheranatomical arguments. The problem is that we do not know at which level of a group the

Plate XII. Cf. Iberosuchus sp., Robiac, France, Bartonian, MP 16, to be compared with Plate XI. USTL; (a)RBN 8705, extremity of a tooth; (b,c) RBN 8705, RBN 8704, magnified view of the serrations of the carina,70.Planche XII. Cf. Iberosuchus sp., Robiac, France, Bartonien, MP 16, à comparer avec la Planche XI. USTL ;(a), RBN 8705 extrémité d’une dent ; (b,c) RBN 8705, RBN 8704, détail des festons d’une des deux carènes,70.



presence of true and false ziphodonts together becomes possible in different forms:surely above the level of genus, probably above the level of the family, but within highergroups such as the Sebecosuchia, for example.

Crocodiles with a false ziphodonty. This “morphotype” is present with variations ex-pressing its heterogeneity in origin: single striations or true ridges more or less dividedon the border of the crest (compare Plate XVI, Fig. b; Plate XVII, Fig. b), more or lessisolated denticulations (Brinkmann, 1992), size of the ridges and their regularity andamount of anostomosing ridges at the apex.

• Among the various crocodiles with this morphotype, it is already present in a formattributed to the marine teleosaurid Machimosaurus Meyer, 1837 (figures in Hua,1999) from the Jurassic (upper Kimmeridgian) of France (the only marine formexamined in this work). It has conical teeth with acutely rounded apex and circularcross section, surface ornamented with a network of interwoven irregular ridges thatare more accentuated at the apex, and crenulated anterior and posterior carinae as inTrematochampsa taqueti (Plates XV, XVI). But it differs from the latter in havingbroad flutings on the labial and lingual surfaces of the crown.

• The morphotype “ false ziphodonty” is well marked in early Cretaceous Theriosu-chus Owen, 1879 (Plate III) (Ortega, Buscalioni, 1992) of England. A closely similarmorphology is present in teeth from the early Cretacous of Spain from Uña(Brinkmann, 1992) and Galve localities. Compressed teeth with wide false serra-tions at the apex from the latter locality have been attributed to Atoposauridae(Estes, Sanchiz, 1982). These teeth are apparently similar to those of Hamadasu-chus, but they differ by the fact that the “denticulations” are clearly the prolongationof the enamel ridges. Sanz et al. (1984) attributed teeth from Galve, with ridges andfalse serrations similar to those of Theriosuchus, to cf. Machimosaurus sp.(somewhat acute and high teeth) and to Theriosuchus sp. (lanceolated and bluntteeth).

Actually, the ornament of the enamel and crests present in this morphotype is widelyrepresented in a number of taxa from different parts of the world, even if the shape anddetails of the ornament of the teeth is variable acording to the taxa. The teeth may beacute and only variable in height. The series may have together variably acute,

Plate XIII. Comparison of serrations of ziphodont crocodile teeth; detail of the carina x 70. (a) Hamadasuchusrebouli, Erfoud area, Guir, Morocco, early Cretaceous, MNHN (P) MRS 3104; (b) Pristichampsus rollinati,Grauves, France, Cuisian, MP 10, MNHN (P) GR 17294; (c) P. rollinati, Argenton-sur-Creuse, France,Lutetian, MP 11, MNHN (P) AG 20, syntype; (d) cf. Iberosuchus sp., Chéry-Chartreuve, France, Bartonian, MP16, Landréat coll.; (e) cf. Iberosuchus sp., Robiac, France, Bartonian, MP 16, MNHN (P) ERH 1001; (f)Sebecus sp., Miocene, Colombia, MNHN (P) VIV 69.Planche XIII. Comparaison des festons dentaires de crocodiles ziphodontes; détail de la carène x 70 ; (a)Hamadasuchus rebouli, région d’Erfoud, Guir, Maroc, Crétacé inférieur, MNHN (P) MRS 3104 ; (b)Pristichampsus rollinati, Grauves, France, Cuisien, MP 10, MNHN (P) GR 17294 ; (c) P. rollinati,Argenton-sur-Creuse, France, Lutétien, MP 11, MNHN (P) AG 20, syntype ; (d) cf. Iberosuchus sp.,Chéry-Chartreuve, France, Bartonien, MP 16, coll. Landréat ; (e) cf. Iberosuchus sp., Robiac, France,Bartonien, MP 16, MNHN (P) ERH 1001 ; (f) Sebecus sp., Miocène, Colombie, MNHN (P) VIV 69.



lanceolated and blunt teeth as in Theriosuchus. Generally, there are more rounded veryanterior and caniniform teeth and more compressed intermediate and posterior teeth(lanceolated and blunt). The posterior blunt teeth may be still slightly pointed at the apexas in the Naskal tooth VPL/JU/IR/119 (Plate VII, Fig. c) or completely worn as theNaskal tooth VPL/JU /IR /122 (Plate VII, Fig. d).

The tooth ornamentation of this wide “ false ziphodont morphotype” is, for example,present in :

• Gondwanan forms such as the early Cretaceous (late Aptian) Sarcosuchus Broin &Taquet, 1966 (Niger, Algeria, Tunisia). It is a long-snouted Pholidosauridae,mesosuchian in grade with relatively homodont teeth, although variable in size andheight in the series, short, conical and rounded in section, not lanceolated andwithout basal constriction of the crown. Sarcosuchus is unrelated with Machimo-saurus.

• The teeth of Sphagesaurus Price, 1950, from the late Cretaceous of Brazil arelanceolated and compressed, strongly and widely keeled with coarse ridges and withwide tubercles on the posterior carina appearing as false serrations.

• Among many other forms: - the late Cretaceous (early Senonian) Trematochampsataqueti Buffetaut, 1974, from Niger (Plate XV, Figs. b,c; Plate XVI), type of theTrematochampsidae, a short-snouted form (mesosuchian grade) unrelated to Sarco-suchus and Machimosaurus; - another unrelated crocodile (mesosuchian grade),“Thoracosaurus” cherifiensis Lavocat, 1955 (a new genus, Lapparent de Broin inprep.) from the late Albian-early Cenomanian from Algeria (Broin et al., 1971),Niger and Morocco, is partially a false ziphodont. Only some of the teeth (unwornyoung teeth) or only a part of the crests close to the apex are falsely denticulated.The denticulations are not the prolongation of enamel ridges, but they are sparse, notelevated and not completely isolated on the margin of the carinae.

• Early Tertiary forms (late Paleocene-Eocene of western Europe) attributed (Berg,1966) to the Eocene Mongolian eusuchian Asiatosuchus Mook, 1940 (Plate XV, Fig.b; Plate XVII), which presents heterodonty in shape (acute and more posterior bluntteeth as in Ostaeolemus, Plate I). In Asiatosuchus (Buffetaut, 1985; Rauhe,Rossmann, 1995), the surface of the teeth is ornamented by anastomising irregularridges that converge laterally to form coarse carinae with crenulations (Plate XV,Fig. b; Plate XVII). To a large extent, similar ornament is present in Crocodylus(probably C. niloticus, Plate XV, Fig. a) on unworn teeth. Similarly Trematochampsataqueti, which also exhibits heterodonty in shape and size in having conical, high,anterior teeth and low, globular or obtuse posterior teeth, has also an ornamentation

Plate XIV. Comparison of tooth serrations of three ziphodont crocodiles; details of the carina x 100. (a) cf.Iberosuchus sp., Robiac, France, Bartonian, MP 16, MNHN (P) ERH 1001; (b), Sebecus sp., Miocene,Colombia, MNHN (P) VIV 69; (c) Pristichampsus rollinati, Argenton-sur-Creuse, France, Lutetian, MP 11,MNHN (P) AG 20, syntype.Planche XIV. Comparaison des festons dentaires de trois crocodiles ziphodontes; détail de la carène x 100 ; (a)cf. Iberosuchus sp., Robiac, France, Bartonien, MP 16, MNHN (P) ERH 1001 ; (b) Sebecus sp., Miocène,Colombie, MNHN (P) VIV 69 ; (c) Pristichampsus rollinati, Argenton-sur-Creuse, France, Lutétien, MP 11,MNHN (P) AG 20, syntype.



similar to that of Asiatosuchus on the middle part of the crown and crenulations onthe anterior and posterior carinae (Plate XV, Figs. c,d; Plate XVI). But crenulationsin the former are slightly different from those of Asiatosuchus. Although it differsfrom Naskal teeth in false ziphodonty, Asiatosuchus (see Berg, 1966) exhibits asimilar range of heterodonty - high recurved anterior teeth with pointed apex,intermediate lanceolate crowns, and short posterior teeth with a horizontal crest andelliptical cross section. Besides false ziphodont nature of the teeth, it also differsfrom Naskal specimens in lacking intermediate triangular teeth. The dentition ofTrematochamsa oblita Buffetaut & Taquet, 1979 from the late Cretaceous ofMadagascar, is unknown. The remains of the lower jaw (holotype) only showrounded alveoli, variable in size, some of them with remains of rounded teeth, butwithout preserved lateral crests.

• “Sebecus” querejazus Buffetaut & Marshall, 1991 from the Paleocene of Bolivia,South America. This form is surely a sebecosuchian (s. l.) by many charaters of itsskull (high and narrow dorsal skull, posterior ventral palate morphology andelevated basioccipital relative to basisphenoid and to pterygoids, ornament, mor-phology of the maxillary etc.), but is surely not a Sebecus (in details of the peculiarpterygoid and basisphenoid area, for example). Its teeth are compressed and are notat all serrated as in the Eocene type of Sebecus from Argentina and the MioceneColombian forms (Plate XIII, Fig. f; Plate XIV, Fig. b). The anterior maxillary teethhave convex anterior carinae and smooth crown surface except for fine wrinkles atthe apex. These wrinkles become more pronounced on the posterior teeth. Posteriorteeth are low crowned, triangular in outline, and have a more pronouncedconstriction at the junction of crown and root, and crenulated carinae as inTrematochampsa taqueti.

• From other Tertiary localities of the old world:For example, a lanceolated compressed posterior tooth, constricted at the base of the

crown, with false serrations and ridged enamel, from the basal Eocene of Dormaal(Belgium) has been attributed to a ziphodont crocodile indet. (Buffetaut, 1985, Plate I,Figs. V, W). This new form is also present in the new basal Eocene (Nel et al., 1999)locality of Le Quesnoy (France).

As seen above, from the Eocene of Subathu Formation, in Jammu and Kashmir (Sahniet al., 1978), India, Eocene Kuldana Formation of Pakistan (Buffetaut, 1978) and Eoceneof South Nepal (Sah, Schleich, 1990), teeth have been attributed to Pristichampsinae.

Plate XV. Crocodylus sp., probably C. niloticus, extant from Africa or Madagascar, MNHN (P): (a) x 2.Asiatosuchus sp., Mont-Berru, France, Thanetian, MP 6, MNHN (P): (b) BR 15203, complete young anteriortooth crown, lingual view, x 3. Trematochampsa taqueti, Ibeceten, Niger, Senonian, MNHN (P): (c) IBC 1657,complete young anterior tooth crown, lingual view, x 3; (d) IBC 1656, complete juvenile tooth crown ofintermediate position, lingual view, x 15.Planche XV. Crocodylus sp., probablement C. niloticus, actuel d’Afrique ou Madagascar, MNHN (P) : (a) x 2.Asiatosuchus sp., Mont-Berru, France, Thanétien, MP 6, MNHN (P) ; (b) BR 15203, jeune couronne de dentantérieure complète, vue linguale, x 3. Trematochampsa taqueti, Ibeceten, Niger, Sénonien, MNHN (P) ; (c)IBC 1657, couronne de jeune dent antérieure complète, vue linguale, x 3 ; (d) IBC 1656, couronne de dentjuvénile complète de position moyenne, vue linguale, x 15.



Some of these teeth at least, the most posterior in the two first cases, are similar to thoseof false ziphodont crocodiles (see below, Indian subcontinent crocodiles section).

There is no phyletic relationships between all these “ false ziphodont” forms.

2.4.2.2. Non-ziphodont other than false ziphodont crocodiles. Blunt posterior com-pressed teeth with striations or ridges as in false ziphodont forms and also as in Naskalteeth occur in some forms from the lower Eocene of western Europe attributed toAllognathosuchus Mook, 1921 (Berg, 1966; Lucas, 1992), considered as a Alligatoroid(see Brochu, 1999). They are eusuchian crocodiles with button-shaped teeth as in extantOstaeolemus or Melanosuchus. Some have been figured (Berg, 1966; Buffetaut, 1985;Rauhe and Rossman, 1995). Allognathosuchus has a dentition differentiated into conical,laterally compressed canine teeth, lanceolate posterior teeth with pointed to horizontalapices with constrictions between the crown and root, and posterior sub-globular toglobular teeth (button-shaped). Worn posterior teeth have a rectangular outline as inNaskal specimens. The ornamentation of Allognathosuchus teeth (as considered inEurope) is also partly similar to that of Naskal specimens. The teeth of Allognathosuchusare ornamented by fine longitudinal parallel ridges that converge at the apex as in Naskalteeth and in Asiatosuchus posterior teeth. But in marked contrast to those of Naskal, theteeth of Allognathosuchus lack serrations.

Heterodont dentitions with ornamentation somewhat similar to those of Naskal arealso seen in alligators and caimans which lack serrations on their teeth. The posteriorteeth of Brachychampsa montana Gilmore, 1911 and Albertochampsa langstoni Erick-son, 1972, two other alligatoroids, are laterally compressed (Norell et al., 1994) as inNaskal teeth. Brachychampsa sealeyi documented from the upper Cretaceous (lowerCampanian) Menefee Formation, northwestern New Mexico, USA (Williamson, 1996)differs from Naskal form in having relatively blunt and conate anterior teeth and nearlyhemispherical to circular, bulbuous, non-serrated posterior teeth. Moreover in all thesealligatoroids, the crown surface is heavily wrinkled (presence of anostomizing ridges).The Naskal teeth also differ from those of Bernissartia fagesii Dollo, 1883 (Buffetaut,1975; Buffetaut, Ford, 1979), a basal eusuchian (Brochu, 1999), in the shape of posteriorteeth (hemispherical to circular occlusal outline of posterior teeth in Bernissartia),ornamentation (fine irregular wrinkles radiating from the apex to base in Bernissartia)and their non-serrated nature.

Plate XVI. Trematochampsa taqueti, Ibeceten, Niger, Senonian, MNHN (P) IBC 1656, complete juvenile toothcrown of intermediate position, false ziphodont, striations curve towards the border to form false “serration-s” of the carina: (a) a part of the apex, x 30; (b) magnified view of the carina, x 70.Planche XVI. Trematochampsa taqueti, Ibeceten, Niger, Sénonien, MNHN (P) IBC 1656, couronne de dentjuvénile complète de position moyenne, faussement ziphodonte, les striations de l’émail se courbent vers lebord pour former les fausses “dentations” des carènes : (a) partie avec l’apex, x 30 ; (b) détail d’une des deuxcarènes, x 70.



2.4.3. Synthesis on the crocodile dentition

2.4.3.1. Crocodile dentitionIn primitive forms, there are relatively high teeth, acutely pointed, non-serrated and

apparently only differentiated in height (higher caniniform teeth, shorter posterior teeth).Besides exceptional teeth for extraordinary dietary adaptations in Mesozoic croco-

diles, there are, from Mesozoic to Present, ziphodont and non-ziphodont dentitions whichare either nearly homodont in shape (not in size), or clearly heterodont in shape.

Both ziphodont and non-ziphodont crocodiles may have heterodont dentition in shapewith anterior conical teeth, intermediate triangular to lanceolate teeth and short and bluntposterior teeth, possibly with horizontal or rounded apex (button-shaped teeth).

In all categories, there are smooth or ridged, striated and fluted teeth. A constrictionat the limit of the crown and the root may or may not be present. Teeth are more or lesscompressed, generally more compressed in ziphodont dentition, but also in some falseziphodont forms.

True ziphodont dentition differs, as a rule, from false ziphodont dentition, havinganterior and posterior carinae with true denticles well separated from each other andwhich are clearly not the lateral prolongation of the enamel ridges.

The serrated teeth may be straight (anterior and canine teeth). They may have aslightly recurved apex (all along the series), or a abruptly shortened apex (posteriorly),depending on the taxa. The number of denticles per millimeter is variable with the sizeof the tooth (its age and position) and with the taxon. The length and width of thedenticles is variable according to the position on the carina and according to the taxa; thelength is variable according to the size of the tooth (its age).

All the parameters have to be included to recognize a taxon. Ziphodont forms do notrepresent a monophyletic group but various independent monophyletic taxa (family,genus) which may be defined on the basis of complete skeleton and not on themorphology of the teeth alone.

In false ziphodont dentition, the anterior and posterior carinae are relatively coarse andbear crenulations generally formed by anastomising, irregular ridges issued from themain body of the crown. As a rule, these crenulations are not isolated from each other inthe true sense. But on the margin of anterior and posterior carinae, the falsedenticulations may sometimes appear isolated.

Some intermediate states exist: denticles which are the prolongation of the enamelridges but which appear isolated on the carina. It is often difficult to distinguish true and

Plate XVII. Asiatosuchus sp., Mont-Berru, France, Thanetian, MP 6, MNHN (P) BR 12084, complete youngtooth crown of intermediate position, false ziphodont, striations more or less linked, curving towards the borderto form false “serrations” of the carina: (a) a part of the apex, the striations form an anastomising network, x30; (b) magnified view of the carina, x 70.Planche XVII. Asiatosuchus sp., Mont-Berru, France, Thanétien, MP 6, MNHN (P) BR 12084, couronne dedent jeune complète de position moyenne, faussement ziphodonte, les striations de l’émail, plus ou moinsunies, se courbant vers le bord pour former les fausses “dentations” des carènes : (a) partie avec l’apex, lesstriations s’anastomosant en un réseau, x 30 ; (b) détail d’une des deux carènes, x 70.



false ziphodont dentition in the absence of sufficiently magnified views of the teeth.Some crocodile taxa such as Crocodylus may include both false ziphodont and non-ziphodont states.

2.4.3.2. Naskal dentitionThe teeth from the inter-trappean beds of Naskal fall in the category of a true, but

possibly partial ziphodont and highly heterodont dentition. The collection includes high,laterally compressed recurved teeth; high teeth with rounded cross section and verticalorientation of the apex; high recurved teeth with rounded cross section; sub-triangularteeth with elliptical cross section and acutely pointed apex; lanceolate labiolinguallycompressed teeth with elliptical to strongly elliptical cross section and serrated carinae;sub-globular teeth with anteroposteriorly long apex, elliptical cross section, and possibleserrated carinae (not evidenced because of the erosion); and globular to sub-globularteeth with elliptical cross section and horizontal or flat apex, and possible serrated carinae(not evidenced because of the erosion). So the teeth under discussion exhibit the rangeof variations that occur in the most heterodont crocodile dentitions and the ziphodontcategory of crocodilians. The Naskal specimens coming from a single microvertebrateassemblage represent several individuals.

These morphotypes represent different positions on the jaw - anterior, intermediate,anteriormost posterior, and posterior. The heterodonty of Naskal teeth is found in anumber of unrelated crocodilian groups (based on anatomical characters of the skeleton),which are true, false ziphodonts and non-ziphodont (including extant forms). Within theziphodont crocodiles, a true similarity is possible with Mahajangasuchus (subject to theverification of the presence of true isolated denticles and on the discovery of all the seriesin the Malagasy form) and some similarity exists with the Hamadasuchus group,particularly the form from Cameroon. But no identity has been found with the knowntaxa and thus we consider the Naskal form as a new taxon. The ziphodonty is animportant character of discrimination of the taxa but not sufficient in itself.

3. Comparable fossil crocodiles from the Indian subcontinent

Prior to the present detailed study, fossil ziphodont crocodiles have been describedfrom the Indian subcontinent from the middle Eocene Subathu Formation, India (Sahniet al., 1978), Kuldana Formation, Pakistan (Buffetaut, 1978), and Eocene strata of Nepal(Sah and Schleich, 1990) .

Sahni et al. (1978) described isolated teeth of crocodiles from the upper part of MiddleEocene Subathu Formation, near Metka coal field, Kalakot (Jammu & Kashmir state),India. These teeth were considered to have close affinities to those of Pristichampsus.The morphotype A of Sahni et al. (1978) includes conical, laterally compressed andposteriorly recurved crowns with smooth or strongly fluted surfaces and crests lookingfinely serrated. A close examination of one of these fluted teeth (LUVP/16302) showspossible true serrations along one of its preserved lateral crest. The tooth is not fairly wellcompressed laterally as in the European Pristichampsus rollinati, but the teeth of the


North-American Pristichampsus vorax were possibly more rounded as evident from thealveoli. Their referal to the genus Pristichampsus and even to its family needs to beestablished. In some of the teeth referred to morphotype B (LUVP16304, 16308; PlateI, Figs. 7, 8), coarse serrations (or crenulations) are confined to the apical part of thecrown and the crown surface appears to be covered by anastomising ridges that convergelaterally into crenulations, the lateral edges are sharply differentiated from the centralcore of the tooth, and the crown surface is wrinkled apically (?anastomising). In some ofthe teeth (Plate I, Figs. 7, 8), the crown surface appears to have anastomising ridgeswhich extend laterally into crenulations as in false ziphodonty of Trematochampa andAsiatosuchus. These teeth might belong to the posterior part of the jaw.

Buffetaut (1978) assigned three types of crocodilian teeth from the middle EoceneKuldana Formation to the eusuchian subfamily Pristichampsinae. The first type,represented by strongly laterally compressed teeth with serrations and smooth crownsurface (Buffetaut, 1978, Figs. 6D, E), appear to be true ziphodonts having wellindividualised marginal denticles. But the enlargemnt of the figures does not show if itis a true ziphodonty or a false one. The second type, comprising compressed, low crownwith fine anastomising ridges (Buffetaut, 1978, Figs. 6A, C) and the third type, consistingof fairly high crowns with circular cross section and surface ornamentation similar to thatof second type (Buffetaut, 1978, Fig. 6F), probably represent false ziphodont teeth. Inthese teeth, anastomising enamel ridges of crown surface seem to merge on marginalcrenulation-like structures as in false ziphodonts.

An isolated and badly preserved tooth from the Eocene sediments of Bhainskati Khola(Dumri area), southern Nepal, has been referred to the subfamily Pristichampsinae basedon lateral compression, supposed marginal serrations and smooth crown surface (Sah andSchleich, 1990). From the Plate 1, Figs. 1 and 2, the serrations on the tooth from Nepalappear less like well-individualised festoons of a typical ziphodont form. However thiscould be the result of extensive rolling of the tooth before final burial. There also, it isimpossible to attribute the tooth to Pristichampsinae or to a non-ziphodont group withoutother anatomical elements.

At least a part of the material from the three localities belong to a false ziphodontform. In the two first cases, we observe that only the caniniform teeth might be of aziphodont form and not the most posterior teeth of the sample, which is very curious.

4. Discussion and palaeogeographical considerations

Rana (1990) noted the occurrence of crocodilian teeth identical to the present formsin an inter-trappean beds section exposed southwest of the village Rangapur, RangareddiDistrict, Andhra Pradesh (India). According to him, the affinities of these teeth lie withthose of upper Cretaceous-Palaeogene Laurasiatic eusuchians: the North-American andEuropean Eocene Hassiacosuchus kayi Mook, 1941 (Procaimanoidea in Brochu, 1999),Brachychampsa montana (see Carpenter, Lindsey, 1980), Allognathosuchus and Asiato-suchus, all forms considered as alligatoroids (see Berg, 1966; Brochu, 1999). Sincealligatorids have a typical Laurasian distribution in the early part of their evolutionary


history, Rana (1990) concluded that the crocodile teeth provide an additional evidencefor a upper Cretaceous Laurasian connection for the Indian subcontinent besidesostracodes, charophytes, amphibians, lizards, and mammals.

More recently, Rana and Sati (2000) redescribed the teeth from the inter-trappean bedsof Rangapur. They also included some teeth from the inter-trappean beds of Naskal intheir study. Without giving due consideration to positional variation of crown morphol-ogy and nature of marginal denticles, they have assigned the isolated crocodilian teethfrom the Deccan infra- and inter-trappean beds to seven genera (Dyrosauridae gen. et sp.indet., Allognathosuchus sp., Asiatosuchus sp., Brachychampsa sp., cf. Bottosaurus sp.,Thoracosaurus sp., Crocodylus sp.). All these groups and genera come from deposits ofvarying ages, from late Cretaceous to Tertiary (Steel, 1973) and are Laurasiatic in origin.Dyrosauridae and Thoracosaurus are littoral forms. Besides, there are also someinconsistencies in their paper. The figures do not conform to the morphological detailsgiven in the text. These authors placed the teeth studied by them from the Naskalinter-trappean beds in three genera, Allognathosuchus sp., Asiatosuchus sp., andThoracosaurus sp. The teeth referred to Allognathosuchus sp. (Rana, Sati, 2000, Plate I,Figs. 6-12; Plate III, Figs. 6-18) are similar in crown morphology to those ofMorphotypes III and V of the present study. According to Rana and Sati (2000), thecrown surface of these teeth is wrinkled and non-striated. Contrary to this, their figuresclearly show that the crown is not wrinkled, rather has longitudinal ridges and grooves(Rana, Sati, 2000, Plate III, Figs. 4-12). We observed longitudinal ridges and grooves onboth Morphotypes III and V. On the other hand, high, recurved, conical teeth with fineto coarse longitudinal striations (Rana, Sati, 2000, Plate II, Figs. 12-13; Plate IV, Figs.10-12, 15), which can be referred to Morphotype I of the present study, have beenassigned to Thoracosaurus sp. (a longirostrine littoral eusuchian from the Cretaceous-Paleocene of North-America and western Europe). Teeth with morphology identical toMorphotype IV of this paper, have been described under Asiatosuchus sp. (Rana, Sati,2000, Plate I, Fig. 13; Plate II, Figs. 1, 2; Plate III, Figs. 19-21; Plate IV, Figs. 1, 2). Asdiscussed earlier, Asiatosuchus has false ziphodont teeth with anastomising ridges of thecrown surface merging into crenulations of the margins (Plates XV, XVI). But the teethof Morphotype IV bear true ziphodont denticles and the surface is ornamented withlongitudinal ridges and grooves. This also seems to be the case with specimens describedunder Asiatosuchus by Rana and Sati (2000, Plate IV, Figs. 2a-b). Our observations onNaskal teeth indicate that the teeth included in cf. Bottosaurus sp. (see Rana, Sati, 2000,Plate II, Figs. 10, 11; Plate IV, Figs. 16-19) (a Cretaceous North American form (Mook,1925) of undefined phylogeny) are most likely juvenile forms or teeth representing theanterior series. Same is the case with the placement of high conical teeth in Brachy-champsa sp. (see Rana, Sati, 2000, Plate II, Fig. 9; Plate IV, Figs. 3, 5-8). This genus hasrelatively blunt anterior and hemispherical to circular, bulbous, posterior teeth and all theteeth are heavily wrinkled (anostomising ridges) and non-serrated (Carpenter, Lindsay,1980). In addition to the erroneous identifications, Rana and Sati (2000) have also reliedon these taxa for assigning a late Cretaceous and Palaeocene ages for the infra- andinter-trappean beds, respectively, which they should not have attempted as crocodiles areleast reliable for age determinations, particularly at the genus level.


4.1. Biogeographic affınities

Subsequent to Rana’s work (Rana, 1990), the presence of alligatorids in the upperCretaceous inter-trappean beds of peninsular India has been shown as one of theevidences in support of late Cretaceous biotic exchanges between the Indian plate andAsia near the K/T boundary. Such biotic interchanges were facilitated by interveningisland-arc systems or early collision between the Indian plate and Asia (Prasad, Khajuria,1995; Sahni, Bajpai, 1991; Sahni et al., 1987). Contrary to the inferences drawn by Rana(1990) regarding the taxonomic status of the inter-trappean crocodilian teeth, our studyclearly demonstrate that these teeth are of a new true ziphodont crocodile, and probablycloser to the Hamadasuchus group and perhaps Mahajangasuchus, known from the earlyCretaceous of Africa and upper Cretaceous of Madagascar, respectively, in havinglanceolate, laterally compressed anteriormost posterior teeth with serrated carinae andstriated enamel (although variably), and the former showing a similar divergence of thelargest medial denticles on the crest. Despite the close similarity of Indian teeth to theabove taxa from Africa and Madagascar, we have refrained from identifying them withany of the Gondwanan families in view of their isolated nature. However, it is veryapparent from their morphology that the inter-trappean teeth are not even distantlyrelated to alligatoroids or any other Crocodylidae or other eusuchian family.

The separation of these teeth from alligatoroids, removes one line of evidence for theearly India/Asia (K/T boundary) collision model. Rather it supports possible dispersalfrom a southern route. Buckley and Brochu (1999) argued that Mahajangasuchus mighthave evolved in isolation on Madagascar after the breakup of land connections betweenAfrica and Madagascar from pre-breakup “crocodyliforms” . Similarly, turtle taxa fromthe upper Cretaceous of Madagascar or of India (Lapparent de Broin, 2000a,b; Lapparentde Broin, Werner, 1998) are closely related to Afro-South-American forms but differentin genera and in groups (podocnemidoid Carteremys group in India). There is also othervertebrate faunal evidences for terrestrial links between Indo-Madagascar block andSouth America up to late early Cretaceous or early-late Cretaceous. Lavanify miolakaKrause et al. 1997, a sudamericid mammal from the upper Cretaceous (Campanian)Maevarano Formation of Madagascar, has been regarded as a sister group of an unnamedIndian form known from the upper Cretaceous (Maastrichtian) Deccan inter-trappeanbeds (Krause et al., 1997). The sudamericid mammals were first reported from upperCretaceous-Palaeocene of Argentina (Bonaparte, 1990). Therefore, the Indian andMadagascaran finds are the only gondwanathere mammals known outside SouthAmerica. The occurrence of closely related abelisaurid dinosaurs has been recorded fromSouth America, Madagascar, and India. The upper Cretaceous Carnotaurus sastrei,Bonaparte, 1985, the upper Cretaceous (Campanian) Majungasaurus crenatissimus(Depéret, 1896) of Madagascar (Sampson et al., 1996) and the upper Cretaceous(Maastrichtian) Indosuchus raptorius Chatterjee, 1978 (Bonaparte et al., 1991) areconsidered to be closely related abelisaurids (Sampson et al., 1996). Particularly the lasttwo share many derived characters. In turtles, particular links between South-Americaand Africa during the very early Cretaceous, have induced the formation of different butvery closely related forms after the breakup (including a common genus, Araripemys,possibly up to early Cenomanian of Baharija, Egypt, at least up to latest Albian-earliest


Cenomanian from Morocco). They are known as early as in Aptian-Albian and some ofthem are at the origin of the Malagasy and Indian forms of the upper Cretaceous(Podocnemididae, Bothremydidae) (Jain, 1977, 1986; Lapparent de Broin, 2000a,b andothers).

In the light of these recent discoveries, the recovery of crocodilian teeth from theUpper Cretaceous of India with morphological resemblances to those of Mahajangasu-chus (to be confirmed) and the Hamadasuchus group appears to be consistent with thepalaeobiogeographical history of Gondwanan continents. However, close phylogeneticrelationship of the Indian forms with any of these Gondwanan taxa can be firmlyestablished only when well preserved cranial and postcranial bones are recovered.

Acknowledgements

This work has been supported by field grants from the National Geographic Society(Grant No 5400-94) and University Grants Commission (Research Award), New Delhi,to GVRP. GVRP is thankful to Dr. Philippe Taquet and Dr. Philippe Janvier, Laboratoirede paléontologie, Muséum national d’histoire naturelle (MNHN), UMR 8569 of CNRS,for providing laboratory facilities and comparative material, and to MNHN for thefinancial support in the form of Maître de conférences. We are grateful to Dr M.T.Antunes for his helpful suggestions on the manuscript as a reviewer. We thank Dr.J. Sudre, University of Montpellier II, for the loan of Robiac teeth, J.L. Landréat(Soissons) for the loan of the Chéry-Chartreuve tooth, J. Congleton, Shuler Museum ofPaleontology (Dallas), for the gift of teeth casts from Cameroon, and Bruno Fectay andFrançois Escuillé for new material from Morocco. We acknowledge with gratitude thehelp from C. Weber-Chancogne in taking scanning electron micrographs, D. Serrette forphotographs, H. Lavina for figures, the Laboratoire d’anatomie comparée and theLaboratoire de zoologie des reptiles et amphibiens (MNHN) for the extant comparativematerial.

References

Antunes, M.T., 1975. Iberosuchus, un crocodile sébécosuchien nouveau, l’Eocène ibérique au Nord de laChaîne Centrale et l’origine du canyon de Nazaré. Com. Serv. Geol. Port. 49, 285–330.

Antunes, M.T., 1986. Iberosuchus et pristichampsus, crocodiliens de l’éocène - données complémentaires,discussion, distribution stratigraphique. Ciências da Terra (UNL) 8, 111–122.

Bajpai, S., Sahni, A., Jolly, A., Srinivasan, S., 1990. Kachchh inter-trappean beds biotas: affinities andcorrelation. In: Sahni, A. (Ed.), Cretaceous Event Stratigraphy and Correlation of the Indian Non-marineStrata (IGCP 216, 245). pp. 101–105.

Bakshi, A.K., 1987. Critical evaluation of the age of Deccan Traps, India: implications for flood basaltvolcanism and faunal extinction. Geology 15, 147–150.

Berg, D.E., 1966. Die Krokodile, insbesondere Asiatosuchus und aff. Sebecus aus dem Eozän von Messel beiDarmstadt/Hessen. Abh. Hess. L. Amt. Bodenforsch 52 (105S), 1–105.

Bhatia, S.B., Rana, R.S., 1984. Palaeogeographic implications of the Charophyta and Ostracoda of theinter-trappean beds of peninsular India. Mém. Soc. géol. Fr., N. S. 147, 29–35.

Bonaparte, J.F., 1985. A horned Cretaceous carnosaur from Patagonia. Nat. Geog. Res. 1 (9), 263–272.


Bonaparte, J.F., 1990. New Late Cretaceous mammals from the Los Alamitos Formation, northern Patagonia.Nat. Geog. Res. 6, 63–93.

Bonaparte, J.F., Powell, J.F., Coria, R.A., 1991. Carnotaurus sastrei Bonaparte, the horned, lightly builtcarnosaur from the Middle Cretaceous of Patagonia. Contr. Sc., Nat. Hist. Mus. Los Angeles Co 416,1–42.

Brinkmann, W., 1992. Die Krokodilier -Fauna aus der Unter-Kreide (Ober-Barremium) von Uña (ProivinzCuenca, Spanien). Berliner Geowiss. Abh. E 5, 1–123.

Brochu, C.A., 1999. Phylogenetics, taxonomy, and historical biogeography of Alligatotoidea. Jour. Vert. Pal. 19(suppl. to 2), 9–100.

Broin, F. de, Grenot, C., Vernet, R., 1971. Sur la découverte d’un nouveau gisement de Vertébrés dans leContinental Intercalaire saharien : la Gara Samani (Algérie). C. R. Acad. Sc. Paris 272 (D),1219–1221.

Broin, F. de, Taquet, P., 1966. Découverte d’un Crocodilien nouveau dans le Crétacé inférieur du Sahara. C.R. hebd. Séanc. Acad. Sci. Paris 262 (D), 2326–2329.

Brunet, M., Coppens, Y., Dejax, J., Flynn, L., Heintz, E., Hell, J., Jacobs, L., Jehenne, Y., Mouchelin, G.,Pilbeam, D., Sudre, J., 1990. Nouveaux mammifères du Crétacé inférieur du Cameroun, Afrique del’Ouest. C . R. Acad. Sc. Paris 310 (II), 1139–1146.

Buckley, G.A., Brochu, C.A., 1999. An enigmatic new crocodile from the Upper Cretaceous of Madagascar.Spec. Pap. Pal. 60, 149–175.

Buckley, G.A., Brochu, C.A., Krause, D.W., Pol, D., 2000. A pug nosed crocodyliform from the LateCretaceous of Madagascar. Nature 405, 941–944.

Buffetaut, E., Taquet, P., 1979. Un nouveau crocodilien mésosuchien dans le Campanian de Madagascar:Trematochampsa oblita n. sp. Bull. Soc. géol. Fr. 21 92 (7), 183–188.

Buffetaut, E., 1974. Trematochampsa taqueti, un crocodilien nouveau du Sénonien inférieur du Niger. C. R.Acad. Sci. Paris 279 (D), 1749–1752.

Buffetaut, E., 1975. Sur l’anatomie et la position systématique de Bernissartia fagesii Dollo, 1883, crocodiliendu Wealdien de Bernissart, Belgique. Bull. Inst. R. Sci. nat. Belg. 51 (2), 1–20.

Buffetaut, E., 1978. Crocodilian remains from the Eocene of Pakistan. N. Jb. Geol. Paläont. Abh. 156 (2),262–283.

Buffetaut, E., 1981. Die Biogeographische Geschichte der Krokodilier, mit Beschriebung einer neuen Art,Araripesuchus wegeneri. Geol. Rundschau 70, 611–624.

Buffetaut, E., 1985. Les crocodiliens de l’Eocène inférieur de Dormaal (Brabant, Belgique). Bull. Soc. BelgeGéol. 94 (1), 51–59.

Buffetaut, E., 1986. Un Mésosuchien ziphodonte dans l’Eocène supérieur de La Livinière (Hérault, France).Geobios 19 (1), 101–108.

Buffetaut, E., 1989. A new ziphodont mesosuchian crocodile from the Eocene of Algeria. PalaeontographicaAbt. (A) 208, 1–10.

Buffetaut, E., 1994. A new crocodilian from the Cretaceous of southern Morocco. C. R. Acad. Sci. Paris 319(II), 1563–1568.

Buffetaut, E., Ford, R.L.E., 1979. The crocodilian Bernisssartia in the Wealden of the Isle of Wight.Palaeontology 22 (4), 905–912.

Buffetaut, E., Marshall, L.G., 1991. A new crocodilian, Sebecus querejazus nov. sp. (Mesosuchia, Sebecidae)from the Santa Lucia Formation (Early Paleocene) at Vila Vila, southcentral Bolivia. In: Suarez-Soruco, R. (Ed.), Fósiles y Facies de Bolivia, 1, Vertebrados. Rev. Téc. Yac. Petrol. Fisc. Bol. 2.pp. 3–4.

Carpenter, K., Lindsey, D., 1980. The dentary of Brachychampsa montana Gilmore (Alligatorinae; Crocodyl-idae), a Late Cretaceous turtle-eating alligator. Jour. Paleont. 54 (6), 1213–1217.

Carvalho, I.S., 1993. Um crocodilo cum heterodontia (Notosuchia, Cretáceo inferior. Brasil. An. Acad. Bras,Ci. 65 (4), 459.

Carvalho, I.S., 1994. Candidodon: Um crocodilo com heterodontia (Notosuchia, Cretáceo Inferior - Brasil).An. Acad. bras. Cienc. 66 (3), 331–346.

Carvalho, I.S., Campos, D.A., 1988. Um Mamífero Triconodonte do Cretáceo Inferior do Maranhão. Brasil,An. Acad. bras. Ci. 60 (4), 437–446.


Chatterjee, S., 1978. Indosuchus and Indosaurus, Cretaceous carnosaurs of India. Jour. Paleont. 52,570–580.

Clark, J.M., Jacobs, L.L., Downs, W.R., 1989. Mammal-like dentition in a Mesozoic crocodylian. Science 244,1064–1066.

Colbert, E.H., 1946. Sebecus, representative of a peculiar suborder of fossil Crocodilia from Patagonia. Bull.Amer. Mus. Nat. Hist. 87 (4), 221–270.

Colbert, E.H., Mook, C.C., 1951. The ancestral crocodilian Protosuchus. Bull. Amer. Mus. Nat. Hist. 97 (3),149–182.

Courtillot, V., 1990. Deccan volcanism at the Cretaceous-Tertiary boundary: Past climatic crises as a key tofuture? Pal. Pal. Pal. 89, 291–299.

Courtillot, V., Besse, J., Vandamme, D., Montigny, R., Jaeger, J.J., Capetta, H., 1986. Deccan flood basalts atthe Cretaceous/Tertiary boundary? Earth Planet. Sc. Let. 80, 361–374.

Courtillot, V., Feraud, G., Maluski, H., Vandamme, D., Moreau, M.G., Besse, J., 1988. Deccan flood basalts andthe Cretaceous/Tertiary boundary. Nature 333, 843–846.

Currie, P.J., 1987. Bird-like characterisitcs of the jaws and teeth of Troodontid Theropods (Dinosauria,Saurischia). Jour. Vert. Pal. 7 (1), 72–81.

Currie, P.J., Keith Rigby Jr, J., Sloan, R.E., 1990. Theropod teeth from the Judith River Formation of southernAlberta, Canada. In: Carpenter, J., Currie, P.H. (Eds.), Dinosaur Systematics, approaches and Perspec-tives. Cambridge Univ. Press, Cambridge, N.Y., Melbourne 8, pp. 107–125.

Cuvier, G., 1824. Recherches sur les ossemens fossiles. Dufour d’Occagne. Paris, N. éd. 5 (2), 1–547.Das Sarma, D.C., Anantharaman, S., Vijayasarathi, G., Nath, T.T., Rao, Ch.V., 1995. Palaeontological studies

for the search of micromammals in the infra- and inter-trappean beds horizons of Andhra Pradesh. Rec.Geol. Surv. India 128 (5), 223.

Dollo, L., 1883. Première note sur les crocodiliens de Bernissart. Bull. Mus. R. Hist. Nat. Belg. 2,309–338.

Duncan, R.A., Pyle, G., 1988. Rapid eruption of the Deccan flood basalts at the Cretaceous/Tertiary boundary.Nature 333, 841–843.

Dutt, N.V.B.S., 1975. Deccan Traps of the western part of Hyderabad District, Andhra Pradesh. Rec. Geol.Surv. India 106 (2), 126–141.

Erickson, B.R., 1972. Albertochampsa langstoni, gen. et. sp. nov., a new alligator from the Cretaceous ofAlberta. Sc. Pub. Sc. Mus. Minnesota N.S. 2, 1–13.

Estes, R., Sanchiz, B., 1982. Early Cretaceous lower vertebrates from Galve (Teruel). Spain. Jour. Vert. Pal. 2(1), 21–39.

Farlow, J.O., Brinkman, D.L., Abler, W.L., Currie, P.J., 1991. Size, shape, and serrations density of Theropoddinosaur lateral teeth. Modern Geol. 16, 161–198.

Gasparini, Z., Chiappe, L.M., Fernandez, M., 1991. A new Senonian peirosaurid (Crocodylomorpha) fromArgentina and synopsis of the South American Cretaceous crocodilians. Jour. Vert. Pal. 11 (3),316–333.

Gervais, P., 1853. Observations relatives aux reptiles fossiles de France. C. R. hebd. Acad. Sc. 36,374–377.

Godinot, M., Prasad, G.V.R., 1994. Discovery of Cretaceous arboreal eutherians. Naturwissenschaften 81,79–81.

Gomani, E.M., 1997. A crocodyliform from the Early Cretaceous dinosaur beds, northern Malawi. Jour. Vert.Pal. 17, 280–294.

Gray, J.E., 1831. Synopsis reptilium or short descriptions of the species of reptiles. I. Cataphracta. Tortoises,Crocodiles, and Enaliosaurians. Treutzel, Wurst and Co., London, pp. i–viii 1–86.

Hislop, S., 1860. On the Tertiary deposits associated with trap rock in the East Indies with description of fossilshells. Quart. Jour. Geol. Soc. London 16, 154–189.

Hua, S., 1999. Le crocodilien Machimosaurus mosae (Thalattosuchia, Teleosauridae) du Kimméridgien duBoulonnais (Pas de Calais, France). Palaeontographica (A) 252, 141–170.

Jaeger, J.J., Courtillot, V., Tapponnier, P., 1989. Palaeontological view of the ages of the Deccan Traps, theCretaceous/Tertiary boundary and India/Asia collision. Geology 17, 316–319.

Jain, S.L., 1977. A new fossil pelomedusid turtle from the Upper Cretaceous Pisdura sediments, Central India.Jour. Pal. Soc. India 20, 360–365.


Jain, S.L., 1986. New pelomedusid turtle (Pleurodira: Chelonia) remains from Lameta Formation (Maastrich-tian) at Dongargaon, Central India, and a review of pelomedusids from India. Jour. Pal. Soc. India 31,63–75.

Jiménez Fuentes, E., 1985. Cocodrilos. In: Melendez, B. (Ed.), Paleontologia, 2. Vertebrados, 11. ParaninfoS.A., Madrid, pp. 289–300.

Jiménez Fuentes, E., Jambrina Leal, C., 1984. Sobre dos pelomedúsidos fósiles hallados en Babilafuente(Salamanca). Salamanca Rev. Prov. Est. 13, 119–128.

Kellner, A.W.A., 1987. Ocorrência de um novo crocodiliano no Cretaceo Inferior da Bacia do Araripe, nordestedo Brasil. An. Acad. Bras, Ci. 59 (3), 219–232.

Khajuria, C.K., Prasad, G.V.R., 1998. Taphonomy of a Late Cretaceous mammal-bearing microvertebrateassemblage from the Deccan inter-trappean beds of Naskal, peninsular India. Pal. Pal. Pal. 137,153–172.

Khajuria, C.K., Prasad, G.V.R., Manhas, B.K., 1994. Palaeontological constraints on the age of Deccan Traps,peninsular India. Newslet. Strat. 31, 21–32.

Krause, D.W., Prasad, G.V.R., Koenigswald, W.V., Sahni, A., Grine, F.E., 1997. Cosmopolitanism amongGondwanan Late Cretaceous mammals. Nature 390, 504–507.

Langston, W., 1965. Fossil crocodilians from Columbia and the Cenozoïc history of the Crocodilia in SouthAmerica. Univ. California Press, Berkeley & Los Angeles, pp. 1–157.

Langston, W., 1975. Ziphodont crocodiles: Pristichampsus vorax (Troxell), a new combination, from theEocene of North America. Fieldiana (Geol.) 33, 291–314.

Lapparent de Broin , F. de, Werner, C., 1998. New late Cretaceous turtles from the Western Desert. Egypt. Ann.Pal. 84 (2), 131–214.

Lapparent de Broin, F. de., 2000a. African chelonians from the Jurassic to the Present. A preliminary catalogof the African fossil chelonians. Palaeont. Afr. 36, 43–82.

Lapparent de Broin, F. de., 2000b. The oldest pre-Podocnemidid turtle (Chelonii, Pleurodira), from the earlyCretaceous, Ceará state, Brasil, and its environment. Treballs Mus. Geol. Barcelona 9, 43–95.

Larsson, H.C.E., Sidor, C.A., 1999. Unusual crocodyliform teeth from the Late Cretaceous (Cenomanian) ofsoutheastern Morocco. Jour. Vert. Pal. 9 (2), 398–401.

Legasa, O., Buscalioni, A.D., Gasparini, Z., 1994. The serrated teeth of Sebecus and the iberocertaniancrocodile, a morphological and ultrastructural comparison. Stud. Geol. Salm. 29, 127–144.

Lucas, S.G., 1992. Cretaceous-Eocene crocodilians from the San Juan Basin, New Mexico. New Mexico Geol.Soc. Guide Book 43, 257–264.

Martín de Jesús S., Jiménez-Fuentes E., Mulas-Alonso E., 1987. Los cocodrilos de la Cuenca del Duero. Salade las Tortugas. Notas informativas 4, Universidad de Salamanca Ed.,1–4.

Martín de Jesús, S., Jiménez-Fuentes, E., Fincias, B., Del Prado, J.M., Mulas-Alonso, E., 1987. Los crocodyliadel eoceno y oligoceno de la Cuenca del Duero. Dientes y osteodermos. Rev. española Paleont. 2,95–108.

McClean, D.M., 1985. Deccan Traps mantle degassing in the terminal Cretaceous marine extinctions. Cret.Res. 6, 235–259.

Megirian, D., 1994. A new species of Quinkana Molnar (Eudsuchia: Crocodylidae) from the MioceneCampfield beds of Northern Australia. Beagle. Rec. Mus. Art Gall. Northern Terr. 11, 145–166.

Michard, J.-G, Broin, F. de, Brunet, M., Hell, J., 1990. Le plus ancien crocodilien néosuchien spécialisé àcaractères “eusuchiens” du continent africain (Crétacé inférieur, Cameroun). C. R. Acad. Sci. Paris (II)311, 365–371.

Molnar, R.E., 1981. Pleistocene ziphodont crocodilians of Queensland. Rec. Austr. Mus. 33 (19).Mook, C.C., 1925. A Revision of the mesozoic Crocodilia of North America. Bull. Amer. Mus. Nat. Hist. 51

(9), 319–432.Mook, C.C., 1941. A new crocodilian from the Lance Formation. Amer. Mus. Nov. 1128, 1–5.Nel, A., Plöeg, G. de, Dejax, J., Dutheil, D., de Franceschi, D., Gheerbrant, E., Godinot, M., Hervet, S.,

Menier, J., Augé, M., Bignot, G., Duffaud, S., Gaudant, J., Hua, S., Jossang, A., Lapparent de Broin, F.de, Pozzi, J.P., Paicheler, J.C., Beuchet, F., Rage, J.-C., 1999. Un gisement sparnacien exceptionnel àplantes, arthropodes et vertébrés (Eocène basal, MP7): Le Quesnoy (Oise, France). C. R. Acad. Sc. Paris(II) 329, 65–72.


Norell, M.A., Clark, J.M., Hutchison, J.H., 1994. The Late Cretaceous alligatorid Brachychampsa montana(Crocodylia): new material and putative relationships. Amer. Mus. Nov. 3116, 1–26.

Officer, C.B., Hallam, A., Drake, C.L., Devine, J.D., 1987. Late Cretaceous and paroxysmalCretaceous/Tertiary extinctions. Nature 6109, 143–149.

Ortega, F., Buscalioni, A.D., 1992. Cocodrilos fósiles de Castilla y León. In: Jiménez Fuentes, E. (Ed.),Vertebrados fósiles de Castilla y León Museo de Salamanca. Junta de Castilla y León, Salamanca,pp. 59–70.

Ortega, F., Buscalioni, A.D., Gasparini, Z., 1996. Reinterpretation and new denomination of Atacisauruscrassiproratus (Middle Eocene, Issel, France) as cf. Iberosuchus (Crocodylomorpha, Metasuchia).Geobios 29 (3), 353–364.

Ortega, F., Gasparini, Z., Buscalioni, A.D., Calvo, J.O., 2000. A new species of Araripesuchus (Crocodylo-morpha, Mesoeucrocodylia) from the Lower Cretaceous of Patagonia (Argentina). Jour. Vert. Pal. 20 (1),57–76.

Owen, C.B., 1879. Monograph on the fossil Reptilia of the Wealden and Purbeck Formations. Pal. Soc. London.Suppl. IX. pp. 10–19.

Pande, K., Venkatesan, T.R., Gopalan, K., Krishnamurthy, P., McDougall, J.D., 1988. 40Ar-39Ar ages of alkalibasalts from Kutch, Deccan volcanic province, India. Memoir, Geol. Soc. India 10, 145–150.

Prasad, G.V.R., Godinot, M., 1994. Eutherian tarsal bones from the Late Cretaceous of India. Jour. Pal. 68,892–902.

Prasad, G.V.R., Jaeger, J.J., Sahni, A., Gheerbrant, E., Khajuria, C.K., 1994. Eutherian mammals from theUpper Cretaceous (Maastrichtian) inter-trappean beds of Naskal, Andhra Pradesh. India. Jour. Vert. Pal.14, 260–277.

Prasad, G.V.R., Khajuria, C.K., 1990. A record of microvertebrate fauna from the inter-trappean beds of Naskal.Andhra Pradesh. Jour. Pal. Soc. India 35, 151–161.

Prasad, G.V.R., Khajuria, C.K., 1995. Implications of the infra- and inter-trappean biota from the Deccan, India,for the role of volcanism in Cretaceous-Tertiary boundary extinctions. Jour. Geol. Soc. London 152,289–296.

Prasad, G.V.R., Khajuria, C.K., Manhas, B.K., 1995. Palaeogeographic significance of the Deccan infra- andinter-trappean beds biota from peninsular India. Hist. Biology 9, 319–334.

Prasad, G.V.R., Rage, J.-Cl., 1991. A discoglossid frog in the latest Cretaceous Maastrichtian) of India. Furtherevidence for a terrestrial route between India and Laurasia in the latest Cretaceous. C. R. Acad. Sc. Paris313, 273–278.

Prasad, G.V.R., Rage, J.-Cl., 1995. Amphibians and squamates from the Maastrichtian of Naskal, India. Cret.Res. 16, 95–107.

Prasad, G.V.R., Sahni, A., 1987. Coastal-plain microvertebrate assemblage from the terminal Cretaceous ofAsifabad, Andhra Pradesh. Jour. Pal. Soc. India 32, 5–19.

Prasad, G.V.R., Sahni, A., 1988. First Cretaceous mammal from India. Nature 332, 638–640.Prasad, G.V.R., Singh, V., 1991. Microvertebrates from the inter-trappean beds of Rangareddi District, Andhra

Pradesh and their biostratigraphic significance. Bull. Indian Geol. Assoc. 24 (1), 1–20.Price, L.I., 1945. A new reptile from the Cretaceous of Brazil. Minist. Agricul., Bol. Div. Geol. Min., Notas

Prel. Est. 25, 1–8.Price, L.I., 1950. On a new crocodilian, Sphagesaurus, from the Cretacreous of the State of São Paulo, Brazil.

Anais. Acad. Brasil. Ciên. 22 (1), 77–83.Price, L.I., 1955. Novos crocodilídeos dos arenitos da série Baurú, Cretáceo do estado de Minas Gerais. Anais.

Acad. Brasil. Ciên. 27 (4), 487–498.Price, L.I., 1959. Sôbre um Crocodilideo notossuquio do Cretacico brasileiro. Bol. Div. Geol. Min. Rio de

Janeiro 118, 1–55.Rage, J.C., Prasad, G.V.R., 1992. New snakes from the Late Cretaceous (Maastrichtian) of Naskal, India. N.

Jb. Geol. Paläont. Abh. 187, 83–97.Rana, R.S., 1984. Microvertebrate Palaeontology and biostratigraphy of the infra- and inter-trappean beds of

Nagpur. Maharashtra. Ph.D. thesis, Panjab University, Chandigarh.Rana, R.S., 1987. Dyrosaurid crocodile (Mesosuchia) from the inter-trappean beds of Vikarabad, Hyderabad

District. A.P. Current Sc. 56 (11), 532–534.


Rana, R.S., 1990. Alligatorine teeth from the Deccan inter-trappean beds near Rangapur, Andhra Pradesh,India: Further evidence of Laurasiatic elements. Current Sc. 59, 49–51.

Rana, R.S., Sati, K.K., 2000. Late Cretaceous-Palaeocene crocodilians from the Deccan Trap associatedsedimentary sequences od peninsular India. Journ. Pal. Soc. India 45, 123–136.

Rauhe, M., Rossmann, T., 1995. News about fossil crocodiles from the middle Eocene of Messel and Geiseltal,Germany. Hallesches Jahrb. Geowiss. 17, 81–92.

Rossmann, T., 1998. Studien an känozoischen Krokodilen: 2. Taxonomische Revision der familie Pristi-champsidae Efimov (Crocodilia: Eusuchia). N. Jb. Geol. Paläont. Abh. 210 (1), 85–128.

Rossmann, T., 2000. Studien an känozoischen Krokodilen: 4. Biomechanische Untersuchung am Schädel undder Halswirbelsäule des paläogenen Krokodils Pristichampsus rollinati (Eusuchia : Pristichampside). N.Jb. Geol. Paläont. Abh. 215 (3), 397–432.

Sah, R.B., Schleich, H.H., 1990. An Eocene crocodile record from Bhainskati Khola (Dumri Area). SouthNepal. Mitt. Bayer. Staatsslg. Paläont. Hist. Geol. 30, 51–56.

Sahni, A., 1984. Cretaceous-Palaeocene terrestrial faunas of India: Lack of endemism during drifting of theIndian plate. Science 226, 441–443.

Sahni, A., Bajpai, S., 1991. Eurasiatic elements in the Upper Cretaceous nonmarine biotas of peninsular India.Cret. Res. 12, 177–183.

Sahni, A., Kumar, K., Hartenberger, J.L., Jaeger, J.-J., Rage, J.-Cl., Sudre, J., Vianey-Liaud, M., 1982.Microvertébrés nouveaux des Trapps du Deccan (Inde) : Mise en évidence d’une voie de communicationterrestre probable entre la Laurasie et l’ Inde à la limite Crétacé-Tertiaire. Bull. Soc. géol. Fr. 24,1093–1099.

Sahni, A., Rana, R.S., Prasad, G.V.R., 1987. New evidence for palaeogeographic intercontinental Gondwanarelationships based on Late Cretaceous-Earliest Palaeocene coastal faunas from peninsular India.American Geophysical Union, Gondwana Six, Mon. 41, 207–218.

Sahni, A., Srivastava, M.C., DeSouza, R., 1978. Eocene ziphodont Crocodilia from northwestern India.Geobios 11 (5), 779–785.

Sahni, A., Venkatachala, B.S., Kar, R.K., Rajnikanth, A., Prakash, T., Prasad, G.V.R., Singh, R.Y., 1996. Newpalynological data from the Deccan inter-trappean beds: Implications for the latest record of dinosaurs andsynchronous initiation of volcanic activity in India. Geol. Soc. India Mem. 37, 267–283.

Sampson, S.D., Forster, C.A., Krause, D.W., Dodson, P., Ravoady, F., 1996. New dinosaur discoveries from theLate Cretaceous of Madagascar: implications for Gondwanan biogeography. North Amer. Pal. Conv.,Washington D.C. Pal. Soc., Spec. Pub., 8.

Sanz, J.L., Buscalioni, A., Casanovas, M.L., Santafe, J.V., 1984. The archosaur fauna from the UpperJurassic/Lower Cretaceous of Galve (Teruel, Spain). In: Reif, W.E., Westphal, F. (Eds.), Third Symp. Mes.Terr. Ecosyst. Short Papers Tubingen, pp. 207–209.

Steel, R, 1973. Crocodylia. Handbuch der Paläoherpetologie. Gustav Fisher Ver., Stuttgart, Portland-USA, 16,pp. i–vii + 1–123.

Venkatesan, T.R., Pande, K., Ghevariya, Z.G., 1996. 40Ar-39Ar ages of Anjar trap sequence in the westernDeccan province (India) and its relation to the Cretaceous-Tertiary boundary events. Current Sc. 70,990–996.

Wellnhofer, P., 1971. Die Atoposauridae (Crocodylia, Mesosuchia) der Oberjura-Plattenkalke Bayerns.Palaeontographica, (A) 138, 133–165.

Wermuth, H., Mertens, R., 1961. Schildkröten-Krokodile-Brückenechsen. Gustav Fischer Verlag, Jena,pp. 1–422.

Williamson, T.E., 1996. ?Brachychampsa sealeyi, sp. nov., (Crocodylia, Alligatoroidea) from the UpperCretaceous (Lower Campanian) Menefee Formation, northwestern New Mexico. Jour. Vert. Pal. 16 (3),421–431.

Wu, X.-C., Sues, H.-D., 1996. Reassessment of Platyognathus hsui Young 1944 (Archosauria: Crocodyli-formes) from the Lower Lufeng Formation (Lower Jurassic) of Yunnan. China, Jour. Vert. Pal. 16 (1),42–48.

Wu, X.C., Sues, H.D., Sun, A., 1995. A plant eating crocodyliform reptile from the Cretaceous of China. Nature376, 678–680.


Documents

Late Cretaceous crocodile remains from Naskal (India): comparisons and biogeographic affinities