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Cretaceous Research 45 (2013) 7e15

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Cretaceous Research

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Review paper

Knoblochia cretacea, Late Cretaceous insect eggs from Central Europe

Zuzana He�rmanová a,b,*, Emese Bodor c,d, Ji�rí Kva�cek a

aNational Museum Prague, Václavské nám�estí 68, 115 79, Prague 1, Czech RepublicbCharles University, Institute of Geology and Palaeontology, Albertov 6, 128 43 Prague 2, Czech Republicc Eötvös Loránd University, Department of Palaeontology, Pázmány Péter sétány 1/C, H-1117 Budapest, HungarydGeological and Geophysical Institute of Hungary, Stefánia Street 14, H-1117 Budapest, Hungary

a r t i c l e i n f o

Article history:Received 21 December 2012Accepted in revised form 4 July 2013Available online 9 August 2013

Keywords:Knoblochia cretaceaSpirellea kvacekiiFossil insect eggsFossil seedsLate Cretaceous

* Corresponding author. National Museum Prague,Prague 1, Czech Republic.

E-mail addresses: zuzka.hermanova@gmail.com (Zgmail.com (E. Bodor), jiri.kvacek@nm.cz (J. Kva�cek).

0195-6671/$ e see front matter � 2013 Elsevier Ltd.http://dx.doi.org/10.1016/j.cretres.2013.07.001

a b s t r a c t

The genus Knoblochia is established for fossil insect eggs. The fossils are small, longitudinally ridged,ovoid to round with projections on both ends. Their thin perforated wall is covered by minute papillae,inner surface of the wall is smooth or covered by rectangular files of cells. Fossils assigned here toKnoblochia cretacea were earlier assigned to the genus Spirellea, which encompass a heterogenouscomplex of small fossils being or resembling angiosperm seeds from the Late Cretaceous. The majorityof species of the genus Spirellea clearly represents remains of angiosperms. However, fossils describedby Knobloch and Mai (1986) as Spirellea kvacekii are distinct, particularly in having external wallsperforated, neither apex nor basal projection showing any absition scar or micropyle in the botanicalsense. Attribution of these fossils to insects led us to designate the new name Knoblochia cretacea witha new holotype for fossils of this kind. Comparison of Knoblochia with insect eggs of species ofPhasmatodea and Lepidoptera, and seeds of Stemonaceae showed clear affinity to insects. Due to thehigh amount of extinction among insects since the Cretaceous, the systematic affinity of Knoblochiaremains open.

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1. Introduction

Insects are represented by more than a million described extantspecies (Bisby et al., 2012) that amount to more than half of allknown living organisms; at the family level, insects are also themost diverse group of organisms. Insects are known from thePalaeozoic onward (Grimaldi and Engel, 2005; Jarzembowski,2003). From the Mesozoic, many informative insect body fossilsare found in fine-grained sediments and in amber (Jarzembowski,2003; Labandeira and Sepkoski, 1993). However, there are manygaps in the fossil record and each new report is important for un-derstanding the geological history of this extremely diverse groupof organisms. Insect eggs are particularly scarce in the fossil record.Currently only a few Mesozoic insect eggs have been described,most of which are positioned on leaves (Gall and Tiffney, 1983;Krassilov et al., 2007; Popa and Zaharia, 2011; Pott et al., 2008;Van Konijnenburg-Van Cittert and Schmeissner, 1999). Thepaucity of insect eggs could perhaps be explained by their general

Václavské nám�estí 68, 115 79,

. He�rmanová), emesebodor@

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minute size, and they may simply have been overlooked in thesediment samples. Insect eggs may also superficially resemblesmall seeds, and they may have been misinterpreted as such. Ourrecent investigations of fossil remains of Spirellea kvacekii (Kno-bloch) Knobloch et Mai (discussed below) show features stronglysuggesting that these fossils are ornamented eggs of insects.

Reinvestigation of Spirellea kvacekii (Knobloch) Knobloch andMai (1983), originally described as an angiosperm fruit (Micro-carpolithes kvacekii Knobloch, 1977), and later as seeds from theStemonaceae family (Knobloch and Mai, 1984), revealed severalcharacters that are typical for insects and not known in plants. Thegenus Spirellea Knobloch et Mai was established to encompassangiosperm seeds, typically with ridged or reticulate surfaceornamentation (Knobloch and Mai, 1984) and assigned by them tothe family Stemonaceae. Fossils of the genotype Spirellea bohemicaKnobloch and Mai (1983) do represent seeds. They are anatropouswith a distinct raphe, chalaza and micropyle, and the seed wall haswell defined large cells. Fossils assigned to Spirellea kvacekii how-ever stand out from the genotype and all other species of Spirellea,particularly in the organization of wall structure, as well as in de-tails of morphology. A new genus Knoblochia gen. nov. is suggestedto accommodate this clearly distinct material. Attribution of thesefossils to insects led us to designate the new name Knoblochiacretacea.

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2. Material and methods

2. 1. Material

Twenty-seven specimens of Knoblochia cretaceawere examinedfrom the collection of the National Museum, Prague (NMP F3345,F3348, F3351, F3354, F3356e58, F3364, F3374e77, F3379e80,K970e982). The material was collected and prepared by ErvínKnobloch around 1980. The spherical to ovoid fossils are usuallybroken, but the outer surface characters and the surface orna-mentation (ridges and papillae) are well preserved, which allowdetailed description and comparative studies. The specimens comefrom various localities of the Carpathian Flysch (Be�cva-B�u�ckový,Bílá, Glogoczow, Karpentná, Rabka-Zaryte, Rusava, Staré Hamry),the South Bohemian Basins (Ole�snice), the Gosau Formation(Wietersdorf) and the Alpine Flysh (Sievering), see 2.3 geology.

2.2.. Methods

All specimens come from the collection of Ervin Knobloch,which he donated to the National Museum in Prague. During therecent studies, all specimens were studied by binocular microscope(Olympus SZX 12). Selected specimens (K. cretacea no. F3345,F3348, F3374e76, K970, K972, K973e78) were mounted onaluminum stubs using nail polish, coated with gold and studiedusing Hitachi S-4300 and JEOL JSM 6380 field emission scanningelectron microscopes. A uniform black background was preparedfor all SEM micrographs in the plates using Adobe Photoshop CS3.

The morphology of the genus Knoblochia was compared withnumerous different kinds of recent insect eggs (Hinton, 1981),which were gathered from various sources. The study was focusedon the most similar taxa to the fossils; Phasmatodea and Lepi-doptera groups. The data regarding Lepidoptera originate from theauthors’ personal observations and published data (Döring, 1955;Fehrenbach, 2003). The data used for Phasmatodea are based onauthors’ personal observations and published data (Clark, 1979;Grimaldi and Engel, 2005; Hinton, 1981). By Stemona tuberosa L.personal observations were used and data from Kubitzki (1998)were involved. In the description of Phasmatodea eggs, Psgnumbers are used, in accordance with Bragg (2008). The studiedPhasmatodea egg species were Psg 9 Extatosoma tiaratum tiaratumMacleay, Psg 10 Phyllium bioculatum Gray, Psg 14 Eurycnema goliathGray, Psg 19 Lonchodes brevipes Gray, Psg 29 Lonchodes imitatorBrunner, Psg 100 Lonchodes amaurops Westwood, Psg 195 Sungayainexpectata Zompro, Psg 214 Haplopus jamaicensis Drury, Psg 283Diapherodes venustula Audinet Serville, Lonchodes sp., Pharnacia sp.,

Table 1Geological information to localities, where Knoblochia was recorded.

Name ofFormation

Locality (Country) Sediment type

Gosau Wietersdorf (Austria) Siliciclastic and limestone

Sievering Sievering (Austria) Flysch-type sediments

Solá�n Rusava (Czech Republic) Sandstone with claystone i

Istebna Be�cva-Bu�ckový; Bílá; Staré hamry(Czech Republic); G1ogoczów (Poland)

Turbiditic, Sandstones and

Frýdek Karpentná (Czech Republic). SandstoneKanina Rabka-Zaryte (Poland) Turbiditic limestones and m

Klikov Ole�snice (Czech Republic) Conglomeratic sandstone, smudstone, sandy claystone

Phyllium sp. Eggs of the following lepidopteran species werestudied: Attacus atlas L., Caligo memnon C. and R. Felder, Cossuscossus L., Eryphanis polyxena Meerburgh, Papilio memnon L.

2.3. Geology

The studied fossils were mainly found in clastic, sandy, sedi-mentary rocks. Most of the examined material was fossilized inflysch-type sediments (Table 1). These fossils were found in sevenlocalities of four countries of the Central European region (Fig. 1).Most of the material comes from the Carpathian Flysch of Moravia(Czech Republic), from the Istebna and Solá�n Formations. TheCarpathian Flysch represents rootless allochthonous unit withcomplex sedimentary and tectonic history composed of two groupsof nappes. They were mainly deformed by the Alpine orogenyduring the Middle Miocene (M. Bubík, pers. com., 2011).

Most of the material comes from the Istebna Formation of theSilesian Unit (Menilite-Krosno Group of Nappes). Thick-beddedsandstones and conglomerates constitute the formation. From asedimentological point of view, the formation comprises hemi-pelagites, common turbidites, debris flows, grain flows and slumps(pebblymudstones). Early Campanian to Danian foraminiferal zoneswere described by Hanzlíková (1972) from the Istebna Formation.The Late CampanianeEarly Maastrichtian age of the formation wasconfirmed by studies on Dinoflagellates (Skupien and Mohamed,2008). Two specimens come from the G1ogoczów locality inPoland from the upper part of the Istebna Formatione theWieliczkaFacies (ConiacianeMaastrichtian). The stratigraphic position of thespecimen from the Karpentná locality is questionable. This localitymay belong to the Istebna Formation or the Frýdek Formation. Todate there has been no closer classification (Knobloch, 1977).

The Solá�n Formation is a part of the Ra�ca Unit (Magura Group ofNappes). These samples were collected by Knobloch at the Rusavalocality. The section at this locality shows yellowish gray, fine tomedium grained sandstone beds. Fossiliferous, greenish gray sandyclaystone occurs as a 4 cm interbedding between the thick sand-stone beds (Knobloch, 1977).

One specimen of K. cretacea from the Rabka-Zaryte locality inPoland comes from the Kanina Formation. The Kanina Formationis formed by turbiditic limestones (Oszczypko-Clowes andOszczypko, 2004). The age of the Kanina beds is based on foramin-ifer studies in Early toMiddle Campanian (BakandOszczypko, 2000).

The Gosau Group in the Austrian Alps is of Late Cretaceous toPalaeogene age. It consists of clastic, frequently terrestrial sedi-ments of the synorogenic Gosau Group (Kühn, 1947; Plöchingeret al., 1961; Summesberger et al., 2002). Studied material comes

Age of layers bearingKnoblochia

Samples and their collectionnumbers

Upper CampanianeMaastrichtian

5 Samples (NM K00978eK00982)

CampanianeMaastrichtian

5 Samples (NM K00970, K00971,K00973eK00975)

nterbeddings Upper Cretaceous 4 Samples (F3358, F3375, F03379,F03380)

conglomerates ConiacianeMaastrichtian

10 Samples (NM F03345, F03374,F03376, F03356, F03364, F03351,F03357, F03354, K00972, K00977)

Upper Cretaceous 1 Sample (F03377)arls EarlyeMiddle

Campanian1 Sample (K00976)

andyand claystone.

Late TuronianeSantonian

1 Sample (F03348)

Fig. 1. Map of localities, where Knoblochia was recorded: Gosau Formation 1 e

Wietersdorf; Klikov Formation 2 e Ole�snice; Sievering Formation 3 e Sievering;Solá�n Formation 4 e Rusava; Kanina Formation 5 e Rabka-Zaryte; Istebna For-mation 6 e G1ogoczów, 7 e Be�cva-B�u�ckový, 8 e Bílá, 9 e Staré Hamry 1; FrýdekFormation 10 e Karpentná.

Z. He�rmanová et al. / Cretaceous Research 45 (2013) 7e15 9

from the locality Wietersdorf. The sequence of the Gosau Group inthe broader vicinity of Wietersdorf, Krappfeld area is divided intothe Windisch, Mannsberg, Wendel and Pemberger Formations. Itranges from the Campanian to the Maastrichtian (Radl, 2008). Thefossils come from the Pemberger Formation, consisting of dark-graymarl, light gray to pink limestones, light-gray, green and blackconglomerates and light-gray, green and black breccias. Its totalthickness is about 118 m. The section shows well-bedded depositsof flysch character (Radl, 2008).

The locality Wien-Sievering where the Sievering Formationcrops out belongs to the Flyschzone. It comprises predominantlysiliciclastic sediments and is of CampanianeMaastrichtian age(Knobloch and Mai, 1986).

One specimen (no. F3348) comes from the locality Ole�snice,from sediments of the Klikov Formation (Late TuronianeSantonian,Czech Republic). This formation represents the most widelydistributed stratigraphic unit in the South Bohemian Basins(Slánská, 1974). Three rock types occur repeatedly and irregularly inthe Klikov Formation: (1) light gray or yellow conglomeratic,coarse- to medium-grain sandstone beds, (2) mainly fine-grainedred beds and (3) gray mudstone beds (Slánská, 1976).

3. Systematics

Genus Knoblochia gen. nov.Syn:1983 Spirellea Knobloch et Mai, p. 314 pro parte

Type species. Knoblochia cretacea sp. nov.

Derivation of name. In honor of Ervín Knobloch, who first describedthis fossil.

Diagnosis. Obovoid, ovoid to rounded fossils; surface longitudinallyridged; the ridges rarely anastomosing; the surface covered bypapillae; projections on both ends; in apical end show a smallconical projection surrounded by a coronal rim; in the basal part ofthe fossil it shows a round collar with central projection; thin wall;inner surface of wall smooth or covered by angular, regularstructures.

Remarks. Spirellea is a large genus established for a heterogenousgroup of fossil seeds generally with ovoid shape and often withlongitudinal ribbing. One of the species included in this complex isSpirellea kvacekii (Knobloch) Knobloch et Mai, originally thought tobe fruit and described asMicrocarpolithes kvacekii (Knobloch,1977),and later reinterpreted by Knobloch andMai (1983, 1984, 1986) as aseed Spirellea kvacekii (Knobloch) Knobloch et Mai. However, Spir-ellea kvacekii is distinctly different from the type of the genusSpirellea bohemica Knobloch and Mai 1984.

The genus Spirellea was invalidly introduced as a nomen nudumby Knobloch and Mai (1983). Later the same authors published thediagnosis of the genus (Knobloch and Mai, 1984) and provided thetype S. bohemica. The first legitimate name, S. kvacekii appeared inthe monograph by Knobloch and Mai (1986).

The type species Spirellea bohemica is longitudinally ridgedanatropous seed, with subapical, round, hilum and apical, small,wart-like micropyle. The inner raphe indistinct, but indicated bynarrow structure on the surface. The chalaza is basal (Knoblochand Mai, 1986). These above-mentioned characters of S. bohemicaproved dissimilarity from Knoblochia. S. bohemica is similar toKnoblochia in the ovoid shape and ridged surface. In apical end,Knoblochia shows a small conical projection surrounded by a cor-onal rim; in the basal part of the fossil, it shows a small roundcollar with a projection. The micropyle, hilum and chalaza ofS. bohemica are different from both Knoblochia projections. Theinner raphe is visible on the surface of S. bohemica, but Knoblochiahas no raphe at all. The surface of Knoblochia is papillate, with notraces of exothestal cells. The surface of S. bohemica is covered bylarge, well-defined cells. The appearance of transversal ridges isalso an important difference on some Knoblochia specimens, whichare missing in S. bohemica. The holotypus of S. bohemica is1.1 �1 mm in size, while the holotypus of K. cretacea is 1 � 0.5 mmin size. Number of ridges in S. bohemica is 14e20, while K. cretacea17e30.

Knoblochia cretacea sp. nov.

Figs. 2AeJ and 3AeI

?1977 Microcarpolithes kvacekii Knobloch: PaläokarpologischeCharakteristik der Flyschzone der mährischen Karpaten,p. 109, pl. 7, fig. 13, pl. 8, figs. 4, 13e15, 17e19, pl. 12, fig. 13.

?1983 Spirellea kvacekii (Knobloch) Knobloch et Mai, p. 314, pl. 8,fig. 7, comb. invalid.

?1986 Spirellea kvacekii (Knobloch) Knobloch et Mai, p. 148, pl. 44,fig. 12.

Holotype. Specimen NMP K00974 (Fig. 2DeF)

Type locality. Sievering (Austria)

Type horizon. Sievering Formation (CampanianeMaastrichtian, LateCretaceous)

Other material studied. NMP F03345, F03348, F03351, F03354,F03356e58, F03364, F03374e7, F3379e80, K970e982.

Fig. 2. Knoblochia cretacea. A Ovoid fossils, longitudinal ridges, no. F3345, scale bar 500 mm, locality Be�cva B�u�ckový (Czech Republic). B Ovoid fossils, anastomosing ridges, smallprojection surrounded by a coronal rim in the apical part, no. K970, scale bar 500 mm, locality Sievering (Austria). C Ovoid fossils, longitudinal ridges, no. K973, scale bar 500 mm,locality Sievering. DeF Complete longitudinally ridged specimen, projections on both ends, no. K974, locality Sievering D one side, apical projection, scale bar 500 mm E other side,basal projection, scale bar 500 mm F detail of basal projection, round structure with small central projection and collar, scale bar 100 mm. G Small conical projection surrounded by acoronal rim, no. F3345, scale bar 100 mm, locality Be�cva B�u�ckový. H Small projection surrounded by a rim, no. K970, scale bar 100 mm, locality Sievering. I Small projection sur-rounded by a rim, no. K976, scale bar 100 mm, locality Be�cva B�u�ckový. J Round collar with small central projection, no. F3374, scale bar 100 mm, locality Be�cva B�u�ckový.

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Fig. 3. Knoblochia cretacea. A Smooth inner surface, no. K972, scale bar 300 mm, locality Glogoczow (Poland). B Smooth inner surface, pitted with small perforations, no. K977, scalebar 200 mm, locality Glogoczow. C Inner surface covered by rectangular cells arranged in rows, no. K978, scale bar 400 mm, locality Wietersdorf (Austria). D Wall composed ofelongated cells, no. K972, scale bar 50 mm, locality Glogoczow. E Compact wall, no. K977, scale bar 50 mm, locality Wietersdorf. F Detail of ridges, no. F3376, scale bar 100 mm, localityBe�cva B�u�ckový (Czech Republic). G Detail of ridges, no. F3359, scale bar 100 mm, locality Sievering (Austria). H Detail of ridges, no. F3374, scale bar 100 mm, locality Be�cva-Bu�ckový.I Outside surface micropapillate, no. K970, scale bar 10 mm, locality Sievering.

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Occurrence. Be�cva-B�u�ckový, Bílá, Karpentná, Ole�snice, Rusava, StaréHamry (Czech Republic); Sievering, Wietersdorf (Austria); Glo-goczow, Rabka-Zaryte (Poland).

Stratigraphical range. Campanian, Late CretaceouseDanian, EarlyPalaeocene.

Diagnosis. Fossils ovoid; longitudinally ridged; ridges distinct,triangular in cross section, occasionally anastomosing, coveringthe entire surface. In places, small transversal ridges. At apicalend, small conical projection surrounded by coronal rim; at basalend, round collar with small central projection; outer surfacemicropapillate; papillae small and scattered on surface; innersurface of wall smooth or ornamented with angular cell-likestructures. Wall sporadically perforated by small holes.

Description. The holotype is rather compressed, preserved as three-dimensional charcoal (Fig. 2DeF). It is ovoid, 1 mm long and0.75 mmwide, having 22 anastomosing longitudinal ridges. Apical

ends show a small conical projection surrounded by a coronal rimapproximately 200 mm in diameter. Ridges approaching the rim areseptated, bearing perpendicular striae. The basal end shows around structure, the inner part of the basal projection forms smallconical projection divided into 13 segments and surrounded by acollar approximately 100 mm diameter (Fig. 2F). The outer wall issparsely micro-papillated.The remaining material is also carbonized, ovoid, varying between0.5 and 2 mm in size. The specimens are covered with longitudinal,distinct, sometimes anastomosing ridges (Fig. 2B, E), that appeartriangular in cross section, and the number of ridges varies from 17to 30. Transversal ridges sometimes occur (Fig. 3G, H), the width oftransversal ridges is one tenth the width of the longitudinal ridges.Transversal ridges are more common at the apical end. The fossilshave projections at both ends (Fig. 2D, E). At the apical end, thefossils show a small conical projection, surrounded by a rim 200 mmin diameter (Fig. 2GeI). At basal end, it shows a round collar with asmall projection (Fig. 2F, J). The inner surface of the wall is smooth

Z. He�rmanová et al. / Cretaceous Research 45 (2013) 7e1512

(Fig. 3A) or pitted with small perforations (Fig. 3B). The perforationsare 5 mm in diameter and penetrate the entire thickness of the wall.Wall thickness is 40 mm. The wall itself is composed of elongatedcells (Fig. 3D). In a few cases, thewall is compact (Fig. 3E). The outersurface of the wall is partly or completely striated and sparselymicropapillated (Fig. 3I). The papillae are 1e5 mm in diameter.Specimen K973 shows the ridges striated along their entire length.In this specimen there are 70 striae per ridge. The width of eachridge is about 60 mm; the distance between two septa is about10 mm (Fig. 3G). In specimens no. K978 and K982, the inner surfaceof thewall is covered by rectangular cells arranged in rows (Fig. 3C).The shape and size of this inner structure is similar to the outerstructure transversal ridges (Fig. 2G).

Remarks. The original taxon Microcarpolithes kvacekii wasdescribed as a fossil plant. However, our revision shows that thesefossils are insect remains. For such fossils it is necessary to userules of the zoological nomenclatorial, instead of the botanicalcode. From this point of view, the new zoological taxon Knoblochiacretacea was erected. Additionally, the preservation of the holo-type of Microcarpolithes kvacekii (NMP F03345) does not showenough details necessary for closer determination and clearinterpretation. Knoblochia cretacea is therefore based on its ownholotype: NMP K974.

Interpretation. Knoblochia cretacea is interpreted as an ovoid insectegg. It is covered by longitudinal (Fig. 2A, D), sometimes anasto-mosing ridges (Fig 2B, E). Its apical part is interpreted as a roundshape operculum with a small capitulum (Fig. 2GeI). Its basal partis a round structure surrounded by a collar interpreted as micropyle(Fig. 2F). Its surface is often papillate (Fig. 3I); chorion consists oflarge cells (Fig. 3D), inner surface is structureless (Fig. 3A) or

Fig. 4. Stemona tuberosa, extant. A Longitudinally ridged seed, scale bar 5 mm. B Vesicular arscale bar 200 mm. E Detail of trichomes covering surface of seed, scale bar 50 mm.

covered by small aeropyles penetrating the entire wall. These aer-opyles form lines running parallel with ridges (Fig. 3B).

4. Discussion

The aim of this study is a comparison of the new genus Kno-blochia with selected recent material (seeds of Stemona tuberosa,and insect eggs of Phasmatodea and Lepidoptera), focused ontaxonomically important characters such as operculum, micropyle,wall structure and surface ornamentation.

4.1. Comparison of Knoblochia and recent material

4.1.1. StemonaceaeThe possible relationship of the genus Spirellea and the monocot

family Stemonaceae, especially with Stemona, has already beendiscussed by Knobloch and Mai (1984, 1991). All members of theStemonaceae family have longitudinally ridged seeds, similar toKnoblochia, but elaboration of the seed coat of Stemona has adifferent pattern. Stemona tuberosa, which was studied in detail hasa more elongated shape than Knoblochia (compare Figs. 2A and 4A).The seeds of S. tuberosa are larger than those of Knoblochia.S. tuberosa has seeds cca. 15e22 mm long; the fossils of Knoblochiaare 0.8e2 mm long. The number of the longitudinal ridges is 17e30in Knoblochia and 16e20 in S. tuberosa. The seeds of S. tuberosa showtwo types of trichomes (Fig. 4E), in contrast to those of Knoblochia,which are devoid of any hair (Fig. 3FeH). The surface of Knoblochiais papillated (Fig. 3I). The shape of the acumen of Stemona (Fig. 4D)does not correspond with the apical part of Knoblochia (Fig. 2G), norwith the projection on the basal part of Knoblochia (Fig. 2F). Ste-monaceae are also characteristic in having multilayered testa

il of seed (base), scale bar 1 mm. C Seed wall, scale bar 1 mm. D Acumen of seed (apex),

Z. He�rmanová et al. / Cretaceous Research 45 (2013) 7e15 13

(Fig. 4C), however Knoblochia shows a thin compact wall (Fig. 3E), ora wall composed of elongated cells (Fig. 3D). The wall thickness is400 mm in Stemona and 40 mm in Knoblochia. Only few micrometerperforations penetrate the wall of Knoblochia. In some water plants,seeds have perforations, but Stemonaceae are not water plants andtherefore do not have perforations. Stemona itself is characterizedby having seeds with variously shaped aril (Fig. 4B). This aril is notevident in Knoblochia. None of the Knoblochia specimens have anycharacteristics resembling an aril. Another important difference isthe appearance of transversal ridges upon longitudinal ridges insome Knoblochia specimens (Fig. 2G). These transversal ridges arenever present in Stemona (Fig. 4E).

4.1.2. LepidopteraThe eggs of Attacus atlas (Fig. 5D, E), Cossus cossus (Fig. 5A) and

Eryphanis polyxena (Fig. 5B, C) were studied in detail, because theseare representatives of Lepidoptera groups similar to Knoblochia, andthey represent three well-defined egg morphogroups. Lepidopteraare known from the Cretaceous period (Gaunt and Miles, 2002).

The first egg morphogroup is represented by Attacus atlas,where the wall structure is well exposed (Fig. 5D). The smoothouter surface of this species is not a recurrent character withinLepidoptera. The egg shape is upright and belongs to the Saturniapavonia type of Döring classification (1955). The second egg mor-photype is represented by Cossus cossus. This species was used byDöring (1955) as a special butterfly egg morphotype. The egg isupright “characterized by circumference and height” (Fehrenbach,2003). The ridges are anastomosing (Fig. 5A). C. cossus has nomicropylar rosette structure.

The third studied morphogroup is represented by Eryphanispolyxena. That has a properly constituted surface ridge structure oflongitudinal and transverse ridges. The micropyle of this egg is arosette, which character is fairly common in recent Lepidoptera.

Fig. 5. Lepidoptera eggs, extant. A Cossus cossus, longitudinally ridged ovoid egg topped witpart, scale bar 1 mm. C Eryphanis polyxena outer surface of chorion covered with transversAttacus atlas inner surface of chorion, scale bar 1 mm. E Attacus atlas detail of inner part o

The most common shapes of eggs in Lepidoptera are ovoid(Fig. 5A), obovoid or rounded forms, which are features in commonwith Knoblochia fossils. The size of Knoblochia is on the average1.4 mm long and 1 mm broad. It corresponds with the observedeggs: A. atlas is 2.3mm long� 1.9mmbroad, C. cossus is 1.5mm longand 1mmbroad and E. polyxena is round, 2mm in diameter. Surfaceridges occur in the Lepidoptera group (Fig. 5A, C), just as in Kno-blochia (Fig. 2AeE); the ridges may be anastomosing (Figs. 2E and5A) in both groups, and both groups have transversal ridges(Figs. 3G and 5C). The number of the ribs is around 30 in Knoblochiaand around 40 in Lepidoptera. Papillae are also a common characterin both Knoblochia and Lepidoptera. Both groups have thin walls(Figs. 3D and 5E). Only a fewmicrometer perforations penetrate thewall of Knoblochia. Recent Lepidoptera eggs have aeropyles, whichappear as small perforations through thewall. The embryo inside theinsect eggs needs to have access to air (Figs. 3B and 5C). Wallthickness is 40 mm in Knoblochia and 35 mm in Lepidoptera. Mostimportant is the similarity of the inner structures. Both groups havetheir inner surface smooth (Figs. 3A and 5E) or coveredwith angularstructures (Figs. 3C and 5C). The shape and size is highly variablewithin Lepidoptera, butKnoblochia specimens fit into this size range.

However, this similarity is not sufficient for identification,because none of the recent Lepidoptera eggs bear projections onboth ends. These insects fix their eggs on leaf surfaces, which ex-plains why that projection usually appears only on one side.However, Knoblochia might have different egg laying strategy fromthe recent butterflies.

4.1.3. PhasmatodeaRepresentatives of this group are known from the Cretaceous

period (Grimaldi and Engel, 2005). Several genera were chosen forcomparison (see Material 2.2.), based on morphological similaritywith Knoblochia. The shape of Phasmatodea eggs is extremely

h micropyle, scale bar 500 mm. B Eryphanis polyxena round egg, opercula in the centralal and longitudinal ridges, aeropyles arranged regularly in ridges, scale bar 200 mm. Df chorion, scale bar 50 mm.

Fig. 6. Phasmatodea eggs, extant. A Lonchodes brevipes, ovoid egg, scale bar 1 mm. B Phyllium sp., inner surface of wall, scale bar 1 mm. C Lonchodes brevipes, detail of posterior partof egg, showing conical projection surrounded by coronal rim, scale bar 200 mm. D Lonchodes amaurops, round operculum in anterior part with small projection (capitulum), scalebar 200 mm. E Lonchodes amaurops, inner surface of wall, scale bar 100 mm. F Phyllium sp., detail of wall, scale bar 100 mm. G Phyllium sp., micropapillae on surface of egg, scale bar100 mm.

Z. He�rmanová et al. / Cretaceous Research 45 (2013) 7e1514

variable (Clark, 1979). For example, Extatosoma tiaratum or Lonch-odes brevipes are ovoid in shape, similar to Knoblochia, but theyhave any ridges on their surface. Phyllium has ridges on the eggsurface, the same as Knoblochia, but Knoblochia has more ridges.Some Phasmatodea eggs have projection on both sides; this is acharacter also occurring in Knoblochia. The genus Lonchodes has around operculum in the anterior part and a small cone-shapedstructure in the posterior part. The operculum is a special struc-ture that opens when the egg is mature. The apical projection of thegenus Lonchodes, the operculum, is similar to Knoblochia (compareFigs. 2G and 6D) in having a collar and a capitulum, a small raisedstructure on the top. Sometimes there are apical or basal pro-jections in Phasmatodea eggs, and in Knoblochia surrounded with acoronal rim (compare Figs. 2F and 6C). The inner membrane ofPhyllium is less pronounced than in Knoblochia specimens(compare Figs. 3A and 6B). However, the wall of Phyllium iscomposed of several layers (Fig. 6F), like in some specimens ofKnoblochia (Fig. 3D). The wall thickness of Phasmatodea eggs ishigher (150 mm) than Knoblochia (30 mm). The outer surface ofPhyllium eggs is also papillated, the same as in Knoblochia (compareFigs. 3I and 6G).

4.2. Other fossil insect eggs from Central Europe

Knoblochia fossils are similar in a few details to Palae-oaldrovanda splendens Knobloch et Mai, because both seem tobe closer to the group of insects than fossil plant remains(He�rmanová and Kva�cek, 2010). Palaeoladrovanda splendens aswell as one specimen of Knoblochia come from the Klikov For-mation in the Czech Republic. Several characters of recent insecteggs correspond with those of Palaeoladrovanda and Knoblochia.The most important ones are: small ovoid shape, presence of aconical projection surrounded by a coronal rim resembling aposterior polar mound in the genus Lonchodes (Phasmatodea), andthe structure of the inner surface, showing rectangular cells inrows and resembling the inner surface of the chorion in the genusCossus (Lepidoptera). Such an inner surface, characteristic for

Palaeoladrovanda, is not common in Knoblochia cretacea e it wasfound in only a few specimens (Fig. 3C).

Knoblochia is more similar morphologically to a questionablefossil Costatheca dentata in the Costatheca genus, which is possiblyalso an insect egg (Batten and Zavattieri, 1995; Batten pers. com.,2012). It shows longitudinal surface ridges and cross ridges. Oneend is usually not closed, while the other end bears a coronal rimwith a conical projection. This structure suggests a relation toKnoblochia specimens. The number of the ridges is usually smaller(10e12) in Costatheca (Knobloch, 1981). The largest difference be-tween Costatheca dentata and Knoblochia is the quality of preser-vation, which makes detailed comparison impossible. The genusCostatheca was established for compression material, while Kno-blochia is preserved as three-dimensional charcoal.

5. Conclusions

Fossils described now as Knoblochia cretacea were originallydescribed as an angiosperm fruits. Subsequently, they were re-interpreted as seeds and assigned to the fossil genus Spirellea,with possible relation to Stemonaceae (Knobloch and Mai 1984,1991). However, recent reinvestigations identified several charac-ters which are typical for insects. The following similarities wereobserved between Knoblochia and insect eggs: surface ridges,papillae, projection on both ends, apical projection with raisedstructure, basal projection surrounded by collar, wall perforations,smooth inner wall or angular structures on the inner wall. Amongvery diversified class Insecta, similar eggs were observed in ordersLepidoptera and Phasmatodea, especially Lonchodes.

In accordance with the above-described morphological simi-larities, we interpret the genus Knoblochia as representing insecteggs. At present it is not possible to define its nearest living relativeor define its exact systematic position. There is a high diversity ofinsect eggs superficially resembling seeds and the number of fossilcharacters is limited by preservation.

Interpretation of these fossils provides further arguments forthe original biodiversity in the Mesozoic. The most diverse

Z. He�rmanová et al. / Cretaceous Research 45 (2013) 7e15 15

terrestrial group, insects, are rarely fossilized, and since the aim ofthe study is the comprehension of the original ecosystem, everytrace of this important group needs to be taken into consideration.

Acknowledgment

We thank Else Marie Friis and Maria Barbacka for their usefuldiscussions, Attila Virág for help with preparing figure 1. We thankFranti�sek Krampl (National Museum) for the fruitful discussion oninsect eggs, Jaroslav Zají�cek (private collector) for providing us Pha-samtodea eggs and Eva Smr�zová (Prague Botanical Garden) forproviding us Lepidoptera eggs. We are also grateful to Zsolt Bálint,who provided several useful comments on recent insect systematicsand insecteggphysiology.WethankMiroslavBubík (CzechGeologicalSurvey, Brno) for the fruitful discussion on the Carpathian Flysch, andDavidBatten forhisuseful commentsabout thegenusCostatheca. Thiswork was financially supported by Ministry of Culture of the CzechRepublic (DKRVO 2013/05, National Museum, 00023272). The workwas also supported by a grant of the Hantken Miksa Foundation.

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