Mystus heoki & m. indicus two new fish species

Mystus indicus and M. heoki, two new catfishes from Kerala, India

MATHEWS PLAMOOTTIL AND NELSON P. ABRAHAM

Asst. Professor, Govt. College Chavara, Kollam Dt., Kerala, India

Associate Professor, St.Thomas College, Kozhencherry, Pathanamthitta Dt., Kerala, India

ABSTRACT - Mystus indicus, a new species of the family Bagridae, is described from Kuttoor of ManimalaRiver in Kerala, India. It is distinguished from its congeners by the following combination of characters: snoutlonger; median groove on head appear as double cephalic fontanels; occipital process reaches to basal bone ofdorsal fin, on both sides of occipital process a thick layer of flesh present, which conceals the former from sideview; rayed dorsal base prominently swollen on both sides. Mystus heoki, new species, differs from its relativespecies in having a markedly elongate body, shorter head and smaller eyes; occipital process short and it neverreach basal bone of dorsal fin and the former is not visible as it is concealed under a thick layer of flesh; adiposedorsal fin small, its base short, and it is located fairly away from rayed dorsal fin. The new species of fishes aredescribed and compared with related species.

KEYWORDS – Manimala River, taxonomy, new description, Mystus malabaricus.

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Introduction

Catfishes constitute a large group of chiefly fresh waterfishes distributed around the world. Africa, India andSouth America are rich in quantity and species diversityof catfishes. Rita, Sperata, Mystus, Hemibagrus,Horabagrus, Rama, Chandramara and Batasio arethe bagrid cat fish genera found in India (Misra, 1976;Talwar & Jhingran, 1991; Jayaram & Sanyal, 2003;Jayaram, 2006); of these Mystus, Hemibagrus,Horabagrus and Batasio alone are known from inlandwater bodies of Kerala.

Mystus is the most common genus in India,especially in Kerala. The fishes of this genus though notgrowing to large size, excepting a few, provide bynumbers the required protein to the masses (Jayaram &Sanyal, 2003). Mystus vittatus, M. oculatus, M.montanus, M. malabaricus, M. armatus, M.canarensis and M. gulio are the major Mystus speciesof Kerala (Misra, 1976; Easa & Shaji, 2003; Jayaram &Sanyal, 2003; Jayaram, 2006, 2010).

BiosystematicaISSN: 0973-7871(online)ISSN: 0973-9955 (print)

Biosystematica, 2013,7(1): 43-5843

© Prof. T.C. Narenderan Trust for Animal Taxonomyhttp://www.tcntrust.org/journal.php

Corresponding author: [email protected]

The first author could collect eight specimens ofMystus species from Kuttoor of Manimala River inKerala, India and other different six specimens of thisgenus from Elankadu of the same river; these bagridfishes bear features of the genus but carry enoughcharacters to distinguish from their congeners; so theyare described here as two new species Mystus indicusand M. heoki respectively.

Materials and methods

Fishes were collected using cast nets and preserved in10% formalin. Identification of various Mystus specieswas carried out following Jerdon (1849), Day (1865, 1877& 1889), Misra (1976), Jayaram & Sanyal (2003) andJayaram (2006 & 2010). Methods used are those ofJayaram (2002) and measurements follow standardpractices. Body depth and body width were measuredboth at dorsal-fin origin and anus, vertically from dorsal-fin origin to belly and from anus to dorsum, respectively.

Abbreviations: ZSI- Zoological Survey of India,Kolkata, West Bengal; ZSI/SRC- Zoological Survey of

Biosystematica, 2013, 7(1)

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India, southern regional centre, Chennai, Tamil Nadu;ZSI/WGRC- Zoological Survey of India, Western Ghatsregional centre, Calicut, Kerala; KFRI- Kerala ForestResearch Institute, Peechi, Kerala; STC/DOZ- St.Thomas college, Department of Zoology; TL- totallength; SL- standard length; HL- head length; BDD-body depth at dorsal fin origin; HD- head depth; RD-rayed dorsal fin; AD- adipose dorsal fin; LBA- lengthof base of anal fin; LBAD- length of base of adiposedorsal fin; LBRD- length of base of rayed dorsal fin;LCP- length of caudal peduncle; DCP- depth of caudalpeduncle; CL- caudal lobe; DspT- dorsal spine teeth;PspT- pectoral spine teeth; HT- holotype; PT- paratype.

Mystus indicus, sp. nov( Fig. 1 & 2; 6. G, 7. G & Table 1, 3 & 4)

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Materials Examined

Holotype: ZSI/FF 4627, 100 mm SL, Kuttoor, ManimalaRiver, Kerala, India; collected by Mathews Plamoottil,17 February 2011.

Paratypes: ZSI/WGRC/2418, 7 specimens, 81- 107 mmstandard length, Kuttoor of Manimala River, Kerala,India; collected by Mathews Plamoottil, 07 March 2011.

Diagnosis: The new species can be differentiated fromall its relative species in having an elongated snout, athick layer of flesh present on both sides of occipitalprocess, pectoral spine with more teeth, greater pre pelviclength, rayed dorsal fin base prominently swollen on bothsides and wide caudal peduncle. Mystus indicus canbe differentiated from M. montanus in having doublemedian cephalic fontanels (vs. a single medianlongitudinal groove), pectoral fin with 6- 8 branched rays(vs. 6 branched rays) and lesser pre dorsal length (30.8-36.0 % SL vs. 39.1- 43.8). The new species differs fromMystus armatus in having pectoral fin with 6-8 branchedrays (vs. 9), caudal fin with 15- 17 rays (vs. 19) andmedian longitudinal groove on head shallow and wide(vs. narrow and moderately deep). The new speciesdiffers from Mystus oculatus in having a cephalicfontanel which never reach occiput (vs. fairly reachocciput in M. oculatus), 7- 8 branched rays in anal fin(vs. 9- 10), and longer adipose dorsal fin base (26.2-33.7 % SL vs. 17.2- 19.0). The new species differsfrom Mystus malabaricus and M. canarensis in havingoccipital process reaching basal bone of dorsal fin (vs.never reach) and occipital process naked and visible (vs.a thick flesh covers occipital process and so it is invisible).

Description: Body elongate, compressed. Headdepressed, head length 5.0- 5.7 in total length and 3.8-4.5 in standard length; head width 68.0- 83.3 and snoutlength 36.2- 42.5 in percent of head length. Body heightat dorsal origin 5.0- 6.8 in total length and 4.0- 5.3 instandard length; ventral profile of the body more convexthan dorsal profile. No considerable rise in the profilefrom snout to base of first dorsal fin. Dorsal surface ofhead rough; occipital process rugose with granulatedlines; opercle rough with radiating lines; shoulder bonerather longer than deep at its base with rough lines. Eyeswith free orbital margins, 3.6- 4.2 in head, 1.3- 1.7 insnout and interorbital width. Greatest width of the headgreater than its length behind the angle of mouth. Mouthsub terminal, transverse, upper jaw longer, its gape width34.8- 40.9 in percent of head length. Maxillary barbelsreach to posterior end of anal fin base, outer mandibularsreach considerably behind half way between pectoralsand pelvics, inner mandibulars reach middle of pectoralbase and nasals extend to occiput. Nasals located nearerto snout than orbit. A prominent depression presentbetween nasal barbels. Median longitudinal groove onhead shallow, wide and appear as two fontanels, reachingfairly behind orbit mostly near to occiput. Occipitalprocess reaches to basal bone of dorsal fin; on both sidesof the former a thick layer of flesh present, whichconceals the occipital process from side view but it nevercover the occipital process. Teeth villiform in band injaws. A prominent depression present on the humeralregion of the body.

Rayed dorsal fin, 1.1- 1.7 in head, arises at 1/2 to1/3 of length of pectoral from its anterior end, nearer toadipose dorsal origin than to snout end; its tip reachesorigin of adipose dorsal, above at or behind the middleof ventral fin. Outer margin of dorsal fairly convex.Only a little space present between rayed dorsal andadipose dorsal; inter dorsal space considerably shorterthan rayed dorsal base. Rayed dorsal base, 1.6- 2.5 inadipose dorsal base, prominently swollen on both sides,mostly flesh colored. Dorsal spine, 1.6- 2.2 in headlength, osseous, moderately strong; posterior half of itsinner surface serrated, outer side smooth. Adipose dorsaloriginates a little behind rayed dorsal base and abovemiddle of ventral and fairly in front of anal origin; itsheight 5.2- 6.5 and its base 26.2- 33.7 in percent ofstandard length.

Pectorals, 1.3- 1.6 in head, low, not reaching pelvicfin, with a strong spine, 1.4- 1.7 in head and with 16strong denticulations, of which 7 or 8 teeth morepronounced in the terminal half. Base of pectoral isslightly fleshy. Ventral, 1.4- 1.8 in head, arises just

PLAMOOTTIL & ABRAHAM


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below the last dorsal ray or a little in front of it, near toanal fin than pectoral fin base; its tip never reaches analfin, but reaches anal opening and its outer margin slightlyconvex; its base swollen and light red colored. Anal fin,1.6- 2.4 in head, originates a snout length behind adiposedorsal origin, near to pelvic fin origin than caudal baseand its tip reach anal papilla; its outer margin convex.Length of base of anal fin 1.9- 3.1 in adipose dorsalbase. Tips of caudal lobes pointed; upper lobe the longer;least height of caudal peduncle 1.3- 1.7 in its length.

Skin smooth. Lateral line proceeds to extreme tipof caudal peduncle. Lateral line and sense organs on itclearly visible. Body muscles are distinctly seen onlateral sides of body.

Coloration: Upper lateral sides yellowish green; lowerlateral sides white; rayed dorsal, adipose dorsal and analfin greenish yellow; caudal hyaline; its base light yellow;a thin bluish black line passes through lateral line; lightgrayish indistinct bluish black spot present on humeraland caudal regions. One to two anterior dorsal rays,ventral and anal fins with a light black shade. Eyesbluish.

Distribution. - Currently known only from the typelocality in Kerala.

Habitat. – Manimala River at Kuttoor, the type localityof Mystus indicus, is floored by means of gravelly sanddominated sediments. River width varies between 50m and 125 m; the depth ranges from 1 m to 15 m andriver bank height varies between 0.5 and 1.5 m. Thisstretch of the river contains many pools, including Kallelikadavu with a depth of 15 m, most of them are formedby illicit and indiscriminate scooping of sand. A majorportion of the river is covered by moderately developedriparian vegetation. The major species in the riparianflora include Bambusa bambos, Bambusa vulgaris andOchreinauclea missionis. The varities that occur inminor proportions comprise Hibiscus tiliaceus, Ficusglomerata , Hydnocrpus pentandra, Holigarnaarnottiana ,Pongamia pinnata, Ficus exasperata andTribulus terrestris. Anquilla bengalensis, A. bicolor,Barilius bakeri, Danio malabaricus, D.aequipinnatus, Salmostoma boopis, Rasboradaniconius, Puntius vittatus, Dawkinsia filamentosa,Haludaria fasciata, Pethia ticto, Horabagrusbrachysoma, Mystus gulio, Mystus armatus,Heteropneustus fossilis, Clarias dussumeiri, Etroplussuratensis, Etroplus maculatus, Oreochromismossambica, Mastacembelus armatus,Macrognathus guentheri etc are the co- occurring fishspecies.

Etymology. – Species name refers to the country fromwhich it was described firstly. Latin word “indicus”means ‘of India’.

Comparisons

The present fish shows some similarities to Mystusmontanus reported firstly by Jerdon (1849) fromManantavady River in Wayanad and redescribed laterby Day (1865, 1877 & 1889) from the same locality;similar to the present species, in M. montanus (Fig. 6.C & 7. C; Table 3 & 4) occipital process reaches thebasal bone of dorsal fin. But the present fish greatlydiffers from M. montanus in many other taxonomicaspects. In M. montanus median longitudinal groove issingle (vs. median longitudinal groove on head appearas two fontanels in the new fish), dorsal surface of headsmooth (vs. dorsal surface of head rough), maxillarybarbels extend up to half way between ventral and analfins (vs. maxillary barbels reaching posterior end of analfin base), external mandibulars reach behind half lengthof pectoral fin (vs. external mandibulars extendconsiderably behind half way between pectoral andpelvic), dorsal spine with 8 teeth (vs. 6-7), adipose dorsaloriginates from above the middle of origin of ventral andanal fins (vs. adipose dorsal originates above middle ofventral fin), highest point of adipose dorsal is roughly onthe level of dorsal profile of body (vs. adipose dorsalprojects fairly above the dorsal surface of body), pectoralfin with 6 branched rays (vs. 6- 8), caudal fin with 15rays (vs. 15- 17), pre dorsal length greater (39.1- 43.8% SL vs. 30.8- 36.5), an oval or roughly rectangulardistinct deep black spot present on caudal base (vs. nodistinct black spot present on caudal base), a silvery linealong the side and two light yellow bands one above andone below the lateral line (vs. a bluish black line alongthe lateral line and light bands absent above or belowlateral line) and anal origin an eye diameter behindadipose dorsal fin origin (vs. anal origin, a snout lengthbehind adipose dorsal origin).

Mystus oculatus (Fig. 6. E & 7. E; Tabel 3 & 4),described by Valenciennes (1839) from Malabar, is arelated species of the new species; but some scientistssuch as Steven Grant (1999, 2004) are of opinion thatM. oculatus is a synonym of M. armatus. Mystusoculatus is similar to M. armatus in having a black spoton the front of dorsal spine, median longitudinal grooveformed of two fontanels and occipital process reachesthe basal bone of dorsal fin. But Mystus oculatus showsmany taxonomical differences to M. armatus. In M.oculatus, anal fin rays are iii, 9- 10 (vs. iii, 8 in M.armatus), caudal fin with 17 rays (vs. 19), height of



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adipose dorsal fin is greater (5.5- 6.7 % SL vs. 4.7),length of base of adipose dorsal fin shorter (17.2- 19.0% SL vs. 28.9), inter dorsal distance greater (16.5- 18.2% SL vs. 8.3), dorsal spine longer (14.4- 16.5 vs. 11.8),median fontanel starts from in front of nasals and it reachoccipital process (vs. median fontanel starts from behindnasal barbels origin and it never reach occipital process),nasal barbels reach half way between posterior marginof orbit and occiput (vs. reach occipital process),maxillary barbels reach posterior most base of anal fin(vs. reach to caudal base), posterior tip of adipose dorsalfin never reaches the tip of anal fin (vs. reach behindanal fin tip ), posterior base of adipose dorsal is in thelevel of posterior base of anal fin (vs. considerably behindthe posterior base of anal fin), ventral fin tip never reachanal fin origin (vs. reach anal fin origin), tip of pectoralfin never reach anterior base of adipose dorsal (vs. reachfairly behind the adipose dorsal origin) and no spine letpresent before dorsal fin ( vs. a spine let present beforedorsal spine).

The new species differs greatly from Mystusoculatus. In M. oculatus median longitudinal grooveon head fairly reach occiput (vs. it never reach occiputin M. indicus), nasal barbels never reach occiput (vs.reach occiput), tip of rayed dorsal never reach adiposedorsal origin (vs. fairly reach adipose dorsal origin),posterior base of adipose dorsal never reach above thelevel of posterior base of anal fin (vs. fairly reach), 8- 9branched rays present in pectoral fin (vs. 6- 8), 9- 10branched rays present in anal fin (vs. 7- 8), 12- 14 teethpresent on inner side of pectoral spine (vs. 15- 16), adistinct black spot present in front of dorsal spine base(vs. no black spot), dorsal spine longer (14.4-16.5 % SLvs. 8.8- 14.0), adipose dorsal fin base shorter (17.2- 19.0% SL vs. 22.9- 33.7), inter dorsal distance greater (16.5-18.2 % SL vs. 5.5- 9.4) and eye diameter greater (33.0-40.0 % HL vs. 21.7- 29.2)

The present fish shows distinct differences fromMystus armatus (Fig. 6. D & 7. D; Table 3 & 4)described by Day (1865) from Karavannor River ofKerala. In Mystus armatus, a spine let present in frontof dorsal spine (vs. spine let absent in the new species),pectoral fin with 9 branched rays (vs. 6- 8), longer analfin (length of anal 18.2 % SL vs. 9.3- 15.4), adiposedorsal fin shorter (4.7 % SL vs. 5.2- 6.5), caudal finwith 19 rays (vs. 15- 17), median longitudinal groove onhead narrow and moderately deep (vs. shallow and wide),maxillary barbels reach to caudal fin base (vs. maxillarybarbels reach only to posterior end of anal fin base), ablack spot present in front of dorsal spine (vs. blackspot absent), tip of ventral fin reaches anal fin origin

(vs. never reaches anal origin) and dorsal fin as high asbody below it (vs. dorsal fin fairly shorter than bodyheight at dorsal origin).

Mystus indicus can be distinctly separated fromMystus malabaricus (Fig. 6. A & 7. A; Table 3 & 4)described by Jerdon (1849) from ‘mountain streams ofMalabar’ and redescribed later by Day from Wayanad(Day, 1865, 1877, 1889). It is a common Mystus speciesof northern Kerala especially rivers of Wayanad (Hora& Law, 1941; Hora, 1942; Jayaram, 1954, 1966, 1977& Rajan, 1955). But no type specimens are availablefor M. malabaricus. First author of this paper collectedsome specimens of M. malabaricus from MananthvadyRiver of Wayanad, from where Day collected andredescribed it. As many new fishes of Jerdon weredescribed from Wayanad especially from MananthavadyRiver, M. malabaricus might also have been describedfrom there. The presently collected specimens ofMystus malabaricus from Mananthavady River werefound to be similar in characters with Jerdon’sdescription. But Jerdon had not mentioned about a colorband in the mid lateral line of the body. But this charactercan be seen only in larger specimens; smaller specimensof M. malabaricus are without any distinct bands orspots. That may be the reason why Jerdon not mentionedabout the mid lateral body stripe.

In Mystus malabaricus cephalic fontanel is single(vs. two cephalic fontanels in the new species), occipitalprocess never reach basal bone of dorsal fin (vs. reachesbasal bone of dorsal fin), pectoral spine with 7- 13 teeth(vs. 15- 16), head width equaling its length behind angleof mouth (vs. width of head greater than its length behindthe angle of mouth), depth of caudal peduncle greater(13.3- 15.5 % SL vs. 10.0- 12.3), width of caudalpeduncle shorter (3.0- 4.7 % SL vs. 5.0- 7.2), inter orbitalwidth lesser (26.8- 30.0 % HL vs. 31.0- 45.0) and widthof gape of mouth greater (40.0- 44.4 % HL vs. 31.0-40.0).

The present species can be distinctly separatedfrom Mystus canarensis (= Hara malabarica) (Fig.6. B & 7. B; Table 3 & 4) in many characters. ‘Haramalabarica’ was described originally by Day (1865)from Mundakkayam of Travancore Hills in Kerala.Mystus canarensis was a replacement name suggestedfor Hara malabarica by Steven Grant (1999, 2004). Itwas based on a specimen from Canara (AMS B.7624)and Grant considers it was from Mangalore ofKarnataka. But Day (1865) described Haramalabarica from ‘Travancore’- “I received somespecimens of this fish from Rev. H. Baker (junior) from



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the mountain streams of Travancore”. Day (1865, 1877and 1889) described many other new species of fishes(Haludaria fasciatus (=Puntius melanympyx Day),Garra malabarica, Mesonemacheilus triangularis,Puntius denisonii) all which were ‘received from Rev.H. baker, jun…obtained in the stream at Mundakkayam,in the hill ranges of Travancore’ (Day, 1865). Haramalabarica also might have been received fromMundakkayam of Kottayam district. More over the fivespecimens collected by the first author of this paper fromMundakkayam match in all taxonomical characters toDay’ s description (1865) of Hara malabarica. Similarto Day’s description (1865) the color of the presentlycollected specimens is deep leaden, a dark brown spoton shoulder surrounded by a lighter margin, bases ofpectoral and anal yellowish, no distinct colour band onlateral line, occipital process never reaches basal boneof dorsal fin, lateral line with sensory organs in the formof short parallel tubes, pectoral fin with 8 teeth on innermargin and outer margin finely serrated externally andcaudal fin lunated. As the Mystus canarensis of Grant(1999) does not possess many of the above mentionedcharacters and also because it was not collected fromits type locality in Kerala, the neotype designation cannotbe accepted here and the replacement name isconsidered as invalid. (Wayanad, the locality of Rahulkumar’s (photo of) Mystus canarensis is 245 miles awayand Mangalore, the type locality of Grant’s species (AMSB.7624) is 314 miles away from Mundakkayam, the typelocality of Hara malabarica). The fresh specimens of’Mystus canarensis’ from Wayanad by Rahul Kumargiven in Grant’s paper (1999, 2004) are undoubtfuly ofyoung ones of Mystus malabaricus. The first authorcollected many specimens (ZSI FF 4931) of the latterspecies from Mananthavady of Wayanad; young onesof it are very similar to the photos of fresh specimensgiven by Grant and they have no distinct mid lateral colourband similar to ‘Hara malabarica’. The name Mystuscanarensis is used here tentatively as more studies arerequired to propose a new name.

The Mystus indicus differs from Mystuscanarensis in having an occipital process which reachesbasal bone of dorsal fin (vs. occipital process never reachbasal bone of dorsal fin in Mystus canarensis), tip ofrayed dorsal fin reaches origin of adipose dorsal fin (vs.never reach), maxillary and mandibular barbels with usualthickness (vs. maxillaries and mandibulars with unusualthickness), maxillaries reach to posterior end of anal finbase (vs. maxillaries extend only to ventral tip or a littlebehind it), caudal fin with 15- 17 rays (vs. caudal finwith 18 rays), pectoral spine with 15- 16 teeth (vs. 8)

and dorsal spine with 6-7 teeth (vs. without teeth), headdepth greater (14.4- 16.2 % SL vs. 11.2- 13.0), pre dorsallength shorter (30.8- 36.0 % SL vs. 36.2- 38.1), adiposedorsal fin longer (5.2- 6.5 % SL vs. 3.8- 4.9), distancefrom dorsal front to occiput shorter (60.6- 64.2 % HLvs. 72.1- 79.6) and head length excluding snout longer(72.0- 75.7 % HL vs. 65.3- 70.7).

Remarks: Mystus indicus is an edible fish present inthe lower reaches of Manimala River in Kerala. Localfishermen have observed these bagrid fishes appear alongwith other catfishes and Puntius species during monsoonseason. It is expected that more details of its biologicaland taxonomical aspects may be unveiled in future bycollection and analysis of more specimens of these fishes.

Mystus heoki, sp. nov (Fig. 3- 5; 6. F & 7. F; Table 2, 3 & 4)

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Holotype: ZSI/FF 4626, 137 mm SL, Elankadu,Manimala River, Kerala, India; collected by MathewsPlamoottil, 10 January 2011.

Paratypes: ZSI/WGRC 2419, 5 specimens, 85.5- 120mm standard length, Elankadu, Manimala River, Kerala,India; collected by Mathews Plamoottil, 10 January 2011.

Diagnosis: The new species can be differentiated fromall its congeners in having a markedly elongated body(body height 15.0- 16.9 % SL), shorter head (18.9- 22.5%SL), smaller eyes (16.7- 20.4 % HL), shorter rayeddorsal (14.3- 15.4 % SL) and shorter pectoral fin (13.3-14.3 % SL). Mystus heoki can be differentiated fromMystus malabaricus in having seven branched rays inpectoral fin (vs. eight in M. malabaricus), shorter head(18.9- 22.5 % SL vs. 23.8- 24.7), and greater inter dorsaldistance (12.9- 15.3 % SL vs. 8.2- 11.3). The newspecies differs from Mystus canarensis in having alonger snout (36.4- 41.7 % HL vs. 31.7- 36.3 in the newspecies), 7 branched rays in pectoral fin (vs. 8) and adistinct blue band present on mid lateral line (vs. absent).The new species differs from Mystus armatus, M.montanus and M. oculatus in having short occipitalprocess which never reach basal bone of dorsal fin (vs.comparatively long occipital process which reaches basalbone of dorsal fin), dorsal spine without distinct teeth(vs. 6-8 teeth), shorter head and shorter pectoral spine.

Description: Body elongate and compressed; bodydepth at dorsal fin origin 7.3- 7.9 in total length and 5.9-6.7 in standard length; Head depressed, head length5.5- 6.5 in total length and 4.5- 5.3 in standard length;



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dorsal profile roughly straight from caudal base to dorsalfront and then bends moderately to snout tip. Ventralprofile nearly straight. Snout broad and its length 1.0-1.3 times inter orbital distance; mouth sub terminal,transverse, width of its gape 41.7- 48.7 in percent ofhead length, upper jaw longer. Eyes comparativelysmaller, 4.1- 6.0 in head length, 1.9- 2.6 in inter orbitalwidth and 1.9- 2.2 in snout length; median longitudinalgroove on head reaches considerably behind posteriorborder of orbit, but never reach occipital process; thelatter is short and does not reach the basal bone of dorsalfin. Occipital process invisible as a thick layer of fleshcovers the region between its origin and dorsal fin front.Teeth villiform and in bands on jaws and palate, a slightlycurved continuous band on upper jaw and a mesiallyinterrupted band on lower jaw.

Four pairs of barbels: one pair maxillaries reachingconsiderably behind pelvic fin, mostly reach near tothe origin of anal fin, one pair nasals extending fairlybehind orbit, mostly reach very near to occiput, onepair inner mandibulars reaching base of pectoral spineand a pair of outer mandibulars reaching nearly end ofpectoral fin.

Rayed dorsal fin shorter, 1.2- 1.5 in head and 0.9-1.1 in body depth at dorsal fin, originates near to theposterior tip of pectoral, fairly in front of pelvic fin base,nearer to adipose dorsal origin than to snout tip; rayeddorsal fin provided with a slender spine, 1.7- 2.5 in head,shorter than pectoral spine, its tip non- osseous,filamentous and finely serrated behind, outer surfacesmooth. Length of base of rayed dorsal fin 0.9- 1.1 ininter dorsal distance, and 1.4- 1.8 in adipose dorsal base;a fleshy ridge present at the base of first dorsal fin; outermargin of the fin fairly convex. Adipose dorsal base1.4- 1.6 times length of base of rayed dorsal fin, 1.6- 1.8times anal fin base and 1.4- 1.7 in inter dorsal distanceand extending considerably behind the base of last analray; posterior tip of adipose dorsal extends to tip of anal.A moderate mid dorsal ridge present between rayeddorsal and adipose dorsal. Pectoral fin short, 1.4- 1.6 inhead, its spine strong, 1.6-2.0 in head, with 10- 11 teethon inner edge but smooth externally, its tip non- osseousand never reach pelvic fin; outer margin of pectoralnearly straight. Pelvic fin, 1.6- 1.8 in head, origin justbehind last dorsal ray, nearer to anal origin than to pectoralbase. Pelvic fins shorter than pectoral fins and does notreach anal fins; its outer margin convex. Anal fin, 1.9-2.3 in head, origin just behind adipose dorsal origin,nearer to pelvic origin than to caudal base and not reachcaudal fins; posterior margin of anal fairly straight.Caudal fin bilobed, upper lobe longer 1.1- 1.2 times the

lower lobe, depth of caudal peduncle 1.4- 1.7 in its lengthand 8.5- 9.1 in standard length; outer margin of caudallobes rounded.

Skin smooth; dorsal surface of head almost smoothbut with a number of minute pores. Sensory organsclearly visible on lateral line.

Coloration: Fresh specimens: greenish above lateral line,below it greenish white; fins hyaline to light greenish. Abluish oval spot present on shoulder, another triangularbluish spot on caudal base and a distinct and thick bandof bluish color in between the two along the lateral line,width of which is more than half the diameter of eyes.Body and fins decorated with tiny black dots.

Preserved specimens: after long preservation in formalinbody color turns to light brownish.

Distribution. - Currently known only from the typelocality in Kerala.

Habitat.- Manimala River at Elankadu, the type localityof Mystus hoeki, is floored generally by rockysubstratum; patches of cobbles, boulders and gravellysand occur at certain places. The width of the riverchannel varies between 20 m and 42 m. This high levelarea is characterized by intermittent occurrence ofmoderately dense riparian vegetation. Ficusexasperata, F. glomerata, Gmelina arborea, Bambusabambos and B. vulgaris are the major trees. Wood treessuch as Teaks and Albizia, herbaceous plants such asMaranta arundinacea, Colocasia esculenta andEclipta prostrata are infrequently seen. Anquillabengalensis, Danio malabaricus, Barilius bakeri,Rasbora daniconius, Etroplus maculatus, Garramullya, Dawkinsia filamentosa, Mesonemacheilustriangularis, Clarias dussumeiri, Glyptothoraxelankadensis, Mastacembelus armatus,Macrognathus guentheri, Haludaria fasciatus etc arethe co- occurring fish species.

Etymology. – The specific epithet “heoki” is namedafter the eminent scientist Heok Hee Ng, Singapore,who contributed much to the taxonomy of catfishes.

Comparisons: The present species shows somesimilarities to Mystus malabaricus, M. canarensis, M.armatus, M. oculatus and M. montanus found inKerala. But these Bagrids can be distinctly distinguishedfrom the present fish in many taxonomic characters (Fig.5 & 6; Table 1 & 2). In Mystus malabaricus (Jerdon)8 branched rays present in dorsal fin (vs. 7 in Mystusheoki), head is longer (head length 23.8- 24.7 % SL vs.18.9- 22.5), body at dorsal fin origin higher (BDD 19.0-20.5 % SL vs. 15.0- 16.9), pre dorsal distance greater(34.8- 37.1 % SL vs. 31.7- 34.2), rayed dorsal fin longer



49

(17.6- 19.8 % SL vs. 14.3- 15.4), tip of rayed dorsal finreaches adipose dorsal front (vs. never reach adiposedorsal), adipose dorsal base length greater (27.3- 30.7% SL vs. 20.0- 23.9), anal fin longer (11.2- 15.1 % SLvs. 9.2- 10.5), inter dorsal distance shorter (8.2- 11.3 %SL vs. 12.9- 15.3), orbits set closely (inter orbital distance26.8- 30.0 % HL vs. 32.4- 38.6), maxillaries reach onlyto tip of pelvic fin (vs. reach origin of anal fin), nasalbarbels reach the midpoint between orbit and occiput(vs. reach very near to occiput) and snout shorter (29.3-34.7 % HL vs. 36.4- 41.7). Moreover, numerous tinypores are present on the head of the new fish which areabsent in M. malabaricus.

The present species can be distinctly separatedfrom Mystus canarensis in many characters. In Mystuscanarensis median longitudinal groove on head is dividedinto two portions (vs. cephalic fontanel is single in Mystusheoki), maxillaries reach to end of ventral fins (vs. reachnear to anal origin), outer mandibulars reach near tomiddle of pectoral fins (vs. reach tip of pectorals), occipitalprocess covered by a thin sheath of flesh (vs. occipitalprocess covered by a thick layer of flesh), head longer(HL 22.8- 24.3 % SL vs. 18.9- 22.5), body at dorsal finorigin higher (17.2- 20.8 % SL vs. 15.0- 16.9), a darkbrown humeral spot surrounded by a lighter margin (vs.absent), pre dorsal length greater (36.2- 38.1 % SL vs.31.7- 34.2), rayed dorsal fin longer (15.8- 17.8 % SL vs.14.3- 15.4), dorsal spine shorter (8.1- 9.4 % SL vs. 9.6-12.8), 8-9 branched rays in pectoral fin (vs. 7), 18 raysin caudal fin (vs. 15), both lobes of caudal fin overlapeach other (vs. caudal lobes never overlap), body deepleaden (vs. greenish) and snout shorter (31.7- 36.3 %HL vs. 36.4- 41.7).

Mystus oculatus, Mystus armatus and M.montanus are not much related to the new speciesbecause in them, unlike M. heoki, occipital processreaches basal bone of dorsal fin. Mystus armatus (Day)can be distinctly differentiated from the new species.In Mystus armatus, head longer (26.0 % SL vs. 18.9-22.5 in M. heoki), body deep (body height at rayed dorsalfin 22.4 % SL vs. 15.0- 16.9), median longitudinal grooveon head divided into two fontanels (vs. single fontanel),occipital process reaches the basal bone of dorsal fin(vs. never reach), occipital process naked (vs. coveredby a thick layer of flesh), maxillaries reach near to caudalfin base (vs. reach near to anal fin origin), outermandibulars reach near to ventral fin origin (vs. reachnear to tip of pectorals), rayed dorsal fin longer (22.4 %SL vs. 14.3- 15.4), tip of first dorsal reach considerablybehind the origin of adipose dorsal (vs. never reachadipose dorsal), length of base of adipose dorsal greater

(28.9 % SL vs. 20.0- 23.9), inter dorsal distance equalsto snout length (vs. fairly greater than snout length), tipsof caudal lobes pointed (vs. rounded), a black spot presenton the base of dorsal spine front (vs. no color spot) andcaudal fin with 19 rays (vs. 15).

Mystus oculatus (Valenciennes) can be distinctlydifferentiated from the new species. In M. oculatus,pectoral fin with 8-9 branched rays (vs. 7 in Mystusheoki), anal fin with 9-10 branched rays (vs. 8), caudalfin with 17 branched rays (vs. 15), median longitudinalgroove on head divided into two fontanels (vs. a singlefontanel), occipital process reaches basal bone of dorsalfin (vs. never reach), eye diameter nearly equal to interorbital width (vs. fairly shorter than inter orbital width),a deep black spot present in front of dorsal spine (vs.absent), head longer (HL 23.3- 25.6 % SL vs. 18.9- 22.5),head depth greater (66.0- 71.0 % HL vs. 52.0- 62.5),inter dorsal distance greater (16.5- 18.2 % SL vs. 12.9-15.3) and adipose dorsal fin base shorter (17.2- 19.0 %SL vs. 20.0- 23.9).

Mystus montanus (Jerdon) is not a closely relatedspecies to Mystus heoki. In M. montanus, occipitalprocess reaches the basal bone of dorsal fin (vs. occipitalprocess never reach the basal bone of dorsal fin in thenew species), tip of rayed dorsal fin reaches origin ofadipose dorsal (vs. never reach), posterior tip of outermargin of dorsal spine with three small teeth (vs. outermargin of dorsal spine smooth), a deep black rectangularor oval spot present on caudal base (vs. a triangularbluish spot), no distinct color band on mid lateral line(vs. a thick blue band) and two thin yellowish linespresent one above and one below lateral line (vs. nodistinct color lines above or below lateral line).

Mystus heoki can be distinctly separated from M.indicus in many relevant taxonomic characters. InMystus heoki body depth is lesser (15.0- 16.9 % SL vs.18.8- 25.3 in Mystus indicus), head shorter (18.9- 22.5% SL vs. 22.4- 26.0), head depth lesser (10.9- 12.5 %SL vs. 14.4- 16.2), eyes smaller (16.7- 20.4 % HL vs.24.0- 29.2), frontal groove single (vs. double), occipitalprocess shorter, never reaches basal bone of dorsal fin(vs. longer, reaches basal bone of dorsal fin), rayed dorsalfin shorter (14.3- 15.4 % SL vs. 15.8- 21.8) and pectoralspine shorter, 10.5- 13.3 % SL (vs. 13.5- 17.6), 10- 11teeth on pectoral spine (vs. 15- 16). M. heoki differsfrom M. indicus in many other morphometric charactersas shown in Table 4.

Comparative material

Mystus malabaricus: ZSI FF 4931, 5 ex., 71.5-102 mmSL, Kallodi, Mananthavady River, Wayanad, Kerala, coll.



50

Table 1. Morphometric features of Mystus indicus (n=8)

Sl. No. Characters Holotype(HT) Range(HT+7 Paratypes) Mean SD

1 Total length (mm) 131.0 102.5-136.0 120.4 10.82 Standard length(mm) 100.0 81.0-107.0 94.1 8.0

Percentage of standard length

3 Head length 24.0 22.4-26.0 24.8 2.24 Head depth 15.0 14.4-16.2 15.3 0.65 Head width 18.0 16.7-20.2 18.2 1.06 Body depth at dorsal origin 21.0 18.8- 25.3 20.5 3.07 Body depth at anal origin 19.0 17.8- 21.2 18.8 1.98 Body width at dorsal origin 17.8 16.7-19.2 17.2 1.29 Body width at anal origin 13.0 9.4-13.0 11.5 1.110 Pre dorsal length 36.0 30.8-36.0 34.3 2.011 Post dorsal length 70.0 64.5-70.8 66.3 3.412 Pre pectoral length 22.0 20.0-22.9 21.6 1.013 Pre pelvic length 51.0 50.6-55.5 53.8 1.614 Pre anal length 70.0 69.2-76.8 73.8 2.715 Length of rayed dorsal fin 17.5 15.8-21.8 18.6 2.116 Height of adipose dorsal fin 5.5 5.2- 6.5 5.8 0.617 Length of pectoral 19.0 17.3- 19.2 18.1 1.318 Length of pelvic 17.0 12.1-17.6 14.7 2.119 Length of anal 13 9.3-15.4 11.5 1.920 Length of dorsal spine 11.2 10.2- 14.0 12.0 1.721 Length of pectoral spine 17.0 13.5- 17.6 15.3 1.722 Length of base of RD 16.0 15.6- 17.8 16.6 1.323 Length of base of AD 28.0 26.2- 33.7 29.3 3.124 Length of base of pectoral 5.2 4.6- 5.8 5.2 0.725 Length of base of pelvic 3.2 3.2- 4.3 3.7 0.426 Length of base of anal 15.0 11.2-15.0 13.3 2.127 Length of base of caudal 13.0 12.9-14.0 13.3 0.928 Distance from pectoral to pelvic 30.0 29.2-33.3 31.2 1.629 Distance from pelvic to anal 24.0 20.6- 24.0 22.4 1.430 Distance from anal to caudal 29.8 29.2- 30.6 29.8 1.6


Mathews Plamoottil, 20.03.2013; ZSI/SRC 313, 2 ex.,Muthanga, coll. R. S. Pillai, 12.10.1976; ZSI/WGRC 9395,1 ex., Ranipuram, Kazargod Dt, coll. M. madhavan,idenfified by K.C. Gopi, 07.07.1996; ZSI unreg. 7 ex.,Mananthavady River at Choothakadavu near Kaniyaram,coll. K. C. Jayaram, 14.02.1985; ZSI uncat, 3 ex., CauveryRiver, Kerala, coll. G. M. Natarajan, 1984; Mystusoculatus: ZSI FF 4933, 5 ex., 85- 91 mm SL, Arattupuzha,Karavannoor River, Trichur, Kerala, coll. MathewsPlamoottil, 10.01.2013; ZSI 487, I ex., India, purchasedfrom Francis Day; ZSI, unreg, 4 ex., 78.0- 86.8 mm SL,Chaliyar River at Edavanna, 2 km from Manjeri, Kerala,coll. K. C. Jayaram and Anuradha, 18.02. 1985; Mystusarmatus: STC/DOZ 10, 1 ex., 84.8 mm SL, Arattupuzha,Karavannoor River, Trichur, coll. Mathews Plamoottil,13.01. 2013; ZSI/WGRC 7886, 2 ex., Kuniyanpuzha,

Kazargod, coll. Jafer Sherif, identified by K. C. Gopi,01.07.1995; ZSI/WGRC 7425, 1 ex., Bhavani River,Wayanadu, coll. P. M. Suresh, 02.02. 1995; ZSI/WGRC/8470, 3 ex., Thoonacadavu dam, Parambikkulam WLS,Palakkadu, coll. P. M. Sureshan, identified by. K. C. Gopi,27.10.95; ZSI uncat. 10 ex., 60- 84 mm SL, Puzhakkal,15 km north of Trichur, Kerala, coll. K. C. Jayaram andAnuradha Sanyal, 20. 02. 1985; ZSI uncat. 6 ex., 56- 77mm SL, Muppinipotti on Punnanpuzha, Kerala, coll. K.C. Jayaram & Anuradha Sanyal, 18.02. 1985; ZSI/WGRC/9397, 1 ex., Ranipuram, Kazargod, coll. M.Madhavan, idenfified by K.C. Gopi, 07.07.1996; Mystusmontanus: STC/DOZ 11, 1 ex., 67.5 mm SL, Koodalkadavu, Mananthavady River, Wayanad, coll. MathewsPlamoottil, 16.03.2013; KFRI/88, 1 ex., Noolpuzha, coll.Shaji, C. P, 11.06.1996; ZSI uncat, 8 ex., 65- 76 mm SL,


51Mystus indicus and M. heoki, two new catfishes from Kerala, India

Sl. No. Characters Holotype(HT) Range(HT+7 Paratypes) Mean SD

31 Distance from AD to caudal 12.3 11.5- 13.7 12.5 0.932 Length of caudal peduncle 16.0 15.9-17.9 16.7 0.833 Depth of caudal peduncle 11.8 10.0-12.3 11.5 0.834 Width of caudal peduncle 7.2 6.0-7.2 6.6 0.935 Distance from RD to AD 8.0 7.2- 9.4 8.0 1.236 Length of upper caudal lobe 32.0 26.2-32.0 28.4 1.837 Length of lower caudal lobe 28.0 20.6-28.0 24.7 2.338 Distance from anal to vent 4.7 3.9- 4.9 4.5 0.739 Distance from ventral to vent 15.2 14.2- 16.6 15.3 1.140 Head length (mm) 24.0 20.0- 29.0 23.4 2.9

Percent of head length

41 Head depth 62.5 59.0- 66.7 63.4 3.842 Head width 75.0 68.0-83.3 73.9 6.343 Distance from occiput to snout 86.0 85.4- 86.2 85.8 3.744 Distance from occiput to dorsal 62.8 60.6- 64.2 62.5 4.045 Length of frontal groove 62.8 56.6- 66.5 62.0 3.946 Length of occipital process 56.6 43.6- 56.8 48.4 2.847 Width of base of occipital process 9.6 8.3- 12.0 10.3 1.048 Eye diameter 29.2 24.0- 29.2 26.7 2.449 Postorbital length 45.9 40.4-46.8 44.4 1.850 Head length excluding snout 72.2 72.0-75.7 73.3 2.651 Inter orbital width 37.5 36.3- 45.0 39.2 4.452 Inter narial width 21.7 20.0- 25.0 23.2 2.253 Snout length 37.5 36.2- 42.5 38.8 3.154 Width of gape of mouth 37.5 34.8- 40.9 38.4 3.355 Length of maxillary barbels 295.8 289.7- 375.0 328.1 29.956 Length of nasal barbels 56.3 44.8-80.0 61.1 10.957 Length of outer mandibular barbels 120.8 106.9-170.0 141.9 21.858 Length of inner mandibular barbels 87.5 75.8-105.0 94.8 9.8

Ratios

59 TL/head length 5.4 5.0- 5.7 5.4 0.560 TL/body height at dorsal fin origin 6.2 5.0- 6.8 5.6 1.161 SL/ head length 4.2 3.8- 4.5 4.1 0.462 SL/ body depth at dorsal fin origin 4.6 4.0- 5.3 4.8 0.563 SL/ height of adipose dorsal fin 5.6 5.2-6.5 5.8 1.164 HL/height of rayed dorsal fin 1.3 1.1- 1.7 1.3 0.365 HL/length of dorsal spine 1.7 1.6- 2.2 2.0 0.366 HL/length of pectoral fin 1.3 1.3- 1.6 1.4 0.367 HL/length of pectoral spine 1.6 1.4- 1.7 1.6 1.068 HL/length of pelvic fin 1.5 1.4- 1.8 1.6 0.669 HL/length of anal fin 2.2 1.6- 2.4 2.0 1.070 HL/eye diameter 4.0 3.6- 4.2 3.8 0.471 Length of base of AD/ LBRD 1.8 1.6- 2.5 1.9 0.372 Length of base of AD/LBA 2.0 1.9- 3.1 2.1 0.373 Length of caudal peduncle/DCP 1.5 1.3- 1.7 1.4 0.374 Inter orbital width/Eye diameter 1.3 1.3- 1.7 1.4 0.275 Snout length/eye diameter 1.5 1.3- 1.7 1.4 0.3


52

Table 2. Morphometric features of Mystus heoki new sp. (n=6)

No Characters Holotype (HT) Range(HT+ 5 PT) Mean SD

1 Total length (mm) 167.0 105.5- 167.0 134.8 18.52 Standard length (mm) 137.0 85.5- 137.0 108.0 15.8

Percentage of standard length

3 Head length 18.9 18.9- 22.5 21.1 1.14 Head depth 10.9 10.9- 12.5 12.1 0.75 Head width 15.3 14.8- 17.4 16.1 0.96 Body depth at dorsal origin 16.8 15.0- 16.9 16.2 1.27 Body depth at anal origin 15.3 13.3- 16.4 15.2 0.98 Body width at dorsal origin 16.1 12.5- 15.2 15.4 1.79 Pre dorsal length 32.8 31.7- 34.2 33.7 1.510 Post dorsal length 67.2 59.7- 67.2 64.9 2.311 Pre pectoral length 14.6 14.6- 19.2 18.6 1.512 Pre pelvic length 45.9 43.3- 45.9 45.2 1.213 Pre anal length 66.1 60.9- 66.1 64.9 2.314 Length of rayed dorsal 15.3 14.3- 15.4 16.3 1.315 Length of adipose dorsal 3.6 3.6- 5.7 4.2 0.716 Length of pectoral 13.9 13.3- 14.3 13.9 0.617 Length of pelvic 11.7 11.7- 13.1 12.4 0.618 Length of anal 10.0 9.2- 10.5 10.9 1.219 Length of caudal fin 23.7 22.7- 24.5 23.6 24.020 Length of dorsal spine 10.2 9.6- 12.8 10.6 1.421 Length of pectoral spine 12.0 10.5- 13.3 12.6 1.522 Length of base of rayed dorsal 14.6 14.0- 14.8 14.6 0.423 Length of base of adipose dorsal fin 23.3 20.0- 23.9 22.4 2.924 Length of base of anal fin 12.4 11.7- 13.5 13.0 0.925 Length of base of caudal fin 14.8 14.8- 15.2 15.0 0.626 Distance from pectoral to pelvic 28.1 21.0- 28.1 24.3 2.627 Distance from pelvic to anal 19.4 17.3- 19.4 18.5 0.928 Distance from anal to caudal 28.6 29.4- 33.0 31.2 1.629 Distance from Adipose dorsal to caudal fin 15.6 14.1- 16.8 15.8 1.430 Length of caudal peduncle 16.0 16.0- 18.7 17.9 1.231 Depth of caudal peduncle 10.9 10.0- 11.8 10.7 0.732 Width of caudal peduncle 5.1 5.1- 5.9 5.6 0.733 Distance from rayed dorsal to adipose dorsal 13.9 12.9- 15.3 13.6 1.134 Distance from ventral to vent 16.8 15.4- 17.2 16.4 1.135 Distance from anal to vent 3.3 2.8- 4.8 3.5 1.436 Head length (mm) 26.0 18.5- 26.0 23.1 2.5

Percentage of head length

37 Eye diameter 19.2 16.7- 20.4 19.9 3.538 Inter orbital width 38.5 32.4- 38.6 35.9 2.339 Snout length 38.5 36.4- 41.7 38.9 1.740 Width of gape of mouth 46.2 41.7- 48.7 46.7 2.841 Distance from occiput to snout 85.0 83.7- 85.2 84.4 4.242 Distance from occiput to dorsal fin 74.2 73.8- 75.4 74.6 1.4



53

No Characters Holotype (HT) Range(HT+ 5 PT) Mean SD

43 Head length excluding snout 67.1 66.8- 67.7 67.2 0.744 Post orbital length 46.2 45.8- 47.3 46.6 1.345 Length of frontal groove 63.7 62.7- 63.9 63.2 2.146 Length of maxillary barbels 284.6 200.0- 284.6 258.9 26.947 Length of nasal barbels 65.4 64.8- 70.8 66.9 3.848 Length of outer mandibulars 130.8 92.0- 137.5. 120.5 16.849 Length of inner mandibulars 76.9 72.0- 83.3 77.2 5.1

Ratios

50 Total length/head length 5.7 5.5- 6.5 5.8 0.751 TL/body height at dorsal fin origin 7.6 7.3- 7.9 7.6 0.452 Standard length/head length 4.8 4.5- 5.3 4.8 0.653 SL/body height at dorsal fin origin 6.2 5.9- 6.7 6.2 0.754 Length of rayed dorsal fin/BDD 0.9 0.9- 1.1 1.0 0.155 Head length/length of rayed dorsal fin 1.3 1.2- 1.5 1.3 0.156 Head length/length of dorsal spine 2.0 1.7- 2.5 2.0 0.557 Head length/length of pectoral spine 1.8 1.6- 2.0 1.8 0.258 Head length/length of pelvic 1.6 1.6- 1.8 1.7 0.159 Head length/ length of anal fin 2.0 1.9- 2.3 2.1 0.460 Length of base of RD/inter dorsal distance 1.1 0.9- 1.1 1.0 0.161 Length of base of AD/Length of base of RD 1.5 1.4- 1.6 1.5 0.162 Length of base of adipose dorsal/LBA 1.6 1.6- 1.8 1.7 0.263 LCP/depth of caudal peduncle 1.5 1.4- 1.7 1.6 0.164 Length of lower CL/ length of upper CL 1.2 1.1-1.2 1.1 0.165 LBAD/inter dorsal distance 1.5 1.4- 1.7 1.5 0.166 Head length/eye diameter 5.2 4.1- 6.0 5.2 0.667 SL /depth of caudal peduncle 8.8 8.5- 9.1 8.9 0.468 Inter orbital length/eye diameter 2.1 1.9- 2.6 2.2 0.569 Snout length/eye diameter 2.0 1.9- 2.2 2.0 0.470 Inter orbital width/ snout length 1.0 1.0-1.3 1.2 0.1


Table 3. Meristic counts of Mystus heoki, M. indicus and relative species

Characters Mystus heoki M. indicus M. montanus M. armatus M. malabaricus M. canarensis M. oculatus

Dorsal fin II, 7 I, 7 I, 7 II, 7 I, II, 6-7 I, 7 I,7Pectoral fin I, 7 I, 6-8 I, 6 I, 9 I, 7-8 I, 9 I, 8-9Ventral fin i, 5 i, 5 i, 5 i, 5 i, 5 i, 5 i, 5Anal fin ii- iii, 8 iii, 7-8 iii, 8 iii, 8 iii,8 iii, 8 iii, 9-10Caudal fin 15 15-17 15 19 17 18 17DspT 0 6-7 8 6 0 0 2-8PspT 10- 11 15-16 14- 15 10-14 7-13 8 12-14


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Table 4. Biometric characters of relative species of Mystus heoki and M. indicus

Characters M. heoki M. indicus M. M. oculatus M.armatus M. M.malabaricus ZSI 4933 STC/ montanus canarensis

ZSI 4931 DOZ 10 STC/DOZ 11 ZSI 4939

Total length (mm) 105.5- 167.0 102.5-136.0 92.0-127.0 111.0- 122.0 112.8 86.3 107.0- 126.0Standard length(mm) 85.5- 137.0 81.0-107.0 71.5- 102.0 85.0- 91.0 84.8 67.5 87.0-101.0

Percentage of Standard length

Head length 18.9- 22.5 22.4-26.0 23.8- 24.7 23.3- 25.6 26.0 28.1 22.8-24.3Head depth 10.9- 12.5 14.4-16.2 13.2- 14.4 16.0- 18.2 16.0 17.0 11.2-13.0Head width 14.8- 17.4 16.7-20.2 16.7- 17.8 15.1- 18.3 19.5 20.7 15.0-17.8Body depth at dorsal origin 15.0- 16.9 18.8- 25.3 19.0- 20.5 20.9- 23.0 22.4 23.0 17.2-20.8Body depth at anal origin 13.3- 16.4 17.8- 21.2 16.8- 17.8 17.4- 19.2 18.9 19.3 16.6-18.1Body width at dorsal origin 12.5- 15.2 16.7-19.2 15.2- 16.8 15.5-16.7 17.7 17.0 14.7-16.8Pre dorsal length 31.7- 34.2 30.8-36.0 34.8- 37.1 37.2- 37.8 36.0 40.0 36.2-38.1Post dorsal length 59.7- 67.2 64.5-70.8 64.8- 67.1 63.1- 66.2 66.0 64.4 62.0-65.8Pre pectoral length 14.6- 19.2 20.0-22.9 20.4- 22.3 22.0-26.1 23.6 23.7 18.7-21.3Pre pelvic length 43.3- 45.9 50.6-55.5 49.0- 51.0 47.1- 51.2 49.5 50.4 48.7-49.7Pre anal length 60.9- 66.1 69.2-76.8 67.1- 69.4 68.1-75.6 67.8 72.6 66.3-70.7Length of rayed dorsal fin 14.3- 15.4 15.8-21.8 17.6- 19.8 21.1- 23.6 22.4 20.4 15.8-17.8Height of adipose dorsal 3.6- 5.7 5.2- 6.5 4.1- 5.7 5.5-6.7 4.7 6.0 3.8-4.9Length of pectoral 13.3- 14.3 17.3- 19.2 15.7- 17.8 18.0-20.0 20.0 17.8 16.6-17.2Length of pelvic 11.7- 13.1 12.1-17.6 13.7- 15.3 13.9-15.6 18.3 13.3 14.0-16.1Length of anal 9.2- 10.5 9.3-15.4 11.2- 15.1 13.0-15.1 18.2 15.6 11.3-13.6Length of dorsal spine 9.2- 10.5 10.2- 14.0 9.8- 10.8 14.4-16.5 11.8 10.4 8.1-9.4Length of pectoral spine 10.5- 13.3 13.5- 17.6 12.0- 13.3 15.1-17.2 15.3 16.2 11.2-13.0Length of base of RD 14.0- 14.8 15.6- 17.8 15.3- 16.2 14.0-15.3 17.1 16.3 13.0-15.0Length of base of AD 20.0- 23.9 26.2- 33.7 27.3- 30.7 17.2-19.0 28.9 21.5 22.8-25.1Length of base of anal 11.7- 13.5 11.2-15.0 13.6- 15.3 12.8-14.0 12.8 11.1 9.8-12.4Length of base of caudal 14.8- 15.2 12.9-14.0 15.3-16.5 11.8- 13.9 14.5 14.5 12.0- 14.7Inter dorsal distance 12.9- 15.3 7.2- 9.4 8.2- 11.3 16.5- 18.2 8.3 8.9 11.8-15.5Distance from pectoral to pelvic 21.0- 28.1 29.2-33.3 28.3- 31.7 25.9-30.8 28.3 28.1 28.7-32.4Distance from pelvic to anal 17.3- 19.4 20.6- 24.0 19.6-20.1 19.8-22.2 18.2 22.2 18.7-22.4Distance from anal to caudal 29.4-33.0 29.2-30.6 30.0-3.6 28.3- 314 30.7 28.1 30.2- 31.6Distance from AD to caudal 14.1-16.8 11.5-13.7 12.0- 14.2 16.1- 18.0 14.2 14.7 11.8- 14.9Length of caudal peduncle 16.0- 18.7 15.9-17.9 16.4- 18.5 15.6-19.2 18.9 14.8 18.2-20.1Depth of caudal peduncle 10.0- 11.8 10.0-12.3 13.3- 15.5 10.6-11.6 11.8 11.9 11.9-14.1Width of caudal peduncle 5.1- 5.9 6.0-7.2 3.0- 4.7 4.7-6.1 3.5 5.6 4.0-5.4Distance from anal to vent 2.8-4.8 3.9-4.9 3.6-5.1 6.0-7.6 5.1 4.4 4.8-5.4Distance from ventral to vent 15.4-17.2 14.2-16.6 15.3-16.8 14.0-15.9 14.2 15.6 14.1-16.7Head length (mm) 18.5- 26.0 20.0- 29.0 17.5- 24.5 20.0-23.0 22.0 19.0 20.0—24.5

Percentage of head length

Head depth 52.0- 62.5 59.0- 66.7 53.7- 60.0 66.0-71.3 61.4 60.5 48.8-56.1Head width 70.3- 83.3 68.0-83.3 68.3- 72.2 65.0- 71.7 75.0 73.7 65.1-74.1Eye diameter 16.7- 20.4 24.0- 29.2 23.7- 29.3 28.3- 40.0 30.0 26.3 20.4-27.5Inter orbital width 32.4- 38.6 36.3- 45.0 26.8- 30.0 23.6- 27.5 28.6 33.2 30.2-35.0Inter narial width 20.2- 24.3 20.0- 25.0 18.4- 22.2 16.0-17.5 22.7 18.4 18.6- 25.0Snout length 36.4- 41.7 36.2- 42.5 29.3- 34.7 26.1-28.3 31.8 30.5 31.7- 36.3Length of frontal groove 62.7- 63.9 56.6-66.5 55.6-68.3 77.8-89.5 43.2 46.8 40.8-56.1Post orbital length 45.8-47.3 40.4-46.8 41.5-48.9 41.0-45.6 40.5 47.4 44.0-47.0Head length excluding snout 66.8-67.7 72.0-75.7 67.8-70.5 70.5-74.8 68.2 73.7 65.3-70.7Width of gape of mouth 41.7- 48.7 34.8- 40.9 40.0- 44.4 35.0- 41.3 40.0 44.7 39.0- 40.8Distance from occiput to snout 84.5-84.7 85.4-86.2 83.7-87.8 85.0-95.0 84.1 85.3 81.6- 88.4Distance from occiput to dorsal 73.8-75.4 60.6-64.2 61.1-65.8 58.3-66.5 54.5 52.6 70.7-79.6Length of maxillary barbels 200.0- 284.6 289.7- 375.0 253.2- 291.7 308.7-322 363.6 226.3 228.6- 265.9Length of nasal barbels 64.8- 70.8 44.8-80.0 61.2- 75.0 66.0-70.0 77.3 57.9 59.2- 85.4Length of outer mandibulars 92.0- 137.5. 106.9-170.0 110.2- 126.7 122.6-145 170.5 100.0 92.7- 132.1Length of inner mandibulars 72.0- 83.3 75.8-105.0 78.8- 88.6 72.7-90.0 100.0 63.2 65.3- 75.0



55Mystus indicus and M. heoki, two new catfishes from Kerala, India

Fig. 1. Fresh specimen of Mystus indicus, Paratype, ZSI/WGRC/2418

Fig. 2. Formalin preserved specimen of M. indicus, Holotype, ZSI FF 4627

Fig. 3. Freshly collected specimen of M. heoki, Paratype, ZSI/WGRC 2419


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Fig. 4. Freshly collected specimen of M. heoki, Holotype, ZSI FF 4626

Fig. 5. Preserved specimen of M. heoki, Paratype, ZSI/WGRC 2419



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Fig. 6. Relative species of M. indicus and M. heokiA. Mystus malabaricus; B. M. canarensis; C. M. montanus; D. M. armatus; E. M. oculatus; F. M. heoki; G. M. indicus.

Fig. 7. Dorsal view of head of M. indicus, M. heoki and relative speciesA. Mystus malabaricus; B. M. canarensis; C. M. montanus; D. M. armatus; E. M. oculatus; F. M. heoki; G. M. indicus.


Chittoorpuzha at Thathamangalam road bridge about 17km south of Palaghat town, coll. K. C. Jayaram &Anuradha Sanyal, 20. 02. 1985; ZSI uncat, 7 ex., 59- 78mm SL, Malampuzha dam, Kerala, coll. K. C. Jayaram& Anuradha Sanyal, 22.02. 1985; ZSI/SRC/5217, 1 ex.,42 mm SL, Parambikulam, coll. M. B. Reghunathan,13.08.97; Mystus canarensis: ZSI FF 4939, 1 ex., 88.5mm SL, Manimala River at Mundakkayam, Kerala, coll.Mathews Plamoottil, 10.02.12; STC/DOZ 12, 4 ex., 87-101 mm SL, Manimala River at Mundakkayam, Kerala,coll. Mathews Plamoottil, 10.02.12.

AcknowledgmentsFirst author acknowledges the University Grants Commissionof India for sanctioning Faculty Development Programme toundergo research. Both the authors acknowledge Principal,St. Thomas College, Kozhencherry, Kerala for providing thefacilities.

ReferencesDay, F. 1865. The Fishes of Malabar. Bernard Quaritch,

London, pp. 184.Day, F. 1877. The fishes of India: being a natural history of

the fishes known to inhabit the seas and fresh watersof India, Burma, and Ceylon. London, pp. 448- 452.

Day, F. 1889. Fauna of British India including Ceylon andBurma. Taylor and Francis, London, pp. 159- 162.

Easa, P. S., & C. P. Shaji. 2003. Biodiversity documentationfor Kerala, Part 8: Freshwater fishes. Kerala ForestResearch Institute, Peechi, pp.71- 79.

Grant, S. 1999. A replacement name (nomen novum) andneotype designation for Hara malabarica Day, 1865,with notes on related species (Siluriformes). Aqua. J.Ichthyol. & Aquatic Biol. 3 (4): 169- 174.

Grant, S. 2004. The striped cat fishes of the genus MystusScopeli 1777 (Siluriformes: bagridae). J. Catfish StudyGroup 5 (2): 5- 17.

Hora, S. L., & N. C. Law. 1941. Siluroid fishes of India, Burmaand Ceylon. IX. Rec. Indian Mus. 43 (1): 238.

Hora, S. L. 1942. A list of the fishes of the Mysore state andits neighboring hill ranges of the Nilgiris, Wayanadand Coorg. Rec. Indian Mus. 44 (2): 197.

Jayaram, K. C. 1954. Siluroid fishes of India, Burma and Ceylon.XIV. Fishes of the genus Mystus Scopeli. Rec. Indian.Mus. 51 (4): 544.

Jayaram, K. C. 1966. Contributions to the study of Bagridfishes (Siluroidea: Bagridae). 1. A systematic accountof the genera Rita Bleeker, Rama Bleeker, Mystusscopeli, and Horabagrus Jayaram. Int. Rev. Ges.Hydrobiol. 51 (3): 446.

Jayaram, K. C. 1977. An aid to identification of siluroids. 1.Bagridae. Rec. Zool. Surv. India. Occ. Paper No.8: 27.

Jayaram, K. C., & A. Sanyal. 2003. Revision of the fishes ofthe genus Mystus Scopoli. Records of ZoologicalSurvey of India, Occasional Paper No. 207, pp. 1-136.

Jayaram, K. C. 2002. Fundamentals of fish taxonomy. Narendrapublishing House, Delhi, pp. 53-65.

Jayaram, K. C. 2006. Catfishes of India, Narendra PublishingHouse, Delhi, pp. 34-58.

Jayaram, K. C. 2010. Fresh water fishes of the Indian region.Narendra publishing House, Delhi, pp. 256-262.

Jerdon, T. C. 1849. On the fresh water fishes of SouthernIndia. Madras J. Lit. Sci.15:302-345.

Misra, K. S. 1976. The fauna of India and Adjacent countries.Zoological Survey of India, Kolkata, pp. 81-101.

Rajan, S. 1955. Notes on a collection of fish from the headwatersof the Bhavani River, South India. J. Bombay nat. Hist.soc. 53: 45.

Talwar, P. K., & A. Jhingran. 1991. Inland fishes of India andadjacent countries. Oxford and IBH publishing Co.Pvt. Ltd, pp. 554-573.

Valenciennes, M. A. 1839. Histoire Naturelle des Poossons.Paris 14: 424.


Received: 10 Oct 2012

Accepted: 10 May 2013

Published: 4 Nov 2013

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Mystus heoki & m. indicus two new fish species