Hemileiocassis panjang, a new genus and new species of bagrid catfish from Java (Teleostei, Siluriformes)

5 Pages·2000·1.1 MB·English

by  Ng:, H H

Beaufortia
BULLETIN ZOOLOGICAL MUSÉUM
UNIVERSITY OF AMS TERDAM
Vol. 50, no. 11 December 20, 2000
Hemileiocassis panjang, a new genusand new species of bagrid
catfish fromJava(Teleostei, Siluriformes)
H.H. Ng■:*„&** &„ K.K.P. Limr**
*DivisionofFishes, Museumof/foolosy, University ofMichigan, 1109GeddesAvenue,AnnArbor,
Michigan 48109-1079, U.S.A.
HcHt
Department ofBiological Sciences, NationalUniversity ofSingapore, 10KentRidge Crescent, Singapore 119260
Abstract
Anewgenusofthe familyBagridae,Hemileiocassis, isdistinguished fromothergenerainthefollowingcharacters: dorsalspine
with antrorse serrations, vomerinetooth band relatively small and crescentic, with molariform teeth,prominentlyprotrud-
ing snout, 11 branched anal finrays, and anelongatebody (its depth 12.6%in standard length). Itssole species, H.panjang
n.sp.,isknownonly fromthe holotypefromBogor,Java.
INTRODUCTION MATERIALSAND METHODS
Whilerevising the bagrid catfish genusLeiocassis, Measurements were made point to point with
the secondauthorexaminedaspecimen collected dial callipers and data recorded to 0.01 mm.
from Bogor, West Java, deposited in the Countsandmeasurements were madeon the left
Zoôlogisch Museum Amsterdam (ZMA), which side of specimens wheneverpossible. Subunits of
had been labeled Leiocassis micropogon. However, the head are presented as proportions of head
the antrorse serrations on the hind edge of the length (HL). Head length itself and measure-
dorsal spine on the specimen contrast with the ments of body parts are given as proportions of
often indistinct but retrorse serrations of other standard length (SL). Measurements and counts
Leiocassis species. These antrorse serrations sug- were madefollowing Ng & Dodson (1999).
gest placement in either Bagrichthys or Bagroides Fin rays were counted undera binocular dis-
but therelatively large crescentic mouthandslen- secting microscope using transmitted light.
dersnout thatis less deep thanwide suggest oth- Vertebral counts were taken from radiographs
erwise. following the method of Roberts (1994).
Based on its unique features, this specimen is Numbers in parentheses following a particular
described in the present paper as a new genus fin-ray, branchiostegal-ray, gill-raker or vertebral
and newspecies. count indicatethe numberofspecimens withthat
191
count. Drawings of the specimens were made Body long, slender and moderately com-
with a Nikon SMZ-10 microscope and camera pressed. Dorsal profile rising evenly but not
lucida. steeply from tip of snout to origin of dorsal fin,
Material examined in this study are deposited then sloping gently ventrally from thereto endof
inthefollowing institutions: Zoôlogisch Museum, caudal peduncle. Ventral profile flat to anal-fin
University of Amsterdam (ZMA), Natural base, then sloping gently dorsally from there to
History Museum, London (BMNH), California end of caudal peduncle. Anus and urogenital
Academy ofSciences, SanFrancisco (CAS), Field openings located at vertical through middle of
Museum of Natural History, Chicago (FMNH), adpressed pelvic fin. Skin smooth. Lateral line
and Zoological Reference Collection of the complete and midlateral, with long tubular epi-
Raffles Museum of Biodiversity Research, dermalextensionsof sensory pores.
NationalUniversity of Singapore (ZRC). Headsomewhat compressed andnarrow, ante-
rior part produced into a prominent protruding
SYSTEMATICS snout withroundedmargin when viewedlateral-
lyand fromabove. Mouth inferior and relatively
Hemileiocassisn.gen. small, with papillate lips. Gill openings wide,
extending from exposed surface of posttemporal
TYPE SPECIES. - Hemileiocassispanjang n.sp. to beyond isthmus. Gill membranes free from,
and not attachedacross, isthmus. Eye ovoid, hor-
DIAGNOSIS. - Hemileiocassis can be differentiated izontalaxis longest; locatedentirely in dorsalhalf
fromother bagrid generain having the following of head.Orbit with freemargin.
unique combination of characters: dorsal spine Barbelsin fourpairs. Maxillary barbel relative-
with antrorse serrations, vomerinetoothbandrel- ly short, extending to posterior margin of orbit.
atively small and crescentic, with molariform Nasalbarbel slenderandshort, extending to mid-
teeth, prominently protruding snout, waybetween posterior nostril and anterior mar-
ginoforbit. Innermandibular-barbelorigin close
ETYMOLOGY. - From the Greek hemi, meaning to midline; barbel thicker and longer than nasal
half and Leiocassis, a genus of closely-related barbel andextending to levelof posterior margin
bagrid catfish. In reference to the characters the oforbit. Outermandibularbarbel originates pos-
genus shares between Leiocassis and Bagroides. terolateralof innermandibularbarbel, extending
Gender feminine. pastpectoral-fin origin.
Oral teeth small and in irregular rows on all
Hemileiocassis panjang n.sp. tooth-bearing surfaces. Premaxillary tooth band
Figs. 1, 2A, 3 rounded, of equal width throughout. Dentary
tooth band much narrower than premaxillary
MATERIAL.- Holotype: ZMA 121.529, 138.7 mm SL; tooth band at symphysis, tapering laterally.
Indonesia,Java, Bogor; collectoranddate unknown. Vomerine tooth band unpaired, continuous
across midline; smoothly arched along anterior
DIAGNOSIS. - As for genus. Hemileiocassis panjang margin, tapering laterally to point extending pos-
differs from Leiocassis species and Bagroides teriorly well past level of premaxillary band;
melapterus in having arelatively slenderbody (12.6 bandwidth narrower than premaxillary band at
% SLvs. 15.4-18.6inLeiocassisspp. and 17.7-22.9 midline,widening laterally andthentapering to a
inBagroides melapterus). sharp point poterolaterally. Teeth on premaxil-
lary and dentary tooth band conical; teeth on
DESCRIFITON. - As for genus. See Table 1 for vomerine toothbandmolariform.
morphometric and meristic data. Dorsal finlocatedabovemiddleofbody; origin
The specimen is uniformly brown and has no nearer tip of snout than caudal flexure. Dorsal-
discernible colour pattern, although this may fin margin convex, usually with anterior branch
havebeen bleached dueto initial poor preserva- of fin-rays longer thanotherbranches. Last dor-
tion. sal-fin ray without posterior membranous con-
192
Fig. 1.A,dorsal;B,lateral and C, ventralviews oftheholotypeofHemileiocassispanjangn.sp. (ZMA121.529, 138.7mm SL).
193
Table 1.Morphometricand meristic data fromthe holotype pointed at tip. Anterior spine margin smooth;
ofHemileiocassispanjangn.sp.(ZMA 121.529). posterior spine margin with 16 strong serrations
along entire length. Pectoral-fin margin straight
MORPHOMETRY DATA: anteriorly, convex posteriorly.
Standard length 138.7mm
In %SL:
DISTRIBUTION. - Knownonly fromwesternJava.
Predorsallength 39.6
Preanal length 64.7
Prepelvic length 50.5 ETYMOLOGY.-FromtheIndonesianwordpanjang,
Prepectoral length 22.0 meaning long. A reference to its elongate body
Body depthatanus 12.6 shape.
Headlength 24.7
Head width 15.1
DISCUSSION
Head depth 11.0
Pectoral spinelength 11.5
Lengthof anal-finbase 14.1 In his revision of the Bagridae, Mo (1991) con-
Maximum heightofadipose fin 2.5 sideredLeiocassis, Bagrichthys andBagroides amono-
Lengthofadipose-finbase 23.5 phyletic groupeasily differentiatedfromall other
Dorsalspine length 12.2
bagrids in possessing the following synapomor-
Lengthof dorsal-fin base 9.2
Dorsal to adiposedistance 12.3 phies: aprominently protruding snout, long tubu-
Lengthofcaudalpeduncle 20.8 lar epidermal extensionsof the sensory pores, a
Depthofcaudalpeduncle 7.3 hypertrophied posterior cleithral process, and
In %HL: long, thin hair-like epithelial projections on the
Snoutlength 33.3 skin. As these characters are also present in
Interorbital distance 26.6
Hemileiocassis, we considerHemileiocassis to belong
Eye diameter 11.4
Nasalbarbel length 9.6 to this clade.
Maxillarybarbellength 32.7 Hemileiocassis possesses antrorse serrations on
Inner mandibular barbel 13.7 thedorsalspine (Fig. 2)andmolariform vomerine
()utermandibular barbel 18.4 teeth (Fig. 3), characters considered synapomor-
MERISTIC DATA:
phic forBagroides (the formercharacteris consid-
Branchiostegalrays 8
Gill rakers 2+8 ered synapomorphic for Bagrichthys as well).
Dorsal finrays 11,7 However, the overall morphology of Hemileiocassis
Pectoralfinrays 1,9 resembles Leiocassis more than it does Bagroides.
Pelvicfin raysi, 5 Characters that Hemileiocassis sharewithLeiocassis,
Analfinrays v, 11 but not withBagroides (or Bagrichthys) include sep-
Principal caudal fin rays 9/9
arate gill membranes, large crescentic mouth(vs.
Vertebrae 10+ 27 = 37
small circular mouth inBagroides andBagrichthys),
and a slender snout less deep than wide (vs. as
nection to body. Dorsal-fin spine short, straight deep as or deeper than wide in Bagroides and
and robust, with 10 antrorse serrations on poste- Bagrichthys).
rior margin. Adipose fin with margin convex for Based on the morphological evidence we have
entire length; posterior end deeply incised. to date, we consider Hemileiocassis to be a sister
Caudalfindeeply forked; upperlobepointed and groupofLeiocassis.
lowerlobe rounded.Procurrent rays symmetrical
and extend only slightly anterior to fin base. COMPARATIVEMATERIAL
Anal-finbase ventral to posterior halfof adipose Bagroides melapterus: ZRC 39002 (1), 161.1 mm SL; ZRC
fin. Fin margin curved or straight. Last anal-fin 40471 (1), 233.3mm SL;ZRC 41535 (10), 154.2-201.2mm
raywithoutposterior membranousconnectionto SL;ZRC 41901 (5), 206.7-252.7mm SL; Sumatra:Jambi,
Pasar Angso Duo; ZRC 45832(4), 91.0-94.4 mm SL; no
body. Pelvic-fin origin at vertical through posteri- data:aquariumspecimens.
orendof dorsal-finbase. Pelvic-fin margin slight- Leiocassis poecilopterus: ZRC 41455 (7), 76.3-114.2 mm SL;
lyconvex, tip of adpressed finnot reaching anal- Sumatra: market atSungai Dareh.
fin origin. Pectoral fin with stout spine, sharply Leiocassis micropogon: CAS/SU 31005 (1), 148.8 mm SL;
194
Fig. 2. Dorsal spines ofA, Hemileiocassispanjangn.sp. (holo- Fig. 3. Premaxillary and vomerinetooth patches of the
type).B,Bagroidesmelapterus(ZRC 39002, 161.1mm SL). C, holotype ofHemileiocassispanjangn.sp.
Leiocassismicropogon(BMNH 1863.12.14:106,117.6mm SL).
Malaysia: Malacca, Lake Chin Chin; BMNH 1863.12. REFERENCES
14:106 (1), 117.6 mm SL;Sumatra; FMNH 68005 (1), 91.3
mm SL; Borneo: Sabah, Tawau. MO, T.-P., 1991. Anatomy, relationships and systematics of
Leiocassis doriae: BMNH 1868.1.28.30 (holotype); Borneo: the Bagridae(Teleostei: Siluroidei) with a hypothesis of
Sarawak. siluroidphylogeny.Theses Zool. 17: 1-216.
Leiocassis baramensis: BMNH 1898.11.14:1 (holotype); NG, H. H. & J. J. DODSON, 1999. Morphological and
Borneo: Sarawak,Baram. genetic descriptionsofanewspecies ofcatfish, Hemibagrus
Leiocassis merabensis: BMNH 1893.3.6:170-171 (2 syntypes); chrysops,fromSarawak,East Malaysia,with anassessment
Borneo: Merabeh. of phylogenetic relationships (Teleostei: Bagridae).
RafflesBull. Zool. 47: 45-57.
ACKNOWLEDGEMENTS ROBERTS,T.R., 1994.Systematicrevision ofAsianbagrid
catfishes of the genus Mystus sensu stricto, with a new
species from Thailand and Cambodia. Ichthyol. Explor.
We thankIsaacJ.H. Isbrticker (ZMA) for theloan
Freshwaters 5: 241-256.
of the Hemileiocassis specimen, Darrell Siebert
WEBER,M. & L.F. DE BEAUFORT, 1913.The fishes of
(BMNH), David Catania (CAS) and Mary Ann the Indo-Australian Archipelago II. Malacopterygii,
Rogers (FMNH) forpermission to examine com- Myctophoidea, Ostariophysi: I. Siluroidea. E. J. Brill,
parative material, Tan Heok Hui for the pho- Leiden: 1-404.
tographs, and PeterK. L. Ng forhis support and
Received: April 4, 2000
encouragement.
195