Redescription of
siluroid Catfish Pterocryptis barakensis Vishwanath & Nebeshwar
(Siluriformes: Siluridae)
W. Vishwanath 1 & K. Nebeshwar 2
1, 2 Department of Life Sciences, Manipur
University, Canchipur, Imphal, Manipur 795003, India
Email:1 vnath54@yahoo.co.in
Date of publication
(online): 26 August 2009
Date of publication (print): 26
August 2009
ISSN 0974-7907 (online) |
0974-7893 (print)
Editor: Rema Devi
Manuscript details:
Ms # o1795
Received 31 May 2007
Final received 07 December 2007
Finally accepted 30 July 2009
Citation: Vishwanath, W.
& K. Nebeshwar (2009). Redescription of siluroid Catfish Pterocryptis
barakensis Vishwanath & Nebeshwar (Siluriformes: Siluridae). Journal
of Threatened Taxa 1(8): 425-428.
Copyright: © W. Vishwanath
& K. Nebeshwar 2009. Creative Commons Attribution 3.0 Unported License.
JoTT allows unrestricted use of this article in any medium for non-profit
purposes, reproduction and distribution by providing adequate credit to the
authors and the source of publication.
Author Details: Dr. W. Vishwanath is a Professor in the Department of Life Sciences,
Manipur University. His field of specialization is fish and fisheries. He is at
present engaged in taxonomy and systematics of freshwater fishes of
northeastern India.
Dr. K.
Nebeshwaris Project Fellow in a research project on catfish phylogeny of northeastern
India funded by NBFGR (National Bureau of Fish Genetic Resources), Lucknow, an
ICAR institute to Department of Life Sciences, Manipur University. He is well
versed with fish taxonomy and is actively engaged in fish fauna exploration and
description of new taxa in the region.
Author Contribution: The study: WV -
Supervision of taxonomy and phylogeny of freshwater fishes of northeastern
India, KN - Morphometric study and identification of fish species. Current paper: WV - Supervised the work and
helped in identifying the species, KN - Detailed examination of specimens and
comparison with closely related species to establish the new species.
Acknowledgement:The authors are grateful to ICAR-NATP (Indian Council of
Agricultural Research’s National Agricultural Technology Project) for financial
assistance.
Abstract: Description
of Pterocryptis barakensis from the Barak River, Tamenglong
District (Brahmaputra drainage) of Manipur, India is inadequate. It is distinguished from P. berdmorei (Blyth)
and the only other known species of the genus from the Indian region in having
longer caudal fin, distinct sensory pores, serration pattern on posterior edges
of anterior and posterior segments of pectoral spine, rounded tip and
colour of pectoral and ventral fin, dimorphism in genital papillae in males and
females and by a combination of meristic and morphometric characters.
Keywords: Manipur,Pterocryptis barakensis, redescription.
For Figures, Image & Table
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Introduction
Fishes of the genus PterocryptisPeters are distinguished from other siluroids in having small dorsal fin, upper
jaw longer than the lower jaw, and a confluent anal and caudal fin with a
distinct notch between them (Bornbusch 1991). The species distributed in the Indian region are: P. gangelicus(Peters) of the Ganges; P. afghana (Gunther) of Afghanistan, type
locality of which is doubtful (Day 1878; Shaw & Shebbeare 1937; Menon 1999); P. indicus (Datta, Barman
& Jayaram) of Brahmaputra basin; P. wynaadensis (Day) of Western
Ghats in Kerala, Cauvery and Tungabhadra river basins. Arunkumar & Tombi (1997) described Silurus
morehensis from Chindwin drainage basin in Manipur. Ng & Freyhof (2001) considered the
species to be a junior synonym of P. berdmorei and reported 16 nominal
species under the genus.
Vishwanath and Nebeshwar (in
Jayaram 2006) described Pterocryptis barakensis based on 19 specimens
from Vanchengphai village, Barak drainage in Manipur. The description is not adequate. The paper gives a detailed description of the
species, and its relationships with its congeners are also given.
Materials
and Methods
Fish were collected from the
Vanchengphai village using gill nets. The meristic and morphometric measurements followed the techniques of
Jayaram (1999). Osteological study
followed Kobayakawa (1989). For
osteological study, 3 specimens were dissected and stained with Alizarin
S following Hollister (1934). The
description is based on formalin preserved specimens. Measurements were taken with digital calipers
to 0.1mm. The number of specimens
exhibiting a given count is indicated in parentheses. Fin ray counts and osteological studies were
done using a zoom stereoscopic microscope.
Pterocryptis barakensis Vishwanath & Nebeshwar, 2006
(Image 1)
Pterocryptis barakensis Vishwanath and Nebeshwar, In:
Jayaram, 2006: 99-100 (type-locality: Barak River at Vanchengphai
village, Manipur).
Material examined
Holotype: Male, 231mm SL, Barak
R. at Vanchengphai village, Tamenglong District, Manipur (MUMF-4018).
Paratypes: 18 ex., 128.0-227.3 mm
SL, collection data as of holotype (MUMF 4000-4017).
Diagnosis
The species has the following
combination of characters: elongated body and caudal fin, rudimentary dorsal
fin with two rays or completely absent; body from head to caudal-fin base with
12-16 transverse rows of sensory pores extending from mid dorsal region to
lateral line; 12 distinct sensory pores, arranged semicircularly on ventral
surface of head extending from anterior sides of opercular region on either
side to behind lower lip, outer margin of anal fin, ventral and pectoral fins
white to pale white; pectoral fin with 14-15 rays, vomerine teeth band
continuous.
Description
Dorsal fin
absent or minute and soft with two rays, pectoral-fin rays I, 13-14; pelvic-fin
rays i, 7-8; anal fin rays 65-77; caudal fin rays 6-7 + 8-9; vertebrae 54-55;
branchiostegal rays 13. Body elongate,
compressed behind head region. Head
depressed. Upper jaw prominent and
longer than lower jaw. Mouth inferior,
gape of mouth narrow and semicircular, extends upto the region below anterior
margin of orbit. Eyes covered with
skin. Barbel two pairs, maxillary
barbels extend beyond pectoral fin. In
juveniles and in medium sized males (140-185 mm SL), maxillary barbels extend
beyond ventral-fin base. A single pair
of mandibular barbel present, does not extend to pectoral-fin base. 12-16 transverse lines (vertical lateral
line) of widely dotted sensory pores arranged in more or less unequal intervals
from the posterior-most end of supra-occipital bone to the base of the caudal
fin. A distinct horizontal lateral line
is also present in addition to the usual vertical line. Variation in number of transverse lines of
dotted sensory pores, 12-13 numbers in males and 15-16 in females. Caudal fin relatively very long and almost
truncated. Anal fin long and confluent
with caudal fin but with a distinct notch. Anal-fin base extends 1.52-1.64 times of standard length. Anterior nostrils tubular. Anterior margin of pectoral spine smooth,
posterior margin granulated in one or two rows and in female posterior margin
smooth. Dorsal fin rudimentary with two
rays or completely absent.
The species has
characteristic arrangement of pores on head (Fig. 1) as follows: (1) one row of
12 pores on the ventral surface behind lower lip, six on either of the
mandibular region; (2) two sensory pores run vertically upward above the 1stand 12th pores of mandibular row; (3) one row each with three pores
run vertically upward on post-orbital region towards the anterior region of the
frontal, behind the eye; (4) one row of four pores run obliquely on mesethmoid
region towards the tip of head; (5) two pores on middle region of the frontal
behind the frontal pores; (6) two tubercle like structures with pores between
the anterior nostrils; (7) three pores on each side of the head in the
posterior region of frontal; (8) three canals, one each on pre-opercle,
inter-opercle and opercle run towards hyomandibular region.
Colour
Body
grayish brown to dirty yellowish-brown or light grayish-white on dorsal
surface; light brown to dirty white on ventral surface. Outer margin of anal fin white. Half length of ventral fin light grayish-white
or white in colour. ¾ length of pectoral
fin white or light grayish-white. Dotted
sensory pores above the lateral line white in colour.
Sexual
dimorphism
Males
are different from females in having pointed and elongated genital papilla vs.
rounded one; posteriorly granulated pectoral spine vs. smooth one; shorter
caudal-fin base, pectoral-fin base, caudal peduncle; shallower body; shorter
pre-anal length and mandibular barbel length.
Osteology
Three
specimens were dissected for osteological study.
Skull
(Fig. 2a & b):
Lateral process of lateral ethmoid prominent; lateral process of mesethmoid
remarkably long and slender; mesethmoid narrow at base of its lateral process;
sagittal crest confined from middle part to posterior part of supraoccipital
pterotic and epioccipital bones project outward, sensory canals on frontal bone
forming a mere groove.
Suspensorium (Fig. 3a & b): Metapterygoid small compared with hyomandibular, metapterygoid process
well developed; hyomandibular process well developed forming a pterygoid
process, an elongated and sheet-like bone separates from metapterygoid bone,
quadrate process poorly developed.
Shoulder
girdle (Fig. 4a & b): Vertical part of cliethrum short, ventral coracoid
lamina poorly developed, coracoid connected with cliethrum by complex suture.
Caudal
skeleton:All hypural bones separated from each other, hypurapophysis absent, secondary
hypurapophysis forming a well-developed shelf on hypural 1 only.
Etymology
The
species has been named after the river Barak from where it has been collected.
Distribution
Barak
River, Vanchengphai village, Tamenglong district, Manipur, India.
Remarks
This
new species is distinct from Silurus morehensis Arunkumar & Tombi
(1997) in its rounded pelvic fin vs. pointed (Fig. 5); not very distinct notch between anal and caudal fins
vs. a very distinct notch; a line of distinct pores in mandibular region with
two dorsally directed pore lines from its extremities vs. indistinct pore line
without dorsally directed lines; three pore lines obliquely directed towards
hyomandibular vs. two lines. The pores
are prominent and more regularly arranged in S. barakensis (Fig. 1). The species under description is also
different from S. torrentis Kobayakawa in having 0-2 rays on dorsal fin
vs. 2-3 rays; 1-2 rows of finely granulated spines on posterior side of pectoral
fin vs. posteriorly serrated one;
shorter predorsal length (23.9-26.0 vs. 27.8 % SL).
This
new species is also distinct from S. cochinchinensis (as described by
Kobayakawa 1989) in having a well developed sagittal vs. no crest, Cliethrum
and ventral part of coracoid connected by a complex suture vs. simple suture,
lateral line with both vertical and horizontal pores vs. vertical pores,
posterior surface of pectoral spine in males granulated in one or two rows vs.
serrated, vomerine teeth band continuous vs. separated into a pair of small patches, maxillary barbels extend beyond
pectoral fin vs. not reaching tip of pectoral fin and mandibular barbels exceed
the head length vs. not exceeding head length.
An
uncatalogued specimen in the Zoological Survey of India, Kolkata, measuring
161mm SL, labelled as Silurus cochinchinensis, collected from Andhra
Pradesh on 23.xii.1983 was examined for comparison with the new species. As the specimen did not have the characters
as of the label, no comparison could be done.
In
the revision of the genus Silurus, Kobayakawa (1989) included 17
species. Silurus wynaadensis Day
(now Pterocryptis) is found in the Western Ghats. Eschmeyer (1990) and Menon (1999) considered PterocryptisPeters (1861) a synonym of the genus Silurus Linnaeus. However, Bournbusch (1991) removed Pterocryptisfrom synonymy with Silurus. Identity of Silurus cochinchinensis reported by Hora
(1936) from Barak basin in Manipur and also that reported by Shaw &
Shebbeare (1937) from Western Duars, northern Bengal, needs verification.
References
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