First
record of the catfish Gagata dolichonema He, 1996 (Siluriformes:
Sisoridae) from India
W. Vishwanath 1 & A.
Darshan 2
1, 2 Department of Life Sciences, Manipur
University, Canchipur, Manipur 795003, India
Email:
1 wvnath@gmail.com
Date of publication
(online): 26 November 2009
Date of publication (print): 26
November 2009
ISSN 0974-7907 (online) |
0974-7893 (print)
Editor: M. Arunachalam
Manuscript details:
Ms # o1840
Received 17 August 2007
Final received 04 September 2008
Finally accepted 30 October 2009
Citation: Vishwanath, W.
& A. Darshan (2009). First record of the catfish Gagata dolichonemaHe, 1996 (Siluriformes: Sisoridae) in India. Journal of Threatened Taxa 1(11):
578-580.
Copyright: © W. Vishwanath
& A. Darshan 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.
Acknowledgments:The authors are grateful to Ministry of Environment & Forests
(Project No. 14/11/2006/ERS/RE) for financial assistance.
For Figures,
Image & Table – click here
Bleeker (1856) erected the
genus Gagata to accommodate Pimelodus gagata (now Gagata
gagata). de Pinna (1996)
divided the family Sisoridae Bleeker into Subfamilies Sisorinae and
Glyptosterninae. Under subfamily
Sisorinae and tribe Sisorini he proposed subtribe Nangrina and accommodated
genus Gagata. Genus Gagata is diagnosed in having compressed
head; eyes on side of head; depressed snout; small conical teeth in lower jaw;
branchiostegal membranes broadly fused to isthmus; no serrations on anterior
margin of pectoral spine; no well developed maxillary barbel membrane; outer
and inner mental barbels close together with their origins nearly parallel, in
a transverse line; short nasal and maxillary barbels; palatal teeth absent
(Thomson & Page 2006).
Hamilton (1822) describedGagata cenia from rivers in the northern part of Bengal. He (1996) described G. dolichonema from
Yunnan, China and Roberts & Ferraris (1998) described G. gasawyuhfrom Tenasserim River, Myanmar. Ferraris
(2007) considers G. gasawyuh a junior synonym of G. dolichonema. The species differs from G. cenia in
having a continuous blue black lunate mark on caudal fin, the tips pointing
caudad (vs. two separate broad blue black bars in the middle of the two limbs
of caudal fin); saddles on the body extend well below lateral line (vs.
terminate at the level of lateral line).
Manipur state, in the
northeastern region of India, is drained by two river systems, viz.,
Brahmaputra and Chindwin. A series of
collections made from the headwaters of Chindwin in the state included some Gagatawhich are G. dolichonema. This
paper records the species from India and gives a brief description of the
materials.
Materials
and Methods
Materials examined are deposited in
MUMF. Measurement was made with dial
calipers to the nearest 0.1mm. Body proportions are expressed in percentages of
Standard length (SL) and Head length (HL). Numbers in parentheses indicate number of specimens examined for a
particular count. Counts and measurements follow Ng & Kottelat (1998). Gill raker counts follow Roberts &
Ferraris (1998) and vertebral count, Roberts (1983). For osteological studies,
clearing and staining techniques follow Hollister (1934).
Gagata
dolichonemaHe, 1996
(Image
1)
Gagata cenia Hora,
1921: 182 (Imphal River and Amambi stream, Chindwin drainage, Manipur).
Gagata cenia Arunkumar
& Tombi, 1997: 131 (listed from Chindwin dranaige, Manipur).
Gagata ceniaVishwanath et al. 1998: 323 (listed from Lokchao River, Chindwin drainage,
Manipur).
Gagata dolichonema He,
1996: 380 (type locality: Daojieba of Baoshan County, Yunnan, China)
Gagata gasawyuh Roberts
and Ferraris, 1998: 325, fig. 6 and 7 (type locality: Tenasserim River
mainstream upstream from Kita or Htee-tah, Myanmar).
Gagata dolichonema, Ferraris,
2007: 628 pp (synonymy)
Materials Examined: 25.xi.1999,
MUMF 7055, 3 exs (males), 88.5-100.2 mm SL; 7056, 2 exs. (females), 94.3-116.2
mm SL, Lokchao River, Chandel District, Manipur, India, coll. L. Sakuntala
Devi; 23.i.1999, MUMF 9001-9003, 3 exs. (females), 86.1-94.9mm SL, Ithai River,
Manipur, India, coll. L. Juliana.
Distribution: Irrawaddy,
Salween and Tenasserim basins of Myanmar. Lokchao and Ithai Rivers (Chindwin
Basin) Manipur, India.
Diagnosis: The
species can be distinguished from other species of Gagata in having five
saddles oblique, extending downward and backward; one on head crossing eye,
extending to below lower margin of orbit; second at nape across occipital
process extending to the pectoral fin base, third at the posterior half of
dorsal fin base crossing the lateral line but not reaching pelvic fin, forth at
the anterior extent of adipose fin extending obliquely towards anal fin base
but not reaching anal fin and another fifth at the base of caudal fin extending
ventrally to below lateral line. Caudal
fin with a dark grey continuous sub-terminal lunate mark.
Description: Morphometric
data are given in Table 1. Body
elongated and slender. Head and body
compressed, becoming more compressed posteriorly. Snout bluntly rounded. Median longitudinal groove on head extending
from the level of the posterior rim of anterior nostril to the base of occipital
process. Occipital process long narrow but not reaching basal bone of dorsal
fin. Eyes lateral, covered with thin
skin, no free orbital margin. Mouth small, inferior. Oral opening transverse, lies ventral to
nares. Upper jaw and palate
edentulous. Lower jaw with single row of
conical teeth interrupted at the symphysis. Gill opening wide. Gill rakers: 3 + 7 = 10 (1) or 3 + 8 = 11 (2) on the first branchial arch.
Barbels four pairs. Maxillary barbel reaching pectoral fin origin
or slightly beyond. Nasal barbels minute
and its fleshy flap base divide anterior and posterior nares. Mental barbels originate in transverse row
and lie just posterior to lower jaw. Outer mandibular barbel reached opercular
margin and inner mandibular barbels shorter than the inner.
Dorsal fin with spinelet
(first dorsal spine), spine (second dorsal spine) and six branch rays. Second
dorsal spine is laterally compressed, smooth on both the posterior and anterior
edge, distally flexible. Anterior margin
of spine dark and distal half of dorsal fin with broad marginal band. Pectoral fin with a spine and eight-ten
branch rays. Anal fin with four or five
simple rays and eleven or twelve branch rays. Posterior rays shorter and its distal tip grayish. Fin margin slightly concave. Pelvic fin with
one simple and five branch rays. Caudal
fin deeply fork with i,7,8,i. principle rays.
Sexual dimorphism: Mature
individuals are sexually dimorphic. Males differ from female in having flexible
distal tip of second dorsal spine (Fig. 1a) extending well beyond the level of
first branched ray vs. extending upto the level of the first branched ray (Fig.
1b); longer genital papilla, posteriorly elongated and its opening is formed at
its distal tip (Fig. 2a) vs. shorter genital papilla and its opening is formed
at its antero-ventral portion (Fig. 2b).
Osteological Character: Branchiostegal
rays 7. Ribs: 8 (1) in numbers. Vertebrae: 22 abdominal + 17 caudal = 40
(1). First fully developed haemal canal
and ribs appear on 7th vertebra. This
7th vertebra being the first freely movable vertebra. Caudal plate: parhypural and fused hypural 1
and 2 (H 1+2) on the lower lobe and fused hypural 3 and 4 (H 3+4) and hypural 5
(H5) on upper lobe. Proximal portion of
parhypural fused partially with the base of H 1+2. One roughly straight, distally taper epural
lies above the short neural spine of the last half centrum. Second ural centrum well developed at the
base of fused H 3+4. Hypuropophysis and
secondary hypuropophysis fused. Procurrent rays: 8 segmented + 9 unsegmented =
17 (1) rays on each lobes.
Discussion
Gagata gasawyuh differs from
other known species of Gagata in having five saddles over the dorsum of
head and body, and blue black lunate mark at the middle of caudal fin. Diagnostic characters of the species in the
present study fit the original description of G. gasawyuh. Some specimens have indistinct saddle at the
dorsal fin origin which extends well below the lateral line. Similar cases were reported by Roberts &
Ferraris (1998). However, in contrast to
the range of teeth in lower jaw (2-5) they reported, the present alizarin stained specimens show a single row
of 16-18 teeth (8-9 each side). The
conical teeth row is interrupted at symphysis.
The present work also reports the sexual
dimorphism of the species. Tilak (1970)
also reported filamentous extension of the dorsal fin spine in males of G.
sexualis. There is no report of
filamentous extension of dorsal fin spine in G. dolichonema He of
Yunnan, China as a character of sexual dimorphism.
Hamilton (1822) described Gagata cenia from rivers in
the northern part of Bengal. Hora (1921)
reported the occurrence of Gagata cenia (Hamilton) from Imphal River and
Amambi stream streams, Chindwin drainage, Manipur. Vishwanath & Tombi (1985), Arunkumar
& Tombi (1997) and Vishwanath et al. (1998) also reported the occurrence of
the species from the same basin. Menon
(1954) also included the species in his list of fishes from Manipur.
Roberts & Ferraris (1998), however,
reported Gagata cenia to be distributed in the Indus, Ganga and Mahanadi
river systems. There are materials
collected from Barak River in Manipur (Brahmaputra drainage) which are
referable to G. cenia. However, with the description of G.
gasawyuh, the records of G. cenia from Chindwin basin may be treated
as misidentifications and may be replaced by G. gasawyuh. The species is recorded here for the first
time from India.
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