Channa pardalis, a new species of snakehead (Teleostei: Channidae) from Meghalaya, northeastern India

Acknowledgements: I gratefully acknowledge the support provided by the Director, Zoological Survey of India, Kolkata; K. Ilango (Officer-in-charge) and Jayasree Thilak (Scientist-D), of the Southern Regional Centre, Zoological Survey of India, Chennai. I thank Andrew Rao, Nikhil Sood, Beta Mahatvaraj, Pranay Kumar and Praveen Raj for helping me obtain the material used in this study. I am grateful to Ralf Britz for his valuable inputs, Unmesh Katwate for his help in depositing material at the Bombay Natural History Society, Pascal Antler and Paul Jones for constructive discussions. Abstract: Channa pardalis, a new species of snakehead, is described from Khasi Hills, Meghalaya, northeastern India. This species can be distinguished from its congeners by a unique colour pattern consisting of numerous large black spots on the post-orbital region of the head, opercle and body; a broad white and black margin to the dorsal, anal and caudal fins; 36–37 dorsal fin rays; 24–25 anal fin rays; 44–45 pored scales on the body and two scales on the caudal fin base; 41⁄2 scales above lateral line and 61⁄2 scales below lateral line; 45 vertebrae and the palatine with two rows of teeth: outer row with numerous minute teeth and inner row with short, stout inward curved teeth.

Snakeheads of the family Channidae are characterized by accessory air-breathing organs, which are modified expanded epibranchials situated in the suprabranchial cavity in the head (Liem 1980).These fish are distributed in tropical Africa, parts of the Middle East and Asia, and inhabit a wide variety of freshwater habitats ranging from hill streams to derelict swamps (Geetakumari & Vishwanath 2011).Currently there are 35 valid species in the genus Channa, many of which are valued as food fish and a few that are popular in the aquarium trade.The Eastern Himalayan region harbors 10 endemic species of snakeheads (Britz 2013), some of which were recently discovered (Musikasinthorn 2000;Geetakumari & Vishwanath 2011;Britz 2013).Playfair (1867) described Ophiocephalus stewartii (currently assigned to Channa) from Cachar, Assam, characterized by "some larger teeth in the lower jaw and on the vomer and the palatine bone…most of the scales behind the roots of the pectorals have a round black spot in the centre…in young examples the pectorals have transverse darker cross bands…etc" (Fig. 1).For more than 150 years, C. stewartii was the only known Channa species with round black spots on the body until Britz (2008) described C. ornatipinnis and C. pulchra from Myanmar with spots on the body similar to C. stewartii.Subsequently, Geetakumari & Vishwanath (2011) described C. melanostigma from Arunachal Pradesh, northeastern India, a species similar to C. stewartii.Recently, I had an opportunity to examine a colourful species of Channa from the Khasi Hills, Meghalaya, northeastern India, with large well-defined black spots on post-orbital region of the head, opercle and body.Detailed comparison with topotypic C. stewartii revealed that this was a species hitherto unknown to science, which is described herein as Channa pardalis sp.nov.

Material and Methods
Collected specimens were fixed in 10% formalin and preserved in 70% alcohol.Specimens examined in this study are registered in the collections of the Bombay Natural History Society (BNHS), Mumbai, India; Southern Regional Centre, Zoological Survey of India, Chennai, India (ZSI/SRC).Additional material are in the collection of J.D. Marcus Knight (MKC), Chennai, India.Methods for taking counts and measurements follow Musikasinthorn (1998) and Britz (2008).Measurements were made with digital calipers to the nearest 0.1 mm.Numbers in parenthesis after a count denotes the frequency of that count.Osteological preparations were made following the single-staining procedure of Taylor & Van Dyke (1985) and osteological nomenclature follows Britz (2008).Vertebrae were counted from two cleared and stained specimens (MKC 429 and 437).Photographs were taken with Olympus SP570 UZ digital camera using super-macro mode.Data from Musikasinthorn (2000) and Britz (2008Britz ( , 2013) )  Diagnosis: Channa pardalis sp.nov. is diagnosed from all other species of Channa in having a unique colour pattern consisting of numerous large black spots on the post-orbital region of the head, opercle and body; a broad white and black margin to the dorsal fin, anal fin and caudal fin; 36-37 dorsal fin rays; 24-25 anal fin rays; 44-45 pored scales on the body and two scales on the caudal fin base; 4½ scales above lateral line and 6½ scales below lateral line; 45 vertebrae and the palatine with two rows of teeth: outer row with numerous minute teeth and inner row with short, stout inward curved teeth.

Description
See Table 1 for morphometric data and images 1 and 2A for general appearance.Body elongate, round in cross section anteriorly its width a little less than its depth; gradually becoming laterally compressed towards caudal peduncle.Dorsal profile of head gently curved anteriorly, ventral profile almost straight.Caudal peduncle deep, its depth greater than its length.Head large, dorso-ventrally flattened, about one-third standard length its widest portion between eye and opercle.Eyes small, located anteriorly on head, their diameter less than the snout length.
Mouth large, oblique, lips thick, angle of gape extending beyond the posterior margin of the eye.Lower jaw projecting slightly beyond upper jaw.Scales on cheeks in 4(1) -5(4) rows.Both jaws with multiple rows of sharp, pointed teeth.Two rows of teeth on the lower jaw, an outer row of numerous minute slender pointed teeth and single inner row of large uniform sized teeth.Vomer with six small sharp, pointed teeth and four canine-like teeth.Two rows of teeth on the palatine, outer row with numerous minute teeth and inner row with short, stout inward curved teeth.Fifth ceratobranchial slender, with numerous long sharp inward pointing teeth (Image 3A).

Colouration
In alcohol (Image 1), dorsum, sides of head and body uniformly dark grey gradually becoming lighter towards the throat and abdomen.Fifteen to twenty well defined black spots on the post-orbital region of the head, opercle and with numerous black spots along the flanks extending into the dorsal fin and caudal fin, which sometimes fade to become dark grey and on prolonged preservation become inconspicuous.Dorsal, anal and caudal fins dark grey with a broad white and black margin.Pectoral fin cream with three or four dark grey semi-circular bands.Pelvic fin grey with a white margin.
Live specimens (Image 2A) are bluish-grey in colour; top of the head and opercular region bright blue.15-20 well defined black spots on the post-orbital region of the head and opercle.Body with bluish dorsum gradually becoming grey towards the abdomen, with numerous black spots along the flanks extending into the dorsal fin and caudal fin.Dorsal fin, anal fin and caudal fin bright blue with a broad white and black margin.Pectoral fin with bright blue spot at the base, and with three or four alternating pale orange and grey semi-circular bands which fade towards the distal part of the fin which is dark grey.Pelvic fin grey with a white margin.Sclera dark orange with two orange patches: one on the anterior margin of the orbit and the other below the orbit.

Etymology
The specific epithet 'pardalis' is a Latin adjective meaning 'Leopard' referring to the conspicuous spots the species has, similar to a leopard.

Distribution
Channa pardalis sp.nov. is currently known only from the Khasi Hills, Meghalaya, northeastern India.As mentioned by Britz (2008) the monophyly of the Channa gachua species group needs to be confirmed through phylogenetic studies.Further exploration of remote areas in northeastern India and adjoining areas may probably bring to light more snakehead species new to science or possibly find that some of the species currently synonymous with C. gachua to be valid species.

Image 2 .
Channa pardalis: A, paratype, ZSI/SRC F 8954, 139.3mmSL, showing live colouration, West Khasi Hills, Meghalaya.C. stewartii: MKC 100, Cachar, Assam, B, 109.2mmSL, showing live colouration, C, 128.6mmSL, showing colouration in preservative.C. melanostigma: MKC 012, Tinsukia, Assam, D, 118.1mmSL showing live colouration, E, 122.9mmSL, showing colouration in preservative.sp.nov. is known in the ornamental fish trade as Channa sp.Meghalaya leopard.Discussion Britz (2008) proposed the 'Channa gachua species group' comprised of species with pectoral fins having a varying number of dark and light semicircular bands.In addition to C. orientalis, C. gachua, C. burmanica, C. bleheri and C. barca, Britz (2008) also included C. stewartii, C. aurantimaculata, C. ornatipinnis and C. pulchra to the 'C.gachua species group'.Two other recently described species, i.e., C. melanostigma and C. andrao also belong to the C. gachua species group.Channa pardalis sp.nov. in view of its pectoral fins having the characteristic semicircular dark and light bands, unquestionably belongs to this group.Channa pardalis can be distinguished from C. orientalis, C. burmanica, C. bleheri and C. andrao by the presence of pelvic fins, and from C. ornatipinnis and C. pulchra by the pectoral fin having three or four alternating pale orange and grey semi-circular bands which fade towards the distal part of the fin (vs.four to five semicircular, narrow white bands alternating with brown or black bands).Channa pardalis can be further distinguished from both C. ornatipinnis and C. pulchra in having 6½ (vs.7½) scales below lateral line at anal-fin origin, absence of black blotches on the anterior third of the dorsal fin and absence of parallel, linear white marks at anal fin base.Though C. pardalis superficially resembles both C. stewartii and C. melanostigma, it can be easily distinguished from both by the presence of 15-20 welldefined black spots on the post-orbital region of the head and opercle, 6½ (vs.7½) scales below lateral line at analfin origin, 45 (vs.48 and 50-51) vertebrae respectively and a more slender fifth ceratobranchial (Image 3 A-C).Channa pardalis can be further distinguished from C. stewartii by having 36-37 (vs.39-40) dorsal fin rays and 44-45 + 2 (vs.47-48 + 2) lateral line scales, and from C. melanostigma by the absence (vs.presence) of 14-15 distinct zigzag cross bars on the caudal fin.Channa pardalis can be distinguished from C. aurantimaculata and C. barca in having 36-37 (vs.45-52) dorsal fin rays and 44-45 + 2 (vs.> 50) lateral line scales.Though C. pardalis is a part of the C. gachua species group it can be distinguished from C. gachua by the presence of numerous large black spots on the post-orbital region of the head, opercle and body, 45 (vs.42) vertebrae and 36-37 (vs.34-35) dorsal fin rays and a more slender fifth ceratobranchial (Image 3 A, D).There are quite a few names buried in the synonymy of C. gachua.Of these Ophiocephalus aurantiacus Hamilton, 1822 (type locality: Goyalpara on the northeastern Image 3. Fifth ceratobranchial of Channa species: A -C. pardalis; B -C. stewartii; C -C. melanostigma; D -C. gachua.), Ophicephalus marginatus Cuvier, 1829 (type locality: Vizagapattam: see Kottelat 2000) and O. fuscus Cuvier, 1831 (type locality: Bengal) are from India.Channa pardalis can be distinguished from O. aurantiacus by having a bluish dorsum gradually becoming grey towards the abdomen, with numerous black spots along the flanks extending into the dorsal fin and caudal fin, vs. the whole body and fins being of the colour of orangepeel, with some irregular stains of a redder hue, especially on the sides of the head, and on the pectoral and tail fins.Channa pardalis can be distinguished from C. fuscus and C. marginatus (which were similar to C. gachua), in having more than 40 lateral line pored scales and by the presence of conspicuous black spots on the post-orbital region of the head, opercle and on the body.Two other names, Ophicephalus montanus M'Clelland & Griffith, 1842 (type locality: Afghanistan?) and Ophiocephalus kelaartii Günther, 1861 (type locality: Sri Lanka) are also currently synonyms of C. gachua (Kottelat 2013).Channa pardalis can be distinguished from O. montanus by having 36-37 (vs.32) dorsal fin rays and 24-25 (vs.17) anal fin rays.Channa pardalis can further be distinguished from O. kelaartii by having 44-45 + 2 (vs.38) lateral line scales and 24-25 (vs.22) anal fin rays.One other similar species is Ophiocephalus gachua var.basalis Günther, 1861 (type locality: East Indies) which is most probably C. gachua (Kottelat 2013) as Günther mentions that this species has a black ocellus edged with white on the hindmost part of the dorsal fin when young, typical of C. gachua.Channa pardalis can be distinguished from O. gachua var.basalis in having 24-25 (vs.21-23) anal fin rays and 4½ (vs. 3) scales above lateral line.One other species, Ophicephalus nigricans Cuvier & Valenciennes 1831 is currently a synonym of Channa barca.Channa pardalis can be distinguished from O. nigricans by having 36-37 (vs.50) dorsal fin rays.

were used for comparison. Original descriptions of
Ophiocephalus aurantiacus, O. kelaartii, O. gachua var.basalis, Ophicephalus montanus and O. nigricans were also used for comparison.