Pareas kaduri, Bhosale, Harshal, Phansalkar, Pushkar, Sawant, Mandar, Gowande, Gaurang, Patel, Harshil & Mirza, Zeeshan A., 2020

Bhosale, Harshal, Phansalkar, Pushkar, Sawant, Mandar, Gowande, Gaurang, Patel, Harshil & Mirza, Zeeshan A., 2020, A new species of snail-eating snakes of the genus Pareas Wagler, 1830 (Reptilia: Serpentes) from eastern Himalayas, India, European Journal of Taxonomy 729 (729), pp. 54-73 : 57-63

Pareas kaduri sp. nov.

urn:lsid:zoobank.org:act:66902402-DD58-4F83-B8B2-381EC46FA395

Figs 1–5 , Table 1

Differential diagnosis

A new species of Pareas bearing the following suite of characters: (1) SVL 455–550 mm, (2) TaL/ TL 0.184 –0.207, (3) 15 dorsal scale rows (DSR) throughout body and mid-dorsal vertebral scale rows enlarged, 8 rows keeled in males, (4) loreal not touching orbit, (5) ventrals 160–183, (6) subcaudals 65–70 in males, 52 in one female specimen, (7) hemipenis short, unilobed, (8) 6–7 maxillary teeth, (9) dorsum brown with thin black transverse bands, the head with a large black blotch from which two longitudinal black stripes (3–4 scales wide) run on each side of the neck leaving a pale central portion.

The new species is here compared with congeners based on non-overlapping and differing characters: vertebral scales enlarged (vs not enlarged in P. chinensis (Barbour, 1912) , P. macularius Theobald, 1868 , P. margaritophorus (Jan 1866) , P. vindumi Vogel, 2015 ); loreal not in contact with orbit (vs in contact in P. boulengeri (Angel, 1920) , P. monticola (Cantor, 1839) , P. stanleyi (Boulenger, 1914) , P. vindumi ) and Amblycephalus yunnanensis Vogt, 1922 ; eight mid-dorsal vertebral scales keeled (all scales smooth in P. boulengeri and Amblycephalus kuangtungensis Vogt, 1922 , 9–13 keeled dorsal scales in P. komaii (Maki, 1931) , 3–5 in P. modestus ); two anterior temporals (vs one in P. nigriceps Guo & Deng, 2009 ); ventrals 160–183 (vs 195–213 in P. nuchalis (Boulenger, 1900) , 189–194 in P. iwasakii (Maki, 1937) , 151–160 in P. stanleyi , 190–196 in P. monticola , 130–160 in P. margaritophorus ), 6–7 maxillary teeth (vs 4–5 in P. chinensis (Barbour, 1912) and P. boulengeri , 3–5 in P. menglaensis Wang, Che, Liu, Li, Jin, Jiang, Shi & Guo, 2020 ); prefrontals in contact with orbit (vs not in contact in P. carinatus (Boie, 1828)) ; subcaudals 65–70 in males, 52 in female (vs 71–79 in P. atayal You, Poyarkov & Lin, 2015 , 37– 45 in P. andersonii ); single nasal (vs two in P. nuchalis and P. stanleyi ); dentition asymmetry index 4.55 in males (13.51 in P. komaii , 29.03 in P. atayal ).

The new species shares several characters with members of its clade and is here compared to each species in greater detail based on differing and non-overlapping characters. The new species differs from P. formosensis in bearing keeled dorsal scales (vs smooth in P. formosensis ), dentition asymmetry index 4.55 in males (vs 16.13 in P. formosensis ).

The new species differs from P. mengziensis Wang, Che, Liu, Li, Jin, Jiang, Shi & Guo, 2020 in bearing 6–7 maxillary teeth (vs 3–5 in P. mengziensis ) and in having the dorsum with thin black bands (vs connected black reticulations throughout the body in P. mengziensis ).

The new species is most similar to P. hamptoni in sharing the plesiomorphic state, where the loreal shield does not touch the orbit and is separated by the preocular. However, the new species differs from the species as follows: ventrals 160–183 (vs 197–202); two anterior temporals (vs a single temporal scale in P. hamptoni ); subcaudals 65–70 in males, 52 in female (vs 96 in P. hamptoni ); bearing 8 keeled dorsal scales (vs only a single row keeled in P. hamptoni ); hemipenis unilobed and not forked (vs deeply forked in P. hamptoni ).

Etymology

The specific epithet is a patronym honoring wildlife photographer Sandesh Kadur for his contribution to biodiversity documentation in the Himalayas, in particular Arunachal Pradesh, as well as for his constant support to the authors during the expedition.

Type material

Holotype INDIA • ♂ adult; Arunachal Pradesh, Lohit District, outskirts of Kamlang Wildlife Sanctuary, found along the road leading to Hawa camp from Parshuram Kund; 27.880711° N, 96.363239° E; 350 m a.s.l. (Datum WGS84); 23 Jul. 2019; Harshal Bhosale, Mandar Savant, Pushkar Phansalkar and Gaurang Gowande leg.; BNHS 3574 .

Paratypes INDIA • 1 ♀; same collection data as for holotype; BNHS 3575 • 2 ♂♂; same collection data as for holotype; 28 Jul. 2019; Zeeshan Mirza, Harshal Bhosale, Mandar Savant, Pushkar Phansalkar and Gaurang Gowande leg.; NCBS BH655–BH656 .

Description

Holotype Ƌ (BNHS 3574) ( Figs 1–4 )

The specimen is in good condition, preserved in a coil with its head resting outside the coil ( Fig. 2 ). The specimen bears incisions. The hemipenis is partly everted.

Head short, 15.45 mm comprising 2.22% of total length; high, 6.47 mm, with steeply domed snout in lateral view; upper jaw visible from ventral side. Head distinctly broader (9.3 mm) than neck (4.4 mm). Snout abruptly tapers, rounded tip in dorsal view ( Fig. 3 ). Rostral subpentagonal, reaching top of the snout; as wide as high with a distinct furrow towards its ventral edge. Upper jaw distinctly longer than lower jaw. Nostrils large, 2.04 long and 1.32 high in the centre, elliptical-shaped, positioned in the centre and posterior half of nasal scale. Paired internasals, wider (2.07 mm) than long (1.26 mm); smaller than prefrontals. Prefrontals slightly wider (2.83 mm) than long (2.59 mm). Frontal hexagonal, 3.87 mm at the widest portion, median length 5.06 mm. Parietals 6.62 mm long, 3.87 mm at its widest anteriorly. Temporals 2+3+3 on both sides, subequal in size, posterior one inserts deeply between supralabial sixth, seventh and eighth. Five nuchal scales, slightly larger than adjacent dorsal scales, bordering parietals. Supraocular larger than preocular; preocular small, subequal. Loreal slightly longer (1.68 mm) than high (1.54 mm). Two postoculars, subequal in size. Eye large, circular, 3.13 mm (eye diameter/head height 0.48) diameter with a spherical pupil. Seven supralabials, seventh longest. First to third supralabials smallest, first supralabial only contacts second supralabial, rostral and nasal. Second supralabial in contact with nasal, preocular, loreal and first and third supralabials. Third supralabial in contact with preocular, second and forth supralabials and making contact remotely with loreal. Supralabials separated from the orbit by a crescent-shaped subocular.

Mental short, broad, triangular. Infralabials 7, anterior five infralabials short and narrow, fifth onwards larger. First infralabials of both sides in broad contact, separate the mental from the genials. Sixth infralabial broadest. First six infralabials in contact with the genials. Anterior genials almost twice as long as wide; anterior genials in broad contact, posterior genials only in remote contact.

Body laterally compressed, ventral surface a little flattened. Dorsal scales in 15:15:15 rows. Dorsal scales imbricate, regularly arranged, vertebral and adjoined scale rows enlarged and larger than the outermost dorsal scales. Eight scale rows on the mid-dorsum (including vertebral rows) keeled; other dorsal scale rows scales smooth and glossy, lacking apical pits. Ventral scales 160 in number + 2 preventrals.Anal shield undivided, slightly larger than last ventral scale, its posterior margin overlaps nine small, irregular scales on each side, in addition to pair of larger subcaudals medially. Subcaudals paired, 70 in number. Tail terminates in a sharp tapering apical spine. Total length 694 mm, tail length 144 mm, tail/total length ratio 0.207.

Hemipenial morphology (paratype NCBS BH655)

The organ is fully everted and expanded ( Fig. 4 ). Hemipenis short, unilobed, stout and unicaliculate; lobe extends for about 60% of the hemipenis; capitulum restricted to sulcate and dorsal surfaces of the organ, covering nearly half of the lobe’s length at the level of the sulcus spermaticus; capitulum smooth, except for two rows of calyces spanning almost the entire width of the organ; on asulcate surface, lobes ornamented with three to four parallel broken rows of mediolaterally enlarged and papillate body calyces; sulcus spermaticus simple; the sides of the sulcus spermaticus are smooth; truncus and hemipenial base is wrinkled and completely nude.

Colouration in preservative ( Fig. 2 )

Overall, in a shade of brown with 28 paired black transverse bands from nape to the vent. Some of these bands are distinct, whereas some are merely black spots that connect rudimentarily to form bands. The head bears a large black blotch from which two black longitudinal stripes (3–4 scales wide) run on each side of the neck leaving a pale central portion. The ventral scales are white or cream colored with sparse black mottling.

Dentition (paratype, ♂ NCBS BH655) ( Fig. 5 )

Maxilla with six functional (12 total) on right and seven (14 total) on left teeth. All the teeth subequal, lacking a distinct diastema. Pterygoid with total of 6–7 teeth. Palatine with 13–14 functional (24–25 total) teeth that gradually decrease in size posteriorly. Mandibles with 21 and 23 (more than 50 total) functional dentary teeth of left and right, respectively.

Variation shown by paratypes and referred specimens

The paratypes match the holotype in all respect except for the details noted herein: dorsal scales of female paratype BNHS 3575 are smooth, lacking keels, likely a character that is sexually dimorphic, in addition to fewer subcaudal scales. The color of individuals varies greatly in being light brown to dark blackish brown to reddish orange. Other differing characters are listed in Table 1.

Genetic divergence

Interspecific divergence observed is 12–24% for cyt b and intraspecific genetic divergence is 1%. ( Appendix 2).

Natural history

The type specimens were captured on low bushes along roads on the outskirts of Kamlang Wildlife Sanctuary at night. All the specimens were observed actively foraging after dusk. The habitat at the type locality is contiguous with the adjoining Namdapha Tiger Reserve and Mehao Wildlife Sanctuary, which lie in the Mishmi Hill range. Mishmi Hills lie between the Himalayas and the Indo-Burma biodiversity hotspot. The adjoining areas of Myanmar also share similar biotope and it is likely that the new species will be distributed in Myanmar in addition to India. The species was found in sympatry with Pareas monticola , Boiga siamensis Nutaphand, 1971 , Bungarus niger Wall, 1908 , Ahetulla sp. and Trimeresurus popeiorum Smith, 1937 . The new species is common throughout the sampled area ranging from an elevation of 300 m to 1200 m, whereas P. monticola appears to be rare and only a single specimen was found at lower elevation (<300 m).

Distribution

Currently, the new species is known only form the type locality, a tropical wet evergreen forest.

Figures

Fig. 1. Pareas kaduri sp. nov. Holotype, ♂ (BNHS 3574) in life. Photograph by Zeeshan A. Mirza.

Fig. 2. Pareas kaduri sp. nov. Holotype, ♂ (BNHS 3574). A–B. Lateral views. Scale bars = 25 mm.

Fig. 3. Pareas kaduri sp. nov. Holotype, ♂ (BNHS 3574). View of head. A. Left lateral view. B. Dorsal view. C. Ventral view. Scale bars = 5 mm.

Fig. 4. Pareas kaduri sp. nov. Paratype, ♂ (NCBS BH655). A–B. Hemipenis, lateral view. Scale bars = 1 mm.

Fig. 5. Pareas kaduri sp. nov. Holotype, ♂ (BNHS 3574). Micro-CT scans of the head. A. Left lateral view. B. Dorsal view. C. Ventral view, without mandibles. D. Dorsal view of mandibles. Scale bars = 1 mm.