Pareas temporalis, Le & Tran & Hoang & Stuart, 2021

Le, Duong T. T., Tran, Thinh G., Hoang, Huy D. & Stuart, Bryan L., 2021, A new species of Pareas (Squamata, Pareidae) from southern Vietnam, Vertebrate Zoology 71, pp. 439-451 : 439

Pareas temporalis sp. nov.

Figures 3 , 4 , 5

Suggested Common Names.

Di Linh Snail-eating Snake (English), Rắn hổ mây Di Linh (Vietnamese).

Holotype.

UNS 09992 (field number LD25711), adult female, Vietnam, Lam Dong Province, Da Huoai District, Doan Ket Commune, 11.340370°N, 107.620561°E, 496 m a.s.l., coll. 25 July 2020 by Duong T.T. Le and Thinh G. Tran.

Diagnosis.

Pareas temporalis sp. nov. is distinguished from all other Pareas by having the combination of yellow-brown body colouration; hexagonal-shaped frontal, with lateral sides parallel to the body axis; 16-17 temporals, with 4-5 anterior temporals; loreal and prefrontal not contacting eye; 2-3 preoculars; two suboculars; 2-3 postoculars; 8-9 supralabials; 8-9 infralabials (Fig. 4 ); 15-15-15 dorsal scale rows, all keeled (Fig. 3b ), three vertebral scale rows enlarged; 191 (+1 preventral) ventrals, smooth; 92 subcaudals, all divided; undivided anal scale; two postocular stripes; and a solid dark brown vertebral stripe extending from rear of nuchal collar along the entire length of body and tail.

Description of the holotype.

Adult female (Figs 3a , 5 ), SVL 426 mm; TaL 152 mm; TL 578 mm; TaL/TL 0.263. Body slender, compressed; head elongate, clearly distinct from neck; snout round in dorsal view; eye slightly enlarged, pupil vertical and slightly elliptical; rostral slightly visible in dorsal view; nasal scale single; two internasals, wider than long, contacting rostral, loreal, nasals, prefrontals; two prefrontals, large, not contacting eye; frontal hexagonal-shaped with lateral sides parallel to the body axis, frontal smaller than parietals; single loreal contacting nasal, internasal, prefrontal, preocular, 2nd and 3rd supralabial (left) or 2nd supralabial (right), but not contacting eye; 1/1 supraocular; 2/2 suboculars; 2/3 preoculars; 2/3 postoculars; 9/8 supralabial scales, 5th, 6th, 7th/4th, 5th, 6th below (not touching) eye, 9th/8th longest;16-17 temporals (4+3+4+6/5+3+4+4); 8/9 infralabials, without mental groove; three pairs of chin shields, not equal in size, anterior pair of chin shields longer than broad, slightly longer than two posterior pairs; dorsal scales in 15-15-15 rows, all keeled without apical pits; three enlarged vertebral scale rows; 191 ventrals (+1 preventral), all smooth; 92 subcaudals, all divided; undivided anal scale.

Colouration.

In life, top of head light brown with dark brown spots. Sides of head with two postocular stripes: lower stripe extends from the postorbital to the 9th/ 8th supralabial; upper stripe extends from the upper corner of the eye to the temporal area, then divides into two long stripes, with the upper arms meeting at the nape, while the lower arm extends to the corner of the jaw and sides of the neck before converging to form a black nuchal collar (collar six scales long at mid-dorsals). Ground colour of dorsum brown with dark-brown speckling and numerous irregular black cross-bands on lateral sides of body from neck to vent (64 bands on left and 62 bands on right), and a solid dark-brown vertebral stripe extending from the posterior end of the black nuchal collar along entire length of body and tail. Ventrals light brown with dark brown spots on lateral edges and middle of each scale, spotting weaker on chin shields. Ventral surface of tail dark brown. Colouration in preservative as in life, but with dorsum faded to yellowish brown.

Distribution and natural history.

Pareas temporalis sp. nov. is currently only known by the holotype specimen from Da Huoai District, Lam Dong Province, southern Vietnam (Fig. 6 ). The sampling site is located near to the boundary of BinhThuan Province, and so it is likely that the new species is also found in forested areas of that province. The holotype was found at night (2100 hours) on a tree branch 1.5 m above the ground in disturbed mixed broadleaf and bamboo forest, where it occurred in sympatry with P. margaritophorus (e.g., UNS 09993). No further information is currently known on the biology of the new species.

Etymology.

The specific epithet Pareas temporalis L. refers to the high number of temporal scales in the new species.

Comparisons.

Pareas temporalis sp. nov. differs from P. margaritophorus , P. macularius , P. modestus Theobald, 1868 and P. andersonii (Boulenger, 1888) by having a light brown dorsum with irregular dark bands (vs. uniform grey to black to dark colouration, and with bicolored spots in P. margaritophorus , P. macularius and P. andersonii ); prefrontal not contacting the eye (vs. contacting); fully keeled dorsal scale rows at midbody (vs. not fully keeled); three enlarged vertebral scales (vs. not enlarged); and frontal hexagonal with lateral sides parallel to body axis (vs. frontal subhexagonal with lateral sides converging posteriorly) ( Ding et al. 2020; Suntrarachun et al. 2020; Vogel et al. 2020; Wang et al. 2020; Vogel et al. 2021).

Pareas temporalis sp. nov. differs from P. boulengeri (Angel, 1920), P. monticola (Cantor, 1839), P. stanleyi (Boulenger, 1914), P. vindumi (Vogel, 2015), P. victorianus (Vogel, Nguyen, Zaw & Poyarkov, 2021) and P. yunnanensis Vogt, 1922 by having the prefrontal not contacting the eye (vs. contacting); loreal not contacting the eye (vs. contacting); two suboculars (vs. 0-1 or suboculars fused with postoculars); 2-3 postoculars (vs 1-2 or postoculars fused with suboculars); fully keeled dorsal scale rows at midbody (vs. not fully keeled); 4-5 anterior temporals (vs. 1-2); and frontal hexagonal with lateral sides parallel to body axis (vs. frontal subhexagonal with lateral sides converging posteriorly) ( Boulenger 1914; Guo and Deng 2009; Vogel 2015; Wang et al. 2020; Liu and Rao 2021; Vogel et al. 2021).

Pareas temporalis sp. nov. differs from P. geminatus Ding, Cheng, Suwannapoom, Nguyen, Poyarkov & Vogel, 2020, P. atayal You, Poyarkov & Lin, 2015, P. chinensis (Barbour, 1912), P. formosensis (Van Denburgh, 1909), P. hamptoni (Boulenger, 1905), P. iwasakii (Maki, 1937), P. komaii (Maki, 1931), P. niger Pope, 1928, P. xuelinensis Liu & Rao, 2021, P. nigriceps Guo & Deng, 2009 and P. kaduri Bhosale, Phansalkar, Sawant, Gowande, Patel & Mirza, 2020 by having the prefrontal not contacting eye (vs. contacting, except in P. nigriceps ); two suboculars (vs. one or suboculars fused with postoculars); 2-3 preoculars (vs. one); fully keeled dorsal scale rows at midbody (vs. not fully keeled); 4-5 anterior temporals (vs. 1-3); and frontal hexagonal with lateral sides parallel to body axis (vs. frontal subhexagonal with lateral sides converging posteriorly) ( Guo and Deng 2009; You et al. 2015; Bhosale et al. 2020; Ding et al. 2020; Wang et al. 2020; Liu and Rao 2021; Vogel et al. 2021).

Pareas temporalis sp. nov. is most closely related (Figs 1 - 2 ) and morphologically similar to other members of the P. carinatus complex, consisting of P. carinatus (Wagler, 1830), P. nuchalis (Boulenger, 1900), and P. menglaensis Wang, Che, Liu, Li, Jin, Jiang, Shi & Guo, 2020. Pareas temporalis sp. nov. differs from all three species by having 4-5 anterior temporals (vs. three); and a dark brown vertebral stripe on body and tail (vs. absent). Pareas temporalis sp. nov. further differs from P. carinatus by having 2-3 preoculars (vs. one); and all 15 dorsal scale rows keeled at midbody (vs. 0-11). Pareas temporalis sp. nov. further differs from P. nuchalis by having prefrontal not contacting eye (vs. contacting); 191 ventrals (vs. 195-220); and 92 subcaudals (vs. 102-120). Pareas temporalis sp. nov. further differs from P. menglaensis by having 191 ventrals (vs. 176-177); 92 subcaudals (vs. 65-79); 2-3 postoculars (vs. one); 15 dorsal scale rows keeled at midbody (vs. 11); and two black postorbital stripes on lateral side of head (vs. one thin postorbital stripe extending from postocular to neck on lateral side of head) ( Boulenger 1900; Malkmus et al. 2002; Guo and Deng 2009; Stuebing et al. 2014; Ding et al. 2020; Wang et al. 2020; Vogel et al. 2021).

Figures

Figure 1. Fifty percent majority-rule consensus phylogram resulting from partitioned Bayesian analysis of 1,971 aligned characters of the mitochondrial cytochrome b (cyt b), NADH dehydrogenase subunit 4 (ND 4), and flanking tRNA genes of pareid snakes. Trees were rooted with Achalinus rufescens (not shown). Numbers at nodes are Bayesian posterior probabilities. Sample information is provided in Table 1.

Figure 2. Maximum likelihood phylogeny based on a partitioned dataset containing 1,971 aligned characters of the mitochondrial cytochrome b (cyt b), NADH dehydrogenase subunit 4 (ND 4), and flanking tRNA genes of pareid snakes. Trees were rooted with Achalinus rufescens (not shown). Numbers at nodes are bootstrap values based on 1,000 pseudoreplicates. Sample information is provided in Table 1.

Figure 3. Holotype female (UNS 09992) of Pareas temporalis sp. nov. in preservative. a: whole body in lateral view; b: keeled dorsal scales at midbody; c: ventral view of head; d: dorsal view of head; e and f: lateral views of head. Scale bars: 5 mm.

Figure 4. Head scalation of holotype female (UNS 09992) of Pareas temporalis sp. nov. in ventral, dorsal and lateral views. Illustration by Vo Ngoc Thinh.

Figure 5. Holotype female (UNS 09992) of Pareas temporalis sp. nov. in life (above) and view of habitat at its type locality (below).

Figure 6. Holotype locality of Pareas temporalis sp. nov. (black star) in Lam Dong Province, Vietnam.