Pareas nigriceps GUO & DENG, 2009
Can you confirm these amateur observations of Pareas nigriceps?
|Higher Taxa||Pareidae, Colubroidea, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||Xiaoheishan slug-eater snake|
|Synonym||Pareas nigriceps GUO & DENG 2009|
Pareas nigriceps — WALLACH et al. 2014: 537
|Distribution||China (Yunnan: Gaoligong Mountains)|
Type locality: Xiaohei Hill, Gaoligong Mountains National Nature Reserve (24.83671°N 98.76185°E, 2067 m a.s.l.), Longling County, Baoshan District, Yunnan province, Perople’s Republic of China.
|Types||Holotype: HNU 200505004 (Figs. 1–2), an adult male, collected by Yan Hengmei and Guo Keji on 28 May 2005. Paratype: HNU 200505014, adult female from the same area (24.82886°N 98.75917°E, 2010 m a.s.l.), collected by Dong Dazhi, Liang Hongbin and Hou Qingbai on 25 May 2005.|
|Diagnosis||Diagnosis. A small (about 520mm TL) brownish-black, slug-eater snake with the tail comprising 22.1% of the TL. One preocular, one crescent-shaped scale perhaps representing fused subocular and postocular, 15 dorsal scale rows with 9 scale rows slightly keeled at midbody, slightly enlarged vertebral scales, 175 ventrals without lateral keels, 76 divided subcaudals, one big black oval patch on the top of the head, two rounded black spots on each side of the head, 60 slightly billowing vertical dark bars on the trunk, 18 bars on the tail (the bars about 1–2 scales wide), and a black band on the neck (the distance of the band from the vertex spot about 8–10 scale-length).|
In terms of pattern, P. nigriceps differs substantially from all other species of Pareas in having a large, nearly oval black patch on the top of the head and two rounded black spots on each side of the head (Fig. 1, Table 1). Pareas nigriceps is superficially most similar to P. stanleyi, but differs in the following traits: one preocular (absent in P. stanleyi, loreal contacts eye in P. nigriceps), one anterior temporal (two in P. stanleyi, except some specimens from Chong’an, Fujian; Zhao et al. 1998), head spot separated from the nuchal band (continues in P. stanleyi), ventrals 175 (158 or fewer in P. stanleyi), subcaudals 76 (excluding terminal spine) (48 or fewer in P. stanleyi; Zhao et al.1998).
In terms of scalation, the number of ventrals and subcaudals in P. nigriceps is similar to that of P. carinatus and P. formosensis. However, P. carinatus and P. formosensis are separated from P. nigriceps by the following traits: anterior temporals 2 or 3 (only one in P. nigriceps), one subocular (occasionally two in P. carinatus) and one postocular (occasionally two in P. carinatus; subocular and postocular fused into a crescent-shaped scale in P. nigriceps). Furthermore, P. formosensis differs from P. nigriceps in the following traits: slightly enlarged dorsal scales that are smooth or feebly keeled in the 3 median rows (only vertebral scales slightly enlarged, and dorsal scales feebly keeled in median 9 rows in P. nigriceps).
Pareas nigriceps differs from P. carinatus, P. formosensis, P. hamptoni, P. iwasakii, P. margaritophorus, P. nuchalis and P. stanleyi in having one anterior temporal only. Pareas boulengeri differs from P. nigriceps in having a loreal in contact with eye, unenlarged vertebral scales and smooth dorsal scales. As mentioned above, P. monticola differs substantially from P. nigriceps in scalation. Pareas nigriceps is distinguished from P. carinatus, P. formosensis, P. hamptoni, P. iwasakii, P. nuchalis and P. stanleyi and P. monticola by having a subocular and a postocular fusing into a crescent-shaped scale. Important differences in scalation and color pattern among the species of Pareas are summarised in Table 1 in GUO & DENG (2008).
|Etymology||The specific name refers to the large black spot on the upper side of head.|