Anderson's Mountain Keelback

description

Description. Measurements, scalation and body proportions of eight adult specimens are listed in Table 3. The examined specimens roughly conform to the previous descriptions (Boulenger 1888; Zhao et al. 1998), and show significant variation. Body cylindrical; adult specimens measuring 378 – 462 mm in TL; tail short, TaL of 15 – 20 % of TL; Head small, indistinct from neck; rostral concave, visible from above, slightly enlarged, more than twice as broad as deep, RW 31 – 37 % of HW; nasal directed dorsolaterally, rectangular or pentagonal, in contact with first two supralabials ventrally, with loreal and prefrontal posteriorly, with internasal dorsally, with rostral anteriorly; a short vertical cleft below the nostril and dividing nasal into anterior and posterior parts, pointing to the posterior upper-angle of first supralabial (n = 3), to the anterior upper-angle of second supralabial (n = 3), or connecting with the suture between first and second supralabials (n = 4); a single loreal, more than twice as long as deep (LoL / LoD 2.1 – 2.9), not in contact with internasal, in contact with second, third and fourth supralabials (in contact with second, third, fourth and fifth in left s

Revisions of two poorly known species of Opisthotropis Günther, 1872 (Squamata: Colubridae: Natricinae) with description of a new species from China

diagnosis

Revision of diagnosis. This species is characterized by the combination of (1) TL 378 – 462 mm in adult specimens; (2) TaL 15 – 20 % of TL; (3) rostral concave, slightly large, RW 31 – 37 % of HW; (4) nasal in contact with first and second supralabials; (5) loreal more than twice as long as deep; (6) loreal entering orbit or not, in contact with second to fourth or to fifth supralabials; (7) supralabials 7 – 8, the last one significantly smaller than the adjacent preceding one; (8) infralabials 7 – 10; (9) dorsal scale rows 17: 17: 17; (10) dorsal scales smooth on the neck, feebly keeled on the middle part of body, rather strongly keeled on posterior part of body, strongly keeled on the tail; (11) ventrals 141 – 174; subcaudals 43 – 60; (12) olive-green to olive-brown above, with distinct or barely perceptible longitudinal black stripes parallel to each other, crossing each scale; yellow beneath, with black markings in life.

Revisions of two poorly known species of Opisthotropis Günther, 1872 (Squamata: Colubridae: Natricinae) with description of a new species from China

discussion

Remarks. Opisthotropis andersonii was described originally from a single juvenile specimen with TL 240 mm, TaL 45 mm, which was obtained, through the kind mediation of Dr. J. Anderson from the Directors of the City Hall Museum, Hong Kong, labelled as from Hong Kong, presented to the City Hall Museum by C. Ford (Boulenger 1888). As the City Hall Museum has been closed for a long time and we have been unable to examine this preserved specimen. According to the original description of Boulenger (1888), O. andersonii possessed a preocular, two suboculars and a postocular. Zheng (1992) examined two specimens (BM. 217 and 218, collected on 1956) deposited in the British Museum, London and considered that O. andersonii possessed two preoculars and two postoculars, no subocular. Obviously, Zheng (1992) treated two suboculars (i. e., pre-subocular and post-subocular) considered by Boulenger (1888) as lower preocular and lower postocular, respectively. We follow the descriptions of Zheng (1992). Opisthotropis andersonii is oviparous, probably feeds on semi-aquatic earthworms, and sometimes does well in captivity on a diet of earthworms (Karsen et al. 1998).

Revisions of two poorly known species of Opisthotropis Günther, 1872 (Squamata: Colubridae: Natricinae) with description of a new species from China

distribution

Distribution and habitat. Opisthotropis andersonii has been recorded in Hong Kong and adjacent Shenzhen City, extending north to Guangzhou City, China, and in northern and central Vietnam (David et al. 2011). It is a low mountain dweller, commonly found in montane fast or slow-flowing streams, tiniest trickles covered with bare rocks, pools and ditches, surrounded by moist subtropical evergreen broadleaved forests.

Revisions of two poorly known species of Opisthotropis Günther, 1872 (Squamata: Colubridae: Natricinae) with description of a new species from China