Opisthotropis (Gunther, 1872)

Yang, Jian-Huan, Wang, Ying-Yong, Zhang, Bing, Lau, Michael Wai-Neng & Chou, Wen-Hao, 2011, Revision of the diagnostic characters of Opisthotropis maculosa Stuart and Chuaynkern, 2007 with notes on its distribution and variation, and a key to the genus Opisthotropis (Squamata: Natricidae), Zootaxa 2785 (1), pp. 61-68 : 65-66

Key to the species of Opisthotropis

With reference to the literature (see Zhao et al. 1998; Stuart 2006; Stuart an&d Chuaynkern 2007; Murphy et al. 2008; Ziegler et al. 2008) and the information from the additional specimens outlined in this paper, we provide a key to the species of Opisthotropis plus the similar species Parahelicops annamensis and Paratapinophis praemaxillaris . Pope (1935) placed Paratapinophis in the synonymy of Opisthotropis and it remained there until Murphy et al. (2008), without phylogenetic analysis, removed it based on its morphological distinctiveness. Smith (1943) placed Parahelicops in the synonymy of Opisthotropis and most authors have since followed that as recently as Stuart & Chuaynkern (2007) although some do recognize Parahelicops ( Orlov 1995; Orlov et al. 2003, for example). Ziegler et al. (2008) were uncertain about Parahelicops and use both generic names for annamensis . The key is as follows:

1 Midbody scales in 15 rows.............................................................................. 2

- Midbody scales in 17 or 19 rows......................................................................... 6

2 All scale smooth..................................................................................... 3

- Posterior dorsal scales keeled............................................................................ 5

3 Temporal scales 1+2, subcaudals 51–58....................................................... O. guangxiensis

- Temporal scales 1+1, subcaudals 60–97.................................................................... 4

4 Uniformly glossy dark above; internasals in contact with loreals......................................... O. jacobi

- Glossy black dorsum with a distinctly yellow spot on each dorsal scale; internasals not touching loreals....... O. maculosa

5 Supralabials 6, subcaudals 58–89, ventral scales 176–198............................................. O. kikuzatoi

- Supralabials 8–9, subcaudals 117–123, ventral scales 167–169............................. Parahelicops annamensis

6 Midbody scales in 17 rows.............................................................................. 7

- Midbody scales in 19 rows............................................................................. 16

7 Anterior body scales in 17 rows.......................................................................... 8

- Anterior body scales in 19 rows......................................................................... 14

8 Internasals in contact with loreals....................................................................... 9

- Internasals not touching loreals.......................................................................... 10

9 Subcaudals 39–47......................................................................... O. daovantieni

- Subcaudals 55–89............................................................................. O. spenceri

10 Preoculars absent; loreals in contact with eyes.............................................................. 11

- Preoculars present; loreals not touching eyes............................................................... 12

11 Olive dorsum with light yellow crossbars............................................................. O. cheni

- Dorsum with black and yellow striped pattern...................................................... O. latouchii

12 Presence of a dark lateral stripe that sharply separates the dark dorsal from the pale ventral coloration; supralabials 10 (rarely 9 or 11)...................................................................................... O. lateralis

- Dark lateral stripes absent; supralabials 7–9............................................................... 13

13 Olive-black above, each scale edged with white margin; dorsal scales feebly keeled above 2nd scale row from the nape to the tail; supralabials 8 (rarely 9)................................................................... O. andersonii

- Blackish - brown above, each scale with uniform color; dorsal scales smooth on nape, feebly keeled on body, strongly keeled towards the tail; supralabials 7 (rarely 6 or 8)....................................................... O. maxwelli

14 Anterior temporal scales one........................................................................... 15

- Anterior temporal scales two................................................................. O. tamdaoensis

15 With single prefrontal scale......................................................................... O. ater

- With divided prefrontal scales..................................................................... O. rugosa

16 Anterior body scale 21 rows...................................................................... O. alcalai

- Anterior body scale 19 rows............................................................................ 17

17 Posterior body scale 17 rows........................................................................... 18

- Posterior body scale 19 rows.................................................................. O. kuatunensis

18 Dorsal scales smooth (female) or slightly keeled (male)............................... Paratapinophis praemaxillaris

- Dorsal scales strongly keeled........................................................................... 19

19 Suboculars two...................................................................................... 20

- Suboculars absent............................................................................. O. balteata

20 Internasal in contact with loreal, preocular two, suprarabials 11–12........................................ O. typica

- Internasal not in contact with loreal, preocular one, suprarabials 9..................................... O. boonsongi