Description of Neotype. An immature female FMNH 250114, 397 mm SVL with a 99 mm tail, from Singapore collected 1 May 1992 by K. Lim. Rostral slightly visible from above; nasals large, in contact, semi-divided with nasal groove contacting first upper labial. Internasal single; two prefrontals make broad contact with loreal; frontal slightly longer than parietals; loreal single and contacts upper labials 1 – 4. Ocular ring scales: 1 / 1 supraocular, 1 / 1 preocular, 1 / 1 presuboculars, 2 / 1 postoculars, and 1 / 1 postsuboculars. Upper labials 14 / 12, number 6 / 6 are under the orbit, 7 / 7 is the first divided; lower labials 18 / 19, first three contact first chin shield; chin shields in three pairs, first divided lower labial 9 / 8; about 12 gulars before first ventral. Ventrals number 159, the anal plate is divided; ventrals number 74. Dorsal scale rows 39 – 37 – 27, scales are keeled and striated. On the head the snout and anterior crown are dark brown with a posterior occipital pale patch. Upper labials are shaded dark to pale from dorsal to ventral; each side of the head has a dark eye stripe that extends from just before the eye to the buccal " cheeks "; there are 25 light colored bands on the body, 2 – 3 scales wide, outlined in black and separated by 26 dark brown bands that are 5 – 7 scale rows wide. The ventral surface is a uniform yellow with 53 pairs of dark brown spots, one on the outer edge of each ventral; the ventral surface of the tail is mottled black and cream. Variation. The internasal can be single or divided; the loreal is always single in our sample. Scales in the ocular ring number 5 or more (1 supraocular, 1 preocular, 1 presubocular, 1 or 2 postoculars, 1 postsubocular, 0 – 2 suboculars, and rarely upper labial 5 or 6). Upper labials are usually 12 (11 – 14), the first 4 usually contact the loreal (rarely 2 – 4), the first divided upper labial is usually 7; lower labials range from 15 – 19, 16 or 17 are usual; the first 3 or 4 contact the first pair of chin shields. Variation in scale counts: (n = 16 males): Dorsal scale rows at the 10 th ventral 36 – 40 (x = 37.2, SD = 6.11); scale rows at midbody 33 – 39 (x = 36.43, SD = 1.82), scale rows at post body 26 – 29 (x = 27.06, SD = 1.06). Ventrals 159 – 168 (x = 163, SD = 2.55). Subcaudals 78 - 87 (x = 83, SD = 2.43). Variation in females (n = 21 unless otherwise noted): dorsal scale rows on neck 37 – 42 (x = 38.57, SD = 1.09), scale rows at midbody 33 – 40 (x = 37.52, SD = 1.40), scale rows at post body 25 – 30, (x = 27.33, SD = 1.37); ventrals 151 – 166 (x = 160.19, SD = 3.29); subcaudals 65 – 80 (n = 18, x = 74.28, SD = 1.09). Kopstein (1941) reported scale counts for 34 specimens of Homalopsis buccata from four locations on the island of Java (Soetardjo, Grabag, Indramayu, and Bogor). His ranges are very similar to ours; the slight differences in ventral counts may be explained by our use of Dowling’s (1951) ventral scale counting method. Our analysis of Kopstein’s data revealed the following: dorsal scales at midbody 35 – 41; ventrals 158 – 170 (males: n = 20, x = 166.55, SD = 1.87; females: n = 14, x = 163.5, SD = 2.692); subcaudals in males 71 - 86 (n = 17 x = 83.11, SD = 2.61), and subcaudals in females 70 – 84 (n = 11, x = 74, SD = 4.44). Size. Sixteen male SVLs ranged from 167 – 695 mm (x = 479.7, SD = 201.6), and their tails ranged from 56 – 236 mm (x = 150, SD = 58.9). Twenty female SVL’s ranged from 192 – 794 mm (x = 511, SD = 157.08); 15 undamaged tails were 62 – 202 mm (x = 148, SD = 42.59). The SDI is - 1.06 for this species. The largest specimen of H. buccata reported in the literature is a 1228 mm female from Bogor (Kopstein 1941).
Sumber: The masked water snakes of the genus Homalopsis Kuhl & van Hasselt, 1822 (Squamata, Serpentes, Homalopsidae), with the description of a new species