Cryptelytrops insularis (Kramer, 1977)

Kaiser, Hinrich, Carvalho, Venancio Lopes, Ceballos, Jester, Freed, Paul, Heacox, Scott, Lester, Barbara, Richards, Stephen J., Trainor, Colin R., Sanchez, Caitlin & O'Shea, Mark, 2011, The herpetofauna of Timor-Leste: a first report, ZooKeys 109, pp. 19-86 : 47-48

Cryptelytrops insularis (Kramer, 1977) Fig. 27

Common names.

(E) Lesser Sunda Island Pitviper, Island Pitviper, Lesser Sunda White-lipped Pitviper. (T) Samodok. (Mambae) Samor. (Fataluku) Cuale.

Identification.

This snake can be distinguished by both morphology and typical behavior. Characteristic of a pitviper are the paired forward-facing, heat-sensitive pits, posterior to and below to the smaller lateral-facing nares, and the vertically elliptical pupils of the eyes ( Fig. 27 ). Pitvipers documented from Timor-Leste are most frequently bright green in dorsal color with the exception of a reddish stripe on the posterior-most portion of the tail. There exists a second, yellow color morph that apparently is seen in low-rainfall areas in Timor-Leste (CRT, pers. obs.) and also on some of the neighboring islands. Specimens from Wetar are bright yellow whilst some of those from the Komodo Islands are cyan. In the green morph, the labial scales are a yellowish green. The characteristic behavior of these snakes when threatened is to coil the body tightly ( Fig. 27 ) for a defensive strike. These are currently the only venomous reptiles confirmed from Timor-Leste whose bite may have serious implications for humans.

Collection and natural history.

We obtained four specimens of this arboreal pitviper in four localities with distinct habitat types, all in eastern Timor-Leste (Baucau, Viqueque, and Lautém Districts). It is remarkable to note that none of the individuals we located were active in trees, shrubs, or leafy vegetation, as might be expected of members of a supposedly arboreal genus, but were located exclusively on the ground. This leads us to speculate that this island form of the widespread green pitviper ecomorph could be less arboreal than some of its congeners and more of a habitat generalist in the absence of c ompetition from terrestrial pitvipers or true vipers, such as the Southeast Asian Russell’s viper ( Daboia siamensis ) that occurs in sympatry with this species further northwest in the Lesser Sundas. The first specimen we collected was a recent road-kill on the Baucau-Lautém road and was found during the daytime within a very short distance of the beach in dry coastal forest. All other specimens were found by night. Our attention was drawn to the second specimen near Timor Village Hotel by a hotel-worker, who encountered it while walking home in an area of short grass adjacent to human habitations. The third specimen ( Fig. 27 ) was encountered while it rested on a bed of decaying foliage in a forested flood plain adjacent to the large open Lake Ira Lalaro flood plain. The last specimen was found at the edge of a dry rice paddy on the outskirts of Baucau. There were no trees within ca. 50 m of this snake’s position. Reports indicate that pitvipers are relatively common in grassy areas and agricultural plots near human habitations, creating a dangerous situation for barefoot humans active during the hours of darkness. The potential snakebite risk posed by this species is being investigated in collaboration with medical colleagues.

Taxonomic comment.

This species was regarded as a subspecies of the widespread Asian species Trimeresurus albolabris until it was elevated to full species rank by Giannasi et al. (2001). Malhotra and Thorpe (2004) changed the generic assignment from Trimeresurus to Cryptelytrops in their revision of Asian pitvipers.

Figures

Figure 27. Cryptelytrops insularis. Female (USNM [CMD 594], SVL 684 mm, TL 784 mm) from the flood plain of Lake Ira Lalaro, Lautem District. Photo by Hinrich Kaiser.