Sunday, March 27, 2016

Selangor Mud Snake, Raclitia indica Gray 1842

Raclitia indica Gray 1842 Zoological Miscellany, p. 67. Type locality: Malay Peninsula. Syntypes: BMNH 1946.1.2.36, 1946.1.2.46.

Hypsirhina indica - Boulenger, 1896 Catalogue of Snakes in the British Museum.3:4.

Enhydris indica - Tweedie, 1957 Snakes of Malaya, p. 89.

Diagnosis: A snake with seven upper labials, one postocular, and 19 scale rows on the neck and mid-body, which are reduced to 17 rows in front of the vent. The 19 rows of dorsal scales at mid-body will separate it from most other homalopsids with the exceptions of Hypsiscopus plumbea and Miralia alternans. However, plumbea has a single internasal that does not make contact with the loreal and a dorsal pattern that is uniform in coloration, while M. indica has a divided internasal scale that does contact the loreal on each side, and it has a pattern of irregular transverse bands. M. alternans has two postoculars, less than 143 ventral scales, and eight upper labials, while E. indica has 173 - 175 ventral scales.

Etymology: The name indica is probably derived from the Latin Indicus, meaning of India, and probably refers to the “East Indies” or Southeast Asia in a general sense.

Distribution: This poorly known species occurs at Selangor, Malaysia, and possibly Singapore. Literature comments on distribution: Flower (1896) "Malay Peninsula?" Gyi (1970) reported it from the Malay Peninsula. Smith (1930) reported it from near Taiping (Malay Peninsula) based upon a Selangor Museum specimen and from Singapore based upon a Dublin Museum specimen. The Singapore locality is highly problematic. Lim (1975) reported a specimen collected in a jungle stream at Klag in Selangor.

Size: Lim Boo Lait and Kamarudin (1975) reported a specimen with a length of 47 cm. The only specimen measured was a male that had a total length of 345 mm, and a tail length of 42 mm. The tail in the single male was 12% of the SVL.

External Morphology: The body is elongate and the head is slightly depressed. The eyes are dorsolateral and relatively small, having a diameter about equal to the anterior margin of the supraocular.
            On the head the rostral is pentagonal and about twice as broad as tall. The bottom margin shows almost no notching. The rostral is not visible from above. The nasal scales are in contact, both have a nasal cleft that goes to the first labial. The internasal scale is divided and does not penetrate the nasals. The internasals are small, about half the size of the nasals and half the size of the prefrontal scales. The prefrontals are large and are in broad contact with the loreal and are about as long as the supraocular. The frontal is relatively short, less than the interorbital distance, and shorter than the parietals. The parietals are relatively large, about 1.25 times the length of the frontal. The loreal is triangular with the anterior margin much wider than the posterior margin. It is in contact with the second and third upper labials, on the right side. The supraocular is single and much broader posteriorly. It has a tab which extends off the posterior end and forms what could be considered an upper postocular scale. The single preocular is small and taller than long; the postocular is singular and broad; there are no subocular scales. There are seven upper labials, the fourth enters the orbit, and the seventh is the largest. The primary temporal is elongated, as long as the last two upper labials. There are two secondary temporal scales.
            On the chin the lower labials number eight or nine, the fifth is the largest. The first four are in contact with the first pair of chin shields. The anterior chin shields are longer than the second pair. The second pair is separated by a pair of smaller scales and barely distinguishable from the gulars. There are four gular scales.
            On the body the smooth dorsal scales on the neck and mid-body are in 19 rows, these rows are reduced to 17 in front of the vent. The first row is ovate and they become more elongate toward the midline. The ventral scales are about 3 times the length of a nearby dorsal scale. Ventral scales number 173 - 175 in females and 165 - 175 in males (Gyi, 1970). The anal plate is divided. In the single male specimen examined there are four scales lateral and posterior to the anal plate; on the middle two scales on the right and the bottom two scales on the left are swollen tubercles, difficult to see and more obvious on some scales than others.
            On the tail the dorsal scales on the tail are ovate and smooth. The subcaudal scales are divided and number 28 in a female and 34 in the male specimen. At the base of the tail the width is 78% of the height in one specimen.             
            Color and Pattern. The crown of the head is more or less uniform brown with indistinct light spots on the prefrontals, loreals, and upper labials. There is an incomplete crossbar across the back of the head. The chin scales are brown and spotted and a cream cross bar starts at the angle of the jaw and transverses the gular area. There are 61 light cream bars that transverse the ventral surface and extend onto the third dorsal scale row. The dorsal scales are brown with cream spots scattered in areas to form indistinct and incomplete crossbars particularly on the anterior body. The tail has a similar pattern with a central dark area on the ventral surface.

Natural History
            The overall body form of this snake (small narrow head, thin body, short tail, and a relatively low dorsal scale count) suggests a burrowing existence, thus like some other homalopsids this species may be an aquatic burrower. Lim and Kamarudin (1975) collected a specimen in a jungle stream at Klang in Selangor. Tweedie (1983) reported five known specimens; I have seen only the syntypes. Diet and reproduction data are unknown.



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