Wednesday, April 8, 2015

Blackwater Mud Snake, Phytolophis punctata Gray, 1849

Phytolophis punctata Gray,1849 Catalogue of the Specimens of Snakes in the Collection of the British Museum, p. 68. Type locality "India" (in error).  Holotype: BMNH 1946.1.2.37.

Eurostus heteraspis Bleeker, 1859 Natuurkundig Tijdshrift voor Nederlandsch Indiƫ, 14:440. Type locality: Sinkawang, Borneo. Collector: Dr. Bleeker. Holotype: BMNH 1946.1.2.39.

Tachyplotus hedemanni Reinhardt, 1866 Videnskabelige Meddelelser fra Dansk Naturhistorisk Forening i Kjobenhaun, p. 151. Type locality: Billiton Is. [Indonesia]. Holotype: ?RNHM

Pythonopsis borneensis Peters, 1871 Monatsberichte der Preussischen Akademie der Wissenschaften zu Berlin, p. 576. Type locality: Sarawak. Holotype: Berlin Museum?

Hypsirhina hageni Lidth de Jeude, 1890 Notes from the Leyden Museum, 12:20. Pl. 1. Type locality: “Laboean.” David and Vogel (1996:118) note that the type locality given by Lidth de Jeude for it as Laboean or Lubuan is now known as Belawan, Sumatra [3°47’N 98°41’E]. This city is on the northeast coast of Sumatera Utara.  Holotype: RMNH 862.

Hypsirhina punctata - Boulenger, 1896 Catalogue of Snakes in the British Museum 3:12.

Enhydris punctata - Kinghorn, 1929 Snakes of Australia, p. 89. [probably based upon a misidentified Fordonia.]

This is in all likelihood a collection of several species that are isolated in peat swamp forests and associated streams across the range of the species group. It seems probable that one or more of the names in the synonymy above are valid, but because specimens are relatively rare and many specimens lack specific locality data it is not possible to currently sort these out.

Etymology: The name punctata may have originated from the Latin punctum, meaning “spot,” however this snake does not have a spotted pattern, but it does have yellow cross bars. It seems more likely it is derived from the Latin punctura, which means “hole” or “prick”, or “puncture” and refers to its bite. Common Names: The Phytolopsis (Gray, 1849); Spotted Water-snake (Kinghorn, 1929).

Distribution: This is a species endemic to the Sunda Shelf and peninsular Malaysia, it may eventually be found in extreme southern Thailand. Thus, it ranges from Sumatra and the west coast of peninsular Malaysia eastward to Borneo. Confusion about this species’ presence in Australia is widespread in the literature. Kinghorn (1929) appears to be the first person to suggest its presence in Australia, he wrote, "During recent years this species has been found in north Australia but previously it was thought to be restricted to Sumatra, Borneo and neighbouring islands." Cogger (1975) had a map for it in his first edition of Reptiles and Amphibians of Australia, but omitted it from latter editions. Gow (1977, plate 7) has a photo labeled Enhydris punctata from Darwin, Australia. It is in fact a specimen of Fordonia.

Size: The largest specimen measured was 760 mm in total length with a 95 mm tail. David and Vogel (1996) wrote: “This small [snake] has a maximum recorded length of 450 mm, with adults averaging 340 - 400 mm.” Similarly, Ernst and Zug (1996) have a table in Appendix 2 that gives the maximum length of this species as 0.45 m. However, adults of these snakes are massively built and reach at least a length 760 m, but most of the museum specimens available are juveniles. Tails on males are 19 - 21% of the SVL, while females have tails that are 8.5 - 17.8% of the SVL.

External Morphology: The head is slightly distinct from neck; this seems to be true for smaller specimens rather than larger ones. The overall body shape is cylindrical and slightly depressed anteriorly, including the head. The eyes are small; the diameter is about 1.5 times the eye-nostril distance. The eyes are more dorsal than dorsolateral in position. On the head the rostral scale is pentagonal, barely visible from above, and about as broad and it is tall. The nasals are semi-divided with the cleft touching the first labial. The nasals scales have a diameter that is equal to the eye diameter; these and most of the other head scales are tuberculate. The internasal is small and partially penetrates the seam between the nasals; it is about one fourth of a nasal scale in area; in one specimen from Borneo (MCZ 5165) it is divided. It is quadrangular. Each of the prefrontals is about twice the size of the internasal and each is in contact with a loreal. The frontal’s length is about equal to the interorbital distance. It is triangular with the apex pointing posteriorly. The parietals are about equal in length to the frontal. These and most of the other head scales are imbricate. The loreal may be single or divided (it is single in the type specimen), with the anterior section being twice as broad as the posterior section. It is in contact with upper labials 1 - 4 or 1 - 5. The single supraocular is narrower on the front margin than it is on the posterior margin. The preocular can be single or divided. There are two postocular scales, with the ventral scale extending slightly under the orbit to form a partial subocular. There are no suboculars. The temporal formula is 1 + 2; the tertiary temporal scales are indistinguishable from occipitals. There are 12 - 14 upper labials; the first five or six are anterior to the orbit, overlap each other and are very narrow at the point the contact the loreal. The sixth or seventh is wider, enters the orbit and is divided into two tiers. The posterior labials are divided so that they form three or four tiers of scales. At the 11th labial the angle of the lower jaw turns upward. On the chin the lower labials number 12 - 15. The first pair forms the mental groove in most specimens, but in the type specimen (BM 1946.1.2.37) the first two lower labials form the mental groove. The first 5 are in contact with the anterior pair of chin shields. The sixth is the largest. The anterior pair of chin shields are described by Gyi as “petal shaped” – meaning that they are very broad, almost as broad as they are long. The second pair is greatly reduced and separated by a pair of smaller scales. The gulars number seven. On the body the dorsal scales are in 23 - 27 rows on the neck, at mid-body they number 25 - 27, and near the vent the rows are reduced to 21 - 23 rows. The first several rows are ovate and they become slightly more elongated toward the midline; they are smooth and iridescent. Smedley (1931) reported five specimens (possibly immature) in the Raffle’s Museum collected on the east coast of the east coast of the Malay Peninsula, all of which have 23 scale rows, I have not seen any specimens with 23 rows at mid-body. The ventrals are broad, about 3 - 3.5 times the height of a nearby dorsal scale. They number 148 - 160 (148 - 151 in males, 155 - 160 in females).The anal plate is divided and slightly longer than the preceding ventral. On the tail dorsal scales on the tail are ovate. The subcaudal scales are divided and number 27 - 46 (32 - 44 in females, 46 - 48 in males). Three males have tails that are 0.19 - 0.20 of the SVL; nine females have tails that are 0.09 - 0.21 of the SVL. At the base of the tail the width is 94% of the height based upon the average of five specimens. The crown of the head is black with a yellow interorbital stripe that is indistinct. The dorsum is black with the exception of a faint occipital stripe and incomplete transverse bars on the anterior of the body, which may appear as yellow spots. Scale rows one and two are mostly yellow with some invasion of dark pigment. Scale rows 3 - 5 are black with yellow spots or solid black. The lateral areas of the head have some yellow blotches and the snout is black; the chin and ventral are yellow; the ventral tail is yellow with a mid-black line.

Natural History: Museum notes for peninsular Malaysian specimens (FMNH250111-2) state that they were collected in “blackwater streams.” And a specimen collected at Pondak Tanjung Forest Reserve, Selama Perak, Malaysia on 1 March 2001 by Shahrul Anuaroast came from a peat swamp forest. These notes suggest that this uncommon snake is most likely a peat swamp or blackwater habitat specialist. The fragmented nature of this habitat and the high level of fish endemism in the peat swamps of Southeast Asia add an interesting dimension to this species complex, and to homalopsid diversity. The details of its life style remains virtually unknown. One specimen, MCZ 5165, contained 15 yolked follicles.

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