Xenodermus
Xenodermus javanicus, also known as the Dragon Snake, Javan Tubercle Snake, Javan Mudsnake, or Rough-backed Litter Snake,[1][2][3] is a small non-venomous, semi-fossorial Colubrid snake belonging to the monotypic genus Xenodermus.[4] This species is best known for their characteristic dorsal scales and interesting defense mechanism in which they stiffen their entire bodies when threatened. X. javanicus is nocturnal and subsists on a diet of frogs, tadpoles and small fish.[5] While they are known to perish once placed into captivity, some herpetoculturists have been successful in keeping them.
| Xenodermus | |
|---|---|
 | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Xenodermidae |
| Genus: | Xenodermus Reinhardt, 1836 |
| Species: | X. javanicus |
| Binomial name | |
| Xenodermus javanicus Reinhardt, 1836 | |
Distribution and habitat
Xenodermus javanicus is found in the Malay Peninsula (Malaysia, Thailand, and one old record from the southermost tip of Myanmar) and parts of the Greater Sunda Islands (Sumatra, Java, and Borneo, as well as some smaller islands).[1][2] It inhabits damp areas near water, including forests, swamps, marshes, and rice fields, at elevations below 1,300 m (4,300 ft), but most commonly between 500–1,100 m (1,600–3,600 ft) above sea level.[1]
Description
Xenodermus javanicus has a distinct head and long tail. The body is slender and compressed. The total length is about 50 cm (20 in).[6] Males can be distinguished from females by examining the overall size, tail thickness, tail length, and cloacal vent for the presence of a hemipenial bulge. Females will be larger than males and have thinner, shorter tails while lacking a hemipenial bulge. Conversely, males will be smaller in comparison, have thicker, longer tails and exhibit a hemipenial bulge.[5]
Differentiation of sex chromosomes and karyotype characterization
Xenodermus javanicus has an unusual chromosol number of 2n=32, contrasting with the most typical snake karyotype with a stable chromosomal number of 2n=36. The karyotype includes heteromorphic ZZ/ZW sex chromosomes with a heterochromatic W.[8]
Behavior
Diet
Xenodermus javanicus subsist mainly on frogs, tadpoles and small fish.[5]
Conservation status
Xenodermus javanicus are rare in the northern parts of their range, but are common in Java. There seem to be no major threats to them, and they can persist in wet agricultural lands such as rice fields. They could be potentially threatened by agricultural pollutants.[1]
References
- Wogan, G.; Grismer, L. & Chan-Ard, T. (2012). "Xenodermus javanicus". IUCN Red List of Threatened Species. 2012: e.T190514A1954501. Retrieved 2 July 2020.
- Xenodermus at the Reptarium.cz Reptile Database. Accessed 2 July 2020.
- Andrew M. Durso (10 September 2013). "Dragonsnakes". Life is Short, but Snakes are Long. Retrieved 2 July 2020.
- Various (1936). Bulletin of the Raffles Museum, Issues 12-14. University of Michigan. pp. 172–173. Retrieved 2013-08-16.
- "Dragon Snake Care Guide". Creatures of Nightshade. Retrieved 2020-09-26.
- Rooij, Nelly de (1917). The Reptiles of the Indo-australian Archipelago. II Ophidia with 117 Illustrations. Brill Archive. pp. 44–45. Retrieved 2013-08-16.
- Nightshade, Scarlett. "Creatures of Nightshade". Creatures of Nightshade. Retrieved 2020-09-26.
- Rovatsos, Michail; Johnson Pokorná, Martina & Kratochvíl, Lukáš (2015). "Differentiation of sex chromosomes and karyotype characterisation in the dragonsnake Xenodermus javanicus (Squamata: Xenodermatidae)". Cytogenetic and Genome Research. 147 (1): 48–54. doi:10.1159/000441646. PMID 26575989. S2CID 20902555.