Xenotyphlops
| Xenotyphlops | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Infraorder: | Scolecophidia |
| Superfamily: | Typhlopoidea |
| Family: | Xenotyphlopidae Vidal, Vences, Branch & Hedges, 2010 |
| Genus: | Xenotyphlops Wallach & Ineich, 1996 |
| Species | |
|
Two species, see text | |
Xenotyphlops is a genus of snakes, the only genus of the family Xenotyphlopidae, comprising two species found only in Madagascar.[1] These snakes are also known as the Malagasy blind snake.[2]
Evolution
[edit]Xenotyphlops is an ancient group that diverged from other blind snakes during the Cretaceous, following the separation of Madagascar from India. On the newly-isolated Madagascar, the ancestral Xenotyphlopidae and Typhlopidae diverged from one another; Typhlopidae dispersed worldwide from Madagascar while leaving behind a single Malagasy genus (Madatyphlops), while the Xenotyphlopidae remained restricted to Madagascar. Xenotyphlops, Madatyphlops, and the Madagascan big-headed turtle are the only Malagasy terrestrial vertebrates whose isolation on Madagascar is due to Gondwanan vicariance.[3]
Physical characteristics
[edit]The family Xenotyphlopidae is composed of small blind snakes.[2] These members lack cranial infrared receptors in pits or durface indentations.[2] It is thought that these snakes used to have eyes but lost use of them over time.[4] Members of the genus Xenotyphlops are distinguishable externally from the Typhlopidae by possessing a greatly enlarged and nearly circular rostral shield and a single enlarged anal shield.[2] This shield is nearly vertical in a lateral aspect; as a result, the two species have a "bulldozer" appearance. Xenotyphlops get no larger than an earthworm and have translucent pink scales.[4] Xenotyphlops species are internally unique in that they lack a tracheal lung and possess an unexpanded tracheal membrane.[5] Like many other snake families they are assumed to be oviparous.[2] Both species are completely terrestrial.[6]
Geographic range
[edit]Snakes of the genus Xenotyphlops are endemic to the island of Madagascar. Xenotyphlops burrow in the softer sandy soil of Madagascar's coastline forest and shrubland.[4] For over 100 years the genus was known only from the type locality, which was "Madagascar", and only from the type specimens.[7] These snakes presumably live in colonies of subterranean social insects.[2]
Conservation status
[edit]According to the IUCN Red List, X. grandidieri are considered to be critically endangered and X. mocquardi are data deficient.[6] The two biggest threats to these species are Energy production (via mining/quarrying) and biological resource use (via logging and unintentional effects).[6]
Species
[edit]- Xenotyphlops grandidieri (Mocquard, 1905)
- Xenotyphlops mocquardi Wallach, Mercurio & Andreone, 2007
Nota bene: A binomial authority in parentheses indicates that the species was originally described in a genus other than Xenotyphlops.
Etymology
[edit]The specific name, grandidieri, is in honor of French naturalist Alfred Grandidier.[8]
The specific name, mocquardi, is in honor of French herpetologist François Mocquard.[8]
Taxonomy
[edit]In 2013, after examining several newly collected specimens, Wegener et al. concluded that X. mocquardi falls within the range of variation of X. grandidieri, and they proposed that X. mocquardi be considered a synonym of X. grandidieri. This change would make Xenotyphlops a monotypic genus in a monotypic family.[9] The Xenotyphlipidae's sister taxon are the Typhlopidae.[2]
References
[edit]- ^ "Xenotyphlops ". Integrated Taxonomic Information System. Retrieved 29 August 2007.
- ^ a b c d e f g Vitt, Laurie J.; Caldwell, Janalee P. (2013). Herpetology: An Introductory Biology of Amphibians and Reptiles, Fourth Edition. Cambridge, Massachusetts: Academic Press. ISBN 0-12-386919-6. OCLC 934973974.
- ^ Ali, Jason R.; Hedges, S. Blair (2023-05-04). "The colonisation of Madagascar by land‐bound vertebrates". Biological Reviews. doi:10.1111/brv.12966. ISSN 1464-7931.
- ^ a b c "Madagascar blind snake | Xenotyphlops grandidieri ". EDGE of Existence. Retrieved 2020-05-12.
- ^ Species Xenotyphlops grandidieri at The Reptile Database . Retrieved 27 May 2019.
- ^ a b c "The IUCN Red List of Threatened Species". IUCN Red List of Threatened Species. Retrieved 2020-05-12.
- ^ McDiarmid RW, Campbell JA, Touré TA (1999). Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1. Washington, District of Columbia: Herpetologists’ League. 511 pp.
- ^ a b Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Xenotyphlops grandidieri, pp. 105-106; X. mocquardi, p. 181).
- ^ Wegener JE, Swoboda S, Hawlitschek O, Franzen M, Wallach V, Vences M, Nagy ZT, Hedges SB, Köhler J, Glaw F (2013). "Morphological variation and taxonomic reassessment of the endemic Malagasy blind snake family Xenotyphlopidae (Serpentes, Scolecophidia)". Spixiana 36 (2): 269-282.
Further reading
[edit]- Mocquard F (1905). "Note préliminaire sur une collection de Reptiles et de Batraciens offerte au Muséum par M. Maurice de Rothschild ". Bulletin du Muséum National d'Histoire Naturelle 11 (5): 285–288. (Typhlops grandidieri, new species, p. 287). (in French).
- Wallach V, Ineich I (1996). "Redescription of a Rare Malagasy Blind Snake, Typhlops grandidieri Mocquard, with Placement in a New Genus (Serpentes: Typhlopidae)". Journal of Herpetology 30 (3): 367–376. (Xenotyphlops, new genus).
- Wallach V, Mercurio V, Andreone F (2007). "Rediscovery of the enigmatic blind snake genus Xenotyphlops in northern Madagascar, with description of a new species (Serpentes: Typhlopidae)". Zootaxa 1402: 59–68. (Xenotyphlops mocquardi, new species).
External links
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