Uropeltidae

Uropeltidae
Ceylon earth snake, Uropeltis ceylanica
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Reptilia
Order:Squamata
Suborder:Serpentes
Superfamily:Uropeltoidea
Family:Uropeltidae
J.P. Müller, 1832
Synonyms
Common names: Shieldtail or shield-tailed snakes.[2]

The Uropeltidae are a family of primitive, nonvenomous, burrowing snakes endemic to peninsular India and Sri Lanka. The name is derived from the Greek words ura ("tail") and pelte ("shield"), indicating the presence of the large keratinous shield at the tip of the tail. Currently, eight genera are recognized, comprising over 50 species.[2] These snakes are not well known in terms of their diversity, biology, and natural history.

Description

Tails of Uropeltidae

These are small snakes, with adults growing to between 20 and 75 cm in length. They are adapted to a fossorial way of life, which is apparent in their anatomy. The skull is primitive and inflexible, with a short, vertical quadrate bone and rigid jaws; the coronoid bone is still present in the lower jaw. The orbital bones are absent, the supratemporal is vestigial and the eyes are small and degenerate, not covered by a brille, but by large polygonal shields. However, the pelvis and hind limbs, the presence of which is also considered a primitive trait, have disappeared in this family.[3]

The tail is characteristic, ending in either an enlarged rigid scale with two points, or more often an upper surface with a subcircular area covered with thickened spiny scales, or a much enlarged spiny plate. The ventral scales are much reduced in size.[3] The body is cylindrical and covered with smooth scales.

Behaviour and natural history

Many species of shieldtail snakes are rather poorly known in terms of natural history. Field studies indicate that most species are obligate burrowers and may often come out on to soil surface during rainy nights. Even roadkills of these snakes have been recorded by field biologists during peak monsoon rains. They seem to prefer the humus-rich topsoil layers and rarely burrow deeper inside (like during very hot or dry weather).

When approached by predators, these snakes do not bite like most snakes, but coil their bodies into a ball and hide their heads tucked underneath. Some may poke with their harmless tail tip, like a worm snake. Many have a drab and dull-coloured back, but a very bright, contrastingly coloured underside (such as bright yellow, red, etc.) to startle predators by turning upside down and twitching. This aposematic colouration wards off would-be predators.[4]

Geographic range

They are found in peninsular India and Sri Lanka.[1] In India, their distribution is mainly along the hills of Western Ghats, and a few species occur in other areas such as the Eastern Ghats and hills of Central India. In Sri Lanka, they occur in many biotopes including dry zone and the plains.

Evolutionary significance

Because of their peculiar geographic distribution, with many hill ranges in South India and Sri Lanka having an endemic shieldtail, they are thought to be analogous to Darwin's finches, in a broader sense - an evolutionary radiation.[5] This is the only family of snakes endemic to South Asia. Genetic studies on this group have brought forth largely similar results as regards common ancestry and phenotypic diversification patterns.[6][7][8] Molecular dating analysis has suggested that uropeltids originated around the Paleocene - Eocene boundary splitting from its sister clade Cylindrophiidae + Anomochilidae around 56 MYA.[8]

Feeding

Their diets consist mostly of invertebrates, particularly earthworms, and many species have actually been observed in the wild by researchers to eat earthworms. Frank Wall, who dissected many species for analysing the gut contents to study the diet, remarks about the presence of worms and mud.

Reproduction

All members of this family retain eggs that hatch within the body of the mother (ovoviviparity).[9]

Genera

Genus[2] Taxon author[2] Species[2] Common name Geographic range[1][10]
Brachyophidium Wall, 1921 1 Southern Western Ghats, India
Melanophidium Günther, 1864 4 Western Ghats, India
Platyplectrurus Günther, 1868 2 Southern Western Ghats, India
Pseudoplectrurus G.A. Boulenger, 1890 1 Western Ghats, India
Plectrurus A.H.A. Duméril, 1851 4 Western Ghats, India
Rhinophis Hemprich, 1820 18 Sri Lanka and South India
Teretrurus Beddome, 1886 1 Western Ghats
UropeltisT Cuvier, 1829 23 Peninsular India

T) Type genus[1]

See also

References

  1. 1 2 3 4 McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
  2. 1 2 3 4 5 "Uropeltidae". Integrated Taxonomic Information System. Retrieved 17 August 2007.
  3. 1 2 Parker HW, Grandison AGC. 1977. Snakes -- a natural history. Second Edition. British Museum (Natural History) and Cornell University Press. 108 pp. 16 plates. LCCCN 76-54625. ISBN 0-8014-1095-9 (cloth), ISBN 0-8014-9164-9 (paper).
  4. ↑ Rajendran M. V. ( 1985) Studies in Uropeltid Snakes. Madurai university Press, Madurai.
  5. ↑ Ganesh, S. R. 2015. Shieldtail snakes (Reptilia: Uropeltidae)– the Darwin's finches of south Indian snake fauna? Manual on Identification and Preparation of Keys of Snakes with Special Reference to their Venomous Nature in India., Govt. Arts College, Ooty, 13-24.
  6. ↑ Cadle, J.E., Dessauer, H.C., Gans, C. & Gartside, D.F. (1990) Phylogenetic relationship and molecular evolution in uropeltid snakes (Serpentes: Uropeltidae): allozymes and albumin immunology. Biological Journal of the Linnean Society, 40, 293–320.
  7. ↑ Bossuyt, F., Beenaerts, N., Meegaskumbura, M., Gower, D.J., Pethiyagoda, R., Roelants, K., Mannaert, A., Wilkinson, M., Bahir, M.M., Manamendra-Arachchi, K., Oommen, O.V., Ng, P.K.L., Schneider, C.J. & Milinkovitch, M.C. (2004) Local endemism within the Western Ghats-Sri Lanka biodiversity hotspot. Science, 306, 479–481.
  8. 1 2 Cyriac, V.P.; Kodandaramaiah, U. (2017). "Paleoclimate determines diversification patterns in the fossorial snake family Uropeltidae Cuvier, 1829" (PDF). Molecular Phylogenetics and Evolution. 116: 97–107. doi:10.1016/j.ympev.2017.08.017.
  9. ↑ Tinkle, D.W., Gibbons, J.W. (1977). The Distribution and Evolution of Viviparity in Reptiles. University of Michigan Museum of Zoology, Miscellaneous Publications 154. PDF
  10. ↑ Pyron R. A.; Ganesh S. R.; Sayyed A.; Sharma V.; Wallach V.; Somaweera R. (2016). "A catalogue and systematic overview of the shield-tailed snakes (Serpentes: Uropeltidae)" (PDF). Zoosystema. 38 (4): 453–506. doi:10.5252/z2016n4a2.

Further reading

  • Das I. 2002. A Photographic Guide to Snakes and Other Reptiles of India. Sanibel Island, Florida: Ralph Curtis Books. 144 pp. ISBN 0-88359-056-5. (Uropeltidae, p. 59).
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