Friday, October 30, 2015

The diet of Gasperetti’s sand viper

By Zuhair Amr via Wikimedia Commons
Gasperetti’s sand viper, Cerastes gasperetti, is the most common snake in Saudi Arabia. However, this snake remains poorly studied. It is distributed throughout many deserts in Egypt, Jordan and Saudi Arabia. Horned viper is a nocturnal, true desert snake and prefers sandy soil with some vegetation. Horned vipers are generally considered opportunistic predators with varied diets. However no study has specifically addressed the diet of Cerastes gasperettii.  Al-Sadoom et al. (2015) examined 238 specimens from Al-Thumama area, in the central region of Saudi Arabia collected over a period of one year May, 1998 – April, 1999. The digestive system was examined. Eighty specimens of both sexes were studied for gut content analysis. They found larger specimens of Gasperetti’s sand viper feeds mostly on rodents (Gerbillus cheesmani and Mus musculus) which were found in snakes with larger size and formed 70% of the stomach contents. Arthropods (beetles) constituted 15% of the contents and lizards (Acanthodactylus schmiditi and Stenodactylus slevinii) form 10% of the total diet. The remaining 5% of the stomach content was completely digested and could not be identified.

Al-Sadoon, M. K., & Paray, B. A. (2015). Ecological Aspects of the Horned viper, Cerastes cerastes gasperettii in the Central Region of Saudi Arabia. Saudi Journal of Biological Sciences.

Wednesday, October 14, 2015

The Cuban Racer in the Bahamas

Cubophis cantherigerus cantherigerus. Photo by Lisa Ferguso
Dipsadidae is one of the largest snake families with more than 754 species, mostly distributed in the Neotropics. The subfamily Xenodontinae is exclusive to South American to Mexico and the West Indies. Mexico, and the West Indies, and highly diverse in both morphology and natural history. The Tribe Alsophiini holds about 43 species restricted to the West Indies. These are typically slender, fast-moving, and active diurnal foragers often commonly called racers. While taxonomic classifications of xenodontines were historically based on hemipenial, dentition, external morphology, and color pattern, recent molecular analyses of Alsophiini are not necessarily in agreement regarding monophyly of the group In 2012, Krysto et al. (2015) collected the first known dipsadid snake on the Cay Sal Bank, The Bahamas. Only two snake species have been previously recorded from any island on the Cay Sal Bank: the Bahamian Slender Blindsnake, Typhlops biminiensis, on Elbow Cay; and the Northern Bahamas Trope, Tropidophis curtus (Garman 1887), on both Elbow Cay and Double Headed Shot Cay.

Krysto et al. examine the external morphology, dentition, and color pattern, and conduct molecular analyses of Caribbean Alsophiine snakes to determine the species identity and phylogenetic placement of the Cay Sal Bank snake. They analyze 3,426 base pairs (bp) of sequence data derived from five mitochondrial loci and one nuclear locus using Maximum Likelihood (ML) and Bayesian Inference (BI) methods. Our molecular data agree with some aspects of morphology (e.g., scale counts, dentition, and color pattern) supporting identification of this specimen as the Cuban Racer, Cubophis cantherigerus cantherigerus (Bibron 1840), a species previously regarded as endemic to Cuba. This discovery provides another example of the strong Cuban affinities of the terrestrial vertebrate fauna of the Bahamian islands.

KRYSKO, K. L., STEADMAN, D. W., NUĂ‘EZ, L. P., & LEE, D. S. (2015). Molecular phylogeny of Caribbean dipsadid (Xenodontinae: Alsophiini) snakes, including identification of the first record from the Cay Sal Bank, The Bahamas. Zootaxa, 4028(3), 441-450.