Sunday, February 12, 2012

The Herpetofauna of Three Tobago Satellite Islands

Hemidactylus palaichthus, a gecko with an unusual satellite
 island distribution . JCM
The herpetofauna of the satellite islands off Trinidad is fairly well-known as the result of the work done by Hans Boos in the 1980's. However, the herpetofauna of the satellite islands of Tobago is less well-known with the exception of the reptiles of Little Tobago Island reported on Dinsmore. Now, more recent surveys by Stevland Charles and colleagues have examined the second and third largest satellites of Tobago, St. Giles Island and Goat Island, Their new paper documents preliminary searches for amphibians and reptiles on these satelite islands as well as summarizes previous records and literature. Goat Island, Little Tobago Island and St. Giles Island are administered by the Tobago House of Assembly (T.H.A.) with the last two being categorized as game sanctuaries. Brief visits of only a few hours to each of the islands were made by the authors and searches were conducted for reptiles and amphibians. Microhabitats including leaf litter, tree trunks, under rocks, bark and logs, crevices in rocks, and anthropogenic locations including walls, ceilings and crawl spaces under buildings and piles of rubble that may serve as refuges for herpetofauna were searched.

They found four species on Goat Island (Thecadactylus rapicauda, Iguana iguana, Anolis richardii, and Cnemidophorous lemniscatus) all species that are exceptionally good at dispersal and colonization.St. Giles Island produced five speices (Thecadactylus rapicauda, Iguana iguana, Gonatodes ocellatus, Mastigodryas dunni, and an unidentified skink in the genus Mabuya), again species that excell at disperal and colonization.

Little Tobago has a more specious herpetofauna, undoudtedly due to its greater size. The authors report includes: Rhinella marina, Leptodactylus fuscus, Gonatodes ocellatus, Hemidactylus palaichthus, Sphaerodactylus molei, Thecadactylus rapicauda, Bachia heteropa alleni, Ameiva ameiva (now A. atrigularis), Cnemidophorus lemniscatus, Iguana iguana, Leptophis ahaetulla coeruleodorsus, and Mastigodryas boddaertri dunni (now M. dunni). 

Given the proximity of these island to Tobago (Goat Island is about 0.95 km, St. Giles Island is about 0.74km, and Little Tobago is about 1.77 km from Tobago) the presence of these species is not too unexpected. However, it very useful to have these distributions documented for biogeography studies.

Charles, SP, Stephen Smith, S, & de Jonge J. M. A.. 2011. Terrestrial Herpetofauna of Some Satellite Islands North-east of Tobago with Preliminary Biogeographical Comparisons with Some Satellite Islands North-west of Trinidad. The Living World Journal of the Trinidad and Tobago Field Naturalist's Club, 2011, 54-59.

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