Wednesday, February 29, 2012

The Whip Snake & The Lizard

The Machete couesse or Neotropical Whipsnake (Mastigodryas boddaerti) is an often seen Trinidad snake because it is terrestrial, diurnal, and often in open habitats. Mike Rutherford (UWI Zoology Museum) took these photos on February 28 on Paria Beach.The lizard is probably an Ameiva or Cnemidophorus. Mike writes, "
It was on the path when we came across it and stayed there for about three minutes, any time we came too close to it to get a photo it started to wriggle its tail. Eventually it swallowed enough of the lizard so it could move off with just the end of the lizards tail still sticking out of its mouth. It disappeared very quickly into the forest. This happened at around 1:30pm about 1/2km from Paria Beach on the 28th February. That day I also found a dead green turtle on Paria Beach, mostly buried in a sandbank and rotted away to just the skeleton, I dug out the skull and brought it back to the museum. And when we eventually reached Paria Waterfall we came across two naked Homo sapiens enjoying the sun, after a loud hello from me we allowed them to maintain their modesty and eventually they too disappeared into the bush!

Saturday, February 25, 2012

Another Name Change for a Trinidad Lizard

Anolis planiceps from Lopinot Valley. JCM
The Anolis chrysolepis species group is distributed across the entire Amazon basin and currently consists of A. bombiceps and five subspecies of A. chrysolepis. These lizards are characterized by moderate size, relatively narrow digital pads, and a small dewlap that does not reach the axilla. D'Angiolella et al. (2011) used the mitochondrial gene ND2 to estimate phylogenetic relationships among putative subspecies of A . chrysolepis and taxa previously hypothesized to be their close relatives. They also assessed the congruence between molecular and morphological datasets to evaluate the taxonomic status of group members. On the basis of the two datasets, the authors present a new taxonomy, elevating each putative subspecies of A. chrysolepis to species status.

Anolis planiceps is known from Venezuela, Trinidad, Guyana, and the states of Roraima and Amazonas in the northern Brazil.It reaches a maximum body length of 76 mm; has a double row of enlarged vertebral scales extending from the nape to base of tail; a few to several rows of weakly keeled scales, increasing in numbertowards the tail, forming a gradual transition between double row of enlarged scales andgranules on flanks; the scales on the upper arms markedly larger than vertebral scales. Supraorbital semicircle scales and enlarged scales, forming pronounced ridge in some specimens. Supraocular region with distinct group of enlarged, weakly keeled, scales surrounded by smaller scales. Interparietal distinctly larger than adjacent scales

Annelise B. D'angiolella, Tony Gamble, Teresa C. S. Avila-Pires, Guarino R. Colli, Brice P. Noonan, and Laurie J. Vitt. 2011. Anolis chrysolepis Duméril and Bibron, 1837 (Squamata: Iguanidae), Revisited: Molecular Phylogeny and Taxonomy of the Anolis chrysolepis Species Group. Bulletin of the Museum of Comparative Zoology 160(2):35-63.

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.

Wednesday, February 1, 2012

Trinidad Ameiva Populations Re-assigned an Old Name.

Ugento and Harvey (2011) noted Ameiva ameiva has been a polytypic species and that the nomenclatural history of the species has been chaotic. They reviewed the species and concluded that Ameiva ameiva in Venezuela is composed of four species: A. ameiva (Linnaeus), A. atrigularis Garman, A. praesignis (Baird & Girard), and they describe a new species, A. pantherina. Garman’s Ameiva atrigularis inhabits the forested areas of northcentral and northeastern Venezuela, the Isla de Margarita, the Peninsula de Paria and Trinidad.
An Amevia atrigularis from the Arima Valley, Trinidad. JCM
Garman’s Ameiva atrigularis can be distinguished from other species by a combination of traits including: smooth dorsal head scales; a single frontal; and a frontoparietal and parietal that contact the interparietals. Males reach a maximum body length of 186 mm and total length of 526 mm; females are slightly smaller with a body length of 146 mm and a total length of 420 mm.  Ugento and Harvey did not examine Tobago specimens, but note that color photographs suggest the Tobago population is also A. atrigularis.
An Ameiva from central Tobago. JCM

Ugento, GN & Harvey, MB. 2011. Revision of Ameiva ameiva Linnaeus (Squamata: Teiidae) in Venezuela: recognition of four species and status of introduced populations in southern Florida, USA. Herpetological Monographs 25:113-170.