Showing posts with label Tobago. Show all posts
Showing posts with label Tobago. Show all posts

Monday, July 11, 2011

The Herpetofauna of Trinidad and Tobago Website

The website Herpetofauna of Trinidad and Tobago and associated blog are now functional. However, the website is a work in progress and needs photos and text. If you can help with that please contact us. JCM

Thursday, June 9, 2011

The Unhappy Vine Snake

The Brown Vine Snake, Oxybelis aeneus occurs from southern Arizona to Argentina and on the islands of Trinidad and Tobago. We found this snake sleeping on a leaf about 0.7 m above the ground. The black mouth lining contrasting with the white/yellow labials may be aposematic coloration.

Wednesday, June 8, 2011

Under The Leaf in Tobago

Glass frogs frequently deposit their eggs on the underside of leaves over-hanging a stream. This location is also the calling station for the males, and amplexus.

Top: a male glass frog attending its egg mass about 10 m above a stream. Middle:  a crab on the same plant with a glass frog. Bottom: the reason why Hyalinobatrachium oriental are commonly called glass frogs. All photos JCM.

Castroviejo-Fisher et al. (2008) report that Hyalinobatrachium orientale has a complex taxonomic history and they reviewed the species in an attempt to clarify the taxonomic status by means of morphological, bioacoustic, and mitochondrial DNA sequence comparisons of specimens from Tobago and the Venezuelan Cordillera de la Costa. They resurrected Hyalinobatrachium orocostale, and restricted it to the Cordillera del Interior. Additionally, they found specimens from Cordillera del Litoral and Oriental Sector do not form a monophyletic group; and define it as Hyalinobatrachium sp. H. orientale sensu stricto made up the populations from the Oriental Sector. And, they found preliminary bioacoustic and morphological analyses indicated that the populations from Tobago are conspecific with Hyalinobatrachium orientale sensu stricto.

In the last few days we (JCM, Stevland Charles, & Josh Traub) walked streams in northeast Tobago and observed Hyalinobatrachium orientale along several of them. While it is much easier to hear them than see them, one stream was more open and level.  Delia et al. (2010) suggested the underside of the leaf protects the frogs from aerial predators – particularly bats of the genus Trachops that specialize in feeding on frogs. However, on Tobago crabs were readily apparent and on the same plants being used by frogs. Crabs are likely a serious predator on frogs and their eggs, and the underside the leaf position of could easily provide protection for eggs and adults. The egg masses we observed tended to be positioned toward the distil portion of the leaf, making it unlikely a crab could gain access to the eggs or adults. A second, frog predator observed near but not immediately adjacent to the frogs was the snake Leptodiera annulata ashmeadi. Most of the specimens we observed were hunting frogs in drains along the roads side.

Positioning calling males, amplexus, and egg deposition on the underside of a leaf has advantages.

Literature Cited
Castroviejo-Fisher, S., J. Celsa Señaris, J. Ayarzagüena, and C. Vilà. 2008. Resurrection of Hyalinobatrachium orocostale and Notes on the Hyalinobatrachium orientale Species Complex (Anura: Centrolenidae) Herpetologica 64:472-484.

Delia J., D. F. Cisneros-Heredia, J. Whitney and R. Murrieta-Galindo. 2010. Observations on the Reproductive Behavior of a Neotropical Glassfrog, Hyalinobatrachium fleischmanni (Anura: Centrolenidae). Journal of South American Herpetology 5:1-12.

Vockenhuber, E. A., W. Hödl, and A. Amézquita. 2009. Glassy Fathers Do Matter: Egg Attendance Enhances Embryonic Survivorship in the Glass Frog Hyalinobatrachium valerioi. Journal of Herpetology 43(2):340-344.