Tuesday, June 18, 2013

Psuedoboini diet & microhabitat

A Psuedoboa neuwiedii that contained the remains of an Ameiva atrigularis. JCM
Recently, I found a large Pseudoboa neuwiedii lying in vegetation about 50 cm above the ground with its head down. It was most certainly waiting for prey to pass by. We collected the snake, and when removed from the bag the snake regurgitated a partially digested Ameiva atrigularis.

Diet and microhabitat variation within a clade of snakes may provide insight into how the group evolved. Alencar and colleagues (2013) look at the Neotropical Pseudoboini, a clade distributed from Mexico to Argentina and thought to be monophyletic. Psuedoboini consists of  about 47 species in the genera Boiruna, Clelia, Drepanoides, Mussurana, Oxyrhopus, Paraphimophis, Phimophis, Pseudoboa, Rhachidelus, Rodriguesophis and Siphlophis. 

The authors found the diet of pseudoboine snakes consists mainly of lizards and small mammals, as previously reported in the literature. They found Oxyrhopus may show a shift in diet from ectotherm prey as juvenilies to endothermic prey as adults. Ophiophagy was found to be more important than previously thought. The four species of Siphlophis were found to specialize in lizards. Drepanoides anomalus specializes in lizard eggs. Pseudoboines have diverse feeding habits with most of the diversification occurring in terminal taxa. And, they suggest in the evolutionary history of diet it seems that the ancestors of the diet specialists were either specialists in the same type of prey or generalists.

Among pseudoboines, Drepanoides anomalus and the four species of Siphlophis are semi-arboreal. The authors suggest that S. longicaudatus may also use the vegetation based on its slender body and long tail data is lacking. Surprisingly, Clelia clelia, Pseudoboa neuwiedii, P. nigra, and Oxyrhopus vanidicus also use the vegetation although to a lesser degree. The evolution of arboreality in Siphlophis and in Drepanoides anomalus, species known to inhabit primarily forested habitats, supports the hypothesis that more arboreal snakes tend to evolve more frequently in forests.

Alencar LRV, Gaiarsa MP, Martins M. 2013. The Evolution of Diet and Microhabitat use in Pseudoboine Snakes. South American Journal of Herpetology 8:60-66.

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