Over time, the Australian snakes took on most of the body forms found in North American snakes. Grundler and Rabosky compared those body forms by analyzing preserved specimens in the collections of the University of Michigan Museum of Zoology, the Field Museum of Natural History and the Western Australian Museum. They made measurements of head and body dimensions from 786 specimens representing 248 species. "We found that the morphologies of Australia elapid snakes have evolved into the same types of body forms seen across a much more diverse set of snakes from North America," Grundler said. "For example, Australia has the death adder, a stout-bodied ambush predator that looks, for all practical purposes, like a typical viper.
"Vipers are a family of fanged, venomous snakes that includes pit vipers such as rattlesnakes, copperheads and bushmasters. But the death adder is not a viper and is in fact much more closely related to other Australian elapid snakes, most of which look nothing like vipers." Grundler and Rabosky surveyed the published literature for data on the feeding habits of snakes on both continents. The feeding habits were placed in eight prey categories: invertebrates such as insects, earthworms, mollusks and crustaceans; fish; amphibians; lizards and snakes; lizard and snake eggs; birds; bird eggs; and mammals. In many cases, Australian and North American snakes that are similar in appearance differ greatly in their diets, the U-M researchers found. For example, most small snakes that live in sand or leaf litter in North America eat invertebrates such as spiders, scorpions, slugs and centipedes. But in Australia, those snakes tend to be specialists on lizards and other snakes. The physical similarities between North American and Australian snakes are thought to reflect evolutionary advantages that those body forms provide for locomotion, foraging, or habitat use, according to the authors. The research was funded by the National Science Foundation.
Daniel Rabosky: http://bit.ly/1xymDMK
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Proceedings of the Royal Society B