According to An Yin, a professor of geology at UCLA who was not part of the analysis team, the sequence of spiny frog evolution supports a minority view of how the India/Asia collision played out between about 55 million years ago and 15-20 million years ago. Rather than merely pushing the Himalayas upward, as some geologists believe, others have argued that the indenting Indian plate also pushed Southeast Asia and China aside towards the Pacific ocean, a process referred to as extrusion or escape tectonics.
"David and colleagues very cleverly used the frogs and their habitats and came up with very interesting evolutionary stages that are correlated with what this model predicts," Yin said. "It really is proving important support for a model proposed and based on completely different principles and reasoning and different observations."
That theory, originally proposed by Paul Tapponnier of the University of Paris and Peter Molnar of the University of Colorado at Boulder, and subsequently championed by Tapponnier, says that the Indian plate's push into Asia was not continuous, but occurred in a series of northward jumps, first pushing land aside to form Southeast Asia, then pushing South China to the east, and then pushing Central China northeastward.
"If India keeps moving," Yin said, "then North China will move out of the way. So, you have stages that have very important implications for paleogeographic evolution in this area."
Spiny frogs of the tribe Paini (a grouping within the family Dicroglossidae) are often called stone frogs in China because they cling to moss-covered rocks near rapidly flowing streams. When male frogs mate with females, they typically grab the female from behind in a strong grip known as amplexus. Though not all Paini have muscular forearms combined with keratinous spines, like coarse sandpaper, on their chests and forearms, those who live in fast-flowing stream
|Contact: Robert Sanders|
University of California - Berkeley