The genus Crocodylus — that of the 'true' crocodiles (pictured) — seems to have originated in Australasia, rather than in Africa as is commonly thought.

Jamie Oaks at the University of Kansas in Lawrence analysed DNA-sequence data from 76 individuals across 23 crocodylian species. He compiled the data into a species tree and found that the animals originated from an ancestor living in the Indo-Pacific tropics some 11 million years ago, then quickly dispersed around the world. However, the analysis does not clarify whether the animals radiated westwards towards Africa or eastwards towards the Americas.

Credit: A. TOON & S. TOON/NATUREPL.COM

The work also revealed greater species diversity than previously established.

Evolution doi:10.1111/j.1558-5646.2011.01373.x (2011)