Rabbit-proof hoof: Ungulates suppressed lagomorph evolution
Closely related groups can differ dramatically in their diversity, but why this happens is a fundamental question in evolutionary biology, dating back to Darwin's observation that a few hyper-diverse groups dominate the modern biota. One of the most extreme examples of this observation is found in the comparison of rodents (Rodentia) and rabbits (Lagomorpha). These two mammalian orders are sister groups, but while rodents have diversified to over 2000 living species and an enormous range of body sizes, lagomorphs (rabbits, hares, and pikas) are limited to fewer than 100 relatively small species. A new study presented at the Society of Vertebrate Paleontology Annual Meeting shows, surprisingly, that competition with ungulates (hoofed mammals), intensified by climate change, are to blame for the lagomorphs' limited diversity.