A cautionary tale in evolutionary theory is coming straight from the horse’s mouth. When ancient horses diversified into new species, those bursts of evolution weren’t accompanied by drastic changes to horse teeth, as scientists have long thought.
A new evolutionary tree of horses reveals three periods when several new species emerged, scientists report in the Feb. 10 Science. The researchers found that changes in teeth morphology and body size didn’t change very much during these periods of rapid speciation.