Fossil hatchlings challenge theory of tetrapod metamorphosis (opens in new tab)

A study published in Science on June 18 says fossilized juvenile embolomeres from the Mazon Creek fossil beds in northern Illinois show early tetrapods did not necessarily pass through an amphibian-like larval stage before adulthood. The fossils include hatchlings of crocodile-like animals close to the fin-to-limb transition, and researchers found no external gills or other tadpole-like traits that would indicate frog- or salamander-style metamorphosis. The analysis challenges a long-standing...