Scientists prove all major animal groups with internal, external skeletons appeared in the Cambrian period
Wednesday, July 7, 2010 - 11:14
in Paleontology & Archaeology
(PhysOrg.com) -- New York State Paleontologist Dr. Ed Landing is the lead author of an article published in the June issue of Geology that provides the first definitive proof that all major animal groups with internal and external skeletons appeared in the Cambrian geological period (543-489 million years ago).