Insects are famous for their six-legged body plan, but that wasn\u2019t always the rule. A 324-million-year-old fossil dug up from a shale bed in West Texas had a markedly different setup, sporting a whopping 18 extra legs along its belly \u2014 a body plan unlike that of any living insect.<\/p>\n
It is one of the oddest insects ever found, and possibly the most consequential, researchers report August 26 in Nature<\/em>.<\/p>\n The discovery \u201cstraddles a big gap in the fossil record,\u201d says paleoentomologist Erik Tihelka of the University of Cambridge. It offers a glimpse of the transition from many-legged, shrimplike ancestors to the six-legged insects of today. \u201cIt shows that there were these transitional forms along the way,\u201d he says, before insects shed their extra legs and settled on six.<\/p>\n