title: Palaeontology: in a flap about flaps.
abstract: An anomalocaridid from the Ordovician exposes a second set of body flaps and reopens the question of how the two branches of arthropod legs evolved.
authors.affiliation: Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK. Electronic address: g.edgecombe@nhm.ac.uk.
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Edgecombe
mesh_terms: D000818:Animals; D005075:Biological Evolution; D010163:Paleontology / Q000379:methods