Bilateria

(redirected from Urbilateria)

Bilateria

[‚bī·lə′tir·ē·ə]
(zoology)
A major division of the animal kingdom embracing all forms with bilateral symmetry.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
It is phylogenetically implausible that the deuterostome-like traits we describe in Owenia could reflect retention of or simple reversion to the plesiomorphic condition of the Urbilateria. Recent morphological and molecular phylogenies of annelids place the Oweniidae well within the Canalipalpata, as a member of either the Sabellida clade or a clade containing the Polygordiidae (Rouse and Fauchald, 1997, 1998; Rouse, 1999).
The assumed common ancestor of arthropods and vertebrates is the so-called Urbilateria. According to De Robertis and Sasai, we have no anatomical knowledge of this common ancestor (27) which is also presumed to be extinct.