bilaterian

Compare bilateral.

bilaterian (plural bilaterians or bilateria)

1. (zoology) Any animal that has bilateral symmetry, collectively grouped in the clade Bilateria.
   • 2005, N. S. Sharma, Continuity And Evolution Of Animals‎, page 91:

     Whatever the phylogenetic relationship among bilaterians and the diploblastic phyla, there was clearly a significant expansion in genomic information within the internode that connects the bilaterian clade to other branches.

   • 2007, J. W. Valentine, “Seeing ghosts: Neoproterozoic bilaterian body plans”, in Patricia Vickers-Rich, Patricia Komarower, editors, The Rise and Fall of the Ediacaran Biota, page 372:

     Lacking body cavities and both circulatory and excretory organs, with subepidermal nerve plexuses and 'brains' represented, if at all, by thickened anterior commissures, and with simple reproductive set-ups, acoels come close to representing a model stem ancestor for bilaterians.

   • 2010, José Xavier-Neto, Marcos Sawada Simoes-Costa, Rodrigo Abe Castro, Hozana Andrade Castillo, Allysson Coelho Sampaio, Ana Paula Azambuja, “Chapter 1.1: Evolutionary Origins of Hearts”, in Nadia Rosenthal, Richard P. Harvey, editors, Heart Development and Regeneration, volume 1, page 12:

     In most bilaterians, the gut musculature and most vascular muscles derive from the mesoderm.

• nonbilaterian
• prebilaterian
• urbilaterian