ScienceAugust 23, 2026

bilaterian

by-luh-TEER-ee-uhn

Definition

Refers to a group of animals that possess bilateral symmetry, meaning they have a distinct left and right side, front and back, and top and bottom.

Etymology

Derived from the Latin 'bis' (twice) and 'latus' (side), the term describes animals with two-sided, symmetrical bodies, a trait that characterizes the vast majority of all animal species.

In the news

In the article, the term is used to contrast the complex, symmetrical body plans of most animal lineages with simpler, non-bilaterian organisms like sponges to explain the evolutionary placement of the discovered enzyme.

A marine worm with no mouth and no gut makes its own enzyme for digesting the bioplastic its skin bacteria build up, and the same kind of enzyme turned up in 66 more animal species across nine phyla, from a sponge to an earthworm to a springtail

Read the full article ↗

ScienceBlog.com

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