First Evolutionary Branching for Bilateral Animals

Assessing the root of bilaterian animals with scalable phylogenomic methods. 2009. A. Hejnol, et al. Proc. Royal Soc. B. Published online before print September 16, 2009.

Kamandi © DC Comics

Researchers have determined that the flatworm group Acoelomorpha is a product of the deepest split within the bilateral creatures — multicelled organisms that, like humans, have symmetrical body forms.

The worm is “as distant as an animal can be in bilateria and still be a bilaterian,” said Dunn.