Assessing the root of
bilaterian animals with scalable phylogenomic methods.
A comprehensive analysis of
bilaterian mitochondrial genomes and phytogeny.
What is known is that the creatures burrowed as well as walked, were "
bilaterian" - meaning they had pairs of matching appendages - and appear to have been on the clumsy side.
All that the prints suggest was they were formed by some kind of
bilaterian animal which had multiple paired appendages, like arthropods and annelids, to raise its body above the water-sediment interface.
The genomes of several different
bilaterian organisms, including model animals such as mammals, worms, flies, sea urchins, and ascidians, indicate that they all share common extracellular matrix (ECM) components.
Phylogenomic analysis shows that between divergence of ctenophores and cnidarians, the simple porifera and placozoa phyla branch off; this body plan simplification is also observed in divergence of
bilaterian phyla [59-61].
The dawn of
bilaterian animals: the case of the acoelomorph flatworms.
This mechanism of transcriptional regulation provides a plausible explanation for the conservation of this bi-gene cluster among the
bilaterian animals.
The biological identity of these burrowing organisms is unknown, although they were clearly
bilaterian.
Using Hydra rhodopsin as an outgroup, we can only infer metazoan ancestral rhodopsin states as early as in
bilaterian ancestors.
Along with other U of A researchers, the team determined that the tracks were made by a primitive animal called a
bilaterian, which is distinguished from other non-animal, simple life forms by its symmetry-its topside is distinguishable from its bottom side-and a unique set of 'footprints'.
Evidence for the presence of a cellulase gene in the last common ancestor of
bilaterian animals.