Trilobozoa

Trilobozoa, from Ancient Greek τρεῖς (treîs), meaning "three", λοβός (lobós), meaning "lobe", and ζῷον (zôion), meaning "animal", is a phylum of extinct, sessile animals that were originally classified into the Cnidaria. The basic body plan of trilobozoans is often a triradial or radial sphere-shaped form with lobes radiating from its centre.

Fossils of trilobozoans are restricted to marine strata of the Late Ediacaran period.

History and interpretations

Originally, both M.A. Fedonkin and B.N. Runnegar presumed that there were 2–3 families within the Trilobozoa, those families being Albumaresidae (Fedonkin, 1985) and Tribrachididae (Runnegar, 1992). Although, affinities with the Conulariida were made because the conulariids possess similar three-fold symmetry. Fedonkin originally classified the Trilobozoa as a class of the phylum Coelenterata.

Most of the members of what is now the modern day classification for Trilobozoa were thought to have originally been free swimming jellyfish. Tribrachidium was once interpreted as a edrioasteroid echinoderm, although with the discovery of the related Albumares and Anfesta (along with better-preserved White Sea specimens), it became apparent to M. Fedonkin that all of the organisms formed one phylum (originally class) of triradially symmetrical enigmatic organisms from the Ediacaran. The eventual split of Coelenterata into the phyla Cnidaria and Ctenophora led the Trilobozoa to obtain a phylum level of affinities.

The members of the Trilobozoa are now thought to be sessile, benthic organisms of unknown affinities, and are a subject open for interpretations and debate.