Olgunidae


Olgunidae is an extinct family from the Ediacaran, with possible relations to the phylum Porifera. They lived from around 557 to 551 Ma, with the type species being Olgunia.

Description

Olgunids have tubular to sac-like bodies, with sizes ranging from to in height, which are made up of segments/partitions with regular to irregular spacing and sizes, and stand tall from the seafloor, with some genera having dichotomous branching, although a recent study done on one of the olgunid members, Funisia, has noted that branching is only observed in a single specimen, and may have been the result of nonlethal damage, and recovering from said damage. They also all bear small disks at their bases, allowing them to attach to the surface of the substrate. They are also noted be colonial in nature, being found in small to large groups, although specimens of one of the members, Vaveliksia, is more commonly found solitary. Funisia is noted to also show signs of sexual reproduction, making it the oldest known example.
It has been noted that olgunids have similar body-plans to sponges, but also to coelenterates, the grade that includes comb jellies and cnidarians.

Distribution

Genera of the family Olgunidae are found within the White Sea area of Russia, the Dniester River of Ukraine, as well as the Flinders Ranges of South Australia.

Taxonomy

Olgunidae includes the following genera and species:
Vaveliksia was formerly considered as a strange petalonamid by Fedonkin as it showed a disc like structure at the base. Funisia was provisionally included in the oldest animal phylum Vendobionta by Cavalier-Smith. But due to the taxon having no proper definition it was never formally erected.