A group of researchers at the University of Adelaide and the South Australian Museum in Australia published in the journal “BMC Evolutionary Biology” an article that explains why vetulicolians, which are those belonging to the phylum Vetulicolia (image ©Apokryltaros), could be the strangest relatives of humans.
These creatures had lived in the Cambrian, 500 million years ago, and their fossils were discovered for the first time more than a century ago, in 1911, but their taxonomic status remained uncertain. After this new research, things could change.
Vetulicolians were strange-looking sea creatures, with bodies consisting of two parts: the front one was massive with a “mouth” and a row of five large round or oval structures on each side that were perhaps gills. The back part was composed of seven segments. These two parts were separated by a kind of bottleneck.
The phylum Vetulicolia was composed of several species whose fossils have been found in various parts of the world. Several species of vetulicolians have in fact been found in Canada, Greenland, China and Australia. New fossils have been found on Kangaroo Island, part of South Australia. It’s thanks to them, called Nesonektris, that researchers have obtained what they see as evidence of their proper taxonomic placement.
According to the authors of this research, vetulicolians were close relatives of vertebrates and therefore distant cousins of humans. The evidence would be in a rod-like structure in their bodies that supports their long tail. It looks like a notochord, which is the precursor of the backbone.
The researchers point out that this type of structure was found only in vertebrates and their relatives. The consequence is that vetulicolians must also be related to vertebrates. According to Dr. Diego Garcia-Bellido, the main author of the article that describes the research, these animals are a proof of the extraordinary diversity of life during the Cambrian period.
That ancient period saw an explosion of very diverse life forms. Today, it’s often difficult to understand the relations among many creatures of the Cambrian because many of them have very little resemblance to those living today. Vetulicolians don’t look like fishes and even less to mammals yet they could be the unlikely cousins of humans.