The bizarre aquatic creature may be the oldest known vertebrate relative, according to a study published in the journal. The science. This is about yunnanosoanthat inhabited the planet 518 million years ago. According to the article, the cartilaginous features found in its fossilized remains are comparable to modern vertebrates.
For decades, scientists have wondered where the Yunnanozoans fit into the tree of life, and it was with the intention of clarifying the question that a group of scientists analyzed 127 fossils that were subjected to a series of methods. Their results revealed previously unknown details about the anatomy of these living creatures.
According to the researchers, the pharyngeal skeleton of these animals may contain the oldest fossil evidence of the pharyngeal arch, a structure that can be found during the embryonic development of vertebrate organisms and which is the precursor to several different parts of the face and jaw, depending on the organism.
“The pharyngeal arches are a key innovation that likely contributed to the evolution of vertebrate jaws and skulls,” the scientists say.
Yunnanozoans, likely ancient relatives of vertebrates (Image: Tian et al, 2022/Science)
The study also highlights that these arches are made up of cartilage in a matrix of microfibrils similar to those found in vertebrate tissues. In addition, the structure present in the Junnozoids can also be found in some modern jawless fish such as lampreys.
The conclusion is that, although not directly related to modern vertebrates, the Yunnanzoans may help shed light on vertebrate evolution. “The journey to modern vertebrates can be better understood if the family tree is filled with divergent anatomical forms,” the authors of the study justify.
