In a new study published in Nature Communications, scientists led by Flinders University and experts from Canada, Australia, and Europe discovered an exceptionally well-preserved ancient primitive Devonian coelacanth fish in remote Western Australia. This fossil discovery suggests that plate tectonics also significantly influenced animal origin and extinction.
The fossil has been named Ngamugawi Whangarei. Its discovery fills a significant gap in the transition period in coelacanth history between the most primitive forms and other more ‘anatomically modern’ forms.
First author Dr Alice Clement, an evolutionary biologist and paleontologist from Flinders University, said, “We are thrilled to work with people of the Mimbi community to grace this beautiful new fish with the first name taken from the Gooniyandi language.”
“Our analyses found that tectonic plate activity had a profound influence on rates of coelacanth evolution. Namely, new coelacanth species were more likely to evolve during periods of heightened tectonic activity as new habitats were divided and created.”
acid etched out of rock at Museum Victoria, 2009. (J Long, Flinders University).
The fossil dates back to the Devonian Period (359-419 million years ago). It offers detailed insights into the early anatomy of this lineage that eventually led to humans. This study confirmed the Late Devonian Gogo Formation as one of the richest and best-preserved fossil fish and invertebrate assemblages.
Flinders University Strategic Professor of Palaeontology John Long says, “For more than 35 years, we have found several perfectly preserved 3D fish fossils from Gogo sites which have yielded many significant discoveries, including mineralized soft tissues and the origins of complex sexual reproduction in vertebrates.”
“Our study of this new species led us to analyze the evolutionary history of all known coelacanths.”
Many features of human anatomy, like jaws, teeth, and lungs, first appeared in early fishes during the Early Palaeozoic (540-350 million years ago). The Gogo Formation in Western Australia, once a tropical reef with over 50 fish species 380 million years ago, shows evidence of these ancient fish. Scientists found that coelacanths have evolved very slowly since the time of dinosaurs, though there are a few interesting exceptions.
Today, the living coelacanth Latimeria (Sarcopterygii: Actinistia) is an iconic, so-called ‘living fossil’ within one of the most apparently morphologically conservative vertebrate groups. It lives off eastern Africa and Indonesia coasts and can reach up to 2m in length.
They are “lobe-finned” fish, which means they have robust bones in their fins that are not too dissimilar to the bones in our own arms. They are thus considered to be more closely related to lungfish and tetrapods.
However, around 66 million years ago, at the end of the Cretaceous Period, they mysteriously disappeared from the fossil record. It was presumed that the coelacanth fishes had been swept up as a casualty of the mass extinction event that wiped out all dinosaurs.
Another senior co-author, vertebrate paleontologist Professor Richard Cloutier, from the University of Quebec in Rimouski (UQAR), says the new study challenges the idea that surviving coelacanths are the oldest ‘living fossils.’
Professor Richard Cloutier, Université du Québec à Rimouski said, “They first appear in the geological record more than 410 million years ago, with fragmentary fossils from places like China and Australia. However, most early forms remain poorly known, making Ngamugawi wirngarri the best-known Devonian coelacanth.”
“As we slowly fill in the gaps, we can start to understand how living coelacanth species of Latimeria, which commonly are considered to be ‘living fossils,’ actually are continuing to evolve and might not deserve such an enigmatic title,” says Professor Cloutier, a previous honorary visiting scholar at Flinders University.
Journal Reference:
- Clement, A.M., Cloutier, R., Lee, M.S.Y., et al. A Late Devonian coelacanth reconfigures actinistian phylogeny, disparity, and evolutionary dynamics. Nat Commun 15, 7529 (2024). DOI: 10.1038/s41467-024-51238-4
