Coelacanths attained iconic status when a live one was caught near East London, South Africa in 1938, despite the belief that they had been extinct since the Cretaceous. JLB Smith, based in Grahamstown (now Makhanda) described the fish and initiated a search for a dissectable example, which bore fruit in 1952. He named the original specimen Latimeria chalumni, after Courtney Latimer, who had recognized the fish as something new and important (1). At the time the coelacanth was considered to be very near to the missing link between fishes and tetrapods, and it became a worldwide sensation. Although coelacanths are now known to represent a somewhat lower branch on the lobe-fin fish family tree, and not to be on the direct line to tetrapods, they do provide a very rare example of a living lobe-fin fish. Importantly they are less evolutionary modified than lungfish, the other surviving lobe-fins (that are actually more closely related to tetrapods). Today coelcanths are restricted to the deep ocean, but in the Palaeozoic they were widespread in shallow marine settings.
Serenichthus kowiensis Locality: Waterloo Farm Age: latest Devonian It is fitting that a new species of Devonian fossil coelacanth, the oldest in Africa, was to appear in the very town where Smith was based, several decades after Latimeria was described. Serenichthys kowiensis was described on the basis of several dozen whole juveniles from Waterloo Farm (2). At least 36 whole juvenile specimens between 3 and 6 cm in length have been recovered, in addition to a small number of larger isolated bones of the same species. This indicates that Serenichthys was using the estuary as a nursery. This is the oldest record of a coelacanth nursery. |
References:
1) https://www.knysnamuseums.co.za/pages/the-coelacanth/
2) Gess, R. W., & Coates, M. I. (2015). Fossil juvenile coelacanths from the Devonian of South Africa shed light on the order of character acquisition in actinistians. Zoological Journal of the Linnean Society, 175(2), 360-383.
1) https://www.knysnamuseums.co.za/pages/the-coelacanth/
2) Gess, R. W., & Coates, M. I. (2015). Fossil juvenile coelacanths from the Devonian of South Africa shed light on the order of character acquisition in actinistians. Zoological Journal of the Linnean Society, 175(2), 360-383.