UCT scientists unearth remains of ‘wolf-sized otters’ dating back 5 million years
In a statement, UCT said: “Over 5 million years ago, wolf-sized otters and leopard-sized relatives of living wolverines (members of the weasel family that look more like badgers than wolves) lived along the West Coast of South Africa. This is according to recent discoveries by scientists at the UCT and Iziko Museums of SA."
These animals, known as mustelids – a family of carnivorans that include weasels, otters and badgers among others – represent the first mustelid specimens described from Langebaanweg in over 40 years.
It said in the article published in the journal PeerJ, Dr Alberto Valenciano and Dr Romala Govender of UCT’s Department of Biological Sciences describe the teeth, forelimb and hindlimb skeletons of these giant mustelids: the wolf-sized otter (Sivaonyx hendeyi) and the leopard-sized wolverine (Plesiogulo aff monspesulanus).
According to Valenciano, their work has led to important new data about the locomotion and diet of the poorly known giant otter (Sivaonyx hendeyi) that is unique to Langebaanweg.
“In addition, we confirm that Langebaanweg’s wolverine (Plesiogulo aff Monspesulanus), is a different species to that of the large bodied Plesiogulo botori from Kenya and Ethiopia.
"The carnivores at the Langebaanweg fossil locality are quite common and they include a minimum of 20 different species of mustelids, bears, seals, jackals, hyenas, sabre-tooth cats, giant civets and mongoose. We report for the first time the presence of both giant mustelids in the main members at Langebaanweg,” Govender added.
The team hypothesises that the wolf-sized otter that lived 5 million years ago had a role similar to that of the living African clawless otter and the Asian small-clawed otter.
While less semi-aquatic, it could still have possibly been able to dig occasionally. Additionally, its robust dentition suggests a diet based on armoured catfishes, molluscs, crustaceans or even bones.
Over the past 2 to 7 million years, giant otters (Sivaonyx and Enhydriodon) evolved in Africa, with terminal forms about the size of modern black bears and body masses exceeding 200kg, which make them the largest mustelids ever. “This group of giant otters are all extinct, and their new fossils enable us to unravel their biology and evolutionary relationships,” said Valenciano.
This study also confirms that between 5 and 6.5 million years ago (end of the Miocene, beginning of the Pliocene era) there were two large species of wolverines in Africa, from Langebaanweg and from East Africa. These animals were later replaced by hyenas, canids and felids.
UCT palaeobiologist Professor Anusuya Chinsamy-Turan, who was not involved in the study, said: “I am thrilled to hear about these 4 million-year-old giant mustelids that lived on the West Coast of South Africa. This work highlights that although it's important to unearth new fossils, it's essential that existing collections in museums be actively researched.”
According to Govender: “This study shows that there is a need for new and detailed studies of Langebaanweg fauna housed at Iziko in the Cenozoic Collections.
"These studies will not only give us insight into the fauna that lived along the West Coast 5 million years ago, but will also allow us to study and understand the faunal change that has occurred over the last 5 million years.”