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 University of Cape Town (UCT) and Iziko Museums of South Africa.
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.
In an 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).
“Our work has led to important new data about the locomotion and diet of the rather 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,” says Dr Valenciano.
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, saber-tooth cats, giant civets and mongoose. “We report for the first time the presence of both giant mustelids in the main members at Langebaanweg,” Dr Govender adds.
The team hypothesises that the wolf-sized otter (Sivaonyx hendeyi), 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 semiaquatic, 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 7-million to 2-million years giant otters (Sivaonyx and Enhydriodon) evolved in Africa, with terminal forms approximately 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,” says Dr Valenciano.
The study also confirms that between 6,5-million to 5-million years ago (end of the Miocene, beginning of the Pliocene era) there were two large species of wolverines in Africa – that is, 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, says: “I am thrilled to hear about these 5-million-year-old giant mustelids that lived on the West Coast of South Africa. This work highlights that although it is important to unearth new fossils, it is essential that existing collections in museums be actively researched.”
According to Dr 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 five million years ago but will also allow us to study and understand the faunal change that has occurred over the last 5-million years”.