An article published in the “Journal of Vertebrate Paleontology” reports the identification of an extinct species of carnivorous mammal whose estimated weight is higher than that of polar bears. Dr. Nancy Stevens and Dr. Matthew Borths of the Ohio University named it Simbakubwa kutokaafrika after studying fossils dating back some 22 million years ago discovered in Kenya between 1978 and 1980 but never studied. In its ecosystem it was a top predator and is the oldest representative discovered so far of the group of hyaenodonts.
Despite the name, hyaenodonts (Hyaenodonta) aren’t close relatives of hyenas but the similarity of their teeth with those of hyenas led to that name. They were the first carnivorous mammals to live in Africa reaching the top of their ecosystem after the extinction of the dinosaurs. Today they’re extinct but for about 45 million years they were top predators and the species now identified and named Simbakubwa kutokaafrika lived at the beginning of the Miocene period.
A series of fortunate circumstances led the two researchers to study fossils in the possession of the National Museum of Kenya in Nairobi that had remained in a drawer. Only a few bones have been discovered but the part of the jaw in Dr. Matthew Borths’ hands in the top photo (courtesy Matthew Borths. All rights reserved) and the teeth uncovered provided a lot of information about this animal and its predatory skills. The name Simbakubwa kutokaafrika means big lion from Africa even if it wasn’t even a feline but it was a great predator long before lions evolved.
In estimating the size, important to understand Simbakubwa kutokaafrika’s role in its ecosystem, Nancy Stevens and Matthew Borths had to resort to estimates based in particular on the relationship between the size of teeth and those of the body existing in carnivores. The state of the teeth indicates that the specimen found was a young adult when it died and could weigh around 1,500 kg.
The study of Simbakubwa kutokaafrika is interesting not only because it brought to light a top predator but also because this hyaenodont lived at the beginning of a period of very important changes occurred in Africa over the millions of years following the death of the specimen discovered.
About 20 million years ago Africa got closer to Eurasia and there were various migrations of species belonging to a number of groups of animals. Simbakubwa kutokaafrika was a great predator but it needed a lot of meat because it was a so-called hypercarnivorous, that is an animal that gets more than 70% of the calories it absorbs from meat, as lions nowadays. These are animals that need a stable food chain and periods of prolonged change can cause their decline or even their extinction.
In essence, the identification of Simbakubwa kutokaafrika is useful to better understand not only the history of hyaenodonts but also the ecosystem in which this species lived. That thanks to fossils examined decades after their discovery, certainly not the first time that this happened and a further evidence that there might be scientific treasures awaiting attention in some museum or collection.
