New ancient predator species discovered in Egypt

Long-extinct carnivorous mammals could offer clues about today’s predators as they adapt to changing environments.

Hyaenodonts were carnivorous mammals that emerged as top predators after the extinction of the dinosaurs. Fragmentary and incomplete fossil records have made it difficult to understand how these important predators evolved in Africa and spread over four other continents. However, analysis of newly discovered fossils reveals a much more complete record of a new hyaenodont species called Masrasector nananubis that could help connect these dots. We spoke with Matthew Borths, who conducted the research with Erik Seiffert, about the find and its implications.

ResearchGate: Where were these fossils found?

Matthew Borths: The fossils were found in the Fayum Depression in Egypt, a chunk of desert southwest of Cairo that was a thriving resort town for the ancient Egyptians thousands of years ago. It was thriving, swampy forest for our ancient primate ancestors about 34 million years ago, when Masrasector nananubis was alive.

Most of the fossils in the Fayum are pretty fragmentary—lots of isolated bones or teeth. The fossils that were part of this discovery are from a different locality in Fayum that preserves more complete material in salt-infused mudstone. The spot is called L-41, and it is one of the most fossil-dense spots on the African continent. It was discovered in the late 1980s and has been churning out fossils of primates, hyraxes, hippo relatives, fish, rodents, and more ever since. It's really one of the most important spots in the world for understanding what was going on in Africa when the continent was a massive island cut off from the rest of the world.

The researchers' camp in Fayum, where the fossils were found. Credit: Matt Borths

RG: What were Hyaenodonts?

Borths: Hyaenodonts were carnivorous mammals that filled apex predator niches in Europe, Asia, North America, and Africa from the extinction of the dinosaurs until about 15 million years ago when most of them went extinct. The name means "hyena teeth," but they aren’t closely related to the hyena and its carnivoran relatives like cats, wolves, and weasels. They ranged in size from small, weasel-sized creatures up to massive, rhino-sized species that were among the largest meat-eating mammals to ever walk the planet.

RG: Where does this new species fit in?

Borths: What makes Masrasector nananubis so special is we have so much of it. We have multiple skulls, jaws, and parts of the skeleton, making it one of the most completely known African hyaenodonts ever discovered. All of that anatomical information means Masrasector can be a kind of Rosetta Stone for interpreting all those more fragmentary bits and pieces of hyaenodonts from other fossil sites in Africa.

Masrasector nananubis skull. Credit: Matt Borths

RG: What do you know about how Masrasector nananubis lived?

Borths: Based on the teeth of Masrasector nananubis, we know it wasn't a strict carnivore. It had meat-slicing blades on its teeth, which let it attack small rodents and hyraxes, but it also had large basins on its teeth that would have let it mash up other types of food like fruits and seeds. About the size of a skunk, Masrasector was a relatively small hyaenodont that would have been most comfortable scrambling through the undergrowth after its prey.

RG: What do you expect to be able to learn about this species from future studies?

Borths: Because Masrasector nananubis is such a complete species with so many individual specimens, I expect Masrasector will be a crucial touchstone for interpreting other hyaenodont bones from around the world. Along with publishing the new description of the species in PLOS ONE, we also published several digital models of the skulls, jaws, and limb bones of Masrasector that are available for viewing and download. There are a lot of questions that we have yet to answer about the evolution of African ecosystems and the role of carnivores in those ecosystems. I'm excited for Masrasector to become a part of those future investigations.

RG: What are you working on next?

Borths: One of the reasons I became interested in hyaenodonts is they are a natural experiment in how ecosystems change and how climate change and invasive species affect other species. After Africa collided with Eurasia, the climate became warmer and the African grasslands we're familiar with today started to replace the large forests that Masrasector would have called home. Along with the rising climate and changing ecosystem, new carnivores from other parts of the world started moving into Africa.

I want to know how these changing ecosystem dynamics affected hyaenodont evolution. They didn't go extinct all at once. Instead, they changed in response to the changing world, just not enough to survive to the present day. Today, carnivorous mammals like lions and wolves are among the most vulnerable species as the climate and environment changes and invasive species spread across the globe. The fossil record is our only evidence for how species respond to these changes and I want to be part of the group of investigators delving into how ancient extinctions can help us prevent the extinction of many modern carnivores.