Episode 19: Masrasector—Egypt’s Ancient Slicer!

A few weeks ago Past Time co-host Matt Borths published a study that identified a new species of now-extinct carnivorous mammal from Egypt. The animal was near the top of the African food chain when Africa was cut off from the other continents. It lived in the same swampy ecosystem that was home to our earliest monkey-like relatives!

Here’s a link to the original paper in the open access journal PLOS ONE if you want to take a look at the original fossils. You can even see them in 3D at www.morphosource.org

Masrasector means “The Egyptian slicer” because the meat-eater was found in the deserts of Egypt, near the Fayum Oasis southwest of Cairo. The species name, nananubis, means “tiny Anubis,” because the small, fox-sized carnivore resembles the jackal-headed Ancient Egyptian god of embalming and guide through the afterlife. “Tiny Anubis” likely scrambled on the ground, chasing large rodents and small hyraxes through the Fayum wetland. It probably didn’t spend a lot of time weighing the hearts of the dead, but such behaviors don’t fossilize very well.

Masrasector nananubis was part of an extinct group of carnivorous mammals called hyaenodonts. If you think of a meat-eating mammal today, like a wolf, tiger, or hyena, you’re thinking of a species from the mammalian order Carnivora. Carnivorans are united by having one pair of specialized meat-slicing teeth on each side of their face. Next time you see a dog or cat yawn, look in the back of their mouth for the scissor-like blades. Hyaenodonts had three pairs of these meat-slicers on each side of their mouths instead of just one, making it easy to recognize them in the fossil record. Hyaenodonts were the only meat-eating mammals in Africa for over forty million years between the extinction of the dinosaurs and the arrival of the first African carnivorans.

Carnivorous mammals are rare in modern ecosystems, and this was also true in the past. Fossilization itself is a rare event, which means the chances of a rare carnivore becoming a rare fossil are very low. This means African hyaenodonts are a rare find, and most are only known from a few isolated teeth and jaws. But, Masrasector is known from several nearly complete skulls, dozens of jaws, and pieces of arm bone.

A photograph and three-dimensional model of the skull of Masrasector nananubis.

With all this material it’s possible to really dig into what Masrasector ate, and how it moved through its environment. African carnivores like lions and hyenas are fascinating, endangered creatures. Hyaenodonts were a separate experiment in how to be a carnivorous African mammal, and they did it successfully for millions of years.Masrasector offers a detailed view of how African hyaenodonts pursued their prey and what their diet was like.

The specimens were discovered in a quarry called Locality-41, one of the most fossil-rich places from the beginning of the Age of M