Described as the "king of the ancient Egyptian forest," the hypercarnivorous hyaenodonts were enormous mammals—imagine a hyena twice the size of a Kodiak bear—so successful they spread across the globe. 25 millions years ago, though, they vanish from the fossil record. The discovery of the most complete skull yet (from a more modestly-sized species of the lineage, Bastetodon) offers an insight into their fate: they were overwhelmed by their smart and nimble relatives, cats and dogs.
"The end of the Hyaenodonta in the late Oligocene shows how climate change, competitive pressures and changes in prey availability affected carnivores," said Dr. Cathrin Pfaff, a postdoctoral researcher and lecturer at the Institute of Palaeontology at the University of Vienna in Austria. She was not involved with the study.
"The fact that they lost out to cats and dogs in their evolution is still a mystery but might be caused by their highly specialized dentition," Pfaff said in an email, referring to the arrangement and development of the animals' teeth. "Because of this, such a complete find as described here brings us a step closer to solving the mystery, even (if) itis just a medium sized specimen."
Here's the paper: Cranial anatomy of the hypercarnivore Bastetodon syrtos gen. nov. (Hyaenodonta, Hyainailourinae) and a reevaluation of Pterodon in Africa, by Shorouq F. Al-Ashqar and others.
Previously:
• Meet the best-preserved mammoth in history of paleontology
• Paleontology on the Moon
• Society of Vertebrate Paleontology forbid the word 'bone' during online conference
• This may be why T. rex had such tiny arms
