A new species of bear-dog that lived approximately 9 million years ago has been unearthed in Spain. This type of amphithoid is called an “Ammitocyon kainos” and its remains were found at the Batallones 3 site in Madrid between 2008 and 2011. At that time, it was categorized as another species, but new analysis of its teeth has revealed that it was an entirely new species.
The last members of the Thaumastocyoninae subfamily were the Ammitocyon kainos (or “Ammit’s dog”). Ammit was an Egyptian deity that had a crocodile’s head with legs of a lion and hippopotamus.
While they are referred to as “bear-dogs”, they actually weren’t closely related to any bears or dogs. Even though millions of years ago there were large numbers of these animals in Europe and North America, they have no living relatives today.
The muzzle and chin of this new species was long and strong. It had incisors and canines but was missing its first premolars and last molars as well as having pretty small chewing molars. These features were consistent with a condition called “hypercarnivorism” which occurred because its diet would have consisted of at least 70% meat. Juan Abella, who is an ICP researcher and a co-author of the study, described its mouth as being “...like a Swiss Army knife.”
The Ammitocyon kainos had strong front and rear legs, while their feet and hands were quite short. They were very heavy as they could weigh over 230 kilograms (507 pounds). Interestingly, they probably hunted either by stalking their prey or feeding on animals that other carnivores had previously taken down.
It would have lived alongside other large animals like the Magericyon anceps, Machairodus aphanistus (a type of saber-toothed cat), and Indarctos arctoides (a type of bear). (Pictures of the bones and what the bear-dog would have looked like can be seen here.)
The research was conducted by scientists at the National Museum of Natural Sciences (MNCN-CSIC), the Institut Català de Paleontologia Miquel Crusafont (ICP), the University of Alcalá (UAH), the University of Zaragoza, the University Institute for Environmental Sciences Research, and the Instituto Universitario de Ciencias Ambientales (IUCA). The study was published in the Journal of Systematic Palaeontology where it can be read in full.