Researchers from National Museum of Natural Sciences (MNCN-CSIC), the Catalan Institute of Paleontology Miquel Crusafont (ICP), the University of Alcalá (UAH), the University of Zaragoza and the University Institute of Research for Environmental Sciences of Aragon (IUCA) have described the new species of amphithocyon, Ammitocyon kainos, from the craniodental remains of three specimens excavated at the site of Battalions-3, in Madrid.
His mouth is like a Swiss Army Knife! We are in front of a very specialized carnivore
Juan Abella, paleontologist at ICP
The fossils that have made it possible to describe the new species were found between 2008 and 2011 and initially assigned to the genus Thaumastocyon, but subsequent and detailed analyzes of their dentition they have revealed that they really belong to a species new to science.
Ammitocyon kainos is characterized by the length and robustness of its chin Y snout, as well as the incisors and canines that contrast with the absence of the first premolars and last molars. In addition, it had highly developed meat grinding wheels, with large cutting surfaces, and chewing molars relatively small. Both characteristics are considered as adaptations to hypercarnivorism (a condition that occurs when more than 70% of an animal’s diet is based on meat), and they are not present in any current species of carnivore.
Biomechanical studies performed on his bite show that different areas of the jaw served different functions. While the most anterior part was used to grab the prey and tear off large pieces of meat by making sudden lateral movements, the most posterior part was used almost as a guillotine, which would cut this meat into smaller pieces. “His mouth is like a Swiss Army knife!” Juan Abella, ICP researcher and study co-author.
Also, the combination of the characteristics of the chewing apparatus with those of its skeleton has not been observed before and reveals unique ecological adaptations. Their legs front and rear were sturdy and strong, their hands and feet very short. Therefore, the research team estimates that Ammitocyon kainos weighed more than 230 kg.
“We are in front of a very specialized carnivore”, explains Abella. “Due to its anatomical characteristics it could not be an active hunter or too agile, like the current canids or felids. It had to hunt by stalking or prey on prey hunted by other carnivores. Or both! ”, Says the paleontologist.
A ‘bear-dog’ with no current representative
A. kainos lived about nine million years ago and is the last member of the Thaumastocyoninae subfamily to be included within the amphithoid family, popularly known as ‘bear-dogs’, although they are not actually closely related to dogs. nor with bears. This family has no current representatives, but in the past they were one of the most numerous and diverse groups of carnivores in the terrestrial ecosystems of Europe and North America.
In the past they were one of the most numerous and diverse groups of carnivores in the terrestrial ecosystems of Europe and North America.
“In Battalions 3 it coexisted with other great predators weighing more than 150 kg such as the amphithoid Magericyon anceps, Saber-toothed tiger Machairodus aphanistus and the relative of the Panda Indarctos arctoides, so the role in the ecosystem of each of them should be quite defined, to be able to support said species in the same area ”, explains the co-author Alberto Valenciano, paleontologist at the University of Zaragoza and IUCA.
The new species name Ammitocyon kainos means ‘Ammit’s dog’. Ammit was an Egyptian deity with the head of a crocodile and the legs of a lion and hippopotamus, anatomical features that are reminiscent of them. The suffix ‘cyon’ means ‘dog’ in Greek while ‘kainos’ means ‘new’.
3D reconstruction of the skeleton of Ammitocyon kainos. The image shows the fossils found and recreates the missing
Battalions-3, a natural trap for carnivores
“After 30 years of excavations, the Cerro de los Batallones sites continue to give pleasant surprises”, highlights the MNCN researcher Jorge Morales placeholder image and co-author of the study. The first deposit of Cerro de los Batallones was discovered in July 1991 due to the exploitation of the land to obtain sepiolite.
They are natural cavities in which carnivores had to enter in search of prey or water and then they could not get out
In 2001 it was declared an Asset of Cultural Interest as a Paleontological Zone by the Community of Madrid, which has been financing the excavations of the deposits to the present. In total, nine cavities with fossiliferous sedimentary fillings have been found.
Some of these cavities are characterized by the large amount of carnivores which contrasts with the almost total absence of herbivores. In Battalions-3, the percentage of carnivores increases to 99%, when the usual in a site would be between 10-15%. The explanation for this phenomenon lies in its geological nature. They are natural cavities in which carnivores had to enter in search of prey or water and then they could not get out.
“But the interest of the Batallones deposits lies not only in the quality and quantity of the fossils found, but also in the verification of new models of continental paleontological deposits formation and in the enormous potential for carrying out paleobiological and geological studies of all type ”, summarizes Jorge Morales who has directed the paleontological excavations from 1991 to 2020.
Fountain: ICP, MNCN
Rights: Creative Commons.