Lions, tigers, bears, seals, dogs, and cats have different characteristics and live in different habitats, but it has been recently found that they may all come from the same line of carnivorous mammals. Called carnivoraforms, these mammals have roots that go back 55 million years to the Eocene period, but whose actual ancestry has been lost to the mists of time.
Researchers have found over 250 teeth and ankle bone fossils in the Belgian district of Dormaal, that belonged to new specimens of the Dormaalocyon latouri. Researchers explained that these new fossils will allow them to situate the species in the evolutionary history of carnivores and also help them to understand the origin, variability and ecology of the earliest carnivoraforms.
The team of researchers is led by Floréal Solé of the Royal Belgian Institute of Natural Sciences, and its paper has been published in the Journal of Vertebrate Paleontology. In a statement, the Society of Vertebrate Paleontology said, "The new finds even include the deciduous teeth (or 'baby teeth'). The fact that these teeth are very primitive-looking, and from a very early time, implies that Dormaalocyon is close to the origin of carnivoraforms, and that this origin may have been in Europe."
The ankle bones found suggest that this creature lived an arboreal life in a warm and humid wooded area, most likely a forest, during the extremely warm period of time that followed an event known as the Paleocene-Eocene Thermal Maximum, within the Eocene era. The findings suggest that the Dormaalocyon would have weighed about 1 kilogram. The image reconstructions show the creature to be small and with long tail.
These findings are especially important in figuring out the parts of the evolutionary history of mammals in that it provides more evidence for understanding how mammals adapt. Dr. Solé said, "The understanding of the origination of the carnivoraforms is important fo reconstructing the adaptation of placental mammals to carnivorous diet." He also said that the findings support the existence of a continuous evergreen forest belt at high latitudes.
The fossils also suggest that there was an even more primitive carnivoraform ancestor. Dr. Solé explained, "Dormaalocyon provides information concerning the evolution of placental mammals after the disappearance of the largest dinosaurs (at the Cretaceous-Paleogene extinction event). Our study shows that the carnivoraforms were very diversified at the earliest Eocene, which allows hypothesizing that they were probably already diversified during the latest Paleocene." However, he acknowledged that the Dormaalocyon is one of the oldest carnivorous mammals, which is related to present-day carnivores.
All modern carnivores descend from one of four groups of carnivorous mammals found in the Paleocene period, which was from 66 million to 56 million years ago, and the Eocene period, which was from 56 million to 33.9 million years ago.
The area in Belgium where the fossils were found was first discovered in the 1880s, and has since yielded fossils for over 40 different species of mammals. Dr. Richard Smith, also of the Royal Belgian Institute of Natural Sciences and a colleague of Dr. Solé's, has found nearly 14,000 teeth from the site, which included 280 new specimens of teeth from a species hinted at previously from only two molars. With the new information from the teeth and some ankle bones, the team was able to provide a description of this species in their paper.
However, the geographical origins of the carnivoraforms have still not been completely established. One earlier theory suggests that they orignated in North American and Europe, but the more recent findings in Dormaal opens up the possibility of a more complex origin. Dr. Solé believes it is possible that carnivoraforms began in Asia and made it to North America through Europe.
