A trio of new-to-science, prehistoric beasties has provided further insights into the evolution of mammals once dinosaurs gave up their stronghold on Earth, indicating they grew in number more rapidly than previously thought. Unique in their dentition and size, being far larger than the small shrew-like mammals that came before them, they point to a time of emerging diversification following the Cretaceous-Paleogene boundary that waved in the extinction of the dinosaurs.

Published in the Journal of Systematic Palaeontology, a new paper describes the three new species and the features that define them from other closely related creatures that were around during the Paleocene Epoch, when the trio were strutting around North America. In reverse size order, their names are Miniconus jeanninae, Conacodon hettingeri, and Beornus honeyi. The latter was named as a hat tip to The Hobbit’s Beorn, a character that could assume the shape of a bear, who shares the enlarged cheek teeth of B honeyi, which was about the size of a marmot or house cat.

All three hail from a group of placental mammals (early ancestors of extant hoofed mammals) known as the condylarths of the family Periptychidae. What makes them stand out is their unique gnashers which the researchers believe indicate that they may have been omnivores, dining on whatever was going. This is because they were equipped with enlarged premolars and enamel ridges that would’ve complemented a mixed diet, enabling them to grind down plant material as well as meat.

“When the dinosaurs went extinct, access to different foods and environments enabled mammals to flourish and diversify rapidly in their tooth anatomy and evolve larger body size,” said lead author Madelaine Atteberry from the University of Colorado Geological Sciences Department in a statement. “They clearly took advantage of this opportunity, as we can see from the radiation of new mammal species that took place in a relatively short amount of time following the mass extinction.”

While previous research into the “Age of Mammals'' has teetered towards there being a modest number of species across North America, this new research and its three shiny new mammalian members suggests that diversification at this time may have been more rapid and productive than previously thought. And there could be more to come.

“These new periptychid ‘condylarths’ make up just a small percentage of the more than 420 mammalian fossils uncovered at this site,” said Atteberry. “We haven’t yet fully captured the extent of mammalian diversity in the earliest Paleocene, and predict that several more new species will be described.”