Friday, May 17, 2024

Likely ancestor of all modern hoofed animals identified

Amazing stuff! Some skepsis is advised!

"In 2016, a museum volunteer discovered a fossil while exploring the Corral Bluffs, a site near Colorado Springs. Since that time, more fossils (skulls and jaws) from the same species have been found in the area. The research team studied the fossil samples and found evidence that the creature, named Militocodon lydae, is likely the ancestor of all modern hoofed animals.
During their analysis, the researchers found that the fossils had once belonged to an animal approximately the size of a modern chinchilla (or rat) weighing approximately 455 grams. They also dated the creature to approximately 65 million years ago, putting it in the Paleocene epoch, which followed the demise of the dinosaurs. ..."

From the abstract (regrettably, this abstract is written for a handful of specialists):
"The Periptychidae, an extinct group of archaic ungulates (‘condylarths’), were the most speciose eutherian mammals in the earliest Paleocene of North America, epitomizing mammalian ascendency after the Cretaceous–Paleogene (K–Pg) mass extinction. Although periptychids are mostly known from fragmentary gnathic remains, the Corral Bluffs area within the Denver Basin, Colorado, has yielded numerous exceptionally well-preserved mammalian fossils, including periptychids, from the earliest Paleocene. Here we describe a partial cranium and articulated dentaries plus an additional unassociated dentary fragment of a small-bodied (~273–455 g) periptychid from ca. 610 thousand years after the K–Pg mass extinction (Puercan 2 North American Land Mammal ‘age’) at Corral Bluffs. Based on these new fossils we erect Militocodon lydae gen. et sp. nov. The dentition of M. lydae exhibits synapomorphies that diagnose the Conacodontinae, but it is plesiomorphic relative to Oxyacodon, resembling putatively basal periptychids like Mimatuta and Maiorana in several dental traits. As such, we interpret M. lydae as a basal conacodontine. Its skull anatomy does not reveal clear periptychid synapomorphies and instead resembles that of arctocyonids and other primitive eutherians. M. lydae falls along a dental morphocline from basal periptychids to derived conacodontines, which we hypothesize reflects a progressive, novel modification of the hypocone to enhance orthal shearing and crushing rather than grinding mastication. The discovery and thorough descriptions and comparisons of the partial M. lydae skull represent an important step toward unraveling the complex evolutionary history of periptychid mammals."

Likely ancestor of all modern hoofed animals identified


Fig. 6
From: Skull of a new periptychid mammal from the lower Paleocene Denver Formation of Colorado (Corral Bluffs, El Paso County)


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