Extinct family of mammals
Alticonodon is a genus of extinct mammal from the Late Cretaceous of North America. It is one of the geologically youngest known eutriconodonts, and is a fairly more specialised animal than earlier representatives of this clade.[1]
Description
Alticonodon is currently a monotypic genus, represented exclusively by A. lindoei. It is known from the Milk River Formation deposits of the early Campanian of Alberta, Canada. It is known from two specimens: a dentary fragment bearing two molars, and an isolated lower last molar.
Classification
Alticonodon has been consistently recovered as a triconodontid, and more specifically as an alticonodontine,[2] though the latter term may be redundant in relation to the rest of Triconodontidae.[3]
Biology
Compared to earlier eutriconodonts, Alticonodon has molars better specialised for shearing.[1] As eutriconodonts as a group had shearing molars due to their carnivorous habits,[4] it can be inferred that Alticonodon was hypercarnivorous.
This ecological specialisation might have come due to competition with other mammals in the region, such as the various metatherians.[1]
Ecology
The Milk River Formation is a rich fossil environment that covered near-shore and terrestrial deposits. It included a few dinosaur species like Saurornitholestes and Acrotholus, as well as a variety of other vertebrate such as the crocodilian Gilchristosuchus, various turtles and fish.
The mammalian fauna was primarily dominated by metatherians and multituberculates, as usual for Late Cretaceous mammaliafaunas, but a variety of older taxa remained; besides Alticonodon, there was also the symmetrodont Symmetrodontoides, and Potamotelses and picopsids. These were the last non-therian mammals (other than the highly successful multituberculates) in North America, suggesting a relictual element to the region's fauna.
