''Alticonodon'' is a genus of extinct mammal from the Late Cretaceous of North America. It is the geologically youngest known eutriconodont, and is a fairly more specialised animal than earlier representatives of this clade.

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 The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian ...

Alberta Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Terri ...

, 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, though the latter term may be redundant in relation to the rest of

Triconodontidae Triconodontidae is an extinct family of small, carnivorous mammals belonging to the order Eutriconodonta, endemic to what would become Asia, Europe, North America and probably also Africa and South America during the Jurassic through Cretaceou ...

Biology

Compared to earlier eutriconodonts, ''Alticonodon'' has molars better specialised for shearing. As eutriconodonts as a group had shearing molars due to their

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other so ...

habits, it can be inferred that ''Alticonodon'' was hypercarnivorous. This ecological speciation might have come due to competition with other mammals in the region, such as the various metatherians.R. C. Fox. 1969. Studies of Late Cretaceous vertebrates. III. A triconodont mammal from Alberta. ''Canadian Journal of Zoology'' 47:1253-1256

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 ''Saurornitholestes'' ("lizard-bird thief") is a genus of carnivorous dromaeosaurid theropod dinosaur from the late Cretaceous of Canada (Alberta) and the United States (Montana, New Mexico, Alabama, North Carolina, and South Carolina). Two spec ...

'' and ''

Acrotholus ''Acrotholus'' (Greek for "highest dome"- akros meaning highest and tholos meaning dome) is an extinct genus of pachycephalosaur dinosaur that lived during the Santonian of the late Cretaceous, in the Milk River Formation of Canada. The type spec ...

'', as well as a variety of other vertebrate such as the

crocodilian Crocodilia (or Crocodylia, both ) is an Order (biology), order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous Period (geology), period (Cenomanian St ...

Gilchristosuchus ''Gilchristosuchus'' (meaning "Gilchrist he owners of the ranch where the type specimen was found">type_specimen.html" ;"title="he owners of the ranch where the type specimen">he owners of the ranch where the type specimen was foundcrocodile") i ...

'', various

turtles Turtles are an order of reptiles known as Testudines, characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked tu ...

and fish. The mammalian fauna was primarily dominated by metatherians and

multituberculates Multituberculata (commonly known as multituberculates, named for the multiple tubercles of their teeth) is an extinct order of rodent-like mammals with a fossil record spanning over 130 million years. They first appeared in the Middle Jurassic, ...

, as usual for Late Cretaceous mammaliafaunas, but a variety of older taxa remained; besides ''Alticonodon'', there was also the

symmetrodont Symmetrodonta is a group of Mesozoic mammals and mammal-like synapsids characterized by the triangular aspect of the molars when viewed from above, and the absence of a well-developed talonid. The traditional group of 'symmetrodonts' ranges in a ...

'' 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.

References

{{Taxonbar, from=Q12898680 Eutriconodonts Late Cretaceous mammals of North America Mesozoic mammals of North America Cretaceous animals of North America Fossil taxa described in 1969 Milk River Formation Taxa named by Richard C. Fox Prehistoric mammal genera