Pentacosmodon is a mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

 genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 from the Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

 of North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, so it lived somewhat after the "age of the dinosaur

Dinosaur

Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s". It was a member of the extinct order Multituberculata

Multituberculata

The Multituberculata were a group of rodent-like mammals that existed for approximately one hundred and twenty million years—the longest fossil history of any mammal lineage—but were eventually outcompeted by rodents, becoming extinct during the early Oligocene. At least 200 species are...

. It's within the suborder Cimolodonta

Cimolodonta

The Cimolodonta are a taxon of extinct mammals that lived from the Cretaceous to the Eocene. They were some of the more derived members of the extinct order Multituberculata. They probably lived something of a rodent-like existence until their ecological niche was assumed by true rodents...

 and family Microcosmodontidae

Microcosmodontidae

Microcosmodontidae is a poorly preserved family of fossil mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous though the Lower Paleocene of North America. The family is part of the suborder Cimolodonta...

.

The genus Pentacosmodon, named by Jepsen in 1940, is known from the species Pentacosmodon pronus. Fossil remains of this animal have been found in strata

Stratum

In geology and related fields, a stratum is a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers...

 dating to the Upper Paleocene of Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

 (USA) and the Porcupine Hills

Porcupine Hills

The Porcupine Hills refer to geographical features located in the prairie provinces of Canada.-Manitoba-Saskatchewan:A feature known as the Porcupine Hills is located in the Canadian provinces of Saskatchewan and Manitoba. They are part of the Manitoba Escarpment, which was the shoreline of the...

 Formation near the Bow River of Alberta

Alberta

Alberta is a province of Canada. It had an estimated population of 3.7 million in 2010 making it the most populous of Canada's three prairie provinces...

, Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. This genus was previously placed within family Djadochtatherioidea

Djadochtatherioidea

Djadochtatherioidea is a group of extinct mammals known from the upper Cretaceous of Central Asia. They were members of an also extinct order called Multituberculata. These were generally small, somewhat rodent-like creatures, who scurried around during the "age of the dinosaurs". Unusually for...

.