Ctenacodon is an extinct 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...

 from the Upper Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 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...

. It was a member of the also extinct order of 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...

, suborder Plagiaulacida

Plagiaulacida

Plagiaulacida is a group of extinct multituberculate mammals. Multituberculates were among the most common mammals of the Mesozoic, "the age of the dinosaurs"...

, family Plagiaulacidae

Plagiaulacidae

Plagiaulacidae is a family of fossil mammals within the order Multituberculata. Remains are known from the Upper Jurassic of North America through the Lower Cretaceous of Europe...

, and lived at the same time as more famous creatures such as Allosaurus

Allosaurus

Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...

.

The genus "Ctenacodon" is known from one species, "Ctenacodon" brentbaatar (Bakker, 1998), the fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 remains of which were found in the Upper Jurassic Morrison Formation

Morrison Formation

The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...

 in 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. Identification is based on a well-preserved upper tooth (1 mm long).

The species name honours the Wyoming paleontologist Brent Breithaupt. Baatar, Mongolian

Mongolian language

The Mongolian language is the official language of Mongolia and the best-known member of the Mongolic language family. The number of speakers across all its dialects may be 5.2 million, including the vast majority of the residents of Mongolia and many of the Mongolian residents of the Inner...

 for "hero", is apparently a reference to the heroics involved in surviving while being very small and surrounded by 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.