Hypertragulidae is an extinct family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of even-toed ungulate

Even-toed ungulate

The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in odd-toed ungulates such as horses....

s (order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Artiodactyla), endemic to 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...

, Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, and Asia

Asia

Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 during the Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 through Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

, living 46.2—13.6 Ma, existing for approximately .

Hypertragulidae were primitive and ancient ruminant

Ruminant

A ruminant is a mammal of the order Artiodactyla that digests plant-based food by initially softening it within the animal's first compartment of the stomach, principally through bacterial actions, then regurgitating the semi-digested mass, now known as cud, and chewing it again...

s, resembling small deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

 or musk deer

Musk deer

Musk deer are artiodactyls of the genus Moschus, the only genus of family Moschidae. They are more primitive than the cervids, or true deer, in not having antlers or facial glands, in having only a single pair of teats, and in possessing a gall bladder, a caudal gland, a pair of tusk-like teeth...

. However, both deer and musk deer are no longer considered to be closely related to the hypertragulids. Instead, the chevrotain

Chevrotain

Chevrotains, also known as mouse deer, are small ungulates that make up the family Tragulidae, the only members of the infraorder Tragulina. There are 10 living species in three genera, but there are also several species only known from fossils...

s are probably the closest living relatives to these ancient deer-like animals.

Taxonomy

Hypertragulidae was named by Cope (1879). It was considered paraphyletic by Matthew (1908). It was assigned to Ruminantia

Ruminantia

Ruminantia includes many of the well-known large grazing or browsing mammals: among them cattle, goats, sheep, deer, and antelope. All members of the Ruminantia are ruminants: they digest food in two steps, chewing and swallowing in the normal way to begin with, and then regurgitating the...

 by Matthew (1908) and Gregory

William King Gregory

William King Gregory was an American zoologist, renowned as a primatologist, paleontologist, and functional and comparative morphologist. He was an expert on mammalian dentition, and a leading contributor to theories of evolution...

 (1910); to Pecora

Pecora

The Pecora is a group of hoofed mammals that comprises most of the ruminants, including cattle, sheep, goats, antelopes,deer, giraffes, and pronghorn. The only extant members of the Ruminantia that are not pecorans are the chevrotains, which lack horns and whose four-chambered stomach is less...

 by Cook (1934); and to Traguloidea by Carroll (1988).

Morphology

Hypertragulidae have tetradactyl front feet and ditactyl (two digits) rear feet which is specific to this family and no other ruminant. They ranged in body mass from as small as 2.16 kg (4.8 lb) with Parvitragulus

Parvitragulus

Parvitragulus is an extinct genus belonging to the family Hypertragulidae, within the order Artiodactyla, endemic to North America during the Eocene, living 38–33.9 Ma, existing for approximately ....

 to as large as 424.9 kg (936.7 lb) in Hypisodus

Hypisodus

Hypisodus is an extinct genus belonging to the family Hypertragulidae, within the order Artiodactyla, endemic to North America during the Eocene through Oligocene, living 37.2–26.3 Ma, existing for approximately ....

.