Syndyoceras is a small extinct 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...

 of Artiodactyla, of the family Protoceratidae

Protoceratidae

Protoceratidae is an extinct family of herbivorous North American artiodactyls that lived during the Eocene through Pliocene at around 46.2—4.9 Ma., existing for approximately .-Taxonomy:...

, endemic to central 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...

 from 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...

 epoch (Uintan

Uintan

The Uintan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology , typically set from 46,200,000 to 42,000,000 years BP lasting . It is usually considered to fall within the Eocene epoch...

 to Chadronian

Chadronian

The Chadronian age within the North American Land Mammal Ages chronology is the North American faunal stage typically set from 38,000,000 to 33,900,000 years BP, a period of . It is usually considered to fall within the Eocene epoch...

 stage) 24.8—20.6 Ma, existing for approximately .

Taxonomy

Syndyoceras was named by Barbour (1905). Its type is Syndyoceras cooki. It was assigned to Protoceratidae

Protoceratidae

Protoceratidae is an extinct family of herbivorous North American artiodactyls that lived during the Eocene through Pliocene at around 46.2—4.9 Ma., existing for approximately .-Taxonomy:...

 by Barbour (1905) and Carroll (1988); and to Kyptoceratini

Kyptoceratini

Kyptoceratini is an extinct tribe of the subfamily Synthetoceratinae, deer-like mammals within the family Protoceratidae belonging to the order Artiodactyla, endemic to North America during the Miocene through Pliocene, living 23.03—3.6 Ma, existing for approximately .-Taxonomy:Kyptoceratini is a...

 by Webb (1981), Prothero (1998), Webb et al. (2003) and Prothero and Ludtke (2007).

Morphology

Syndyocerass skull

Skull

The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

 decorations, however, looked quite unlike those of a deer. It had two pairs of horn

Horn (anatomy)

A horn is a pointed projection of the skin on the head of various animals, consisting of a covering of horn surrounding a core of living bone. True horns are found mainly among the ruminant artiodactyls, in the families Antilocapridae and Bovidae...

s. The first was a V-shaped pair on the snout, fused at the base. The second pair was placed between the eyes and the ears and was curved inwards, the horns facing towards each other in a semicircular shape. Like giraffe

Giraffe

The giraffe is an African even-toed ungulate mammal, the tallest of all extant land-living animal species, and the largest ruminant...

 ossicones, these protrusions were covered with skin

Skin

-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

. They were probably used for display and fighting.

In addition to the horns, Syndoceras also possessed tusk-like canine teeth, that it may have used to root through soil and undergrowth for food, in a similar manner to a modern 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...

. The shape of the skull also suggests that it may have had an inflated muzzle, like that of a modern saiga.

The 1.5 foot (0.4572 m) creature closely resembled a 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...

, having two hooved

Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...

 toes. Like early horse

Horse

The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

s, such as Merychippus

Merychippus

Merychippus is an extinct proto-horse of the family Equidae that was endemic to North America during the Miocene from 20.43—10.3 Ma living for approximately .It had three toes on each foot and is the first horse known to have grazed...

, it had two vestigal outer toes on each foot, which did not touch the ground.