Equidae is the taxonomic family of horses and related animals, including the extant horses, asses, and zebras, and many other species known only from fossils. The family evolved around 50 million years ago from a small, multi-toed ungulate into larger, single-toed animals. All extant species are in the genus Equus, which originated in North America. Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros, and several extinct families. It is more specifically grouped within the superfamily Equoidea, the only other family being the extinct Palaeotheriidae.
Diceros is a genus of rhinoceros containing the extant black rhinoceros (Diceros bicornis) and several extinct species.
Ceratotherium is a genus of the family Rhinocerotidae, consisting of a single extant species, the white rhinoceros, as well as several fossil species.
Hadar or Hadar Formation is a paleontological fossil site located in Mille district, Administrative Zone 1 of the Afar Region, Ethiopia, 15 km upstream (west) of the A1 road's bridge across the Awash River.
Chalicotheriidae is an extinct family of herbivorous, odd-toed ungulate (perissodactyl) mammals that lived in North America, Eurasia, and Africa from the Middle Eocene to the Early Pleistocene. They are often called chalicotheres, a term which is also applied to the broader grouping of Chalicotherioidea. They are noted for their unusual morphology compared to other ungulates, such as their clawed forelimbs. Members of the subfamily Chalicotheriinae developed elongate gorilla-like forelimbs that are thought to have been used to grasp vegetation. They are thought to have been browsers on foliage as well as possibly bark and fruit.
Ancylotherium is an extinct genus of the family Chalicotheriidae, subfamily Schizotheriinae, endemic to Europe, Asia, and Africa during the Late Miocene-Early Pleistocene, existing for approximately 9.8 million years.
Hippidion is an extinct genus of equine that lived in South America from the Late Pliocene to the end of the Late Pleistocene (Lujanian), between 2.5 million and 11,000 years ago. They were one of two lineages of equines native to South America during the Pleistocene epoch, alongside Equus (Amerhippus) neogeus.
Equus simplicidens, sometimes known as the Hagerman horse or the American zebra is an extinct species in the horse family native to North America during the Pliocene and Early Pleistocene. It is one of the oldest and most primitive members of the genus Equus. It is the state fossil of Idaho, where its abundant remains were discovered in 1928, specifically in Hagerman, Idaho. They are also known from other US states including Arizona, California, Texas, Nebraska and Kansas.
Neohipparion is an extinct genus of equid, from the Neogene of North America and Central America. Fossils of this horse have been found in Texas, Florida, Kansas, South Dakota, Montana, Nevada, Alabama, Oregon, and Mexico. This prehistoric species of equid grew up to lengths of 4.5 to 5 ft long. In Florida, Neohipparion lived in a wooded grassland savanna environment during the dry season but moved to a wet environment when it came time to mate. Speaking of mating, the average age of death for a newborn colt was 3.5 years, with a juvenile mortality rate of 64% during its first 2 years of existence. Its diet consisted of grasses, C3 and C4 plants.
Pseudhipparion is an extinct genus of three-toed horse endemic to North America during the Miocene. They were herding animals whose diet consisted of C3 plants. Fossils found in Georgia and Florida indicate that it was a lightweight horse, weighing up to 90 pounds. In 2005, fossils were unearthed in Oklahoma. Seven species of Pseudhipparion are known from the fossil record which were very small, following the trend of Bergmann's rule.
Nannippus is an extinct genus of three-toed horse endemic to North America during the Miocene through Pleistocene, about 13.3—1.8 million years ago (Mya), living around 11.5 million years. This ancient species of three-toed horse grew up to 3.5 feet and weighed between 165 pounds to 199 pounds, which was around the same size as a domestic sheep.
Cormohipparion is an extinct genus of horse belonging to the tribe Hipparionini that lived in North America during the late Miocene to Pliocene. They grew up to 3 feet long.
Archaeohippus is an extinct three toed member of the family Equidae known from fossils of early Oligocene to middle Miocene age. The genus is noted for several distinct skeletal features. The skull possesses deeply pocketed fossa in a notably long preorbital region. The genus is considered an example of phyletic dwarfism with adults estimated at being on average 20 kilograms in weight. This is in contrast to the most common equid of the period, Miohippus. Characters of the teeth show a mix of both primitive and advanced traits. The advanced traits are very similar to those shown in the genus Parahippus. The noted similarities of Archaeohippus and Parahippus show them to be descended from a common ancestor. They are considered sister species.
The Shungura Formation is a stratigraphic formation located in the Omo river basin in Ethiopia. It dates to the Late Pliocene to Early Pleistocene. Oldowan tools have been found in the formation, suggesting early use of stone tools by hominins. Among many others, fossils of Panthera were found in Member G of the formation.
Hippotherium is an extinct genus of horse that lived in during the Miocene through Pliocene ~13.65—6.7 Mya, existing for 6.95 million years.
This paleomammalogy list records new fossil mammal taxa that were described during the year 2013, as well as notes other significant paleomammalogy discoveries and events which occurred during that year.
Eurygnathohippus woldegabrieli is an extinct species of prehistoric horse. The 4.4 to 4.2 million-year-old fossils of its teeth and bones were found in 2001 and 2002 in Ethiopia. It was identified as a new species in 2013 by researchers at Case Western Reserve University, and the species named after geologist and Case Western alumnus Giday WoldeGabriel.
The Ash Hollow Formation of the Ogallala Group is a geological formation found in Nebraska and South Dakota. It preserves fossils dating back to the Neogene period. It was named after Ash Hollow, Nebraska and can be seen in Ash Hollow State Historical Park. Ashfall Fossil Beds State Historical Park is within this formation.
