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.
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.
Protohippus is an extinct three-toed genus of horse. It was roughly the size of a modern donkey. Fossil evidence suggests that it lived during the Late Miocene, from about 13.6 Ma to 5.3 Ma.
Parahippus leonensis is an extinct proto-horse of the family Equidae that was endemic to North America during the Miocene from 23.030 to 16.3 Ma living for approximately 6.73 million years.
Neohipparion is an extinct genus of equid, from the Neogene of North America and Central America. This prehistoric species of equid grew up to lengths of 4.5 to 5 ft long.
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.
Eurygnathohippus is an extinct genus of hipparionine horse. The majority of known fossils of members of this genus were discovered in Africa, where members of this genus lived during the late Miocene to Pleistocene interval. Fossils of Eurygnathohippus were also reported from the late Pliocene sediments of the Potwar Plateau in Pakistan and the Siwalik Hills in northwest India.
The Parachucla Formation is a geologic formation in the southeastern United States. It preserves fossils from the Aquitanian stage of the early Miocene period. The formation is included in the Hawthorn Group. An exposure at the northern end of the formation has produced fossils estimated to be 19.4 to 20.5 Million years ago (Ma). Another exposure at the southern end of the formation has produced fossils estimated to be 23.9 to 24.7 Ma.
The Alachua Formation is a Miocene geologic formation in Florida. The claystones, sandstones and phosphorites of the formation preserve many fossils of mammals, birds, reptiles and fish, among others megalodon.
The Bone Valley Formation is a geologic formation in Florida. It is sometimes classified as the upper member of the Peace River Formation of the Hawthorn Group. It contains economically important phosphorite deposits that are mined in west-central Florida, as well as rich assemblages of vertebrate fossils.
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.
The Valentine Formation is a geologic unit formation or member within the Ogallala unit in northcentral Nebraska near the South Dakota border. It preserves fossils dating to the Miocene epoch of the Neogene period and is particularly noted for Canid fossils. This unit consists of loosely-consolidated sandstone that crumbles easily. These sands carry the water of the Ogallala Aquifer and is the source of much of the water in the Niobrara River. A particular feature of the Valentine is lenticular beds of green-gray opaline sandstone that can be identified in other states, including South Dakota, Nebraska, Kansas, and Colorado. Although three mammalian fauna stages can be mapped throughout the range of the Ogallala, no beddings of the Ogallala are mappable and all attempts of formally applying the Valentine name to any mappable lithology beyond the type location have been abandoned. Even so, opaline sandstone has been used to refer to this green-gray opalized conglomerate sandstone that is widely found in the lower Ogallala Formation.
The Juntura Formation is a geologic formation in Oregon. It preserves fossils dating back to the Neogene period.
The Dove Spring Formation is a geologic formation in the western Mojave Desert of California. It preserves fossils dating back to the Miocene epoch of the Neogene period.
The Capistrano Formation is a geologic formation in coastal southern Orange County, California. It preserves fossils dating back to the late Miocene to early Pliocene, with the Oso Member representing a near-shore environment. Fifty-nine species and varieties of foraminifera are recognized from the Capistrano Formation alongside a diverse array of marine mammals including up to five species of walrus.
The Gracias Formation is a geologic formation in Honduras. The mainly sandstones, siltstones and claystones preserve vertebrate fossils dating back to the Neogene period.
The Cucaracha Formation (Tca) is a geologic formation in Panama. It preserves vertebrate and plant fossils dating back to the Neogene period; Early to Middle Miocene epochs (Hemingfordian). Fossils of the crocodylian Centenariosuchus, the turtle Rhinoclemmys panamaensis and the artiodactyl Paratoceras have been found in the formation.
Calippus is an extinct genus of hoofed mammals in the horse family (Equidae), known from the Middle Miocene through the Early Pliocene of North and Central America. Fossils have been found in the Central United States and the Eastern United States, ranging south to Honduras. These equines had high crowned teeth and a quadrangular, wide muzzle, and were small compared to their contemporary relatives, with C. elachistus weighing 49 kg, C. cerasinus weighing 102 kg, 132 kg for C. theristes and 73 kg for C. mccartyi.
Moqueguahippus is an extinct genus of notohippid notoungulates that lived during the Late Oligocene of what is now Peru. Fossils of this genus have been found in the Moquegua Formation of Peru, which it was named after.
