Megalonyx is an extinct genus of ground sloths of the family Megalonychidae, native to North America during the Pliocene and Pleistocene epochs. It became extinct during the Quaternary extinction event at the end of the Rancholabrean of the Pleistocene, living from ~5 million to 11,000 years ago. The type species, M. jeffersonii, measured about 3 meters (9.8 ft) and weighed up to 1,000 kilograms (2,200 lb). Megalonyx is descended from Pliometanastes, a genus of ground sloth that had arrived in North America during the Late Miocene, prior to the Great American Biotic Interchange. Megalonyx had the widest distribution of any North American ground sloth, having a range encompassing most of the contiguous United States, extending as far north as Alaska during warm periods.
Megalonychidae is an extinct family of sloths including the extinct Megalonyx. Megalonychids first appeared in the early Oligocene, about 35 million years (Ma) ago, in southern Argentina (Patagonia). There is actually one possible find dating to the Eocene, about 40 Ma ago, on Seymour Island in Antarctica. They first reached North America by island-hopping across the Central American Seaway, about 9 million years ago, prior to formation of the Isthmus of Panama about 2.7 million years ago. Some megalonychid lineages increased in size as time passed. The first species of these were small and may have been partly tree-dwelling, whereas the Pliocene species were already approximately half the size of the huge Late Pleistocene Megalonyx jeffersonii from the last ice age.
Armbruster's wolf is an extinct species that was endemic to North America and lived during the Irvingtonian stage of the Pleistocene epoch, spanning from 1.9 Mya—250,000 years BP. It is notable because it is proposed as the ancestor of one of the most famous prehistoric carnivores in North America, the dire wolf, which replaced it.
Nothrotheriops is a genus of Pleistocene ground sloth found in North America, from what is now central Mexico to the southern United States. This genus of bear-sized xenarthran was related to the much larger, and far more famous Megatherium, although it has recently been placed in a different family, Nothrotheriidae. The best known species, N. shastensis, is also called the Shasta ground sloth.
Melbourne Bone Bed is a paleontological site located at Crane Creek in Melbourne, in the U.S. state of Florida. This site contains fossils from the Late Pleistocene period 20,000 to 10,000 years before present. The fossils include extinct animals such as varieties of camels, dire wolves, Florida cave bears, giant armadillos, giant beavers, giant bison, giant ground sloths, mammoths, mastodons, saber-toothed cats and tapirs.
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.
Eremotherium is an extinct genus of group living ground sloth of the family Megatheriidae, endemic to northern South America, Central America, and parts of southern North America during the Pleistocene epoch. It lived from 4.9 mya —11,000 years ago existing for approximately 4.889 million years. Several species of Eremotherium were among the largest known ground sloths, rivalling Megatherium americanum in size. E. laurillardi was possibly the largest sloth to ever exist, with bulls reaching a length of up to 6 m (20 ft) and a mass of up to 6.5 tonnes.
Hemiauchenia is a genus of laminoid camelids that evolved in North America in the Miocene period about 10 million years ago. This genus diversified and moved to South America in the Early Pleistocene, as part of the Great American Biotic Interchange, giving rise to modern lamines. The genus became extinct at the end of the Pleistocene.
Pliometanastes is an extinct genus of giant ground sloths of the family Megalonychidae endemic to North America during the Late Miocene epoch through very early Pliocene epoch. Its fossils have been found in Costa Rica and across the southern United States from California to Florida.
The Haile Quarry or Haile sites are an Early Miocene and Pleistocene assemblage of vertebrate fossils located in the Haile quarries, Alachua County, northern Florida. The assemblage was discovered during phosphate mining, which began in the late 1940s. Haile sites are found in the Alachua Formation. Two sites within the Ocala Limestone yielded Upper Eocene Valvatida and mollusks.
Hypolagus is an extinct genus of lagomorph, first recorded in the Hemingfordian of North America. It entered Asia during the early Turolian and spread to Europe not much later, where it survived until the Middle Pleistocene. Though unknown in the Iberian Peninsula, fossils of this genus have been found in the Balearic Islands, suggesting an eastern migration during the dry period in the Mediterranean region known as the Messinian Salinity Crisis.
Lestobradys is an extinct genus of ground sloth, which existed in Uruguay during the Late Miocene period; Huayquerian in the South American land mammal age (SALMA). The type species is L. sprechmanni, found in the Camacho Formation of Uruguay.
Paleontology in Florida refers to paleontological research occurring within or conducted by people from the U.S. state of Florida. Florida has a very rich fossil record spanning from the Eocene to recent times. Florida fossils are often very well preserved.
Paleontology in Idaho refers to paleontological research occurring within or conducted by people from the U.S. state of Idaho. The fossil record of Idaho spans much of the geologic column from the Precambrian onward. During the Precambrian, bacteria formed stromatolites while worms left behind trace fossils. The state was mostly covered by a shallow sea during the majority of the Paleozoic era. This sea became home to creatures like brachiopods, corals and trilobites. Idaho continued to be a largely marine environment through the Triassic and Jurassic periods of the Mesozoic era, when brachiopods, bryozoans, corals, ichthyosaurs and sharks inhabited the local waters. The eastern part of the state was dry land during the ensuing Cretaceous period when dinosaurs roamed the area and trees grew which would later form petrified wood.
Paleontology in California refers to paleontologist research occurring within or conducted by people from the U.S. state of California. California contains rocks of almost every age from the Precambrian to the Recent. Precambrian fossils are present but rare in California.
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 Goliad Formation (Tg) is a geologic formation in Texas. It preserves fossils dating back to the Serravallian to earliest Pliocene stages of the Neogene period, including the gomphothere Blancotherium among many other fossil mammals, reptiles, birds and fish.
Surameryx is an extinct genus of herbivorous even-toed ungulates originally described as belonging to the extinct family Palaeomerycidae. A single species, S. acrensis, was described from the Late Miocene of the Madre de Dios Formation, South America. It was originally interpreted as one of the few northern mammals that entered South America before the Pliocene. However, both its identification as a member of the family Palaeomerycidae and claims about its Miocene age were subsequently challenged.
Megistonyx is an extinct genus of ground sloth endemic to South America during the Late Pleistocene (Lujanian). It is known from one skeleton collected in the Andes of Venezuela, and is closely related to Ahytherium.
Archaeomylodon is an extinct genus of mylodontine ground sloths that lived during the Middle Pleistocene of what is now Argentina. It is known so far only from a single skull, which in its dimensions corresponds to those of the giant Lestodon. However, the skull differs from this one by its narrower and higher snout. In addition, the anterior canine teeth, which are usually large in many mylodonts, are greatly reduced. The find comes from the Pampa region of South America and was deposited in about 700,000 years old sediments.
