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Megalonychinae
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 (which was then still connected to South America). 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 (which led to the main pulse of the Great American Interchange). 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 (about 5 to 2 million years ago) species were already approximately half the size of the huge Late Pleistocene ''Megalonyx jeffersonii'' from the last ice age.J.L. White (1993) It was formerly believed, based on morpholog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesopotamocnus
''Mesopotamocnus'' is an extinct genus of megalonychid ground sloth that lived during the Late Miocene in what is now Argentina. Fossils have been found in the Ituzaingó Formation of Argentina. Etymology The generic name, ''Mesopotamocnus'', is derived from "Mesopotam", from its geographic provenance, Mesopotamia, which in turn means "between rivers" in Greek, and -ocnus, meaning "lazy" or "slow" which is commonly used to name extinct sloths. The specific name, ''brevirostrum'', means "short snout". Taxonomy ''Mesopotamocnus'' (as ''"Ortotherium" brevirostrum"'') was originally assigned to the Nothrotheriidae however, the genus ''Ortotherium'' is currently considered to be a megalonychid, without being assigned to a particular clade such as Ortotheriinae, Megalocninae or Megalonychinae. Furthermore most of the genera and species that were traditionally considered nothrotheres are now considered members of the Nothrotheriinae, such as ''Nothrotherium'', ''Nothropus'', '' P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from the Ancient Greek (''olígos'', "few") and (''kainós'', "new"), and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period. The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the more modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meizonyx
''Meizonyx'' is an extinct genus of megalonychid ground sloth from the Pleistocene of El Salvador and southern Mexico. The type and only species, ''Meizonyx salvadorensis,'' was described in 1985 from a mandible found in Barranca del Sisimico and other remains found at Rio Tomayate in El Salvador considered to be Middle Pleistocene in age. Later, in 2021, additional remains were described from Late Pleistocene aged deposits in Sistema Huautla Sistema Huautla is a cave system in the Sierra Mazateca mountains of the southern Mexican state of Oaxaca. it was the deepest cave system in the Western Hemisphere, from top to bottom, with over 55 miles of mapped passageways. Location Siste ..., Oxaca, Mexico. It is considered closely related to '' Xibalbaonyx.'' References {{Taxonbar, from=Q58418070 Prehistoric sloths Pleistocene xenarthrans Prehistoric placental genera Holocene extinctions Rancholabrean Pleistocene Mexico Fossils of Mexico Fossil taxa described in 198 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megistonyx
''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''. History of discovery The holotype (and so far only known) specimen was found in a cave called ''Cueva de los Huesos'' (meaning "Bone Cave") on Cerro Pintado, a mountain found in the Serranía del Perijá range of the Andes, in the extreme northernmost part of the Sierra de Perijá National Park on the border between Venezuela and Colombia at an altitude of . The various known pieces of the skeleton were recovered in two expeditions to the cave in 1993 and 1997. The specimen was found in a scattered condition, with some bones being damaged, notably the skull was missing the left Squamosal bone. The specimen is currently known from the aforementioned skull, both a right and left humerus, a left ulna, two thoracic vertebrae, a complete rib and three rib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australonyx
''Australonyx'' is an extinct genus of ground sloths, endemic to South America during the Late Pleistocene. It was found in Brazil. Discovery The holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ... specimen was recovered from Poço Azul, an underwater cave system in Nova Redenção, Bahia state. (The same cave also yielded remains of another extinct sloth species, '' Ahytherium''.) The specimen was well preserved, consisting of both the front and back half of the skull (but missing the midsection), the mandible, most of the spine, and some elements from the limbs. Additionally, a nearly identical almost complete skull from Rondônia can be referred to this species. References Prehistoric sloths Pleistocene xenarthrans Prehistoric placental genera Holocene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ahytherium
''Ahytherium'' is an extinct genus of megalonychid sloth that lived during the Pleistocene of what is now Brazil. It contains a single species, ''A. aureum''. Discovery and taxonomy The almost-complete skeleton of ''Ahytherium'' alongside remains another extinct sloth species, ''Australonyx'', were discovered in Poço Azul, an underwater cave in Chapada Diamantina National Park in 2005. It was described by Castor Cartelle of Pontifícia Universidade Católica de Minas Gerais. The bones, which had a length of about when put together, belong to an animal which presumably was still growing. Description This animal is known from well-preserved and nearly complete fossils, including a skeleton of an immature specimen, which in life must have been about three meters long, one meter tall and weighing perhaps half a ton. Like all ground sloths, ''Ahytherium'' was equipped with a robust body and legs equipped with powerful claws. ''Ahytherium'' was similar to other ground sloths such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proschismotherium
''Proschismotherium'' is an extinct genus of ground sloth of the family (biology), family Megalonychidae, endemic to Argentina during the Early Miocene. It lived from 17.5 Year, mya — 16.3 mya, existing (as a genus) for approximately .R. L. Carroll. (1988). ''Vertebrate Paleontology and Evolution'' 1-698 The type, and only, species, ''P. oppositum'', was named in 1902 by Florentino Ameghino based on a single specimen found in the Santacrucian-aged Colpodon Beds of Argentina.F. Ameghino. (1902). Première contribution à la connaissance de la fauna mammalogique des couches à ''Colpodon'' [First contribution to the knowledge of the mammalian fauna of the Colpodon Beds]. ''Boletin de la Academia Nacional de Ciencias de Córdoba'' 17:71-141 Ameghino in 1902 placed ''Proschismotherium'' in the Megatheriidae, alongside ''Hapaloides'', which was its sister taxon. The holotype jaw was compared to that of ''Schismotherium, Schismotherium fractum'' and was found to be roughly the same s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
