|
Megalonychidae
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 morpholo ... [...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] |
South American Land Mammal Age
The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Mya (unit), Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as ages, stages, or intervals and were established using geographic place names where fossil materials where obtained.Flynn & Swisher, 1995 The basic unit of measure is the first/last boundary statement. This shows that the first appearance event of one taxon is known to predate the last appearance event of another. If two taxa are found in the same fossil quarry or at the same stratigraphic horizon, then their age-range zones overlap. Background South America was an island continent for much of the Cenozoic, or the "Age of Mammals". As a result, its mammals evolved in their own unique directions, as Australia and Madagascar still have today. Paleogeographic timeline A simplified paleogeography, paleogeographic timeline of South ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proplatyarthrus
''Proplatyarthrus'' is an extinct genus of ground sloths of the family Megalonychidae, endemic to Chubut Province, Argentina in South America. Taxonomy ''Proplatyarthrus'' was named and a talus bone described by Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especially ... in 1905. It was assigned to Megalonychidae by Carroll in 1988.R. L. Carroll. 1988. Vertebrate Paleontology and Evolution. W. H. Freeman and Company, New York 1-698 References Bibliography * Further reading * R. Hitz, M. Reguero, A. R. Wyss and J. J. Flynn. 2000. New interatheriines (Interatheriidae, Notoungulata) from the Paleogene of Central Chile and Southern Argentina. Fieldiana: Geology (New Series) 42:1-26 Prehistoric sloths Oligocene xenarthrans Oligocene genus extinctions O ... [...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] |
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] |
Urumacocnus
''Urumacocnus'' is an extinct genus of megalonychid sloth that lived during the Miocene in Venezuela. The genus contains one known species, ''Urumacocnus urbanii''. Fossils have been found in the Urumaco Formation of Venezuela. Etymology The generic name, ''Urumacocnus'', is derived from the Urumaco Formation in which its fossils have been found in, and -ocnus, which means "hesitating" or "lazy", which is commonly used to name extinct sloths. The specific name honours Franco Urbani, for his important contributions to Venezuelan geology. Description ''Urumacocnus'' is a relatively small sized megalonychid sloth that shares a combination of diagnostic features such as a round femur shaft, a straight femur shaft, albeit with the medial and lateral sides curved the femur head angle with respect to the femur shaft which is more than 160°, the femur neck being well demarcated, a valley between the femur head and the greater trochanter shallow; the femoral head present and larger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hapaloides
''Hapaloides'' is an extinct genus of ground sloth of the family Megalonychidae, endemic to Argentina during the Early Miocene. It lived from 17.5 mya to 16.3 mya, existing (as a genus) for approximately .R. L. Carroll. (1988). ''Vertebrate Paleontology and Evolution'' 1–698 Found in the Colhuehuapian-aged Colpodon Beds of Argentina, three species are known: ''H. ignavus'' (the type species), ''H. laevisculus'' and ''H. ponderosus'', all named by Florentino Ameghino in 1902. ''H. ignavus'' is known from a partial cranium that is smaller than that of '' Hapalops rectangularis'', which it was compared to. Ameghino in 1902 placed ''Hapaloides'' in the Megatheriidae, alongside ''Proschismotherium'', which was its sister taxon, while more recent taxonomic reviews place ''Hapaloides'' within Megalonychidae 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 so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megalonyx
''Megalonyx'' (Greek, "large claw") 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 and weighed up to . ''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. Taxonomy In 1796, Colonel John Stuart sent Thomas Jefferson, shortly before he took office as Vice President of the United States, some fossil bones: a femur fragment, ulna, radius, and foot bones including three ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hapalops
''Hapalops'' is an extinct genus of ground sloth from the Early to Late Miocene of Brazil (Solimões Formation), Bolivia ( Honda Group), Colombia ( Honda Group),Croft, 2007, p.300 and Argentina (Santa Cruz Formation) in South America.''Hapalops'' at Fossilworks.org History ''Hapalops'' was first described by notable Argentine paleontologist and zoologist in 1887, with his description of ''H. rectangularis'' as the type species. It was erected based on the posterior part of a left dentary that had been collected from the |
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] |
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] |
