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Cramaucheniinae
Cramaucheniinae is a paraphyletic subfamily of macraucheniids that originated in the middle Eocene (Mustersan SALMA). The size range of the group ranged from small, basal forms to larger and more derived forms. During their evolution, the cramaucheniines undergone a trend from evolving from small basal forms such as '' Polymorphis'' into larger, more derived taxa such as ''Theosodon ''Theosodon'' is an extinct genus of litoptern mammal from the Early to Middle Miocene of South America. Description ''Theosodon'' was long-legged with a long neck resembling modern llamas or guanacos. It was large for a litoptern, reaching ...''. References Macraucheniids Paleogene mammals of South America Neogene mammals of South America Mammal subfamilies Lutetian first appearances Serravallian extinctions Paraphyletic groups {{Paleo-mammal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pternoconius
''Pternoconius'' is an extinct genus of macraucheniid litoptern from the Late Oligocene and Early Miocene of Argentina. Fossils of this genus have been found in the Sarmiento Formation of Argentina. Etymology The genus name, ''Pternoconius'', is an anagram of the closely related genus '' Coniopternium''. The species name refers to the similarity of the Eocene genus '' Polymorphis''. Species ''Pternoconius tournoueri'' In 1985, fossils found in the Early Miocene Colhué Huapí Member of the Sarmiento Formation were assigned to the genus under the name ''Pternoconius tournoueri'', consisting of a nearly complete hemimandible. ''Pternoconius bondi'' In 2016 a new species of macraucheniid litoptern was described coming from the Bajada del Diablo locality in the Sarmiento Formation, consisting of the anterior portion of the skull with the maxillary region, some fragments of nasal bones, a small portion of the left zygomatic process, and most of the upper dentition (i.e., l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theosodon
''Theosodon'' is an extinct genus of litoptern mammal from the Early to Middle Miocene of South America. Description ''Theosodon'' was long-legged with a long neck resembling modern llamas or guanacos. It was large for a litoptern, reaching up to in length and weighing up to . It had a long neck and tapir-like, three-toed feet, and like other litopterns and modern horses, tapirs and rhinos, it bore its weight on its middle toes. Extraordinarily, rather than having nostrils at the front of its head, ''Theosodon'' had its nostrils on the top of its snout, halfway between the forehead and the tip of the snout, and its nostrils pointed upwards rather than forwards, possibly as an adaptation for browsing on prickly vegetation. History and species ''Theosodon'' has been known since the 19th century, and by 1910 seven species had been described within the genus, all from the early Miocene Santa Cruz Formation in Argentina. The name ''Theosodon'' means "god tooth". The first fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cramauchenia
''Cramauchenia'' is an extinct genus of litoptern South American ungulate. ''Cramauchenia'' was named by Florentino Ameghino. The name has no literal translation. Instead, it is an anagram of the name of a related genus ''Macrauchenia''. This genus was initially discovered in the Sarmiento Formation in the Chubut Province, in Argentina, and later it was found in the Chichinales Formation in the Río Negro Province and the Cerro Bandera Formation in Neuquén, also in Argentina, in sediments assigned to the SALMA Colhuehuapian (in the Early Miocene), as well as the Agua de la Piedra Formation in Mendoza, in sediments dated to the Deseadan (during the Late Oligocene). In 1981 Soria made ''C. insolita'' a junior synonym of ''C. normalis''. A specimen of ''C. normalis'' was described in 2010 from Cabeza Blanca (Chubut, Argentina) in the Sarmiento Formation, in sediments assigned to the Deseadan SALMA (Upper Oligocene). Description This animal had an appearance vaguely similar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymorphis
''Polymorphis'' is an extinct genus of litopterns belonging to the family Macraucheniidae. It lived during the Middle Eocene of Argentina. Taxonomy The type species of ''Polymorphis'' is ''Polymorphis lechei''. Both the genus and the species were named by Santiago Roth in 1899. The lectotype of ''P. lechei'' is the left half of a mandible with teeth. Two other species, ''Megacrodon planus'' and "''Lambdaconus''" ''alius'', have been previously assigned to ''Polymorphis'', but are poorly known and may not belong to the genus. ''Megacrodon'', ''Polyacrodon'' (which has the junior objective synonym ''Oroacrodon''), ''Decaconus'', and ''Periacrodon'' have been considered synonyms of ''Polymorphis''. ''Polymorphis'' is the most basal member of Macraucheniidae. It is considered to be either part of the paraphyletic subfamily Cramaucheniinae, or in a monotypic subfamily of its own, Polymorphinae. ''Polymorphis'' is known from the Eocene of Argentina, belonging to the Mustersan Sout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macraucheniidae
Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled various camelids. The reduced nasal bones of their skulls was originally suggested to have housed a small proboscis, similar to that of the saiga antelope. However, one study suggested that they were openings for large moose-like nostrils. Conversely, prehistoric pictographs by indigenous people seems to depict animals interpreted as macraucheniids with trunks. Their hooves were similar to those of rhinoceroses today, with a simple ankle joint and three digits on each foot. Thus, they may have been capable of rapid directional change when running away from predators, such as large phorusrhacid terror birds, sparassodont metatherians, giant short-faced bears ('' Arctotherium)'' and saber-toothed cats (''Smilodon''). Macraucheniids probably lived in large herds to gain protection against these predators, as well as to facilitate finding mates for reproduction. The family Macrauc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lutetian First Appearances
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene Subepoch. Stratigraphic definition The Lutetian was named after Lutetia, the Latin name for the city of Paris. The Lutetian Stage was introduced in scientific literature by French geologist Albert de Lapparent in 1883 and revised by A. Blondeau in 1981. The base of the Lutetian Stage is at the first appearance of the nanofossil ''Blackites inflatus'', according to an official reference profile (GSSP) established in 2011. Of two candidates located in Spain, the Gorrondatxe section was chosen.See thwebsite of Eustoquio Molinafor these candidates. The top of the Lutetian (the base of the Bartonian) is at the first appearance of calcareous nanoplankton species ''Reticulofenestra reticulata''. The Lutetian overlaps with the Geisel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal Subfamilies
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or hair, and three middle ear bones. These characteristics distinguish them from reptiles (including birds) from which they diverged in the Carboniferous, over 300 million years ago. Around 6,400 extant species of mammals have been described divided into 29 orders. The largest orders, in terms of number of species, are the rodents, bats, and Eulipotyphla (hedgehogs, moles, shrews, and others). The next three are the Primates (including humans, apes, monkeys, and others), the Artiodactyla ( cetaceans and even-toed ungulates), and the Carnivora (cats, dogs, seals, and others). In terms of cladistics, which reflects evolutionary history, mammals are the only living members of the Synapsida (synapsids); this clade, together wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neogene Mammals Of South America
The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868). During this period, mammals and birds continued to evolve into modern forms, while other groups of life remained relatively unchanged. The first humans ('' Homo habilis'') appeared in Africa near the end of the period. Some continental movements took place, the most significant event being the connection of North and South America at the Isthmus of Panama, late in the Pliocene. This cut off the warm ocean currents from the Pacific ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Mammals Of South America
The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning of the Neogene Period Mya. It is the beginning of the Cenozoic Era of the present Phanerozoic Eon. The earlier term Tertiary Period was used to define the span of time now covered by the Paleogene Period and subsequent Neogene Period; despite no longer being recognised as a formal stratigraphic term, 'Tertiary' is still widely found in earth science literature and remains in informal use. Paleogene is often abbreviated "Pg" (but the United States Geological Survey uses the abbreviation PE for the Paleogene on the Survey's geologic maps). During the Paleogene, mammals diversified from relatively small, simple forms into a large group of diverse animals in the wake of the Cretaceous–Paleogene extinction event that ended the preceding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in comparison with the more common isotope 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn") and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope Carbon-13, 13C in the atmosphere was exceptionally low in comparison with the more common isotope Carbon-12, 12C. The end is set at a major extinction event called the ''Grande Coupure'' (the "Great Break" in continuity) or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Popigai impact structure, Siberia and in what is now ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
