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Oldfieldthomasia
''Oldfieldthomasia'' is an extinct genus of Notoungulate, probably related to the suborder Typotheria. It lived during the Middle Eocene, in what is today South America. Description This animal was approximately the size of a marmot, and probably superficially resembled a rodent. The 10 centimeters long skull was rather low and had an elongated muzzle ; the orbits, of large dimension, were posteriorly opened and located in the posterior area of the skull. The zygomatic apophysis was rather slender. The posterior part of ''Oldfieldthomasia debilitata'' was closely studied by George Gaylord Simpson in 1936, through the realization of 55 very thin sections ; the study highlighted numerous cranial characteristics, such as the relationships between the various cavities. The tympanic and hypotympanic cavities were not separated and were devoid of spongy tissue ; the path of the pneumatic orifice can be followed between the epitympanic recess and the epitympanic sinus, filling free, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolichostylodon
''Dolichostylodon'' is an extinct species of mammal, belonging to the order Notoungulata. It lived during the Middle Eocene, and its fossilized remains were discovered in South America. Description About the size of a marmot, this animal was quite similar to other basal notoungulates such as '' Oldfieldthomasia'', '' Ultrapithecus'' and ''Colbertia'', from which it was mainly distinguished by the characteristics of its teeth. The deciduous premolars were more triangular-shaped than in ''Ultrapithecus'', the paracone was more prominent, and the deciduous third lower premolar had a well-developed metaloph. The upper molars had a very prominent parastyle and metastyle. The metacone column was wider than in ''Colbertia'', and the mesiolabial dimple was not present, while the distolabial dimple was wide and shallow. Classification ''Dolichostylodon saltensis'' was first described in 2009, based on fossil remains found in the locality El Simbola, in the Salta Province of Argentina. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notoungulate
Notoungulata is an extinct order of mammalian ungulates that inhabited South America from the early Paleocene to the Holocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined during the Late Neogene, with only the large toxodontids persisting until the end of the Pleistocene. Collagen analysis suggests that notoungulates are closely related to litopterns, another group of South American ungulates, and their closest living relatives being perissodactyls (odd-toed ungulates), including rhinoceroses, tapirs and equines. but their relationships to other South American ungulates are uncertain. Sev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colbertia
''Colbertia'' is an extinct genus of oldfieldthomasiid notoungulate. It lived from the Early to the Middle Eocene, and its fossilized remains were discovered in Argentina and Brazil. Description This animal was roughly the size of a Virginia opossum, reaching approximately 50 centimeters in length excluding its tail. Its weight has been estimated to have been around 2 to 3 kilograms. ''Colbertia'' had a relatively elongated skull, with low-crowned (brachydont) molars ; the cusps of the molars were joined to form ridge-like structures called lophs, and are therefore considered lophodont. The paracone and the metacone had notable folds. The ankle bones of ''Colbertia'' indicates that it was a plantigrade, an ancestral condition within Notoungulata. The bone morphology at the base of the skull was very similar to other basal Notoungulates, although the petrous bone had distinct characteristics also found in similar but slightly more recent notoungulates, such as '' Dolichostylodo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oldfieldthomasiidae
Oldfieldthomasiidae is an extinct family of notoungulate mammals known from the Late Paleocene to Late Eocene of South America. The family was classified by George Gaylord Simpson in 1945 and a synonym is Acoelodidae, defined by Florentino Ameghino in 1901.Oldfieldthomasiidae at .org Etymology The family is named after British zoologistOldfield Thomas
Michael Rogers Oldfield Thomas (21 February 1858 – 16 June 1929) was a British zoologist.
Career
Thomas worked at the Natural Histor ...
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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] |
Allalmeia
''Allalmeia'' was a small notoungulate mammal of around 3 kilograms. It lived in Mendoza Province, Argentina (Divisadero Largo Formation) during the Late Eocene. ''Allalmeia'' belonged to the Oldfieldthomasiidae family within the suborder Typotheria.''Allalmeia'' at .org Description It was a small mammal, with and lophobunodont teeth, teeth that have a combination of ridges ( |
Prehistoric Placental Genera
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Taxa Described In 1901
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taxa Named By Florentino Ameghino
In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping. Initial attempts at classifying and ordering organisms (plants and animals) were set forth in Carl Linnaeus's system in '' Systema Naturae'', 10th edition (1758), as well as an unpublished work by Bernard and Antoine Laurent de Jussieu. The idea of a unit-based system of biological classification was first made widely available in 1805 in the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossils Of Argentina
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the ''fossil record''. Paleontology is the study of fossils: their age, method of formation, and evolutionary significance. Specimens are usually considered to be fossils if they are over 10,000 years old. The oldest fossils are around 3.48 billion years old to 4.1 billion years old. Early edition, published online before print. The observation in the 19th century that certain fossils were associated with certain rock strata led to the recognition of a geological timescale and the relative ages of different fossils. The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleogene Argentina
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 Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene Mammals Of South America
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] |
