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Martinmiguelia
''Martinmiguelia'' is an extinct genus of Notoungulate, belonging to the family Leontiniidae. It lived during the Middle Eocene, and its fossil remains were found in South America. Description This animal is only known from skull and mandible remains, and it probably shared similarities with later and better known leontiniids, such as ''Scarrittia''. It was smaller-sized than those derived genera, approximately the size of a sheep. ''Martinmiguelia'' was characterized by an archaic dental formula, with a complete dentition (three incisors, one canine, four premolars and three molars) and a quasi-absence of diastema, except for small spaces around the small-sized canines. The molars and premolars were low-crowned (brachydont), a primitive condition for leontinnids. The upper incisors were canine-like and possessed labial girdles, and the second upper incisor was larger than the others. Classification ''Martinmiguelia fernandezi'' was first described in 1995, based on fossils fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxodonts
Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The group is named after ''Toxodon'', the first example of the group to be discovered by science. Description Isotemnidae, the oldest and most primitive family of toxodonts, were generally large animals with larger canines than other early notoungulates. The family is probably paraphyletic or polyphyletic since only primitive dental features unite the 12 included genera, such as a complete dentition with unreduced canines and no diastemata in the earliest genera. Likewise, they are only weakly linked to other toxodonts by a few dental features, and their primitive cheek tooth pattern can be basal to all notoungulates except notioprogonians. The oldest of the 12 genera in this family is ''Isotemnus'' known from the Riochican-Casamayoran, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leontiniidae
Leontiniidae is an extinct family comprising eighteen genera of notoungulate mammals known from the Middle Eocene (Mustersan) to Late Miocene (Huayquerian) of South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou .... References Further reading * M. V. Deraco, J. E. Powell, and G. Lopez. 2008. Primer leontínido (Mammalia, Notoungulata) de la Formación Lumbrera (Subgrupo Santa Bárbara, Grupo Salta-Paleógeno) del noroeste argentino. ''Ameghiniana'' 45(1):83–91 * McKenna, Malcolm C., and Bell, Susan K. 1997. ''Classification of Mammals Above the Species Level.'' Columbia University Press, New York, 631 pp. * B. J. Shockey, J. J. Flynn, D. A. Croft, P. Gans, and A. R. Wyss. 2012. New leontiniid Notoungulata (Mammalia) from Chile and Argentina: comparative anato ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elmerriggsia
''Elmerriggsia'' is an extinct genus of Notoungulate, belonging to the family Leontiniidae. It lived during the Late Oligocene in South America. Description This animal, like all leontiniids, had a fairly robust body and strong legs. Unlike most of its relatives, however, ''Elmerriggsia'' was less than 1,5 meters long. ''Elmerriggsia'' had the V-shaped skull when viewed from above, the canine-shaped upper incisors (as well as the third lower incisor), and the mesodont typed dentition characteristic of all leontiniids. The skull of ''Elmerriggsia'' was characterized by the presence of premolars with a grooved protocone, without an intermediate lingual cingulum, and by a well developed labial cingulum on the lower molars. These dental features distinguished ''Elmerriggsia'' from any other leontiniids. Classification ''Elmerriggsia fieldia'' was first described in 2012, based on fossil remains found near Pico Truncado in the Santa Cruz Province of Argentina, in terrains dated f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coquenia
''Coquenia'' is an extinct genus of Notoungulate, belonging to the family Leontiniidae. It lived during the Middle Eocene, in what is today Argentina. Description Known only from skull and mandible remains, ''Coquenia'' may have been a heavily built animal, about the size of a sheep. This animal dentition was low-crowned (brachydont), and the incisors resembled canines, with labial and lingual cingulum. The second upper incisor was more developed than the two others, a typical characteristic of the Leontiniidae, while the upper canines had a rotated crown, with labial and lingual cingulum. The four premolars had an anterolingual cingulum with a small basin located directly in front of the protocone. The premolars progressively increased in size towards the back of the jaw. The upper molars had a labial cingulum, and a posterior dimple, like the lower molars. The third upper molar was wider at the base of its lingual side. Classification ''Coquenia'' is a basal member of the fam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toxodonta
Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The group is named after ''Toxodon'', the first example of the group to be discovered by science. Description Isotemnidae, the oldest and most primitive family of toxodonts, were generally large animals with larger canines than other early notoungulates. The family is probably paraphyletic or polyphyletic since only primitive dental features unite the 12 included genera, such as a complete dentition with unreduced canines and no diastemata in the earliest genera. Likewise, they are only weakly linked to other toxodonts by a few dental features, and their primitive cheek tooth pattern can be basal to all notoungulates except notioprogonians. The oldest of the 12 genera in this family is ''Isotemnus'' known from the Riochican-Casamayoran, but ... [...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] |
Mustersan
The Mustersan age is a period of geologic time (48.0–42.0 Ma) within the Eocene epoch of the Paleogene, used more specifically within the South American land mammal age (SALMA) classification. It follows the Casamayoran and precedes the Divisaderan age.Mustersan at .orgWoodburne et al., 2013 Etymology This age is named after Lake Musters in the |
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] |
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] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded human prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
