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Las Tetas De Cabra Formation
The Las Tetas de Cabra Formation is a geologic formation in Mexico. It preserves fossils dating back to the Wasatchian of the Early Eocene period.Las Tetas de Cabra Formation at .org Fossil content The following fossils have been reported from the formation:Mammals ;Acreodi * '' Dissacus sp.''Alroy, 2002 * '' Wyolestes iglesius''[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxyaena
''Oxyaena'' ("sharp hyena") is an extinct genus of oxyaenid mammal from early Eocene of Europe, Asia and North America (most specimens being found in Colorado). Etymology The name of the genus translates as "sharp hyaena" ( and name of hyena genus '' Hyaena''). Description The species were superficially cat or wolverine-like, with a flexible body long, and short limbs. Some species like ''Oxyaena forcipata'' were bigger with a body mass estimated to be 20 kg. ''Oxyaena'' had a broad, low skull (20 cm long) with a long facial part and a massive lower jaw, while its body and tail were long and its five-toed limbs were short. Oxyaenidae, a family of extinct meat-eating mammals, takes its name from this genus. Oxyaenids may have evolved in North or Central America, and tended to have long bodies and tails with short legs. Because of their shape, early studies often compared them to cats, but this body form has evolved many times in small to medium-sized forest-dwelling ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudata
The Caudata are a group of amphibians containing the extant salamanders ( Urodela) and all extinct species of amphibians more closely related to salamanders than to frogs. They are typically characterized by a superficially lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. Disagreement exists between different authorities as to the definition of the terms "Caudata" and "Urodela". Some maintain that Urodela should be restricted to the crown group, with Caudata being used for the total group. Others restrict the name Caudata to the crown group and use Urodela for the total group. The former approach seems to be most widely adopted and is used in this article. Evolution The origins and evolutionary relationships between the three main groups of amphibians ( apodans, urodeles and anurans) is a matter of debate. A 2005 molecular phylogeny, based on rDNA analysis, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iguanidae
The Iguanidae is a family of lizards composed of the iguanas, chuckwallas, and their prehistoric relatives, including the widespread green iguana. Taxonomy Iguanidae is thought to be the sister group to the collared lizards (family Crotaphytidae); the two groups likely diverged during the Late Cretaceous, as that is when ''Pristiguana'' and ''Pariguana'', the two earliest fossil genera, are known from. The subfamily Iguaninae, which contains all modern genera, likely originated in the earliest Paleocene, at about 62 million years ago. The most basal extant genus, '' Dipsosaurus,'' diverged from the rest of Iguaninae during the late Eocene, about 38 million years ago, with '' Brachylophus'' following a few million years later at about 35 million years ago, presumably after its dispersal event to the Pacific. All other modern iguana genera formed in the Neogene period. A phylogenetic tree of Iguaninae is shown here: Description Iguanas and iguana-type species are divers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boidae
The Boidae, commonly known as boas or boids, are a family of nonvenomous snakes primarily found in the Americas, as well as Africa, Europe, Asia, and some Pacific Islands. Boas include some of the world's largest snakes, with the green anaconda of South America being the heaviest and second-longest snake known; in general, adults are medium to large in size, with females usually larger than the males. Five subfamilies, comprising 12 genera and 49 species, are currently recognized. The Old Tupi name for such snakes was mbói, which figures in the etymology of names such as ''jibóia'' and ''boitatá'' (the Brazilian name for the mythical giant anaconda). Description Like the pythons, boas have elongated supratemporal bones. The quadrate bones are also elongated, but not as much, while both are capable of moving freely so when they swing sideways to their maximum extent, the distance between the hinges of the lower jaw is greatly increased.Parker HW, Grandison AGC. 1977. Snakes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saniwa
''Saniwa'' is an extinct genus of Varanidae, varanid lizard that lived about 48 million years ago during the Eocene epoch. It is known from well-preserved fossils found in the Bridger Formation, Bridger and Green River Formations of Wyoming. The type species ''S. ensidens'' was described in 1870 as the first fossil lizard known from North America. Several other species have since been added, but their validity is uncertain. It is a close relative of ''Monitor lizard, Varanus'', the genus that includes monitor lizards. Description ''Saniwa'' measured . Like other varanid lizards, ''Saniwa'' had a long, pointed snout and nostrils placed farther back in the skull than most lizards and a tail that was almost twice as long as the body. Although similar in appearance to Neontology, extant monitor lizards, ''Saniwa'' had many primitive traits, including teeth on its palate, a jugal bone beneath the eye that extended farther forward, and a suture between the frontal bone, frontal and pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferae
Ferae ( , , "wild beasts") is a mirorder of placental mammalsMalcolm C. McKenna, Susan K. Bell: ''Classification of Mammals: Above the Species Level'' in Columbia University Press, New York (1997), 631 Seiten. that groups together clades Pan-Carnivora and Pholidotamorpha. The Ferae is a sister group to the clade Pan-Euungulata and together they make grandorder Ferungulata. Classification and phylogeny Taxonomy : Phylogeny The phylogenetic relationships of mirorder Ferae are shown in the following cladogram, reconstructed from mitochondrial and nuclear DNA and protein characters, as well as the fossil record.O’Leary, M. A., Bloch JI, Flynn, J. J., Gaudin, T. J., Giallombardo, A., Giannini, N. P., Goldber, S. L, Kraatz, B. P., Luo, Z-X, Jin Meng, Xijun Ni, Novacek, M. J., Perini, F. A., Randall, Z. S., Rougier, G. W., Sargis, E. J., Silcox, M. T., Simmons, N. B., Spaulding, M. Velazco, P. M., Weksler, M., Wible, J. R. Cirranello, A. L. (2013."The Placental Mammal Ancestor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyopsodus
''Hyopsodus'' is a genus of extinct early ungulate mammal of the family Hyopsodontidae, a group associated with or basal to the Perissodactyla. Fossils of this genus have been found in the Eocene of North America, especially the Bighorn Basin region of the United States. It has also been found in Eurasia. Taxonomy Eighteen species of Hyopsodus have been described from North America, four from Asia, and two from Europe. The exact number and identity of species has been contested, as is common when taxa are erected based on fragmentary materials. However, there is broad agreement that multiple species in the genus lived in the Wasatchian, Uintan, and Bridgerian North American Land Mammal Ages, and they have been used both to reconstruct paleoenvironments and to study evolutionary change. Appearance and habits Members of the genus had a long spinal column with short limbs and tail, making them one of the few genera of Paleogene mammal with a common name: "tube-sheep" Rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenacodus
''Phenacodus'' (Greek: "deception" (phenax), "tooth' (odus)) is an extinct genus of mammals from the late Paleocene through middle Eocene, about 55 million years ago. It is one of the earliest and most primitive of the ungulates, typifying the family Phenacodontidae and the order Perissodactyla. Description The typical ''Phenacodus primaevus'' was a relatively small ungulate about long and weighed up to , of slight build, with straight limbs each terminating in five complete toes, and walking in the digitigrade fashion of the modern horse. The middle toe was the largest, and the weight of the body was mainly supported on this and the two adjoining digits, which appear to have been encased in hooves, foreshadowing the tridactyl type common in perissodactyls and certain extinct groups of ungulates. The skull was small, with proportionately minute brain; and the arched back, strong lumbar vertebrae, long and powerful tail, and comparatively feeble fore-quarters all proclaim kinsh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meniscotherium
''Meniscotherium'' is an extinct genus of dog-sized mammal which lived 54–38 million years ago. It was a herbivore and had hooves. Fossils have been found in Utah, New Mexico. and Colorado. Many individuals have been found together, indicating that it lived in groups. Body mass in ''M. chamense'' is estimated to be 5–17 kg, making it about the size of a small dog. A 2014 cladistic analysis places it within stem perissodactyl Odd-toed ungulates, mammals which constitute the taxonomic order Perissodactyla (, ), are animals—ungulates—who have reduced the weight-bearing toes to three (rhinoceroses and tapirs, with tapirs still using four toes on the front legs) ...s. References {{Taxonbar, from=Q4289003 Condylarths Eocene mammals of North America Fossil taxa described in 1874 Prehistoric placental genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectocion
''Ectocion'' (sometimes ''Ectocyon'') is an extinct genus of placental mammals of the family Phenacodontidae. The genus was earlier classified as ''Gidleyina'' (Simpson 1935) and ''Prosthecion'' (Patterson and West 1973). Retrieved May 2013. Paleocene specimens of these hoofed, ground-dwelling herbivores have been found in Canada (Alberta, Saskatchewan) and the United States (Colorado, Montana, North Dakota, and Wyoming). Eocene specimens have been found in Mexico and the United States (Colorado, Mississippi, Wyoming). One of the dramatic effects of the Paleocene–Eocene Thermal Maximum (PETM) was some animals evolving smaller bodies. Fossilized ''Ectocion'' jaw bones show that this genus was smaller during (''E. parvus'', 55.5 mya Mya may refer to: Brands and product names * Mya (program), an intelligent personal assistant created by Motorola * Mya (TV channel), an Italian Television channel * Midwest Young Artists, a comprehensive youth music program Codes * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eohippus
''Eohippus'' is an extinct genus of small equid ungulates. The only species is ''E. angustidens'', which was long considered a species of ''Hyracotherium''. Its remains have been identified in North America and date to the Early Eocene (Ypresian stage). Discovery In 1876, Othniel C. Marsh described a skeleton as ''Eohippus validus'', from el, ἠώς (, 'dawn') and (, 'horse'), meaning 'dawn horse'. Its similarities with fossils described by Richard Owen were formally pointed out in a 1932 paper by Clive Forster Cooper. ''E. validus'' was moved to the genus ''Hyracotherium'', which had priority as the name for the genus, with ''Eohippus'' becoming a junior synonym of that genus. ''Hyracotherium'' was recently found to be a paraphyletic group of species, and the genus now includes only ''H. leporinum''. ''E. validus'' was found to be identical to an earlier-named species, ''Orohippus angustidens'' Cope, 1875, and the resulting binomial is thus ''Eohippus angustidens''. D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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