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Brontothere
Brontotheriidae is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like rhinos, although they were actually more closely related to horses; Equidae and Brontotheriidae make up the suborder Hippomorpha. They lived around 56–34 million years ago, until the very close of the Eocene. Characteristics and evolution Brontotheres retain four toes on their front feet and three toes on their hind feet. Their teeth are adapted to shearing (cutting) relatively nonabrasive vegetation. Their molars have a characteristic W-shaped ectoloph (outer shearing blade). The evolutionary history of this group is well known due to an excellent fossil record in North America. The earliest brontotheres, such as ''Eotitanops'', were rather small, no more than a meter in height, and hornless. Brontotheres evolved massive bodies, although some small species such as '' Nanotitanops'' did p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brontotheriinae
Brontotheriidae is a family (biology), family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like Rhinoceros, rhinos, although they were actually more closely related to horses; Equidae and Brontotheriidae make up the suborder Hippomorpha. They lived around 56–34 million years ago, until the very close of the Eocene. Characteristics and evolution Brontotheres retain four toes on their front feet and three toes on their hind feet. Their teeth are adapted to shearing (cutting) relatively nonabrasive vegetation. Their molar (tooth), molars have a characteristic W-shaped ectoloph (outer shearing blade). The evolutionary history of this group is well known due to an excellent fossil record in North America. The earliest brontotheres, such as ''Eotitanops'', were rather small, no more than a meter in height, and hornless. Brontotheres evolved massive bodies, although some small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhinotitan
''Rhinotitan'' (nose giant) is an extinct genus of brontothere from the Eocene of Mongolia Mongolia; Mongolian script: , , ; lit. "Mongol Nation" or "State of Mongolia" () is a landlocked country in East Asia, bordered by Russia to the north and China to the south. It covers an area of , with a population of just 3.3 millio ..., where three species were described from the Shara Murun formation. The genus included medium to large brontotheres which had long skulls with nasal horns. Like other solid-horned brontotheres, ''Rhinotitan'' was sexually dimorphic in horn size. In living mammals, this pattern is found in species that live in groups; males have the larger horns, and use them in ritualized combats with other males to decide control of territories that offer breeding access to females. Most horned brontotheres had dish-shaped skulls assumed to be adapted for such combats. However, the skull of ''Rhinotitan'' was concave only near the front; the top and back o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanotitanops
''Nanotitanops'' is an extinct genus of Brontothere from the middle Eocene of China. It contains a single species, ''N. shanghuangensis''. It is known only from isolated teeth, the smallest of any known Brontothere. Description This genus is currently known only from dental evidence. Described specimens do not exceed 13.55 millimeters in length and 12 millimeters in width. While it retains some basal traits, the teeth possess features which point toward it being relatively derived. It differs from basal designs in having relatively longer and narrower molars with stronger development of buccal shearing crests and only a vestigial paraconule on the upper molars. The dental morphology is most similar to the much larger genera '' Epimanteoceras'' and ''Rhinotitan''.Li, S. (2018). A new species of Brontotheriidae from the Middle Eocene of Junggar Basin, Xinjiang, China. ''Vertebrata PalAsiatica'', ''56''(1), 25-44. Relationships The exact placement of ''Nanotitanops'' within Bronto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eotitanops
''Eotitanops'' ('dawn titan-face') is an extinct genus of brontothere native to North America and Asia. ''Eotitanops'' is the earliest known genus of brontothere. While brontotheres generally known as very large animals, ''Eotitanops'' was only tall at the shoulder. It probably resembled a larger, bulkier version of its contemporary, the horse-like palaeothere ''Hyracotherium ''Hyracotherium'' ( ; "hyrax-like beast") is an extinct genus of very small (about 60 cm in length) perissodactyl ungulates that was found in the London Clay formation. This small, fox-sized animal was once considered to be the earliest know ...''. Like ''Hyracotherium'', it ate leaves and had five-toed front legs and three-toed hind legs. References * Brontotheres Eocene odd-toed ungulates Eocene mammals of North America {{paleo-oddtoedungulate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hippomorpha
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) or one (equines, third toe) of the five original toes. The non-weight-bearing toes are either present, absent, vestigial, or positioned posteriorly. By contrast, the even-toed ungulates bear most of their weight equally on four or two (an even number) of the five toes: their third and fourth toes. Another difference between the two is that odd-toed ungulates digest plant cellulose in their intestines rather than in one or more stomach chambers as even-toed ungulates, with the exception of Suina, do. The order includes about 17 species divided into three families: Equidae (horses, asses, and zebras), Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). Despite their very different appearances, they were recognized as related families i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Megacerops
''Megacerops'' ("large-horned face", from '' méga-'' "large" + '' kéras'' "horn" + '' ōps'' "face") is an extinct genus of the prehistoric odd-toed ungulate (hoofed mammal) family Brontotheriidae, an extinct group of rhinoceros-like browsers related to horses. It was endemic to North America during the Late Eocene epoch (38–33.9 mya), existing for approximately . Description All of the species had a pair of blunt horns on their snout (the size varying between species), with the horns of males being much larger than those of the females. This could indicate that they were social animals which butted heads for breeding privileges. Despite resembling the rhinoceros, it was larger than any living rhinoceros: the living animal easily approached the size of the African forest elephant, the third-largest land animal today. It stood about tall at the shoulders with an overall length(including tail) of . Its skull reached in greatest length, with some specimens possessing su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolichorhinus
''Sphenocoelus'' is an extinct genus of brontothere endemic to North America during the Middle Eocene 46.2—40.4 mya), existing for approximately . Fossils have been found only in southern Wyoming and eastern Utah. In life, it would have resembled a hornless rhinoceros A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant taxon, extant species (or numerous extinct species) of odd-toed ungulates in the family (biology), family Rhinocerotidae. (It can also refer to a member ..., to which it was distantly related. However, it was smaller than modern rhinos, standing about high at the shoulders, and had a much longer head. Its teeth were adapted to eating soft vegetation, such as forest leaves. Like other brontotheres, it had four toes on the front feet, and three on the hind feet, and the animal is unlikely to have been able to run fast. Species * ''S. blairi'' * ''S. bridgeri'' * ''S. harundivoras'' * ''S. hyognathus'' (syn. ''Dolichorh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protitanops
''Protitanops curryi'' is an extinct species of brontothere that lived during the Eocene, in the Western United States, especially in Death Valley, California, where the best specimens of the species ''P. curryi'' have been found. It bore a strong resemblance to ''Megacerops'' brontothere Brontotheriidae is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like rhinos, although they were actually more closely related to h ...s with its knob-shaped horns. However, the position of the horns differed in ''Protitanops'', in that they pointed straight up, rather than more forwards, like in ''Megacerops''. References Brontotheres {{paleo-oddtoedungulate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratin
Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, horns, claws, hooves, and the outer layer of skin among vertebrates. Keratin also protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. Excessive keratinization participate in fortification of certain tissues such as in horns of cattle and rhinos, and armadillos' osteoderm. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin comes in two types, the primitive, softer forms found in all vertebrates and harder, derived forms found only ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
