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Amblypoda
Amblypoda was a taxonomic hypothesis uniting a group of extinct, herbivorous mammals. They were considered a suborder of the primitive ungulate mammals and have since been shown to represent a polyphyletic group. Characteristics The Amblypoda take their name from their short and stumpy feet, which were furnished with five toes each and supported massive pillar-like limbs. The brain cavity was extremely small and insignificant in comparison to the bodily mass, which was equal to that of the largest rhinoceroses. These animals were descendants of the small ancestral ungulates that retained all the primitive characteristics of the latter, accompanied by a huge increase in body size. The Amblypoda were confined to the Paleocene and Eocene periods and occurred in North America, Asia (especially Mongolia) and Europe. The cheek teeth were short-crowned ( brachyodont), with the tubercles more-or-less completely fused into transverse ridges, or cross-crests ( lophodont type), and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pantolambda
''Pantolambda'' (Greek: "all" (pantos), "lambda" (lambda), in a reference to the shape of upper premolars, similar to the Greek letter lambda) is an extinct genus of Paleocene pantodont mammal. ''Pantolambda'' lived during the middle Paleocene, and has been found both in Asia and North America. Cretaceous mammals, which had to compete with dinosaurs, were generally small insect eaters. ''Pantolambda'' was one of the first mammals to expand into the large-animal niches left vacant by the extinction of the dinosaurs. ''Pantolambda'' and other early pantodonts would quickly evolve into heavy animals such as ''Barylambda'' and '' Coryphodon''. These were the first large browsers, pioneering styles of life later followed by many unrelated groups of mammals: rhinos, tapirs, hippos, ground sloths, and elephants. Pantodonts such as ''Pantolambda'' were definitely not tree dwellers. Description ''Pantolambda'' was large for a Paleocene mammal, about the size of a sheep. A generalized ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammal
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 with Saur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tibia
The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects the knee with the ankle. The tibia is found on the medial side of the leg next to the fibula and closer to the median plane. The tibia is connected to the fibula by the interosseous membrane of leg, forming a type of fibrous joint called a syndesmosis with very little movement. The tibia is named for the flute ''tibia''. It is the second largest bone in the human body, after the femur. The leg bones are the strongest long bones as they support the rest of the body. Structure In human anatomy, the tibia is the second largest bone next to the femur. As in other vertebrates the tibia is one of two bones in the lower leg, the other being the fibula, and is a component of the knee and ankle joints. The ossification or formation of the bone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selenodont
Selenodont teeth are the type of molars and premolars commonly found in ruminant herbivores. They are characterized by low crowns, and crescent-shaped cusps when viewed from above (crown view). The term comes from the Ancient Greek roots (, 'moon' or 'moonlike'), and , (, 'tooth'). They differ from human molars in that the occlusal surface is not covered in enamel; rather, the layers of enamel, dentine, and cementum are all exposed, with cementum in the middle, surrounded by a layer of enamel, then a layer of dentine, all wrapped in a second outer layer of enamel. Viewed from the side, selenodont teeth form a series of triangular cusps. The combination of triangular profiles with ridges formed by the exposed layers makes the lateral chewing motion of ruminant Ruminants (suborder Ruminantia) are ungulate, hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by Enteric fermentation, fermenting it in a specialized stomach p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bunodont
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone tooth", from ''mola'', millstone and ''dens'', tooth. Molars show a great deal of diversity in size and shape across mammal groups. The third molar of humans is sometimes vestigial. Human anatomy In humans, the molar teeth have either four or five cusps. Adult humans have 12 molars, in four groups of three at the back of the mouth. The third, rearmost molar in each group is called a wisdom tooth. It is the last tooth to appear, breaking through the front of the gum at about the age of 20, although this varies from individual to individual. Race can also affect the age at which this occurs, with statistical variations between groups. In some cases, it may not even erupt at all. The human mouth contains upper (maxillary) and lower (mandibul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periptychidae
Periptychidae is a family of Paleocene placental mammals, known definitively only from North America. The family is part of a radiation of early herbivorous and omnivorous mammals formerly classified in the extinct order "Condylarthra", which may be related to some or all living ungulates (hoofed mammals). Periptychids are distinguished from other "condylarths" by their teeth, which have swollen premolar The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...s and unusual vertical enamel ridges. The family includes both large and small genera, with the larger forms having robust skeletons. Known skeletons of periptychids suggest generalized terrestrial habits. References *McKenna, Malcolm C., and Bell, Susan K. 1997. ''Classification of Mammals Above the Species Level.'' Columbia Univ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periptychus
''Periptychus'' is an extinct genus of mammal belonging to the family Periptychidae. It lived from the Early to Late Paleocene and its fossil remains have been found in North America. Description This animal was of medium size and could exceed one meter in overall length; ''Periptychus'' is supposed to have weighed about 23 kilograms. ''Periptychus'' was an unusual mammal that combined a number of rather specialized dental, cranial, and postcranial features with a relatively generalized skeletal structure. Skull The shape of the skull of ''Periptychus'' was almost identical to that of early Eutheria, although it was more robust. The snout of ''Periptychus'' was moderately elongated and tall, and tapered anteriorly without a rostral constriction. The morphology of the rostrum of this animal was very similar to that found in related genera such as '' Carsioptychus'' or '' Ectoconus''; the snout was not elongated as in other condylarths such as ''Arctocyon'', but it was long ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uintatheriidae
Uintatheriidae is a family of extinct ungulate mammals that includes ''Uintatherium''. Uintatheres belong to the order Dinocerata, one of several extinct orders of primitive hoofed mammals that are sometimes united in the Condylarthra. Uintatheres were the largest land animals of their time, surviving from the late Paleocene into the Uintan Epoch of the Middle Eocene. They were heavy animals, with thick legs, massive bones, broad feet, and tiny brains. The most distinctive feature of the great majority of species, however, was the presence of multiple blunt "horns", perhaps similar to the ossicones of modern giraffes, and the presence of large, sabre-like canine teeth. They were eventually replaced as large browsing animals by the even larger brontotheres. Genera Family Uintatheriidae * Subfamily Uintatheriinae ** Genus ''Bathyopsis'' ** Genus ''Eobasileus'' ** Genus ''Prodinoceras'' ** Genus ''Tetheopsis'' ** Genus ''Uintatherium'' * Subfamily Gobiatheriinae ** Genus ''Gobiathe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uintatherium
''Uintatherium'' ("Beast of the Uinta Mountains") is an extinct genus of herbivorous mammal that lived during the Eocene epoch. Two species are currently recognized: ''U. anceps'' from the United States during the Early to Middle Eocene (56–38 million years ago) and ''U. insperatus'' of Middle to Late Eocene (48–34 million years ago) China. Description ''Uintatherium'' was a large browsing animal. With a skull long, tall at the shoulder, body length of about and a weight up to 2 tonnes, it was similar to today's rhinoceros, both in size and in shape. Its legs were robust to sustain the weight of the animal and were equipped with hooves. Moreover, a Uintathere's sternum was made up of horizontal segments, unlike today's rhinos, which have compressed vertical segments. Skull Its most unusual feature was the skull, which is both large and strongly built, but simultaneously flat and concave: this feature is rare and, apart from some brontotheres, not regularly characteristic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coryphodontidae
Coryphodontidae is an extinct family of pantodont mammals known from the Late Paleocene to the Middle Eocene of Eurasia and North America. The type genus ''Coryphodon'' is known from around the Paleocene-Eocene transition in Europe, western United States, northern Canada, and eastern Asia. The remaining genera are known exclusively from the middle Eocene of Asia. The coryphodontids are related to the pantolambdids. ''Coryphodon'' are large, derived pantodonts first described in the mid-19th century, but no intermediate stages leading to their unusual upper molars are known. The last known species of ''Coryphodon'' have bilophodont molars similar to later, more derived coryphodontids, and, most likely, ''Coryphodon'' is the primitive sister taxon to the remaining genera and the entire lineage (or lineages) originated from within this genus. Two coryphodontids considerably larger than ''Coryphodon'' but endemic to China, '' Asiocoryphodon'' and '' Heterocoryphodon'', have more a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
