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Hoofed Mammals
Ungulates ( ) are members of the diverse clade Ungulata which primarily consists of large mammals with hooves. These include odd-toed ungulates such as horses, rhinoceroses, and tapirs; and even-toed ungulates such as cattle, pigs, giraffes, camels, sheep, deer, and hippopotamuses. Cetaceans such as whales, dolphins, and porpoises are also classified as even-toed ungulates, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. The term means, roughly, "being hoofed" or "hoofed animal". As a descriptive term, "ungulate" normally excludes cetaceans as they do not possess most of the typical morphological characteristics of other ungulates, but recent discoveries indicate that they were also descended from early artiodactyls. Ungulates are typically herbivorous and many employ specialized gut bacteria to allow them to digest cellulose. Some modern species, such as pigs, are omnivorous, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleocene
The Paleocene, ( ) or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name is a combination of the Ancient Greek ''palaiós'' meaning "old" and the Eocene Epoch (which succeeds the Paleocene), translating to "the old part of the Eocene". The epoch is bracketed by two major events in Earth's history. The K–Pg extinction event, brought on by Chicxulub impact, an asteroid impact and possibly volcanism, marked the beginning of the Paleocene and killed off 75% of living species, most famously the non-avian dinosaurs. The end of the epoch was marked by the Paleocene–Eocene Thermal Maximum (PETM), which was a major climatic event wherein about 2,500–4,500 gigatons of carbon were released into the atmosphere and ocean systems, causing a spike in global temperatures and ocean acidification. In the Pal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Panperissodactyla
Mesaxonia (near-synonymous with Panperissodactyla) is a clade of ungulates whose weight is distributed on the third toe on all legs through the plane symmetry of their feet. For a while it was often seen to only contain the order Perissodactyla (which includes the equines, rhinos and tapirs). Recent work in morphological cladistics and ancient DNA suggests that several extinct lineages, like the Desmostylia and some of the South American ungulates of Meridiungulata (both groups traditionally seen as Afrotherian relatives) are related to the perissodactyls. Classification *Mesaxonia **†DinocerataBURGER, Benjamin J., THE SYSTEMATIC POSITION OF THE SABER-TOOTHED AND HORNED GIANTS OF THE EOCENE: THE UINTATHERES (ORDER DINOCERATA), Utah State University Uintah Basin Campus, Vernal, UT, United States of America, 84078, SVP 2015 **†Phenacodontidae **Panperissodactyla ***†Anthracobunia ****†Anthracobunidae ****†Cambaytheriidae ****†Desmostylia? ***† Litopterna ***†Noto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Even-toed Ungulate
The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing posteriorly. By contrast, odd-toed ungulates bear weight on an odd number of the five toes. Another difference between the two is that many other even-toed ungulates (with the exception of Suina) digest plant cellulose in one or more stomach chambers rather than in their intestine as the odd-toed ungulates do. Cetaceans (whales, dolphins, and porpoises) evolved from even-toed ungulates, and are therefore often classified under the same taxonomic branch because a species cannot outgrow its evolutionary ancestry; some modern taxonomists combine the two under the name Cetartiodactyla , while others opt to include cetaceans in the already-existing Artiodactyla. The roughly 270 land-based even-toed ungulate species include pigs, peccaries, hippo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helohyidae
Helohyidae were a group of artiodactyl mammals. They were most prominent in the mid-to-upper Eocene (~50 to 39 million years ago). Description Helohyidae share vague similarities to present-day pigs, though were slimmer in build. They possessed prominent canines and molars with bunodont cusps, bulging dental wreaths, and wrinkled enamel. Their upper molars were usually squared, due to the enlargement and displacement of the metaconule, but there was also a small hypocone and hypoconule. The paraconule was reduced and there was no mesostyle. Their lower molars increased in size as they proceeded to the bottom of the jaw, and the paraconid was small or absent. Some forms (e.g. ''Gobiohyus'') possessed small diastemas that separated the premolars from each other. The snout was usually elongated (e.g. in ''Helohyus''), but in some forms ascribed to this family (''Achaenodon''), it was very short. Compared to other primitive artiodactyls such as dichobunids, they possessed hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichobunidae
Dichobunidae is an extinct family of basal artiodactyl mammals from the early Eocene to late Oligocene of North America, Europe, and Asia. The Dichobunidae include some of the earliest known artiodactyls, such as ''Diacodexis''. Description They were small animals, averaging about the size of a modern rabbit, had many primitive features. In life, they would have resembled a long-tailed muntjac or chevrotain. Dichobunids had four or five toes on each foot, with each toe ending in a small hoof. They had complete sets of teeth, unlike most later artiodactyls, with their more specialist dentitions. The shape of the teeth suggests they were browsers, feeding on small leaves, perhaps in the forest undergrowth. The shape of their bodies and limbs suggests they would have been fast-running animals, unlike most of their contemporaries. Taxonomy Classification of dichobunids following McKenna and Bell: * † Family Dichobunidae **'' Paraphenacodus'' **'' Dulcidon'' **'' Chorlakkia'' * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesonychia
Mesonychia ("middle claws") is an extinct taxon of small- to large-sized carnivorous ungulates related to artiodactyls. Mesonychids first appeared in the early Paleocene, went into a sharp decline at the end of the Eocene, and died out entirely when the last genus, ''Mongolestes'', became extinct in the early Oligocene. In Asia, the record of their history suggests they grew gradually larger and more predatory over time, then shifted to scavenging and bone-crushing lifestyles before the group became extinct. Mesonychids probably originated in China, where the most primitive mesonychid, ''Yangtanglestes'', is known from the early Paleocene. They were also most diverse in Asia, where they occur in all major Paleocene faunas. Since other predators, such as creodonts and Carnivora, were either rare or absent in these animal communities, mesonychids most likely dominated the large predator niche in the Paleocene of eastern Asia. One genus, ''Dissacus'', had successfully spread to Eur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctocyonia
Arctocyonians (Arctocyonia; also known as "Procreodi") are a clade of laurasiatherian mammals whose stratigraphic range runs from the Palaeocene to the Early Eocene epochs. They were among the earliest examples of major mammalian predators after the Cretaceous–Paleogene extinction event. While some classify arctocyonians as stem-artiodactyls, others have classified the group as members of Ferae. There are three families classified in the order: Arctocyonidae Arctocyonidae (from Greek '' arktos'' ''kyôn'', "bear/dog-like") has been defined as an extinct family of unspecialized, primitive mammals with more than 20 genera. Animals assigned to this family were most abundant during the Paleocene, but ex ..., Oxyclaenidae, and Quettacyonidae. References {{paleo-mammal-stub Paleocene first appearances Prehistoric mammals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
