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Miacids
Miacidae ("small points") is a former paraphyletic family (biology), family of extinct Primitive (phylogenetics), primitive Placentalia, placental mammals that lived in North America, Europe and Asia during the Paleocene and Eocene epochs, about 65–33.9 million years ago.IRMNG (2018). Miacidae Cope, 1880 †. Accessed at: http://www.irmng.org/aphia.php?p=taxdetails&id=102911 on 2019-01-22 These mammals were basal to order Carnivora, the crown-group within the Carnivoraformes. Miacids are thought to have evolved into the modern carnivorous mammals of the order Carnivora. They were small carnivores, superficially marten-like or civet-like with long, lithe bodies and long tails. Some species were arboreal, while others lived on the Terrestrial animal, ground. They probably fed on invertebrates, lizards, birds, and smaller mammals like shrews and opossums. Their teeth and skulls show that the miacids were less developed than modern carnivorans. They had carnivoran-type carnassials, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miacis
''Miacis'' ("small point") is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from the early to middle Eocene.J. J. Flynn (1998.) "Early Cenozoic Carnivora ("Miacoidea")." In C. M. Janis, K. M. Scott, and L. L. Jacobs (''eds.''"Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals."Cambridge University Press, Cambridge. Description ''Miacis'' was five-clawed, about the size of a weasel (~30 cm), and lived on the North American continent. It retained some primitive characteristics such as a low skull, a long slender body, a long tail, and short legs. ''Miacis'' retained 44 teeth, although some reductions in this number were apparently in progress and some of the teeth were reduced in size. The hind limbs were longer than the forelimbs, the pelvis was dog-like in form and structure, and some specialized traits were present in the vertebrae. It had retractable claw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phlaodectes
''Vulpavus'' ("ancestor of foxes") is an extinct paraphyletic genus of placental mammals from clade Carnivoraformes, that lived in North America from the early to middle Eocene.J. J. Flynn (1998.) "Early Cenozoic Carnivora ("Miacoidea")." In C. M. Janis, K. M. Scott, and L. L. Jacobs (''eds.''"Evolution of Tertiary Mammals of North America. Volume 1: Terrestrial Carnivores, Ungulates, and Ungulatelike Mammals."Cambridge University Press, Cambridge. Phylogeny The phylogenetic relationships of genus ''Vulpavus'' are shown in the following cladogram: See also * Mammal classification * Carnivoraformes * Miacidae References † A dagger, obelisk, or obelus is a typographical mark that usually indicates a footnote if an asterisk has already been used. The symbol is also used to indicate death (of people) or extinction (of species or languages). It is one of the mo ... Eocene mammals of North America Miacids Prehistoric placental genera Fossil taxa described in ... [...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 an asteroid impact (Chicxulub impact) and possibly volcanism (Deccan Traps), marked the beginning of the Paleocene and killed off 75% of 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivoraformes
Carnivoramorpha ("carnivoran-like forms") is a clade of placental mammals of clade Pan-Carnivora from mirorder Ferae, that includes the modern order Carnivora and its extinct stem-relatives.Bryant, H.N., and M. Wolson (2004“Phylogenetic Nomenclature of Carnivoran Mammals.”''First International Phylogenetic Nomenclature Meeting''. Paris, Museum National d’Histoire Naturelle General characteristics The common feature for members of this clade is the presence of the carnassial teeth. The carnassial teeth of the Carnivoramorpha are upper premolar P4 and lower molar m1.Floréal Solé & Thierry Smith (2013."Dispersals of placental carnivorous mammals (Carnivoramorpha, Oxyaenodonta & Hyaenodontida) near the Paleocene-Eocene boundary: a climatic and almost worldwide story"Geologica Belgica 16/4: 254-261 Classification and phylogeny Traditional classification Revised classification Recent phylogenetic studies indicate that the superfamily Miacoidea and family Miacidae are pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ossify
Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in the formation of normal, healthy bone tissue: Intramembranous ossification is the direct laying down of bone into the primitive connective tissue (mesenchyme), while endochondral ossification involves cartilage as a precursor. In fracture healing, endochondral osteogenesis is the most commonly occurring process, for example in fractures of long bones treated by plaster of Paris, whereas fractures treated by open reduction and internal fixation with metal plates, screws, pins, rods and nails may heal by intramembranous osteogenesis. Heterotopic ossification is a process resulting in the formation of bone tissue that is often atypical, at an extraskeletal location. Calcification is often confused with ossification. Calcification is synon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnassial
Carnassials are paired upper and lower teeth modified in such a way as to allow enlarged and often self-sharpening edges to pass by each other in a shearing manner. This adaptation is found in carnivorans, where the carnassials are the modified fourth upper premolar and the first lower molar (tooth), molar. These teeth are also referred to as sectorial teeth. Taxonomy The name carnivoran is applied to a member of the order Carnivora. Carnivorans possess a common arrangement of teeth called carnassials, in which the first lower Molar (tooth), molar and the last upper premolar possess blade-like enamel Crown (tooth), crowns that act similar to a pair of shears for cutting meat. This dental arrangement has been modified by adaptation over the past 60 million years for diets composed of meat, for crushing vegetation, or for the loss of the carnassial function altogether found in pinnipeds. Carnassial dentition Carnassial teeth are modified molars (and in the case of carnivorans pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skull
The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent parts: the neurocranium and the facial skeleton, which evolved from the first pharyngeal arch. The skull forms the frontmost portion of the axial skeleton and is a product of cephalization and vesicular enlargement of the brain, with several special senses structures such as the eyes, ears, nose, tongue and, in fish, specialized tactile organs such as barbels near the mouth. The skull is composed of three types of bone: cranial bones, facial bones and ossicles, which is made up of a number of fused flat and irregular bones. The cranial bones are joined at firm fibrous junctions called sutures and contains many foramina, fossae, processes, and sinuses. In zoology, the openings in the skull are called fenestrae, the most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Teeth
A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tearing food, for defensive purposes, to intimidate other animals often including their own, or to carry prey or their young. The roots of teeth are covered by gums. Teeth are not made of bone, but rather of multiple tissues of varying density and hardness that originate from the outermost embryonic germ layer, the ectoderm. The general structure of teeth is similar across the vertebrates, although there is considerable variation in their form and position. The teeth of mammals have deep roots, and this pattern is also found in some fish, and in crocodilians. In most teleost fish, however, the teeth are attached to the outer surface of the bone, while in lizards they are attached to the inner surface of the jaw by one side. In cartilaginous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opossum
Opossums () are members of the marsupial order Didelphimorphia () endemic to the Americas. The largest order of marsupials in the Western Hemisphere, it comprises 126 species in 18 genera. Opossums originated in South America and entered North America in the Great American Interchange following the connection of North and South America in the late Cenozoic. The Virginia opossum is the only species found in the United States and Canada. It is often simply referred to as an opossum; in North America, it is commonly referred to as a possum (; sometimes rendered as ''possum'' in written form to indicate the dropped "o"). The Australasian arboreal marsupials of suborder Phalangeriformes are also called possums because of their resemblance to opossums, but they belong to a different order. The opossum is typically a nonaggressive animal and almost never carries the virus that causes rabies. Etymology The word ''opossum'' is derived from the Powhatan language and was first recorde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shrew
Shrews ( family Soricidae) are small mole-like mammals classified in the order Eulipotyphla. True shrews are not to be confused with treeshrews, otter shrews, elephant shrews, West Indies shrews, or marsupial shrews, which belong to different families or orders. Although its external appearance is generally that of a long-nosed mouse, a shrew is not a rodent, as mice are. It is, in fact, a much closer relative of hedgehogs and moles; shrews are related to rodents only in that both belong to the Boreoeutheria magnorder. Shrews have sharp, spike-like teeth, whereas rodents have gnawing front incisor teeth. Shrews are distributed almost worldwide. Among the major tropical and temperate land masses, only New Guinea, Australia, New Zealand, and South America have no native shrews. However, as a result of the Great American Interchange, South America does have a relatively recently naturalised population, present only in the northern Andes. The shrew family has 385 kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a four-chambered heart, and a strong yet lightweight Bird skeleton, skeleton. Birds live worldwide and range in size from the bee hummingbird to the common ostrich. There are over 11,000 living species and they are split into 44 Order (biology), orders. More than half are passerine or "perching" birds. Birds have Bird wing, wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds. Wings, which are modified forelimbs, gave birds the ability to fly, although further evolution has led to the Flightless bird, loss of flight in some birds, including ratites, penguins, and diverse endemism, endemic island species. The digestive and respiratory systems of birds are also uniquely a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lizard
Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic islands, oceanic Archipelago, island chains. The grouping is Paraphyly, paraphyletic as some lizards are more closely related to snakes than they are to other lizards. Lizards range in size from chameleons and geckos a few centimeters long to the 3-meter-long Komodo dragon. Most lizards are quadrupedal, running with a strong side-to-side motion. Some lineages (known as "legless lizards") have secondarily lost their legs, and have long snake-like bodies. Some lizards, such as the forest-dwelling ''Draco (genus), Draco'', are able to glide. They are often Territory (animal), territorial, the males fighting off other males and signalling, often with bright colours, to attract mates and to intimidate rivals. Lizards are mainly carnivorous, often b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
