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Sparassodonts
Sparassodonta (from Greek to tear, rend; and , gen. , ' tooth) is an extinct order of carnivorous metatherian mammals native to South America, related to modern marsupials. They were once considered to be true marsupials, but are now thought to be a separate side branch that split before the last common ancestor of all modern marsupials. A number of these mammalian predators closely resemble placental predators that evolved separately on other continents, and are cited frequently as examples of convergent evolution. They were first described by Florentino Ameghino, from fossils found in the Santa Cruz beds of Patagonia. Sparassodonts were present throughout South America's long period of "splendid isolation" during the Cenozoic; during this time, they shared the niches for large warm-blooded predators with the flightless terror birds. Previously, it was thought that these mammals died out in the face of competition from "more competitive" placental carnivorans during the P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great American Interchange
The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange and the Great American Faunal Interchange, was an important late Cenozoic paleozoogeographic biotic interchange event in which land and freshwater fauna (animals), fauna migrated from North America to South America via Central America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor, forming a land bridge between the previously separated continents. Although earlier dispersals had occurred, probably over water, the migration accelerated dramatically about 2.7 million years (Ma (unit), Ma) ago during the Piacenzian age. It resulted from the joining of the Neotropical realm, Neotropic (roughly South American) and Nearctic realm, Nearctic (roughly North American) biogeographic realms definitively to form the Americas. The interchange is visible from observation of both biostratigraphy and nature (neontology). Its most dramatic effect is on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marsupial
Marsupials are a diverse group of mammals belonging to the infraclass Marsupialia. They are natively found in Australasia, Wallacea, and the Americas. One of marsupials' unique features is their reproductive strategy: the young are born in a relatively undeveloped state and then nurtured within a pouch on their mother's abdomen. Extant marsupials encompass many species, including Kangaroo, kangaroos, Koala, koalas, Opossum, opossums, Phalangeriformes, possums, Tasmanian devil, Tasmanian devils, Wombat, wombats, Wallaby, wallabies, and Bandicoot, bandicoots. Marsupials constitute a clade stemming from the last common ancestor of extant Metatheria, which encompasses all mammals more closely related to marsupials than to Placentalia, placentals. The evolutionary split between placentals and marsupials occurred 125-160 million years ago, in the Middle Jurassic-Early Cretaceous period. Presently, close to 70% of the 334 extant marsupial species are concentrated on the Australian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placental
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguished from monotremes and marsupials in that the fetus (biology), fetus is carried in the uterus of its mother to a relatively late stage of development. The name is something of a misnomer, considering that marsupials also nourish their fetuses via a placenta, though for a relatively briefer period, giving birth to less-developed young, which are then nurtured for a period inside the mother's pouch (marsupial), pouch. Placentalia represents the only living group within Eutheria, which contains all mammals that are more closely related to placentals than they are to marsupials. Anatomical features Placental mammals are anatomically distinguished from other mammals by: * a sufficiently wide opening at the bottom of the pelvis to allow the birt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patagosmilus
''Patagosmilus'' ("Patagonian knife" in Greek) is an extinct genus of meat-eating metatherian mammal of the family Thylacosmilidae, that lived in the Middle Miocene in South America.''Patagosmilus'' at .org Like other representatives of this family, such as '' Thylacosmilus atrox'' and '' Anachlysictis gracilis'', it was characterized by its elongated s of the upper jaw, similar to the well know ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Bone
The lacrimal bones are two small and fragile bones of the facial skeleton; they are roughly the size of the little fingernail and situated at the front part of the medial wall of the orbit. They each have two surfaces and four borders. Several bony landmarks of the lacrimal bones function in the process of lacrimation. Specifically, the lacrimal bones help form the nasolacrimal canal necessary for tear translocation. A depression on the anterior inferior portion of one bone, the lacrimal fossa, houses the membranous lacrimal sac. Tears, from the lacrimal glands, collect in this sac during excessive lacrimation. The fluid then flows through the nasolacrimal duct and into the nasopharynx. This drainage results in what is commonly referred to a runny nose during excessive crying or tear production. Injury or fracture of the lacrimal bone can result in posttraumatic obstruction of the lacrimal pathways. Structure Lateral or orbital surface The lateral or orbital surface is divided b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbit (anatomy)
In anatomy Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ..., the orbit is the Body cavity, cavity or socket/hole of the skull in which the eye and Accessory visual structures, its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is about , of which the eye occupies . The orbital contents comprise the eye, the Orbital fascia, orbital and retrobulbar fascia, extraocular muscles, cranial nerves optic nerve, II, oculomotor nerve, III, trochlear nerve, IV, trigeminal nerve, V, and abducens nerve, VI, blood vessels, fat, the lacrimal gland with its Lacrimal sac, sac and nasolacrimal duct, duct, the eyelids, Medial palpebral ligament, medial and Lateral palpebral raphe, lateral palpebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Each has two surfaces and four borders. Structure There is heavy variation in the structure of the nasal bones, accounting for the differences in sizes and shapes of the nose seen across different people. Angles, shapes, and configurations of both the bone and cartilage are heavily varied between individuals. Broadly, most nasal bones can be categorized as "V-shaped" or "S-shaped" but these are not scientific or medical categorizations. When viewing anatomical drawings of these bones, consider that they are unlikely to be accurate for a majority of people. The two nasal bones are joined at the midline internasal suture and make up the bridge of the nose. Surfaces The ''outer surface'' is concavo-convex from above downward, convex from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycopsis Longirostris
''Lycopsis'' is an extinct genus of South American metatherian that lived during the Miocene in Argentina and Colombia. History Although not named until 1927, Florentino Ameghino described a species now seen as synonymous with ''Lycopsis torresi'', ''Anatherium oxyrhynchus'', in 1895 based on a mandibular ramus with several teeth.Marshall, L. G. (1977). A new species of Lycopsis (Borhyaenidae: Marsupialia) from the La Venta fauna (Late Miocene) of Colombia, South America. ''Journal of Paleontology'', 633–642. The fossil was recovered from Puesto Estancia La Costa in Santa Cruz, Argentina, dating to the Miocene. The type material of ''Lycopsis'' was collected in July 1895 by "C. Berry" from the middle Miocene strata of the Santa Cruz Formation along the Santa Cruz River in the same area.Cabrera, Á. (1927). Datos para el conocimiento de los dasiuroideos fósiles argentinos. ''Revista del Museo de la Plata'', ''30'', 271–315. The fossils (MLP 11–113) were fragmentary, cons ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journal Of Mammalian Evolution
The ''Journal of Mammalian Evolution'' is the official journal of the Society for the Study of Mammalian Evolution. The journal is peer-reviewed Bi-monthly is a multidisciplinary forum devoted to studies on the comparative morphology, molecular biology, paleobiology, genetics, developmental and reproductive biology, biogeography, systematics, ethology and ecology, and population dynamics of mammals and the ways that these diverse data can be analyzed for the reconstruction of mammalian evolution. According to the ''Journal Citation Reports'', the journal has a 2014 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 2.357. References {{Reflist English-language journals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Procyonidae
Procyonidae ( ) is a New World family of the order Carnivora. It includes the raccoons, ringtails, cacomistles, coatis, kinkajous, olingos, and olinguitos. Procyonids inhabit a wide range of environments and are generally omnivorous. Characteristics Procyonids are relatively small animals, with generally slender bodies and long tails, though the common raccoon tends to be bulky. Because of their general build, the Procyonidae are often popularly viewed as smaller cousins of the bear family. This is apparent in their German name, ''Kleinbären'' (small bears), including the names of the species: a raccoon is called a ''Waschbär'' (washing bear, as it "washes" its food before eating), a coati is a ''Nasenbär'' (nose-bear), while a kinkajou is a ''Honigbär'' (honey-bear). Dutch follows suit, calling the animals ''wasbeer'', ''neusbeer'' and ''rolstaartbeer'' (curl-tail bear) respectively. However, it is now believed that procyonids are more closely related to musteli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnivorans
Carnivora ( ) is an Order (biology), order of Placentalia, placental mammals specialized primarily in eating flesh, whose members are formally referred to as carnivorans. The order Carnivora is the sixth largest order of mammals, comprising at least 279 species. Carnivorans are found on every major landmass and in a variety of habitats, ranging from the cold polar regions of Earth to the hyper-arid region of the Sahara Desert and the open seas. Carnivorans exhibit a wide array of body plans, varying greatly in size and shape. Carnivora are divided into two suborders, the Feliformia, containing the true felids and several animals; and the Caniformia, containing the true canids and many animals. The feliforms include the Felidae, Viverridae, hyena, and mongoose families, the majority of which live only in the Old World; cats are the only exception, occurring in the Old World and the New World, entering the Americas via the Bering land bridge. The caniforms include the Caninae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phorusrhacidae
Phorusrhacids, colloquially known as terror birds, are an extinct family of large carnivorous, mostly flightless birds that were among the largest apex predators in South America during the Cenozoic era. Their definitive fossil records range from the Middle Eocene to the Late Pleistocene around , though some specimens suggest that they were present since the Early Eocene. They ranged in height from . One of the largest specimens from the Early Pleistocene of Uruguay, possibly belonging to '' Devincenzia'', would have weighed up to . Their closest modern-day relatives are believed to be the seriemas. '' Titanis walleri'', one of the larger species, is known from Texas and Florida in North America. This makes the phorusrhacids the only known large South American predator to migrate north in the Great American Interchange that followed the formation of the Isthmus of Panama land bridge (the main pulse of the interchange began about 2.6 Ma ago; ''Titanis'' at 5 Ma was an early northwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
