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Paraná Formation
The Paraná Formation is a Formation (geology), geologic formation in Argentina. It preserves fossils dating back to the late Miocene epoch. Fossil content Mammals Cetaceans Pinnipeds Rodents Sirenians Xenarthrans Birds Fish Bony fish Rays Sharks Invertebrates Bivalves Bryozoans Echinoderms Plants Correlations Laventan Huayquerian References {{reflist Miocene Argentina Geography of Entre Ríos Province ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radius (bone)
The radius or radial bone (: radii or radiuses) is one of the two large bones of the forearm, the other being the ulna. It extends from the Anatomical terms of location, lateral side of the Elbow-joint, elbow to the thumb side of the wrist and runs parallel to the ulna. The ulna is longer than the radius, but the radius is thicker. The radius is a long bone, Prism (geometry), prism-shaped and slightly curved longitudinally. The radius is part of two joint (anatomy), joints: the elbow and the wrist. At the elbow, it joins with the capitulum of the humerus, and in a separate region, with the ulna at the radial notch. At the wrist, the radius forms a joint with the ulna bone. The corresponding bone in the human leg, lower leg is the tibia. Structure The long narrow medullary cavity is enclosed in a strong wall of compact bone. It is thickest along the interosseous border and thinnest at the extremities, same over the cup-shaped articular surface (fovea) of the head. The tra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal species are rodents. They are native to all major land masses except for Antarctica, and several oceanic islands, though they have subsequently been introduced to most of these land masses by human activity. Rodents are extremely diverse in their ecology and lifestyles and can be found in almost every terrestrial habitat, including human-made environments. Species can be arboreal, fossorial (burrowing), saltatorial/ricochetal (leaping on their hind legs), or semiaquatic. However, all rodents share several morphological features, including having only a single upper and lower pair of ever-growing incisors. Well-known rodents include Mouse, mice, rats, squirrels, prairie dogs, porcupines, beavers, Cavia, guinea pigs, and hamsters. Once included wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seal (animal)
Pinnipeds (pronounced ), commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals), with 34 extant species and more than 50 extinct species described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic group (descended from one ancestor). Pinnipeds belong to the suborder Caniformia of the order Carnivora; their closest living relatives are musteloids (weasels, raccoons, skunks and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal seal to the and southern elephant seal. Several species exhibit sexual dimorphism. They have streamlined bodies and four limbs that are modifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinniped
Pinnipeds (pronounced ), commonly known as seals, are a widely range (biology), distributed and diverse clade of carnivorous, fin-footed, semiaquatic, mostly marine mammals. They comprise the extant taxon, extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals), with 34 extant species and more than 50 extinct species described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular phylogenetics, molecular evidence supports them as a monophyletic group (descended from one ancestor). Pinnipeds belong to the suborder Caniformia of the order Carnivora; their closest living relatives are musteloids (Mustelidae, weasels, Procyonidae, raccoons, skunks and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal seal to the and southern elephant seal. Several species exhibit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monachinae
Monachinae (known colloquially as "Southern seals") is a subfamily of Phocidae whose distribution is found in the tropical, temperate and polar regions of the southern hemisphere, though in the distant past fossil representatives have been found on both sides of the North Atlantic Ocean. The difference between members of this group and members of Phocinae is in monachines the hindclaws are greatly reduced in size. Furthermore, all species have 34 chromosomes. There are three tribes recognized here: Monachini (monk seals), Miroungini (elephant seals), and Lobodontini (Antarctic seals and a handful of Afroamerican fossil genera). While today represented by eight extant and one recently extinct species, Monachinae had an incredibly enriched fossil diversity that went into decline soon to be replaced by southern species of sea lions and fur seal Fur seals are any of nine species of pinnipeds belonging to the subfamily Arctocephalinae in the family Otariidae. They are much mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delphinoidea
Delphinoidea are the largest group of toothed whales, including 66 genera in 6 families. The largest living member of the superfamily is the orca, which can reach 6 tons, while the smallest is the vaquita. Taxonomy Delphinoidea is a very diverse clade. It includes all extant oceanic dolphins, as well as various extinct species, like the unique '' Odobenocetops'.'' There are three extant families within Delphinoidea, with those being Delphinidae (oceanic dolphins), Monodontidae (beluga and narwhal) and Phocoenidae (porpoises). Based on McGowen ''et al''., 2019 Superfamily Delphinoidea :Family † Albireonidae :::Genus '' Albireo'' :Family Delphinidae :: Subfamily Delphininae ::: Genus '' Delphinus'' ::: Genus '' Lagenodelphis'' ::: Genus '' Sotalia'' :::Genus '' Sousa'' ::: Genus ''Stenella ''Stenella'' is a genus of marine mammals in Delphinidae, the family (biology), family informally known as the oceanic dolphins. Species Currently, five species are recognised ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomen Dubium
In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a specimen belongs to that group or not. This may happen if the original type series (i. e. holotype, isotype, syntype or paratype) is lost or destroyed. The zoological and botanical codes allow for a new type specimen, or neotype, to be chosen in this case. A name may also be considered a ''nomen dubium'' if its name-bearing type is fragmentary or lacking important diagnostic features (this is often the case for species known only as fossils). To preserve stability of names, the ''International Code of Zoological Nomenclature'' allows a new type specimen, or neotype, to be chosen for a ''nomen dubium'' in this case. 75.5. Replacement of unidentifiable name-bearing type by a neotype. When an author considers that the taxonomic identity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pontoporiidae
Pontoporiidae is a family of toothed whales, containing the extant genus '' Pontoporia'', and ten extinct genera. ''Pontoporia'' contains the sole extant species, the La Plata dolphin, which is endemic to South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o .... References {{Taxonbar, from=Q13410384 Mammal families Taxa named by John Edward Gray Inioidea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
