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Pelagiarctos Thomasi
''Pelagiarctos'' was a genus of walrus that lived during the Mid Miocene, approx. 13-15 mya. Its remains have been found in the Sharktooth Hill Bonebed, in Kern County, California. It was originally described as an Otariidae, though it is now usually considered to be a basal Odobenidae. Anatomy To date, the only material of ''Pelagiarctos'' that has been found includes a handful of partial mandibles. The mandibles themselves are approximately the same size as those of the contemporaneous pinniped '' Allodesmus kernensis'', but differ in that the cheek teeth have two roots (instead of one, as in ''Allodesmus'') and that the dentary itself is much thicker. They are also highly vascularized and covered in unusually large mental foramina, indicating that ''Pelagiarctos'' may have had somewhat fleshy lips. The cheek teeth resemble those of several terrestrial carnivores, specifically borophagine dogs and hyaenids. This, coupled with the robust dentary, indicates that ''Pelagia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by a single distinct global event but consist rather of regionally defined boundaries between the warmer Oligocene and the cooler Pliocene Epoch. During the Early Miocene, the Arabian Peninsula collided with Eurasia, severing the connection between the Mediterranean and Indian Ocean, and allowing a faunal interchange to occur between Eurasia and Africa, including the dispersal of proboscideans into Eurasia. During the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terrestrial Animal
Terrestrial animals are animals that live predominantly or entirely on land (e.g. cats, dogs, ants, spiders), as compared with aquatic animals, which live predominantly or entirely in the water (e.g. fish, lobsters, octopuses), and amphibians, which rely on a combination of aquatic and terrestrial habitats (e.g. frogs and newts). Some groups of insects are terrestrial, such as ants, butterflies, earwigs, cockroaches, grasshoppers and many others, while other groups are partially aquatic, such as mosquitoes and dragonflies, which pass their larval stages in water. Terrestrial animals tend to be more developed and intelligent than aquatic animals. Terrestrial classes The term "terrestrial" is typically applied to species that live primarily on the ground, in contrast to arboreal species, which live primarily in trees. There are other less common terms that apply to specific groups of terrestrial animals: *Saxicolous creatures are rock dwelling. "Saxicolous" is derived from t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Puffinus
''Puffinus'' is a genus of seabirds in the order Procellariiformes that contains about 20 small to medium-sized shearwaters. Two other shearwater genera are named: ''Calonectris'', which comprises three or four large shearwaters, and ''Ardenna'' with another seven species (formerly often included within ''Puffinus''). The taxonomy of this group is the cause of much debate, and the number of recognised species varies with the source. The species in this group are long-winged birds, dark brown or black above, and white to dark brown below. They are pelagic outside the breeding season. They are most common in temperate and cold waters. These tubenose birds fly with stiff wings, and use a shearing flight technique to move across wave fronts with the minimum of active flight. Some small species, such as the Manx shearwater, are cruciform in flight, with their long wings held directly out from their bodies. Many are long-distance migrants, perhaps most spectacularly the sooty and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteodontornis
''Osteodontornis'' is an extinct seabird genus. It contains a single named species, ''Osteodontornis orri'' (Orr's bony-toothed bird, in literal translation of its scientific name), which was described quite exactly one century after the first species of the Pelagornithidae ('' Pelagornis miocaenus'') was. ''O. orri'' was named after then-recently deceased naturalist Ellison Orr. The bony-toothed or pseudotooth birds were initially believed to be related to albatrosses in the Procellariiformes, but actually they seem to be rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty. Also, their internal taxonomy is not well-resolved. An earlier-described pseudotooth bird, ''Cyphornis magnus'' from Vancouver Island (Canada), was believed to be of Eocene age but is nowadays assumed to have lived about twenty million years ago in the Early Miocene, not too long before the Clarendonian ( M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Psephophorus
''Psephophorus'' is an extinct genus of sea turtle that lived from the Oligocene to the Pliocene. Its remains have been found in Europe, Africa, North America, and New Zealand. It was first named by Hermann von Meyer in 1847, and contains seven species, ''P. polygonus'', ''P. calvertensis'', ''P. eocaenus'', ''P. oregonesis'', ''P. californiensis'', ''P. rupeliensis'',''Proceedings''; page 8. By the Zoological Society of London; published 1891. Retrieved on June 28th, 2008. ''P. scaldii'', and a species discovered in 1995, ''P. terrypratchetti''. ''Psephophorus'' is the only Miocene dermochelyid turtle found in Europe. One species of ''Psephophorus'' could measure up to ten feet in length. Discovery and identification Von Meyer originally named ''Psephophorus'' in 1846. At first he was unable to identify the creature beyond its dermal plates, but when he later received a drawing he was able to describe the specimen, which was then in Pressburg, as a fragment of a carapace ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharocles
''Otodus'' is an extinct genus of mackerel shark which lived from the Paleocene to the Pliocene epoch. The name ''Otodus'' comes from Ancient Greek (, meaning "ear") and (, meaning "tooth") – thus, "ear-shaped tooth". Anatomy This shark is known from its fossilized teeth and vertebral centra. Like other elasmobranchs, the skeleton of ''Otodus'' was composed of cartilage and not bone, resulting in relatively few preserved skeletal structures appearing within the fossil record. The teeth of this shark are large with triangular crown, smooth cutting edges, and visible cusps on the roots. Some ''Otodus'' teeth also show signs of evolving serrations. Size estimation The fossils of ''Otodus'' indicate that it was a very large macro-predatory shark. The largest known teeth measure about in height. The vertebral centrum of this shark are over 12.7 cm (5 inch) wide. Scientists suggest that this shark at least reached in total length (TL), with a maximum length of . Distr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphyrna
''Sphyrna'' (from the Greek word σφῦρα, "hammer") is a genus of hammerhead sharks with a cosmopolitan distribution in the world's oceans. Members of ''Sphyrna'' have a tendency to inhabit coastal waters along the intertidal zone rather than the open ocean, as their prey such as invertebrates, fish, rays, small crustaceans, and other benthic organisms hide in the sands and sediment along these zones. Members of ''Sphyrna'' are also known by synonyms such as ''Zygaena'', ''Cestracion'', and ''Sphyrichthys''. The earliest species described of this genus was ''Sphyrna zygaena'' by Carl Linnaeus in 1758, while the latest described member, '' Sphyrna gilberti'', was discovered and described in 2013. Species The recognized species in this genus are:Martin, R. Aidan. (February 24, 1998)Recent Changes in Hammerhead Taxonomy ''ReefQuest Centre for Shark Research''. Retrieved on October 18, 2008. ;Extant * '' Sphyrna corona'' ( S. Springer, 1940) (scalloped bonnethead) * '' Sphyrn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isurus
''Isurus'' is a genus of mackerel sharks in the family Lamnidae, commonly known as the mako sharks. Description The two living species are the common shortfin mako shark (''I. oxyrinchus'') and the rare longfin mako shark (''I. paucus''). They range in length from , and have an approximate maximum weight of . They both have a distinctive blue-gray color scheme common among mackerel sharks. Several extinct species are known from fossils found in sediments from the Cretaceous to the Quaternary (age range: 99.7 to 0.781 million years ago). The family Lamnidae also includes the great white shark and the porbeagle. Mako sharks are capable of swimming at speeds up to . The great white shark is also closely related to an ancient mako shark species, ''Isurus hastalis''. However, fossil evidence suggests ''I. hastalis'', like the great white shark, also belonged to the genus ''Carcharodon''. Species The genus contains these species: * '' Isurus oxyrinchus'' (Rafinesque, 1810) (shortfi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continents of Asia and Oceania in the west and the Americas in the east. At in area (as defined with a southern Antarctic border), this largest division of the World Ocean—and, in turn, the hydrosphere—covers about 46% of Earth's water surface and about 32% of its total surface area, larger than Earth's entire land area combined .Pacific Ocean . '' Britannica Concise.'' 2008: Encyclopædia Britannica, Inc. The centers of both the |
Postcranial
Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated skeletal elements; these are referred to as ''postcrania''. There is some disagreement over whether the skull and skeleton belong to the same or different animals. One example is the case of a Cretaceous sauropod skull of ''Nemegtosaurus'' found in association with the postcranial skeleton ''Opisthocoelicaudia ''Opisthocoelicaudia'' is a genus of sauropod dinosaur of the Late Cretaceous Period discovered in the Gobi Desert of Mongolia. The type species is ''Opisthocoelicaudia skarzynskii''. A well-preserved skeleton lacking only the head and neck wa ...''. In paleoanthropological studies, reconstruction of relationship between various species/remains is considered to be better supported by cranial characters rather than postcranial c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bite Force
Bite force quotient (BFQ) is a numerical value commonly used to represent the bite force of an animal, while also taking factors like the animal's size into account. The BFQ is calculated as the regression of the quotient of an animal's bite force in newtons The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in r ... divided by its body mass in kilograms. The BFQ was first applied by Wroe et al. (2005) in a paper comparing bite forces, body masses and prey size in a range of living and extinct mammalian carnivores, later expanded on by Christiansen & Wroe (2007). Results showed that predators that take relatively large prey have large bite forces for their size, i.e., once adjusted for allometry. The authors predicted bite forces using beam theory, based on the directly proportional relat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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