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Plioplatecarpinae
Plioplatecarpinae is a subfamily of mosasaurs, a diverse group of Late Cretaceous marine squamates. Members of the subfamily are informally and collectively known as "plioplatecarpines" and have been recovered from all continents, though the occurrences in Australia remain questionable. The subfamily includes the genera '' Latoplatecarpus'', ''Platecarpus'', '' Plioplatecarpus'' and ''Plesioplatecarpus''. Plioplatecarpines were small to medium-sized mosasaurs that were comparatively fast and agile compared to mosasaurs of other subfamilies. The first plioplatecarpines appear in the Turonian and are among the oldest of mosasaurs, and the clade persists throughout the Maastrichtian, a period of approximately 24 million years. The subfamily was seemingly heavily affected during a poorly understood middle-Campanian mosasaur extinction event and its genera appear to have faced competition from mosasaurine mosasaurs during the Maastrichtian, leading to a decline in numbers and in diver ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Selmasaurus
''Selmasaurus'' is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like ''Angolasaurus'' and ''Platecarpus''. Two species are known, ''S. russelli'' and ''S. johnsoni''; both are exclusively known from Santonian deposits in the United States. ''Selmasaurus'' is unique among the mosasaurs in that its skull is unusually akinetic, meaning that it is incapable of widening to swallow larger prey. Most mosasaurs have skulls which possess "coupled kinesis" (mesokinesis and streptostyly), that is, parts of the jaw can open widely to accommodate large prey. Description ''Selmasaurus'' was a small predatory mosasaur at approximately 3–5 meters in length. It possesses a relatively low number of teeth for a mosasaur, the lowest of any known species at the time of its discovery. Originally classified as a plioplatecarpine mosasaur, it differs from all other plioplatecarpine mosasaurs in severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectenosaurus
''Ectenosaurus'' is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like ''Angolasaurus'' and ''Platecarpus''. ''Ectenosaurus'' is known from the Santonian and Campanian of Kansas, Alabama, and Texas. The generic name means "Drawn-out lizard", from Greek ''ectenes'' ("drawn-out") and Greek ''sauros'' ("lizard") referencing the elongated muzzle. Description Based on the length of the preserved skull, about , ''Ectenosaurus'' would have reached in length and weighed . It was a rare genus of mosasaur with several unique characteristics that clearly separate it from other mosasaur genera. The most prominent of these features is its elongated jaws, elongated in a similar vein to other mosasaurs with elongated jaws, such as ''Plotosaurus'' and ''Pluridens''. Russell (1967) considered the form of the teeth, the shape of the frontal and the large suprastapedial process of the quadrate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mosasaur
Mosasaurs (from Latin ''Mosa'' meaning the 'Meuse', and Ancient Greek, Greek ' meaning 'lizard') comprise a group of extinct, large marine reptiles from the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes. Mosasaurs probably evolved from an extinct group of aquatic lizards known as Aigialosauridae, aigialosaurs in the Late Cretaceous, Earliest Late Cretaceous with 42 described genera. During the last 20 million years of the Cretaceous period (Turonian–Maastrichtian ages), with the extinction of the ichthyosaurs and Pliosauridae, pliosaurs, mosasaurs became the dominant marine predators. They themselves became extinct as a result of the Cretaceous–Paleogene extinction event, K-Pg event at the end of the Cretaceous period, about 66 million years ago. Description Mosasaurs breathed air, were powerful swimmers, and were well-adapted to livi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angolasaurus
''Angolasaurus'' ("Angola lizard") is an extinct genus of mosasaur. Definite remains from this genus have been recovered from the Turonian and Coniacian of Angola, and possibly the Coniacian of the United States, the Turonian of Brazil, and the Maastrichtian of Niger. While at one point considered a species of ''Platecarpus'', recent phylogenetic analyses have placed it between the (then) plioplatecarpines '' Ectenosaurus'' and '' Selmasaurus'', maintaining a basal position within the plioplatecarpinae. Its wide geographic range make it the one of the only Turonian mosasaurs with a transatlantic range. Description ''Angolasaurus'' was a small mosasaur, with a total length of about 4 meters (13 feet). It shared much of a body plan with its relative ''Platecarpus'', but with a slightly longer skull relative to body length. Its skull housed 11 maxillary teeth, 4 premaxillary teeth, and 12 dentary teeth. The phylogenetic relationship of ''Angolasaurus'' indicates that individuals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latoplatecarpus
''Latoplatecarpus'' is an extinct genus of plioplatecarpine mosasaur known from the Late Cretaceous (early middle Campanian stage) of the northern Gulf of Mexico and the Western Interior Basin of North America. Discovery ''Latoplatecarpus'' was named by Takuya Konishi and Michael W. Caldwell in 2011 and the type species is ''Latoplatecarpus willistoni''. ''L. willistoni'' is known from the holotype TMP 84.162.01, a nearly complete skull, including the mandible and dentary, and a partial postcranial skeleton. The holotype was collected in the Pembina Mountain, in southern Manitoba, from the Pembina Member of the Pierre Shale, dating to the early middle Campanian stage of the Late Cretaceous period, about 80.5 million years ago. Three specimens are also referred to this species, including DMNH 8769 (a very well preserved cranial and postcranial skeleton), SDSMT 30139 and AMNH 2182. Konishi and Caldwell reassigned a second species, ''L. nichollsae'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platecarpus
''Platecarpus'' ("flat wrist") is an extinct genus of aquatic lizards belonging to the mosasaur family, living around 84–81 million years ago during the middle Santonian to early Campanian, of the Late Cretaceous period. Fossils have been found in the United States and possible specimens in Belgium and Africa. A well-preserved specimen of ''Platecarpus'' shows that it fed on moderate-sized fish, and it has been hypothesized to have fed on squid, and ammonites as well. Like other mosasaurs, it was initially thought to have swum in an eel-like fashion, although another study suggests that it swam more like modern sharks. An exceptionally well-preserved specimen of ''P. tympaniticus'' known as LACM 128319 shows skin impressions, pigments around the nostrils, bronchial tubes, and the presence of a high-profile tail fluke, showing that it and other mosasaurs did not necessarily have an eel-like swimming method, but were more powerful, fast swimmers. It is held in the Natural Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Platecarpus Tympaniticus
''Platecarpus'' ("flat wrist") is an extinct genus of aquatic lizards belonging to the mosasaur family, living around 84–81 million years ago during the middle Santonian to early Campanian, of the Late Cretaceous period. Fossils have been found in the United States and possible specimens in Belgium and Africa. A well-preserved specimen of ''Platecarpus'' shows that it fed on moderate-sized fish, and it has been hypothesized to have fed on squid, and ammonites as well. Like other mosasaurs, it was initially thought to have swum in an eel-like fashion, although another study suggests that it swam more like modern sharks. An exceptionally well-preserved specimen of ''P. tympaniticus'' known as LACM 128319 shows skin impressions, pigments around the nostrils, bronchial tubes, and the presence of a high-profile tail fluke, showing that it and other mosasaurs did not necessarily have an eel-like swimming method, but were more powerful, fast swimmers. It is held in the Natural History ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the Latin word for the white limestone known as chalk. The chalk of northern France and the white cliffs of south-eastern England date from the Cretaceous Period. Climate During the Late Cretaceous, the climate was warmer than present, although throughout the period a cooling trend is evident. The tropics became restricted to equatorial regions and northern latitudes experienced markedly more seasonal climatic conditions. Geography Due to plate tectonics, the Americas were gradually moving westward, causing the Atlantic Ocean to expand. The Western Interior Seaway divided North America into eastern and western halves; Appalachia and Laramidia. India maintained a northward course towards Asia. In the Southern Hemisphere, Australia a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. '' Panthera leo'' (lion) and '' Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should c ... [...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 mammal, marine mammals. They comprise the extant taxon, extant family (biology), 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). There are 34 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular phylogenetics, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). Pinnipeds belong to the order Carnivora; their closest living relatives are Musteloidea, musteloids (Mustelidae, weasels, Procyonidae, raccoons, skunks, and red pandas), having diverged about 50 million years ago. Seals range in size from the and Baikal sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles ( muscular hydrostats) modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology. Cephalopods became dominant during the Ordovician period, represented by primitive nautiloids. The class now contains two, only distantly related, extant subclasses: Coleoidea, which includes octopuses, squid, and cuttlefish; and Nautiloidea, represented by '' Nautilus'' and '' Allonautilus''. In the Coleoidea, the molluscan shell has been internalized or is absent, whereas in the Nautiloidea, the external shell remains. About 800 living species of cephalopods have been i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Belemnite
Belemnitida (or the belemnite) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard. The calcitic guard is the most common belemnite remain. Belemnites, in life, are thought to have had 10 hooked arms and a pair of fins on the guard. The chitinous hooks were usually no bigger than , though a belemnite could have had between 100 and 800 hooks in total, using them to stab and hold onto prey. Belemnites were an important food source for many Mesozoic marine creatures, both the adults and the planktonic juveniles, and likely played an important role in restructuring marine ecosystems after the Triassic–Jurassic extinction event. They may have laid between 100 and 1,000 eggs. Some species may have been adapted to speed and swam in the tu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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