|
Aristonectine
Aristonectinae is a clade of plesiosaurs in the family Elasmosauridae. It includes the Late Cretaceous plesiosaurs ''Aristonectes'' and '' Kaiwhekea'', traditionally grouped with the Late Jurassic ''Tatenectes'' and ''Kimmerosaurus'' in the family Aristonectidae The Aristonectidae is a taxonomic family of poorly known plesiosaurs from the Jurassic and Cretaceous periods. They are closely related to polycotylid plesiosaurs. The family is made up of ''Tatenectes'', ''Kimmerosaurus'', ''Aristonectes'', and .... References Late Cretaceous plesiosaurs {{cretaceous-reptile-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexandronectes
''Alexandronectes'' is a genus of elasmosaurid plesiosaur, a type of long-necked marine reptile, that lived in the oceans of Late Cretaceous New Zealand. It contains one species, ''A. zealandiensis''. Fossils of ''Alexandronectes'' were found in the Conway Formation of Canterbury, at Fossilworks.org which can be dated to the Early stage of the . Fossils of it were found around 1872 near the Waipara River, north of Christchurch, New ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tatenectes
''Tatenectes'' is a genus of cryptoclidid plesiosaur known from the Upper Jurassic of Wyoming. Its remains were recovered from the Redwater Shale Member of the Sundance Formation, and initially described as a new species of '' Cimoliosaurus'' by Wilbur Clinton Knight in 1900. It was reassigned to '' Tricleidus'' by Maurice G. Mehl in 1912 before being given its own genus by O'Keefe and Wahl in 2003. ''Tatenectes laramiensis'' is the type and only species of ''Tatenectes''. While the original specimen was lost, subsequent discoveries have revealed that ''Tatenectes'' was a very unusual plesiosaur. Its torso had a flattened, boxy cross-section and its gastralia (belly ribs) exhibit pachyostosis (thickening). The total length of ''Tatenectes'' has been estimated at . ''Tatenectes'' is related to '' Kimmerosaurus'', although their taxonomic placement has varied. They were once considered to be close relatives of ''Aristonectes'' in the family Cimoliasauridae or Aristonect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aristonectes
''Aristonectes'' (meaning 'best swimmer') is an extinct genus of plesiosaur from the Late Cretaceous Paso del Sapo Formation of what is now Argentina, the Quiriquina Formation of Chile and the Lopez de Bertodano Formation of Antarctica. The type species is ''Aristonectes parvidens'', first named by Cabrera in 1941. Description Analysis of a specimen from the Lopez de Bertodano Formation indicates that ''Aristonectes'' was one of the largest plesiosaurs ever to exist, with an estimated body length of and body mass of per Paul and per O'Gorman and his colleagues. Classification ''Aristonectes'' was classified variously since its original 1941 description, but a 2003 review of plesiosaurs from Patagonia conducted by Gasparini ''et al.'' (2003) found that ''Aristonectes'' was most closely related to elasmosaurid plesiosaurs like ''Elasmosaurus''. The authors also considered '' Morturneria'' a junior synonym of ''Aristonectes'' because the former's holotype has unfu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kaiwhekea
''Kaiwhekea'' () is an extinct genus of plesiosaur from the Late Cretaceous (Maastrichtian age) of what is now New Zealand. History of discovery The type species, ''Kaiwhekea katiki'', was first described by Arthur Cruickshank and Ewan Fordyce in 2002. ''Kaiwhekea'' was approximately long and weighed in body mass. It lived around the middle Maastrichtian. The single known specimen, found in the Katiki Formation near Shag Point on the coast of Otago, is nearly complete, and is on display at the Otago Museum in Dunedin, New Zealand. Classification ''Kaiwhekea'' has been placed as an aristonectine plesiosaur close to ''Aristonectes'' (O'Keefe and Street, 2009). In 2010, ''Kaiwhekea'' was transferred to Leptocleididae, but more recent analyses do not find the same result. The following cladogram shows the placement of ''Kaiwhekea'' within Elasmosauridae following an analysis by Rodrigo A. Otero, 2016: See also * List of plesiosaur genera * Timeline of plesiosaur research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wunyelfia
''Wunyelfia'' is a genus of elasmosaurid plesiosaur, a type of long-necked marine reptile, that lived in the oceans of Late Cretaceous Chile. It contains one species, ''W. maulensis''. Etymology The generic name, meant to be pronounced as "goo-niel-fiah", comes from ''Wüñelfe'', the Mapudungun name for the planet Venus, also seen as a mystic symbol of the flower of the ''Foye'', a sacred tree, and a representation of the Mapuche freedom and untamed spirit. The specific name comes from the Región del Maule of Chile where it was found. Description ''Wunyelfia'' belongs to the elasmosaurid subfamily Aristonectinae and come from the Quiriquina Formation. at Fossilworks
[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Campanian
The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian spans the time from 83.6 (± 0.2) to 72.1 (± 0.2) million years ago. It is preceded by the Santonian and it is followed by the Maastrichtian. The Campanian was an age when a worldwide sea level rise covered many coastal areas. The morphology of some of these areas has been preserved: it is an unconformity beneath a cover of marine sedimentary rocks. Etymology The Campanian was introduced in scientific literature by Henri Coquand in 1857. It is named after the French village of Champagne in the department of Charente-Maritime. The original type locality was a series of outcrop near the village of Aubeterre-sur-Dronne in the same region. Definition The base of the Campanian Stage is defined as a place in the stratigraphic column wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastrichtian
The Maastrichtian () is, in the ICS geologic timescale, the latest age (uppermost stage) of the Late Cretaceous Epoch or Upper Cretaceous Series, the Cretaceous Period or System, and of the Mesozoic Era or Erathem. It spanned the interval from . The Maastrichtian was preceded by the Campanian and succeeded by the Danian (part of the Paleogene and Paleocene). The Cretaceous–Paleogene extinction event (formerly known as the Cretaceous–Tertiary extinction event) occurred at the end of this age. In this mass extinction, many commonly recognized groups such as non-avian dinosaurs, plesiosaurs and mosasaurs, as well as many other lesser-known groups, died out. The cause of the extinction is most commonly linked to an asteroid about wide colliding with Earth, ending the Cretaceous. Stratigraphic definitions Definition The Maastrichtian was introduced into scientific literature by Belgian geologist André Hubert Dumont in 1849, after studying rock strata of the Chalk Group c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morturneria
''Morturneria'' is an extinct genus of plesiosaur from the Late Cretaceous of what is now Antarctica. History of research The Lopez de Bertodano Formation is located on Seymour Island, Antarctica, with exposures present in all but the northernmost third of the island. During the summers of 1981–1982, 1983–1984, and 1984–1985, paleontological expeditions recovered eight partial plesiosaur skeletons in the formation. One of these, TTU P9219, consisted of a skull and some cervical vertebrae. It was found in the upper part of the formation, informally known as the 'molluscan units', high up in a ravine. It was preserved within a tough, calcareous nodule, from which it was difficult to remove. While excavating the specimens, the dig teams faced difficulty in removing the strata above the fossils, due to the presence of permafrost. The cold temperatures also prevented the plaster from setting, so the teams used camp stoves and aluminium foil to heat it up, allowing it to har ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution, and some species at least partly inhabited freshwater environments. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous ''Plesiosaurus'', was named in 1821. Since then, more than a hundred valid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elasmosauridae
Elasmosauridae is an extinct family of plesiosaurs, often called elasmosaurs. They had the longest necks of the plesiosaurs and existed from the Hauterivian to the Maastrichtian stages of the Cretaceous, and represented one of the two groups of plesiosaurs present at the end of the Cretaceous alongside Polycotylidae. Their diet mainly consisted of crustaceans and molluscs. Description The earliest elasmosaurids were mid-sized, about . In the Late Cretaceous, elasmosaurids grew as large as , such as '' Styxosaurus'', ''Albertonectes'', and '' Thalassomedon''. Their necks were the longest of all the plesiosaurs, with anywhere between 32 and 76 (''Albertonectes'') cervical vertebrae. They weighed up to several tons. Classification Early three-family classification Though Cope had originally recognized ''Elasmosaurus'' as a plesiosaur, in an 1869 paper he placed it, with ''Cimoliasaurus'' and ''Crymocetus'', in a new order of sauropterygian reptiles. He named the group Streptos ... [...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 and Ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
