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Alexandronectes Zealandiensis
''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 .org which can be dated to the Early stage of the . Fossils of it were found around 1872 near the Wa ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellate
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are mostly marine plankton, but they also are common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey ( phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, '' Oodinium'' and '' Pfiesteria''). Some dinoflagell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 '' Kaiwhekea''. This group was formerly known as the Cimoliasauridae, but since ''Cimoliasaurus'' is indeterminate and quite possibly elasmosaurid, this replacement name was erected. ''Tatenectes'' and ''Kimmerosaurus'' represent an earlier Oxfordian Jurassic radiation from Laurasia, while '' Aristonectes'' and '' Kaiwhekea'' represent a later Cretaceous radiation from Gondwana. Appearance Aristonectidae were characterized by a relatively larger head and shorter neck than the Plesiosauridae and 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptoclididae
Cryptoclididae is a family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and crustaceans. The earliest members of the family appeared during the early Bajocian, and they represented the dominant group of long-necked plesiosaurs during the latter half of the Jurassic. Classification In 2010, two supposed late Cretaceous members of the group were reclassified as other kinds of plesiosauroids. '' Kaiwhekea'' was reclassified to Leptocleididae, and ''Aristonectes'' was transferred to 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 p .... Cladogram based on Ketchum and Benson (2010): References Exter ... [...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 researc ... [...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] |
Mauisaurus
''Mauisaurus'' ("Māui lizard") is a dubious genus of plesiosaur that lived during the Late Cretaceous period in what is now New Zealand. Numerous specimens have been attributed to this genus in the past, but a 2017 paper restricts ''Mauisaurus'' to the lectotype and declares it a ''nomen dubium''. Description Little can be said about the appearance of ''Mauisaurus'' as the only known material is an undiagnostic, fragmentary pelvic area and flippers. The lectotype material shows some features that may indicate aristonectine affinities, but simultaneously possesses anatomical features more consistent with non-aristonectine elasmosaurs. Etymology ''Mauisaurus'' gets its name from the New Zealand Māori mythological demigod, Māui. Māui is said to have pulled New Zealand up from the seabed using a fish hook, thus creating the country. Thus, ''Mauisaurus'' means "''Māui lizard''". ''Mauisaurus'' gets its scientific last name from its original finder, Julius von Haast, who foun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mauisaurus BW
''Mauisaurus'' ("Māui lizard") is a dubious genus of plesiosaur that lived during the Late Cretaceous period in what is now New Zealand. Numerous specimens have been attributed to this genus in the past, but a 2017 paper restricts ''Mauisaurus'' to the lectotype and declares it a ''nomen dubium''. Description Little can be said about the appearance of ''Mauisaurus'' as the only known material is an undiagnostic, fragmentary pelvic area and flippers. The lectotype material shows some features that may indicate aristonectine affinities, but simultaneously possesses anatomical features more consistent with non-aristonectine elasmosaurs. Etymology ''Mauisaurus'' gets its name from the New Zealand Māori mythological demigod, Māui. Māui is said to have pulled New Zealand up from the seabed using a fish hook, thus creating the country. Thus, ''Mauisaurus'' means "''Māui lizard''". ''Mauisaurus'' gets its scientific last name from its original finder, Julius von Haast, who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basioccipital Bone
The basilar part of the occipital bone (also basioccipital) extends forward and upward from the foramen magnum, and presents in front an area more or less quadrilateral in outline. In the young skull this area is rough and uneven, and is joined to the body of the sphenoid by a plate of cartilage. By the twenty-fifth year this cartilaginous plate is ossified, and the occipital and sphenoid form a continuous bone. Surfaces On its ''lower surface'', about 1 cm. in front of the foramen magnum, is the pharyngeal tubercle which gives attachment to the fibrous raphe of the pharynx. On either side of the middle line the longus capitis and rectus capitis anterior are inserted, and immediately in front of the foramen magnum the anterior atlantooccipital membrane is attached. The ''upper surface'', which constitutes the lower half of the clivus, presents a broad, shallow groove which inclines upward and forward from the foramen magnum; it supports the medulla oblongata, and n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterygoid Bone
The pterygoid is a paired bone forming part of the palate of many vertebrates, behind the palatine bone In anatomy, the palatine bones () are two irregular bones of the facial skeleton in many animal species, located above the uvula in the throat. Together with the maxillae, they comprise the hard palate. (''Palate'' is derived from the Latin ...s. It is a flat and thin lamina, united to the medial side of the pterygoid process of the sphenoid bone, and to the perpendicular lamina of the palatine bone. Bones of the head and neck {{musculoskeletal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Squamosal Bone
The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestral component of the dermal roof and is typically thin compared to other skull bones. The squamosal bone lies ventral to the temporal series and otic notch, and is bordered anteriorly by the postorbital. Posteriorly, the squamosal articulates with the quadrate and pterygoid bones. The squamosal is bordered anteroventrally by the jugal and ventrally by the quadratojugal. Function in reptiles In reptiles, the quadrate and articular bones of the skull articulate to form the jaw joint. The squamosal bone lies anterior to the quadrate bone. Anatomy in synapsids Non-mammalian synapsids In non-mammalian synapsids, the jaw is composed of four bony elements and referred to as a quadro-articular jaw because the joint is between the articular an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
