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Anagymnites
''Anagymnites'' is an extinct genus of cephalopods belonging to the Ammonite subclass. References The Paleobiology Database - ''Anagymnites'' entryAccessed 7 December 2011 Gymnitidae Ceratitida genera Anisian life {{Ceratitida-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anisian
In the geologic timescale, the Anisian is the lower stage or earliest age of the Middle Triassic series or epoch and lasted from million years ago until million years ago. The Anisian Age succeeds the Olenekian Age (part of the Lower Triassic Epoch) and precedes the Ladinian Age. Stratigraphic definitions The stage and its name were established by Austrian geologists Wilhelm Heinrich Waagen and Carl Diener in 1895. The name comes from ''Anisus'', the Latin name of the river Enns. The original type locality is at Großreifling in the Austrian state of Styria. The base of the Anisian Stage (also the base of the Middle Triassic series) is sometimes laid at the first appearance of conodont species '' Chiosella timorensis'' in the stratigraphic record. Other stratigraphers prefer to use the base of magnetic chronozone MT1n. There is no accepted global reference profile for the base, but one ( GSSP or golden spike) was proposed at a flank of the mountain Deşli Caira in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpheus Hyatt
Alpheus Hyatt (April 5, 1838 – January 15, 1902) was an American zoologist and palaeontologist. Biography Alpheus Hyatt II was born in Washington, D.C. to Alpheus Hyatt and Harriet Randolph (King) Hyatt. He briefly attended the Maryland Military Academy and Yale University, and after graduating from Harvard University in 1862, he enlisted as a private in the Massachusetts Volunteer Infantry for the Civil War, emerging with the rank of captain. After the war he worked for a time at the Essex Institute (now the Peabody Essex Museum in Salem, Massachusetts. He and a colleague founded ''American Naturalist'' and Hyatt served as editor from 1867 to 1870. He became a professor of paleontology and zoology at Massachusetts Institute of Technology in 1870, where he taught for eighteen years, and was professor of biology and zoology at Boston University from 1877 until his death in 1902. He also served as curator of the Boston Society of Natural History, where his longtime a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) than they are to shelled nautiloids such as the living '' Nautilus'' species. The earliest ammonites appeared during the Devonian, with the last species vanishing during the Cretaceous–Paleogene extinction event. Ammonites are excellent index fossils, and linking the rock layer in which a particular species or genus is found to specific geologic time periods is often possible. Their fossil shells usually take the form of planispirals, although some helically spiraled and nonspiraled forms (known as heteromorphs) have been found. The name "ammonite", from which the scientific term is derived, was inspired by the spiral shape of their fossilized shells, which somewhat resemble tightly coiled rams' horns. Pliny the Elder ( 79 AD ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gymnitidae
Gymnitidae is a family of Lower to Middle Triassic ammonite cephalopods with evolute, discoidal shells. Hyatt and Smith (1905, p. 114-115) included the Gymnitidae in the suborder Ceratitoidea, which later became the superfamily Ceratitaceae and included in it genera more primitive than ''Gymnites'' as well as the more advanced ''Gymnites''. Those being '' Xenaspis'', '' Flemingites'', and ''Ophiceras''. Derivation as shown in Smith (1932 p. 30) is from ''Xenodiscus''. The more primitive ''Xenaspis'', ''Flemingites'', and ''Ophiceras'', found in Lower Triassic beds in western America have ceratitic sutures. The more developed ''Gymnites'' has deeply digitate ammonitic sutures. Arkell, et al., 1957, in the Treatise on Invertebrate Paleontology, on the other hand included the Gymnitidae in the Pinacocerataceae as the earlier and more primitive of its two families, combining ''Gymnites'' with coeval and more advanced forms. Genera included in the Gymnitidae sensu Arkell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceratitida Genera
Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammonites. Ceratitids overwhelmingly produced planospirally coiled discoidal shells that may be evolute with inner whorls exposed or involute with only the outer whorl showing. In a few later forms the shell became subglobular, in others, trochoidal or uncoiled. Sutures are typically ceratitic, with smooth saddles and serrate or digitized lobes. In a few the sutures are goniatitic while in others they are ammonitic. Taxonomy * Ceratitida ** Ceratitoidea ** Choristoceratoidea **Clydonitoidea ** Danubitoidea ** Dinaritoidea ** Lobitoidea ** Meekoceratoidea ** Megaphyllitoidea ** Nathorstitoidea ** Noritoidea ** Otoceratoidea ** Pinacoceratoidea **Ptychitoidea ** Sageceratoidea ** Tropitoidea ** Xenodiscoidea Only eight superfamilies ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
