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Maccoyoceras
''Maccoyoceras'' is a genus of nautilids included in the family Trigonoceratidae The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous ( Mississippian) to the Early Permian. Diagnosis Trigonoceratidae comprise members of the order Nautilida characterized ... from the Mississippian of North America (Michigan) and Europe. The shell of ''Maccoyoceras''is evolute, volutions only slightly impressed, whorl section hexagonal. Venter flattened, flanks converging, umbilical shoulder prominent. Siphuncle slender, ventral of whorl center. References * Barnhard Kummel, 1964. Nautiloidea - Nautilida; Treatise on Invertebrate Paleongology, Part K. Geological Society of America and University of Kansas Press. Prehistoric nautiloid genera {{paleo-nautiloidea-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trigonoceratidae
The Trigonoceratidae is a family of coiled nautiloid cephalopods that lived during the period from the Early Carboniferous ( Mississippian) to the Early Permian. Diagnosis Trigonoceratidae comprise members of the order Nautilida characterized by a loosely coiled to evolute shell generally bearing longitudinal ribs or ridges with a whorl section that is oval to subquadrate and varying from compressed (squeezed) to depressed (flattened). (Kummel 1964) Classification and phylogeny Taxonomic position The Trigonoceratidae along with four other related families are combined in the Superfamily Trigonocerataceae in the Treatise,(''ibid'' Kummel) a superfamily. They are also the Triboloceratidae (Flower and Kummel, 1950) which form the Tribolocerataceae within the Centroceratina of the Osnovy according to Shimansky. The Trigonocerataceae and Centroceratina are essentially equivalent as are the Trigonoceratidae and Triboloceratidae. Derivation The Trigonerceratidae were derived from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mississippian (geology)
The Mississippian ( , also known as Lower Carboniferous or Early Carboniferous) is a subperiod in the geologic timescale or a subsystem of the geologic record. It is the earlier of two subperiods of the Carboniferous period lasting from roughly 358.9 to 323.2 million years ago. As with most other geochronologic units, the rock beds that define the Mississippian are well identified, but the exact start and end dates are uncertain by a few million years. The Mississippian is so named because rocks with this age are exposed in the Mississippi Valley. The Mississippian was a period of marine transgression in the Northern Hemisphere: the sea level was so high that only the Fennoscandian Shield and the Laurentian Shield were dry land. The cratons were surrounded by extensive delta systems and lagoons, and carbonate sedimentation on the surrounding continental platforms, covered by shallow seas. In North America, where the interval consists primarily of marine limestones, it is treate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nautilida
The Nautilida constitute a large and diverse order of generally coiled nautiloid cephalopods that began in the mid Paleozoic and continues to the present with a single family, the Nautilidae which includes two genera, ''Nautilus'' and ''Allonautilus'', with six species. All told, between 22 and 34 families and 165 to 184 genera have been recognised, making this the largest order of the subclass Nautiloidea. Classification and phylogeny Current classification The current classification of the Nautilida, in prevalent use, is that of Bernhard Kummel (Kummel 1964) in the Treatise which divides the Nautilida into five superfamilies, the Aipocerataceae, Clydonautilaceae, Tainocerataceae, and Trigonocerataceae, mostly of the Paleozoic, and the later Nautilaceae. These include 22 families and some 165 or so genera (Teichert and Moore 1964) Other concepts Shimansky 1962 (in Kummel 1964) divided the Nautilida into five suborders, the mostly Paleozoic Centroceratina, Liroceratina, Rutoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |