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Sactorthoceratidae
The Sactorthoceratidae comprise Orthocerataceaen genera with a subcentral suborthochoanitic siphuncle composed of slightly expanded segments and free of organic deposits. The camerae (chambers) of the phragmocone (chambered portion) likewise have organic deposits that are typically retarded or sparse. Discussion The family, Sactorthoceratidae, was established by Rousseau Flower in 1946, based on the genus '' Sactorthoceras''. In 1962 Flower pointed out the problem of defining the Sactorthoceratidae based on ''Sactorthoceras''; there being three species groups within the genus: those with (1) short camerae and rather short tubular septal necks, (2) long camerae and slightly expanded siphuncle segments, (3) typically tubular siphuncle segments that are rapidly contracted at the septal foremina. In defining the Sactorthceratidae, the second group with slightly expanded segments was considered. However the type species ''S. goniaseptum'' belongs to the third group, with contrac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sigmocycloceras
''Sigmocycloceras'' is a Nautiloidea, nautiloid cephalopod discovered in the Middle Ordovician of Korea, said to be similar to ''Sactorthoceras'', and included in the Sactorthoceratidae, but unique in being longitudinally sigmoid and sculpted with transverse annuli. References * Walter C Sweet 1964. Nautiloidea-Orthocerida; Treatise on Invertebrate Paleontology, Part K. Geol Soc of America and Univ. Kansas Press. Nautiloids {{paleo-cephalopod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sactorthoceras
''Sactorthceras'' is an orthoceratoid genus (subclass Nautiloidea s.l.) known from the Middle Ordovician of eastern North America (NY), Norway and Korea and is the type genus of the Sactorthoceratidae. ''Sactorthceras'' was named by Kobayashi in 1934 to include smooth or striated, straight or slightly curved longicones with short camerae and slender, subcentral, suborthochoanitic siphuncles with segments slightly inflated and no cameral deposits. ''Sactorthocras'' has also been recognized in the Silurian Racine Formation of Wisconsin, and from the Ordovician of China and Iran. Related genera include ''Centroonoceras ''Centroonoceras'' is a middle Ordovician cyrtoconic nautiloid cephalopod, otherwise similar to the orthoconic '' Sactorthoceras'' and also included in the Sactorthoceratidae. It was named by Kobayashi, 1934, and has been found in Korea and in ...'' and '' Sigmocycloceras'' -References- *Sweet, Walter C. 1964. Nautiloidea -Orthocerida. Treatise on Inverteb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braulioceras
Braulioceras is a smooth, orthoconic orthocerid with very close spaced septa (around 8 over a length equal to the diameter of the shell) added to the Sactorthoceratidae in 2007. The type species, ''Braulioceras sanjuanense'' comes from the Middle Ordovician of the San Juan Formation, Argentine Precordillera. ''Braulioceras'' is very similar to ''Sactorthoceras''. The siphuncle The siphuncle is a strand of tissue passing longitudinally through the shell of a cephalopod mollusk. Only cephalopods with chambered shells have siphuncles, such as the extinct ammonites and belemnites, and the living nautiluses, cuttlefish, and ... is central, with orthochoanitic septal necks and segments which are slightly expanded between septa, giving it a beaded appearance. The thickness of the connecting rings is similar to that in ellesmerocerids. Endosiphuncular or cameral deposits are unknown. ''Braulioceras'' is distinguished from ''Sactorthoceras'' by its more closely central siphuncle, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cartersoceras
''Cartersoceras'' is a genus of nautiloid cephalopods placed in the Orthocerida, Orthocerid family Baltoceratidae, established by Rousseau Flower (1964), for species formally included in part in ''Murrayoceras'', and in part in "''Sacotoceras''". This group is typical of ''Murrayoceras'' in all features except that the siphuncle segments are convex in outline.Rousseau H Flower, (1964). The nautiloid order Ellesmeroceratida (Cephalopoda). New Mexico Bureau of Mines and Mineral Resources Memoir 12. It is known from the Middle Ordovician of the eastern United States. The type species ''Cartersoceras shideliri'' Flower from the Carters Limestone, Beach Grove, Tennessee, shows a ventral rod secreted calcite in the siphuncle and thick, fibrous connecting rings which are not layered as in early Ellesmerocerida. ''C.noveboracense'', originally referred to ''Murrayoceras'', from the Amsterdam Limestone of New York, known from a weathered portion of the phragmocone, shows part of the siphu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centroonoceras
''Centroonoceras'' is a middle Ordovician cyrtoconic nautiloid cephalopod, otherwise similar to the orthoconic '' Sactorthoceras'' and also included in the Sactorthoceratidae. It was named by Kobayashi, 1934, and has been found in Korea and in New York state in the eastern U.S. ''Centroonoceras'' is characterized by a smooth, gently expanding shell with a moderate but definite curvature and circular cross section. Septa are close spaced. The siphuncle is subcentral, as in ''Sactorthoceras''. Segments are subfusiform; generally straighter on the dorsal side and more expanded on the ventral side. No cameral or endosiphuncle deposits are known. References * Walter C Sweet 1964. Nautiloidea-Orthocerida; Treatise on Invertebrate Paleontology, Part K. Geol. Soc. of America and Univ. Kansas Press. Prehistoric nautiloid genera Paleozoic life of Newfoundland and Labrador {{paleo-cephalopod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Murrayoceras
''Murrayoceras'' is a nautilid cephalopod included in the orthocerid family Baltoceratidae, widespread in the Middle Ordovician of North America, characterized by a depressed orthoconic shell with a subtriangular cross section and flattened venter and a proportionally large ventral siphuncle, 0.15 to 0.3 the dorso-ventral shell diameter. Septa are close spaced with sutures forming broad lobes on the upper flanks and ventral surface. As originally perceived ''Murrayoceras'' included species differing in siphuncle profile.Rousseau H Flower, 1964. The Nautiloid Order Ellesmeroceratida (Cephalopoda). New Mexico Bureau of Mines and Mineral Resources Memoir 12. Those in which the siphuncle segments are externally convex were redefined as Cartersoceras., leaving Murrayoceras with those having essentially straight, tubular, or slightly concave segments. ''Murrayoceras'' has a ventral rod in the siphuncle, putting it thereby in the rod-bearing Baltoceratidae, and closely related to '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rousseau Flower
Rousseau Hayner Flower (1913–1988) was an extremely prolific 20th century paleontologist, known for his eccentric personality. Career Although trained as an entomologist, and a specialist in dragonflies and orthopterans, Flower began studying paleontology in the middle of the 1930s. He became an expert in North American cephalopods of the Devonian period as well as the stratigraphy of the early Paleozoic era. His main field was the nautiloids, which he studied intensely, often focusing on life habits and theoretical aspects of paleobiology, but he also penned many papers on fossil corals and other invertebrates. Flower described several hundred new fossil species and over 100 new genera. Eccentricities In the paleontology community, Flower's colorful behavior earned him admirers and enemies—whom he would occasionally "thank" in the acknowledgement sections of his papers or, in one case, in the name of a fossil species. His antics included mocking the alleged l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthocerida
Orthocerida is an order of extinct Orthoceratoid cephalopods also known as the Michelinocerida that lived from the Early Ordovician () possibly to the Late Triassic (). A fossil found in the Caucasus suggests they may even have survived until the Early Cretaceous (). They were most common however from the Ordovician to the Devonian. Shell form The shell is usually long, and may be straight (" orthoconic") or gently curved. In life, these animals may have been similar to the modern squid, except for the long shell. The internal structure of the shell consists of concavo-convex chambers linked by a centrally-placed tube called a siphuncle. There is a tendency for the chambers to develop cameral deposits, which were used as ballast to balance the long gas-filled shell. Depending on the family, the siphuncle has orthochoanitic (short and straight) or cyrtochoanitic (outwardly curved) septal necks, which protrude from the septa. The shell surface may be (depending on the speci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treatise On Invertebrate Paleontology
The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, taxa with no fossil record whatsoever have just a very brief listing. Publication of the decades-long ''Treatise on Invertebrate Paleontology'' is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post-Paleozoic era caenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, every so often, previously published volumes of the ''Treatise'' are revised. Evolution of the project Raymond C. Moor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baltoceratidae
Baltoceratidae is an extinct family of orthoconic cephalopods belonging to the subclass Nautiloidea endemic to what would be Asia, Australia, Europe, North America, and South America during the Ordovician living from about 480–460 mya, existing for approximately . Taxonomy Baltoceratidae was named by Kobayashi (1935) and assigned to the Ellesmeroceratida by Flower and Kummel (1950) where it was retained by Unklesbay and Young (1956), again by Flower (1964)Flower 1964. The Nautiloid Order Ellesmeroceratida (Cephalopoda), Memoir 12, New Mexico Bureau of Mines and Mineral Resources, Socorro, NM , and by Furnish and Glenister in Teichert et al. (1964).Teichert et al 1964, Treatise on Invertebrate Paleontology Part K Mollusca 3, Nautiloidea-Ellesmerocerida by Furnish and Glenister, K129- K153 Flower (1964) included the Baltoceratidae in the ellesmeroceratid suborder Ellesmeroceratina. Further study of baltoceratid interiors, namely regarding the generally thin connecting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troedssonellidae
Troedssonellidae is a family of orthoceroid cephalopods from the Ordovician, derived from rod-bearing Baltoceratidae, that have a continuous lining within the siphuncle that resembles very thin and slender endocones. Shells are generally slender and orthoconic. The siphuncle is central or subcentral, composed of straight or slightly expanded segments. Septal necks generally short and connecting rings are thin. Thin cameral deposits (lining the chambers) are known, which along with the position of the siphuncle and thin connecting rings distinguishes them from the endocerids in which they have been included.Flower 1976. Ordovician Cephalopod Faunas and Their Role in Correlation, in The Ordovician System: proceedings of a Palaeontological Association symposium, Sept 1974 Troedsonnellids first appear high in Lower Ordovician ( Cassinian) strata, beginning with ''Tajaroceras'' and extend at least through the Whiterock Stage of the Middle Ordovician.Hook and Flower 1977. Late Can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |