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Jovellaniidae
Jovellaniidae was established as a family within the Oncocerida to include genera characterized by longiconic orthocones and cyrtocones with a subtriangular to depressed cross-section in which the ventral (siphuncular) side is typically angular or more acutely rounded than the dorsal (antisiphuncular) side, and in which the siphuncle is generally large, ventral, and with lamellar actinosiphonate deposits (Flower 1950, Sweet 1964) Jovelaniids have a range that extends from the Middle Silurian to the Upper Ordovician and are known from North America Europe. (Sweet 1964) They are thought to be derived from the Valcouroceratidae The Valcouroceratidae is a family within the Oncocerida, nautiloid cephalopods from the middle and upper Ordovician, established by Rousseau Flower in 1945. Diagnosis Valcouroceratids are characterized by exogastric cyrtocones and brevicones tha .... Jovellaniidae was given its name by Foord in 1888; its type is the genus '' Jovellania'' References * Fl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jovellania
''Jovellania'' is a genus of extinct prehistoric nautiloids from the order Oncocerida known from the Lower Devonian of Europe (France, Germany).Sweet, W. C. (1964). "Nautiloidea -Oncocerida". '' Treatise on Invertebrate Paleontology''. Part K Nautiloidea, Teichert & Moore (eds) Nautiloids form a broad group of shelled cephalopods that were once diverse and numerous but are now represented by only a handful of species in two genera. ''Jovellania'' was named by Bayle (1879) and is type genus for the Jovellaniidae, a family assigned to the Oncocerida by Flower (1950)Flower, R. H & Kummel, B. (September 1950). "A Classification of the Nautiloidea". '' Journal of Paleontology''. 24 (3). Morphology ''Jovellania'' can be described as having a slowly widening, straight or slightly cytoconic shell with faint undulations and nearly circular or slightly depressed cross-section Kroger, B. (March 2008). "Nautiloids Before and During the Origin of Ammonoids ...". '' Special Papers in Palaeonto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laumontoceras
''Laumonttoceras'' is a genus in oncocerid family Jovellaniidae from the lower Devonian of Europe characterized by uncompressed, moderately expanding, orthocones with a central siphuncle composed of cylindrical segments that are slightly contracted at the septal openings and which contain discrete, discontinuous actinosphonate deposits. ''Laumontoceras'' differs from ''Jovellania ''Jovellania'' is a genus of extinct prehistoric nautiloids from the order Oncocerida known from the Lower Devonian of Europe (France, Germany).Sweet, W. C. (1964). "Nautiloidea -Oncocerida". '' Treatise on Invertebrate Paleontology''. Part K Nau ...'', also from the lower Devonian of Europe, primarily in having a central rather than a subventral siphuncle, as in ''Jovellania''. References *Sweet, W. C. 1964. Nautiloidea- Orthocerida. Treatise on Invertebrate Paleontology, Part K. Geol Soc of America and Univ of Kansas Press. Teichert & Moore, (eds) {{Taxonbar, from=Q6498307 Prehistoric nautiloid g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projovellania
''Projovellania'' is an extinct nautiloid cephalopod belonging to the oncocerid family Jovellaniidae found in mid Silurian sediments in Europe. The shell is a longiconic cyrtocone, like that of ''Jovellania ''Jovellania'' is a genus of extinct prehistoric nautiloids from the order Oncocerida known from the Lower Devonian of Europe (France, Germany).Sweet, W. C. (1964). "Nautiloidea -Oncocerida". '' Treatise on Invertebrate Paleontology''. Part K Nau ...'' or '' Mixosiphonoceras'', except for being compressed rather than depressed. References * Sweet W.C. 1964. Nautiloidea-Oncocerida. Treatise on Invertebrate Paleontology, Part K. Geological Society of America and Univ. of Kansas press. Teichert & Moore, (eds) {{Taxonbar, from=Q7249501 Prehistoric nautiloid genera Oncocerida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oncocerida
The Oncocerida comprise a diverse group of generally small nautiloid cephalopods known from the Middle Ordovician to the Mississippian (early Carboniferous; one possible member is known from the Early Permian), in which the connecting rings are thin and siphuncle segments are variably expanded (Flower, 1950). At present the order consists of some 16 families, a few of which, such as the Oncoceratidae, Brevicoceratidae, and Acleistoceratidae contain a fair number of genera each while others like the Trimeroceratidae and Archiacoceratidae are represented by only two or three (Sweet, 1964). Physical characteristics The shells of oncocerids are primarily somewhat compressed cyrtoconic brevicones. More advanced forms include gyrocones, serpenticones, torticones, and elongate orthocones and cyrtocones, reflective of the different families and genera (Flower, 1950; Sweet, 1964). The siphuncle in the Oncocerida is commonly located at or near the ventral margin. Connecting rings are mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valcouroceratidae
The Valcouroceratidae is a family within the Oncocerida, nautiloid cephalopods from the middle and upper Ordovician, established by Rousseau Flower in 1945. Diagnosis Valcouroceratids are characterized by exogastric cyrtocones and brevicones that change during the life span from compressed to depressed or subtriangular in cross section, and which have ventral siphuncles that are cyrtochoanitic and which contain lamellar actinosiphonate fillings. The actinosiphonate fillings, commonly referred to as deposits, are radially inward projections of the connecting rings that extend longitudinally along the inner wall of the siphuncle and project forward as blades into the siphuncle interior from the septal foramina.(Sweet 1964, Flower 1950) Distribution Most valcouroceratids come from North America but Valcouroceras has been found in northern Europe (Norway) as well. (Sweet 1964) Genera The Valcouroceratidae includes 8 genera: *'' Valcouroceras'' *'' Actinomorpha'' *'' Augustoceras'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prehistoric Nautiloid Families
Prehistory, also known as pre-literary history, is the period of human history between the use of the first stone tools by hominins 3.3 million years ago and the beginning of recorded history with the invention of writing systems. The use of symbols, marks, and images appears very early among humans, but the earliest known writing systems appeared 5000 years ago. It took thousands of years for writing systems to be widely adopted, with writing spreading to almost all cultures by the 19th century. The end of prehistory therefore came at very different times in different places, and the term is less often used in discussing societies where prehistory ended relatively recently. In the early Bronze Age, Sumer in Mesopotamia, the Indus Valley Civilisation, and ancient Egypt were the first civilizations to develop their own scripts and to keep historical records, with their neighbors following. Most other civilizations reached the end of prehistory during the following Iron Age. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
