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Hammatoceratidae
Hammatoceratidae is a family of lower and middle Jurassic ammonites included in the superfamily Hildoceratoidea. Diagnosis Hammatoceratidae comprises genera which are characterized by ribbed evolute shells (all whorls visible), some bearing keels along the venter. Those in the Phymatoceratinae have more simple ribbing while those in the Hammatoceratinae have ribbing that branch higher up on the whorl sides, divided into primaries and secondaries. Taxonomy In the outdated classification of the 1957 American Treatise on Invertebrate Paleontology, Hammatoceratidae was included in the superfamily Hildoceratoidea and divided into two subfamilies, the earlier Phymatoceratinae, and later Hammatoceratinae.W.J.Arkell ''et al.'', 1957. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology Part L Hammatoceratidae is now divided into four subfamilies, the Hammatoceratinae, Erycitinae, Podagrosiceratinae, and Zurcheriinae. Hammatoceratinae includes ''Rarenodia'', ''Geczyceras'', '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammatoceratidae
Hammatoceratidae is a family of lower and middle Jurassic ammonites included in the superfamily Hildoceratoidea. Diagnosis Hammatoceratidae comprises genera which are characterized by ribbed evolute shells (all whorls visible), some bearing keels along the venter. Those in the Phymatoceratinae have more simple ribbing while those in the Hammatoceratinae have ribbing that branch higher up on the whorl sides, divided into primaries and secondaries. Taxonomy In the outdated classification of the 1957 American Treatise on Invertebrate Paleontology, Hammatoceratidae was included in the superfamily Hildoceratoidea and divided into two subfamilies, the earlier Phymatoceratinae, and later Hammatoceratinae.W.J.Arkell ''et al.'', 1957. Mesozoic Ammonoidea. Treatise on Invertebrate Paleontology Part L Hammatoceratidae is now divided into four subfamilies, the Hammatoceratinae, Erycitinae, Podagrosiceratinae, and Zurcheriinae. Hammatoceratinae includes ''Rarenodia'', ''Geczyceras'', '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bredyia
''Bredyia'' is a genus of ammonites from the lower part of the Middle Jurassic, found in Europe and North America. ''Bredyia'' is a member of the Hammatoceratidae, a family which comprises part of the Hildoceratoidea Hildoceratoidea, formerly Hildoceratacaea, is a superfamily of compressed or planulate ammonites, some tending to develop acute outer rims; generally with arcuate or sigmoidal ribs. Aptichus were found in place are double-valved.Arkell ''et al.' .... Its shell is involute, strongly ribbed, with a small umbilicus. Whorls are strongly embracing; ribs thick, radially straight on the sides, curves forward on the venter but do not meet. The sides or flanks are outwardly bowed. The venter has a narrow keel and may be fastigate, like a gable roof. References * W.J. Arkell ''et al.'', 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L, Ammonoidea. Geological Society of America.Bredyiain Fossilworks Gatewayin Ammonites et Autres Spirales (Fr). * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hildoceratoidea
Hildoceratoidea, formerly Hildoceratacaea, is a superfamily of compressed or planulate ammonites, some tending to develop acute outer rims; generally with arcuate or sigmoidal ribs. Aptichus were found in place are double-valved.Arkell ''et al.'', Treatise on Invertebrate Paleontology, Part L Ammonoidea, (1956) Hildoceratoidea is an upper Lower to lower Middle Jurassic group belonging to the Ammonitina that unites the Hildoceratidae, Hammatoceratidae, Graphoceratidae, and Sonniniidae. In some taxonomies the name Phymatoceratidae is substituted for the Hammatoceratidae Hildoceratidae, which is the ancestral family, is derived from the Acanthopleuroceratinae, a subfamily in the Eoderoceratoidean family, Polyorphitidae. The Stephanoceratoidea, Perisphinctoidea, and Haploceratoidea Haploceratoidea, formerly Haplocerataceae, is an extinct superfamily of ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haploceratidae, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haplopleuroceras
''Haplopleuroceras'' is a Middle Jurassic ammonite and likely member of the Hildoceratacean family Sonniniidae with which it shares the same sort of ribbing. Description ''Haplopleuoceras'' has a small, strongly ribbed, evolute shell of about 2 volutions. Whorl section is subquadrate, slightly compressed, flanks slightly convex, venter rounded. Ribs are undivided, smooth, moderately concave, and slope forward on the ventro-lateral region to form chevrons pointing toward the aperture. The venter on the outer rim is bisected by a rounded keel bordered by distinct but shallow grooves, interrupting the ribbing in the middle of the chevrons. ''Haplopleuroceras'' shares its simple undivided ribbing with the contemporary Sonniniidae in which it probably belongs (e.g. ''Treatise'' L, 1957) although others since then (e.g. Donovan et al. 1981) have removed it to the Hammatoceratidae Hammatoceratidae is a family of lower and middle Jurassic ammonites included in the superfamily Hild ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hammatoceras
''Hammatoceras'' is a genus of ammonites belonging to the family Hammatoceratidae which lived during the Toarcian stage of the Early/Lower Jurassic between about 184 and 175 million year ago. Taxonomy ''Hammatoceras'' is included in the subfamily Hammatoceratinae, which in the outdated 1957 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 co ... was part of the Hammatoceratidae, but of the Phymatoceratidae in D.T. Donovan ''et al.'', 1981, a case of what to base the family name on. Both accordingly contain the earlier Phytmatoceratinae and derived Hammatoceratinae. The superfamily Hammatoceratoidea in which the Hammatocaratidae and related families are currently placed is abandoned in favor of the older, equivalent, Hildoceratoidea. (M. K. Howarth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zurcheria
''Zurcheria'' is a genus of dwarf ammonites from the Middle Jurassic included in the Hammatoceratidae Hammatoceratidae is a family of lower and middle Jurassic ammonites included in the superfamily Hildoceratoidea. Diagnosis Hammatoceratidae comprises genera which are characterized by ribbed evolute shells (all whorls visible), some bearing keel ... and lacking a keel. The shell is evolute, inner whorls exposed; whorls compressed and slightly overlapping. Bears ribs, which are sinuous folds that project strongly onto the arched venter. References ;Notes ;Bibliography * W.J. Arkell, ''et al.'', 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Geological Society of America and University of Kansas Press. Hammatoceratidae Ammonitida genera Middle Jurassic ammonites {{Ammonitina-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fissilobiceras
''Fissilobiceras'' ist ein glatter, komprimierter, involuter Ammonit aus dem unteren mittleren Jura (Aalenium/Bajocium) Europas, der 1919 von Buckman benannt wurde. ''Fissilobiceras'' gehört zur Familie der Hildoceratoiden (Hammatoceratidae Hammatoceratidae is a family of lower and middle Jurassic ammonites included in the superfamily Hildoceratoidea. Diagnosis Hammatoceratidae comprises genera which are characterized by ribbed evolute shells (all whorls visible), some bearing keel ...). ''Fissilobiceras'' is similar to '' Shirbuirnia'', except primarily for being more involute and having complex sutures. More of the inner whorls show in ''Shirbuirnia'' and its sutures are simple. ''Fissilobiceras'' also has a low keel running along the venter and only a small part of the inner whorls are exposed in the small umbilicus. References *Arkell ''et al.'', 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L, Ammonoiea. Geological Society of America an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euaptetoceras
''Euaptetoceras'' is an evolute hildoceratoid ammonite from the lower Middle Jurassic, included in the family Hammatoceratidae and the subfamility Hammatoceratinae. The genus may be a junior synonym for '' Eudmetoceras'' of Buckman, 1920. The shell of ''Euaptetoceras'' has an evolute, compressed, discoidal shape with a whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral ... section higher than wide. The inner whorls have long primary ribs while the outer whorls become smooth. The venter, which is the outer rim, is narrowly to sharply rounded and its suture is rather complex. ''Euaptetoceras'' is found in strata of Europe, Iran, and Argentina. References * Arkell ''et al.'', 1957. Mesozoic Ammonoidea; Treatise on Invertebrate Paleontology, Part L (Mollusca 4, Ammonoidea). Geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eudmetoceras
''Eudmetoceras'' is an extinct genus from a well-known class of fossil cephalopods, the 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) ...s. It lived during the Jurassic Period, which lasted from 171.6 to 168.4 million years ago. References Hammatoceratidae Ammonitida genera Jurassic ammonites Fossils of British Columbia Fossils of Spain {{ammonitina-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
