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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 Ammonoidea, ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haplocer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erycitidae
Erycitidae is a family of Lower and Middle Jurassic ammonites included in the Hildoceratoidea. The hammatoceratid subfamily Erycitinae is equivalent. Genera include '' Erycites'' (type) and '' Abbasites''. Description Erycitids are generally evolute with all whorls showing and are strongly ribbed with ribs branching on the outer part of the flanks and crossing over the outer rim, or venter. Classification In older taxonomies, e.g. W.J. Arkell ''et al.'', 1964 and D.T. Donovan ''et al.'', 1981, the Hammatoceratidae, which then included erycitid genera, was part of the Hammatoceratoidea. More recently the Erycitidae was reassigned to the Hammatoceratoidea which also includes the Hammatoceratidae, Graphoceratidae and Sonniniidae removed from the Hildoceratoidea, left with only the Hildoceratidae and its included subfamilies. References * W.J. Arkell ''et al.'', 1957. Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology,'' published from 1953� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hildoceratidae
Hildoceratidae is a family of Ammonoidea, ammonoid cephalopods from the Lower Jurassic, lower Pliensbachian (''Jamesoni'' zone) to lower Bajocian (maybe even upper Bajocian) substages, generally with strongly ribbed, involute shells. They are combined with the Hammatoceratidae (= Phymatoceratidae), Graphoceratidae, and Sonniniidae to make up the Hildoceratoidea. As many as seven subfamilies have been included in late 20th century, principle being the Arieticeratinae, Harpocertinae, Hildoceratinae, to which the Treatise, Part L, adds the Bouleiceratinae, Grammoceratinae, and Tmetoceratinae. Donovan et al. (1981) includes the same and adds the Leioceratinae which the older Treatise includes in the Graphoceratidae. Currently Leioceratinae are again members of Graphoceratidae and into Hildoceratidae are added newly established subfamily Leukadiellinae and Protogrammoceratinae, which has been by Donovan et al. (1981) considered as part of Harpoceratinae.M. K. Howarth 2013. Treatise on ... [...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 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.' ... and divided into two subfamilies, the earlier Phymatoceratinae, and later Hammatoceratinae.W.J.Arkell ''et al.'', 1957. Meso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephanoceratoidea
Stephanoceratoidea, formerly Stephanocerataceae, is a superfamily of middle- upper Jurassic ammonoid cephalopods within the order Ammonitida containing diverse forms, generally with sharp ribbing and complex suture lines. Aptychi are believed to be mostly granular (Granulaptycus) or concentrically ribbed on the surface (Praestriaptychus) (Arkell ''et al.'' 1957) Morphologic variation The shells of the Stephanoceratoidea, which determine the different included families, are highly variable in form. They are discoidal and evolute with all whorls exposed, spheroidal and involute with only the outer whorl showing, cadiconic with a deep umbilicus and broad ventral margin, and oxiconic with the ventral margin sharp. They are united by being generally sharply ribbed and by their complex suture lines with a dominant 1st lateral lobe and a well-developed umbilical lobe. (Arkell ''et al.'' 1957) Taxonomy Stephanoceratoidea contains five families according to Donovan ''et al.'' (1981), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonitina
Ammonitina comprises a diverse suborder of Ammonoidea, ammonite cephalopods that lived during the Jurassic and Cretaceous periods of the Mesozoic Era. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific Geologic time scale, geological time periods. The shells of Ammonitina are typically planospiral, coiled in a single plane and symmetrical from side to side. They come in various forms, including evolute shells where all whorls are exposed, and strongly involute shells with only the outer whorl visible. Shells may be heavily ribbed, with some featuring nodes and spines, while others are completely smooth. Some shells have broad, rounded venters (the outer rim), while others have a sharp, keel-like venter. Sutures are generally ammonitic, characterized by complex saddle and lobe patterns. However, in some derived forms, the suture pattern becomes simplified, appearing ceratitic or even goniatitic. The Ammonitina are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonniniidae
Sonniniidae is a diverse family of Middle Jurassic ammonites ranging from those with stout evolute shells to those whose shells are sharply rimmed, oxyconic. The keel, which runs along the middle of the venter, is typically hollow. Sutures vary from simple to complex. The aptychus is shiny with coarse folds (Cornaptychus). Sonniniidae are included in the superfamily Hildoceratoidea. Most lived during the middle Bajocian stage. Distribution is worldwide except for boreal. Taxonomy Sonniniidae is divided into subfamilies with 10 genera. *Sonniniidae Buckman, 1892 ** Sonniniinae Buckman, 1892 ***'' Dorsetensia'' ***'' Pseudoshirbuirnia'' Dietz, 2005 ***'' Shirbuirnia'' ***'' Sonninia'' ***'' Sonninites'' Buckman, 1923 ** Witchelliinae Callomon and Chandler, 2006 ***'' Asthenoceras'' ***'' Fontannesia'' ***'' Guhsania'' ***'' Newmarracarroceras'' Hall, 1989 ***'' Witchellia'' Distribution Argentina, Canada, China, Germany, Hungary, Morocco, Saudi Arabia, Spain, the United Kingdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphoceratidae
Graphoceratidae is an extinct family of ammonites in the order Ammonitida, which lived during the Jurassic. Distribution Fossils are found in the Jurassic marine strata of Canada, France, Germany, Hungary, Italy, Morocco, Saudi Arabia, Spain and the United Kingdom. Genera Subfamily Graphoceratinae Buckman, 1905 * '' Brasilia'' * '' Graphoceras'' * ''Hyperlioceras ''Hyperlioceras'' is an extinct genus of cephalopod included in the ammonitid family Graphoceratidae that lived during the Bajocian stage of the Middle Jurassic. The type species is ''Hyperlioceras discites'' (Waagen, 18567) Morphology The sh ...'' * '' Ludwigia'' Subfamily Leioceratinae Spath, 1936 * '' Canavarella'' * '' Costileioceras'' * '' Vaceckia'' * '' Leioceras'' * '' Staufenia'' * '' Ancolioceras'' Subfamily Dumortieriinae Haug, 1885 * '' Dumortieria'' * '' Pleydellia'' * '' Catulloceras'' * '' Cotteswoldia'' * '' Walkericeras'' * '' Canavarina'' * '' Paradumortieria'' Subfamily Tmetocerat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonitida Superfamilies
Ammonitida, or true ammonites, are an order of ammonoid cephalopods that lived from the Jurassic through Paleocene time periods, commonly with intricate ammonitic sutures. Ammonitida is divided into four suborders, the Phylloceratina, Lytoceratina, Ancyloceratina, and Ammonitina. The Phylloceratina is the ancestral stock, derived from the Ceratitida near the end of the Triassic. The Phylloceratina gave rise to the Lytoceratina near the beginning of the Jurassic which in turn gave rise to the highly specialized Ancyloceratina near the end of the Jurassic. Both the Phylloceratina and Lytoceratina gave rise to various stocks combined in the Ammonitina. These four suborders are further divided into different stocks, comprising various families combined into superfamilies. Some like the Hildoceratoidea and Stephanoceratoidea are restricted to the Jurassic. Others like the Hoplitoidea and Acanthoceratoidea are known only from the Cretaceous. Still others like the Perisphincto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic–Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.7 ±0.8 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias and Carbonif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jurassic Ammonites
The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately 143.1 Mya. The Jurassic constitutes the second and middle period of the Mesozoic, Mesozoic Era as well as the eighth period of the Phanerozoic, Phanerozoic Eon and is named after the Jura Mountains, where limestone strata from the period were first identified. The start of the Jurassic was marked by the major Triassic–Jurassic extinction event, associated with the eruption of the Central Atlantic magmatic province, Central Atlantic Magmatic Province (CAMP). The beginning of the Toarcian Age started around 183 million years ago and is marked by the Toarcian Oceanic Anoxic Event, a global episode of Anoxic event, oceanic anoxia, ocean acidification, and elevated global temperatures associated with extinctions, likely caused by the eruption of the Kar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eoderoceratoidea
Eoderoceratoidea is a superfamily of true ammonites (suborder Ammonitina) from the Lower Jurassic, comprising seven phylogenetically related families, characterized in general by having ribbed evolute shells that commonly bear spines or tubercles. Adult shell size ranges from 2 or 3 cm to giants reaching 50 cm in such genera as ''Apoderoceras'', ''Epideroceras'', and ''Liparoceras''.Donovan,D.T., Callomon and Howarth 1981. Classification of the Jurassic Ammonitina; Systematics Association. Arkell ''et al.'', 1957. Mesozoic Ammonoidea, in Treatise on Invertebrate Paleontology, (Part L); Geological Soc. of America and University of Kansas press The earliest known eodoceroceratoidean is the eoderoceratid genus ''Microderoceras''. Although its origin is uncertain, it is likely that it is derived from the Psiloceratoidea. It has also been proposed, with some imagination, that ''Microderoceas'' has its origin some earlier Jurassic Lytoceratina, lytoceratid such as ''Analy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
