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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] |
Harpoceratinae
Harpoceratinae is an extinct subfamily of cephalopods belonging to the family Hildoceratidae. Ammonites of this subfamily had involute and compressed shells with strong keels. Keel might be rarely missing, but this is considered to be an abnormality. This has been observed both in '' Cleviceras'' and ''Harpoceras'' and called as genus '' Monestieria'', which is now known to be invalid (into this invalid genus were added also abnormal unkeeled specimens of genus '' Protogrammoceras''). Another example is '' Pseudolioceras'', whose unkeeled specimen was used as type for description of invalid genus '' Praehaploceras''. Oxyconic forms of this subfamily ('' Polyplectus'' and '' Sphenarpites'') does not have any keel. Ribs were single, but in some genera also bifurcating with shapes from sigmoidal to falcate. Sometimes, shell can have only striate ribs or is smooth (''Sphenarpites'' and older specimens of '' Eleganticeras'' and '' Ovaticeras''). Tubercules are rare. Dimorphism is known ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hildoceratinae
Hildoceratinae is an extinct subfamily of cephalopods belonging to the family Hildoceratidae. Ammonites of this subfamily had shells with elliptical or quadrate whorl section with keel or tricarinate, bisulcate venter. Ribs were variable, from falcate to strongly angled and from fine to strong. They can be interrupted by spiral groove in midlateral part of the shell. While some species can be smooth, strongly ribbed ones can have tubercules. Microconchs have short lappets that is in its shape similar to the shape of growth lines in spiral midlateral groove. Genera Bardin, J., Rouget, I., & Cecca, F. (2016). The phylogeny of Hildoceratidae (Cephalopoda, Ammonitida) resolved by an integrated coding scheme of the conch. Cladistics. * '' Hildaites'' Buckman, 1921 * '' Orthildaites'' Buckman, 1923 * '' Cingolites'' Sassaroli et Venturi, 2010 * ''Hildoceras ''Hildoceras'' is a genus of ammonite from the Jurassic period in the family Hildoceratidae. The shells are characterized by ... [...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 Ammonoidea, ammonoid cephalopods belonging to the Ammonitida that unites three families, Strigoceratidae, Oppeliidae, and Haplocer ... [...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] |
Pliensbachian
The Pliensbachian is an age of the geologic timescale and stage in the stratigraphic column. It is part of the Early or Lower Jurassic Epoch or Series and spans the time between 192.9 ±0.3 Ma and 184.2 ±0.3 Ma (million years ago). The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian. The Pliensbachian ended with the extinction event called the Toarcian turnover. During the Pliensbachian, the middle part of the Lias was deposited in Europe. The Pliensbachian is roughly coeval with the Charmouthian regional stage of North America. Stratigraphic definitions The Pliensbachian takes its name from the hamlet of Pliensbach in the community of Zell unter Aichelberg in the Swabian Alb, some 30 km east of Stuttgart in Germany. The name was introduced into scientific literature by German palaeontologist Albert Oppel in 1858. The base of the Pliensbachian is at the first appearances of the ammonite species '' Bifericeras donovani'' and genera '' Apo ... [...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] |
Pliensbachian First Appearances
The Pliensbachian is an age (geology), age of the geologic timescale and stage (stratigraphy), stage in the stratigraphic column. It is part of the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series and spans the time between 192.9 ±0.3 annum, Ma and 184.2 ±0.3 Ma (million years ago). The Pliensbachian is preceded by the Sinemurian and followed by the Toarcian. The Pliensbachian ended with the extinction event called the Toarcian turnover. During the Pliensbachian, the middle part of the Lias Group, Lias was deposited in Europe. The Pliensbachian is roughly coeval with the Charmouthian regional stage of North America. Stratigraphic definitions The Pliensbachian takes its name from the hamlet of Pliensbach in the community of Zell unter Aichelberg in the Swabian Alb, some 30 km east of Stuttgart in Germany. The name was introduced into scientific literature by German palaeontologist Albert Oppel in 1858. The base of the Pliensba ... [...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] |
Ammonitida Families
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] |
Polymorphitidae
Polymorphitidae is a family of Early Jurassic ammonoid cephalopods that contribute to the Eoderoceratoidea. Two subfamilies, the Polymorphtinae and Tropidoceratinae, are included. Polymorphitid ammonites produced typically evolute shells, which are more compressed than in most members of the superfamily. Many possess ventral chevrons and/or a fastigate venter resembling a gable roof, which in some develops into a true keel on the outer whorls. The Polymorphtinae is the larger and more diverse subfamily of the two. their shells have venters (outer rims) that may be smooth or ribbed, or have a median row of beading or serrations. The Tropidoceratinae, referred to as the Acanthopleuroceratinae in the Treatise A treatise is a Formality, formal and systematic written discourse on some subject concerned with investigating or exposing the main principles of the subject and its conclusions."mwod:treatise, Treatise." Merriam-Webster Online Dictionary. Acc ... L 1957, instead ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
