Pseudohaploceras Temporal range: Early Cretaceous ~ | |
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Genus: | Pseudohaploceras Hyatt, 1900 |
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Pseudohaploceras is a genus of desmosceratid ammonites from the Early Cretaceous; Valanginian to Albian epochs. [1]
The genus is distinguished by its moderately involute, slightly to moderately compressed shell with convex sides and regular straight or sinuous constrictions between which are fairly fine, distinct, sharp or rounded branching ribs extending from the umbilical edge and crossing the venter, the outer rim.
Pseudohaploceras is considered[ who? ] an offshoot of early Valdedorsella , which differ in having a more broadly rounded whorl section and generally straight radial constrictions. It is included in the subfamily Pizosiinae.
Fossils of Pseudohaploceras have been found in Austria, Bulgaria, China, Colombia (Tibasosa Formation, Santa Rosa de Viterbo and Yuruma and Apón Formations, La Guajira), Egypt, Italy, Japan, Mexico, Serbia and Montenegro, Spain, Tanzania, and the former USSR. [2]
Abrytasites (Abrytusites) is an extinct genus of cephalopods belonging to the Ammonoidea subclass.
Acrioceras is an extinct genus of cephalopods belonging to the ammonite subclass.
Anagaudryceras is an extinct genus of ammonite from the later Cretaceous belonging to the Ammonoidea family Gaudryceratidae. Anagaudryceras has a moderately involute shell with a deep umbilicus and strongly ribbed outer whorl. Ribs are thick and rounded and cross over the venter uninterrupted.
Anahamulina is an extinct ammonoid cephalopod genus from the Lower Cretaceous. Named by Hyatt, 1900.
Anapachydiscus is an extinct cephalopod genus from the Upper Cretaceous, Santonian - Maastrichtian of Europe, Africa, Madagascar, S.India, N Z, Calif. Mexico, Argentina, and the Antarctic belonging to the ammonoid family Pachydiscidae.
Astieridiscus is an extinct lower Cretaceous ammonite. Its shell evolute, covered by dense, simple or branching, slightly flexuous ribs. The sides are slightly flattened, the venter rounded. No umbilical or other tubercles except on innermost whorl. Superficially resembles Olcostephanus.
Barremites is an ammonoid cephalopod genus belonging to the family Desmoceratidae, that lived during the Hauterivian and Barremian stages of the Early Cretaceous.
Heteroceras is a genus of Lower Cretaceous heteromorph ammonites belonging to the ancyloceratoidean family, Heteroceratidae.
Neoptychites is an extinct ammonoid cephalopod genus from the Turonian stage of the Upper Cretaceous, with a worldwide distribution.
Desmoceratoidea, formerly Desmocerataceae, is a superfamily of Cretaceous ammonites, generally with round or oval-whorled shells that are mostly smooth or weakly ribbed and rarely tuberculate, but commonly with constrictions. Regarded as monophyletic, the Desmocerataceae are derived from the Phylloceratidae, splitting off in the Early Cretaceous (Valanginian) and persisting to the end of the Maastrichtian.
Lytoceras is an ammonite genus that was extant during most of the Jurassic and Cretaceous periods, and is the type genus for the family Lytoceratidae. These cephalopods were fast-moving nektonic carnivores.
Neocomites is a genus of ammonite from the Lower Cretaceous, Berriasian to Hauterivian, and type genus for the Neocomitidae.
Melchiorites is a desmoceratid ammonite genus included in the subfamily Puzosiinae. Member species are characterized by an essentially evolute shell in which the early whorls are smooth, with sinuous radial or oblique constrictions but in which later whorls have feeble intermediate ribs on the outer part of the sides and venter.
Spitidiscus is a genus of ammonites placed in the family Holcodiscidae.
Hamulina is an extinct ammonoid cephalopod genus belonging to the family Hamulinidae. These cephalopod were fast-moving nektonic carnivores. They lived during the Cretaceous period, Barremian age. The type species is Hamulina astieriana.
Hemihoplites is an extinct genus of ammonoid cephalopods belonging to the family Hemihoplitidae. These fast-moving nektonic carnivores lived in the Cretaceous period, from Hauterivian age to Barremian age.
Holcodiscidae is an ammonite family placed in the superfamily Desmoceratoidea.
Holcodiscus is an extinct ammonite genus placed in the family Holcodiscidae. Species in this genus were fast-moving nektonic carnivores. The type species of the genus is Ammonites caillaudianus.
Olcostephanus is an extinct ammonoid cephalopod genus belonging to the family Olcostephanidae. These fast-moving nektonic carnivores lived during the Cretaceous, from the upper Valanginian to the lower Hauterivian age.
Euomphaloceras is an early Upper Cretaceous ammonite genus,, included in the Acanthoceratinae until established as the type genus for the Euomphaloceratinae by Cooper, 1978.