| Spitidiscus | |
|---|---|
 | |
| Fossil shell of Spitidiscus species from Alpes-de-Haute-Provence, on display at Galerie de paléontologie et d'anatomie comparée in Paris | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | † Ammonoidea |
| Order: | † Ammonitida |
| Family: | † Holcodiscidae |
| Genus: | † Spitidiscus Kilian, 1910 |
Spitidiscus is a genus of ammonites placed in the family Holcodiscidae. [1] [2]
List of species within Spitidiscus: [3]
Member species have a rather evolute shell in which the whorl section is more or less circular, venter broadly rounded and dorsum fairly deeply impressed. Close, fine low, single or rarely branching ribs are interspersed by frequent straight or slightly sinuous, moderately deep but wide constrictions. The type species S. rotulia is from the Hauterivian of England.[ citation needed ]
The first appearance of the species Spitidiscus hugii or Spitidiscus vandeckii are proposed to be the marker for the beginning of the Barremian. [4]
Spitidiscus has been found in: [3]
Acanthohoplites is an extinct genus of ammonites in the family Parahoplitidae that lived in the Aptian and Early Albian stages of the Early Cretaceous.
Anahamulina is an extinct ammonoid cephalopod genus from the Lower Cretaceous. Named by Hyatt, 1900.
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.
Berriasella is a discoidal evolute perisphinctacean ammonite, and type genus for the neocomitid subfamily Berriasellinae. Its ribbing is distinct, consisting of both simple and bifurcated ribs that extend from the umbilical seam across the venter; its whorl section generally compressed, the venter more or less narrowly rounded. The species Berriasella jacobi traditionally has been regarded an index fossil defining the base of the Cretaceous, however since 2016 this had been replaced by the first occurrence of Calpionella alpina. Some authors regard B. jacobi as instead belonging to the genus Strambergella.
Nipponites is an extinct genus of heteromorph ammonites. The shells of Nipponites form "ox-bow" bends, resulting in some of the most bizarre shapes seen among ammonites.
Oecoptychius is an extinct genus of fossil ammonite cephalopods. The species lived during the Middle Jurassic.
Heteroceras is a Lower Cretaceous heteromorph ammonite belonging to the ancyloceratoidean family, Heteroceratidae.
Zetoceras is an extinct ammonoid cephalopod genus from the suborder Phylloceratina that lived during the Early and Middle Jurassic in what is now Europe, and is included in the (family) Phylloceratidae.
Polonoceras is a genus included in the goniatitid subfamily Aulatornoceratinae named by Dybczynski, 1913. The type species is Polonoceras planum Dybczynski. According to Miller, et al. in the American Treatise on Invertebrate Paleontology, 1957, Polonoceras is a subgenus of Tornoceras.
Neocomites is a genus of ammonite from the Lower Cretaceous, Berriasian to Hauterivian, and type genus for the Neocomitidae.
Schlotheimia is a genus of extinct cephalopods belonging to the subclass Ammonoidea that lived during the Hettangian stage at the beginning of the Early Jurassic.
Pseudohaploceras is a genus of desmosceratid ammonites from the Early Cretaceous; Valanginian to Albian epochs.
Puzosia is a genus of desmoceratid ammonites, and the type genus for the Puzosiinae, which lived during the middle part of the Cretaceous, from early Aptian to Maastrichtian. Sepkoski defines the range from Albian to Santonian. The generic name comes from the Serbian words "Puž" (snail) and "oce/ose" (axis), gaining its name from the shell's snail-like appearance.
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.
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.
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.
The Acanthoceratinae comprise a subfamily of ammonoid cephalopods that lived during the Late Cretaceous from the latter early Cenomanian to the late Turonian
Watinoceras is a genus of acanthoceratid ammonite that lived during the early Turonian stage of the Late Cretaceous.
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