Saxoceras Temporal range: | |
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Scientific classification ![]() | |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Cephalopoda |
Subclass: | † Ammonoidea |
Order: | † Ammonitida |
Family: | † Schlotheimiidae |
Genus: | † Saxoceras Lang, 1924 |
Species [2] | |
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Saxoceras is a genus of very evolute schlotheimiid ammonoids from the Lower Jurassic.
The shell of Saxoceras is discoidal, bearing strong, generally straight ribs that arise on the umbilical shoulder and thicken in the middle of the venter. Similar Waehneroceras has ribs that curve forward as they approach the venter, and Kammerkarites has finer ribs with secondaries. Both are also evolute schlotheimiids with all whorls exposed. Epamminites of the Arietitidae is similar from the side but has a smooth band running along the venter with a median keel.
British Columbia, France and Alaska [2]
Karapadites is an extinct ammonoid genus belonging to the desmoceratacean family Kossmaticeratidae and considered by some to be a subgenus of Kossmaticeras.
Aulacostephanus is an extinct ammonoid cephalopod genus from the Upper Jurassic Tithonian belonging to the perisphinctoidean family Aulacostephanidae.
Astiericeras is an ammonite from the Lower Cretaceous, the shell of which is evolute, stout; outer whorl with strong, well spaced, transverse ribs that cross smoothly over the broad venter; early whorls with lateral tubercles. The outer, mature whorl separates from the coil but hooks back quickly, referred to as a heteromorph.
Arnioceras is an extinct genus of large, evolute, discoidal ammonite from the Lower Jurassic. The shell is normally coiled so that all whorls are exposed. Sides bear strong sharp ribs that are straight until reaching the ventrolateral edge where they swing forward and fade. The rim (venter) is keeled and free of grooves.
Argonauticeras is an extinct ammonoid cephalopod genus that lived during the latter part of the Early Cretaceous, included in the Lytoceratida and found in lower and possibly middle Aptian marine sediments. It has been thought of as a subgenus of Ammonoceratites.
Docidoceras is an extinct ammonite genus from the order Ammonitida that lived during the Middle Jurassic. Docidoceras is included in the family Otoitidae which makes up part of the ammonite superfamily Stephanoceratoidea.
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.
Zurcheria is a genus of dwarf ammonites from the Middle Jurassic included in the Hammatoceratidae 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.
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.
Oecotraustes is an extinct cephalopod genus included in the ammonid family Oppeliidae and named by Waagen in 1869. The genus lived during the Middle Jurassic.
Normannites is a strongly ribbed evolute Middle Jurassic genus of ammonite included in the stephanoceratoid family Stephanoceratidae.
Hildoceras is a genus of ammonite from the Jurassic period in the family Hildoceratidae. The shells are characterized by a narrow discoidal evolute shape, keeled venter, concave ribs along the outer flanks, and a shallow spiral groove running along smooth inner flanks. Whorls slightly overlap, cross sections are compressed. The ventral keel is bordered on either side by a shallow groove. The genus was named by Alpheus Hyatt after Saint Hilda in 1876.
Promicroceras is an extinct ammonite genus from the upper Sinemurian of Europe, named by Leonard Spath in 1925. Promicroceras is included in the family Eoderoceratidae, which is part of the ammonitid superfamily Eoderoceratoidea.
Peltoceras is an extinct ammonite genus from the aspidoceratid subfamily Peltoceratinae that lived during the later part of the Middle Jurassic.
Kepplerites is a moderately evolute ammonite from the lower Callovian included in the Stephanoceratoidea.
Distichoceras is a member of the Haploceratacean family, Oppeliidae, and type genus for the subfamily Distichoceratinae, found in upper Middle and lower Upper Jurassic sediments in Europe, Algeria, India, and Madagascar. The shell is essentially evolute and compressed with the outer flanks converging on a narrow, keeled venter; inner flanks which may be feebly ribbed, are separated from outer by a shallow spiral groove or band. Ribs on outer flanks end on or are looped to tall clavi that line the venter, standing above the keel.
Kilianella is a genus of the ammonite family Neocomitidae. The shell of Kilianella is evolute with a slightly grooved venter and covered by strong, gently flexious, single or bifurcating ribs.
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.
Dasyceras is an early phylloceratid from the Sinemurian stage of the lower Jurassic, found in Europe.
Reynesocoeloceras is genus of ammonite that lived during the lower Pliensbachian stage of early Jurassic, ammonite zones Ibex—Davoei.