| Schlotheimia | |
|---|---|
 | |
| Schlotheimia lymense | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Subclass: | † Ammonoidea |
| Order: | † Ammonitida |
| Family: | † Schlotheimiidae |
| Genus: | † Schlotheimia Bayle, 1878 |
| Synonyms | |
| |
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. [2]
The shell, or conch, of Schlotheimia rather evolute, coiled with all whorls exposed and only slightly embracing. The umbilicus is perforate as with more finely ribbed Angulaticeras . whorls are compressed, bearing ribs that cross the venter in chevrons, less developed in Sulciferites
Fossils of Schlotheimia species have been found in Lower Jurassic rocks of Argentina, Austria, Belgium, Canada, France, Germany, Indonesia, Italy, Luxembourg, Switzerland, United Kingdom, United States. [1]
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids than they are to shelled nautiloids such as the living Nautilus species. The earliest ammonites appeared during the Devonian, with the last species vanishing during or soon after the Cretaceous–Paleogene extinction event.
Xiphogymnites is an extinct ammonoid cephalopod genus from the Triassic included in the family Gymnitidae. It is known from the Balkans in eastern Europe.
Alsatites is an extinct genus of cephalopod belonging to the Ammonite subclass. They lived during the Early Jurassic, Hettangian till the Sinemurian and are generally extremely evolute, many whorled. Keel broad and blunt organisms, they also exhibit a primary ribbing which is close and persistent.
Aulacosphinctoides is an extinct ammonoid cephalopod that lived during the Late Jurassic, included in the ammonitid family Perisphinctidae.
Aspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae.
Ammonitina comprises a diverse suborder of 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 geological time periods.
Bradfordia is a moderately involute to involute genus included in the ammonoid cephalopod family Oppeliidae, coiled so that the outer whorl encloses most, or much, of the previous, but with a small umbilicus exposing inner whorls. The shell is compressed, whorl height much greater than width, extending well out from the contact with the adjacent inner whorl. Outer flanks are finely ribbed and the rounded venter is smooth.
Otoites is the type genus of the ammonite family Otoitidae that live during the Middle Jurassic.
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.
Oecoptychius is an extinct genus of fossil ammonite cephalopods. The species lived during the Middle Jurassic.
Eoderoceratidae is the ancestral and most primitive family of the Eoderoceratoidea; lower Jurassic ammonite cephalopods, characterized by evolute, commonly serpenticonic, shells that had long body chambers and would have had no stable floating position; and thus resemble contemporary Psiloceratoidea. Spines, or tubercles, are typically found in two rows on the inner and outer parts of the whorl sides, joined by radial ribs. These are often more developed on the inner and middle whorls, becoming less so or absent on the outer. Sutures are highly complex.
Eoderoceras is an evolute, round whorled ammonite from the Lower Jurassic with an outer row of distinct spines, and in some, an inner row of tubercles, on either side; ribs only on the inner whorls.
Microderoceras is a flat sided, evolute, radially ribbed Lower Jurassic ammonite belonging to the ammonitid family Eoderoceratidae and superfamily Eoderoceratoidea. Its whorls are subquadrangular in section; venter on the outer rim, rounded; sides with two rows if distinct spines, tubercles on internal molds, formed at either end of the ribs. The lateral surface of the ribcage is concave toward both sides, the lateral side of the dorsal and the lateral side of the ventral surface. The ribs are divided into six pairs (1-3) of the following types: 2-3 is the only type. In the first type, the ribs on the ventral face are fused to the ribs on the ventral sides; the ribs on the dorsal face are fused to the ribs on the dorsal sides. The second type represents the ribbed body, the ribs are in the same arrangement as in the first type and the rib cage does not fuse to the dorsal surface.
Crucilobiceras is an ammonoid cephalopod genus from the Lower Jurassic belonging to the eoderoceratoidean family Eoderoceratidae. Cruciliboceras has an evolute shell, such that all whorls are well exposed, with persistent radial ribbing and with spines or tubercles on the outer, ventral, rim, and in some, tubercles in the inner, umbilical, rim. The genus Crucilobiceras is commonly found along the Jurassic Coast of England.
Haploceras is a genus of late Upper Jurassic ammonoid cephalopods and the type for the Haploceratidae, similar to Lissoceras but with a broader whorl section and small blunt lappets and a blunt rostrum; some species with feeble ventral folds on body chamber.
Lytoceratidae is a taxonomic family of ammonoid cephalopods belonging to the suborder Lytoceratina, characterized by very evolute shells that generally enlarge rapidly, having whorls in contact but mostly overlapping very sightly, or not at all.
Lytoceratinae is a subfamily of ammonoid cephalopods that make up part of the family Lytoceratidae.
Dayiceras is a finely ribbed polymorphitid eoderoceratacean ammonoid cephalopod from the Jurassic, named by Spath in 1920. The shell is evolute, coiled such that all whorls are exposed. The whorl section is compressed such as to be higher than wide. A row of fine tubercles runs along the middle of the outer rim, the venter.
Schlotheimiidae is an extinct family of cephalopods belonging to the Ammonite subclass. These cephalopods existed in the Jurassic period.
Orthaspidoceras is an extinct ammonoid cephalopod genus belonging to the family Aspidoceratidae. These nektonic carnivores lived during the Jurassic period, Kimmeridgian age.
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