Euhoplites

Euhoplites is an extinct ammonoid cephalopod from the Lower Cretaceous, characterized by strongly ribbed, more or less evolute, compressed to inflated shells with flat or concave rims, typically with a deep narrow groove running down the middle. In some, ribs seem to zigzag between umbilical tubercles and parallel ventrolateral clavi. In others the ribs are flexious and curve forward from the umbilical shoulder and lap onto either side of the venter.

Fossils of this animal are commonly found in Lower Cretaceous, Albian age strata with some coming from the Upper Cretaceous Cenomanian.

Its shell was covered with lumps and bumps. The function of these adornments are unknown, although they may have been a source of hydrodynamic drag, preventing Euhoplites from swimming at high speeds. Studying them, therefore, may give some insight into the lifestyle of this ancient marine predator. Euhoplites was a small Ammonite with shells of diameters of at most a few inches in diameter, depending on the age, species and possibly gender of the individual.

Distribution

Euhoplites has been found in Middle and Upper Albian beds in France where it is associated respectively with Hoplites and Anahoplites, and with Pleurohoplites, Puzosia, and Desmoceras; in the Middle Albian of Brazil with Anahoplites and Turrilites; and in the Cenomanian of Texas. It is the most common ammonite fossil of the Folkstone (sometimes spelt "Folkestone") fossil beds in southeastern England where a variety of species are found.

Classification

Taxonomic relations

Euhoplites is closely related to Hoplites and to other hoplitid genera such as Epihopites and Protohoplites included in the subfamily, Hopliitinae. Other subfamilies in the Hoplitidae, with more distantly related genera are the Cleoniceratinae and Gastrohoplitinae.

Species

Euhoplites includes a number of species such as E. bucklandi, which may have given rise to E. proboscideus, E. lautus, E. nitidus, E. ochetonotus, E. opalinus, and E. reesidei; some of which may be synonyms and therefor invalid, or belong to other genera, and subject to paleontological revision.

References

• Treatise on Invertebrate Paleontology, Part L, Mollusca 4, 1957. Geological Soc. of America and Univ. Kansas Press.

External links

for pictures of Euhoplites:

• Gault ammonites
• Les Euhoplites