Hoplitidae

Hoplitidae
Temporal range: Aptian–Cenomanian
Fossil of Sonneratia dutempleana from France, on display at Galerie de paléontologie et d'anatomie comparée in Paris
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Subclass: Ammonoidea
Order: Ammonitida
Superfamily: Hoplitaceae
Family: Hoplitidae

The Hoplitidae is a family of Cretaceous ammonites that lived during the middle of the period from the late Aptian to the Cenomanian. They are part of the superfamily Hoplitaceae.

Members of the Hoplitidae are typically evolute, with inner whorls exposed, although some are more involute, and are commonly stout and strongly ribbed, with pronounced tubercles.

The Hoplitidae are thought to be derived from the U Aptian -M Albian Uligella of the Desmoceratidae, or some related form and have been divided into three subfamilies.

Subfamlies

Cleoniceratidae: high-whorled, compressed hoplitids with narrowly arched to acute venters and sigmoid to falcoid ribs at least on the inner whorls and in some cases strong umbilical tubercles. Genera include Aioloceras, Anadesmoceras, and Cleoniceras.

Hoplitinae: generally discoidal and strongly ribbed forms that make up most of the family. Ribs come off of umbilical tubercles and may be branched, looped, or zigzagged. Venters, the outer rims, may be rounded or flat and in some cases concave and may be a smooth band running along the middle. Includes genera such as Euhoplites, Hoplites, Pluerohoplites , and Sonneratia.

Gastrohoplitidae: mostly boreal hoplitids, similar in general appearance to the other two subfamilies, represented by Gastrohoplites

Phylogenetic relations

The Hoplitidae may have given rise to the Schloenbachiidae and seems to be in a different branch of the Hoplitaceae from earlier families included.

References

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