Arkanites

Arkanites Temporal range: Lower Pennsylvanian
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Ammonoidea
Order:	Goniatitida
Suborder:	Goniatitina
Superfamily:	Gastriocerataceae
Family:	Reticuloceratidae
Genus:	Arkanites McCaleb et al. 1964

Arkanites is a goniatitid ammonite that lived during the Early Pennsylvanian that has been found in Arkansas and Oklahoma in the U.S.

Morphology

The shell of Arkanites is subglobose, rather evolute, with a moderately wide umbilicus and a broadly rounded venter (or rim). Sculpture consists of well developed umbilical ribbing, sometimes with nodelike bases, and broad, deep, ventrolateral grooves. The ventral lobe of the suture, which sits on the outer rim, is large, with a median saddle that exceeds half its overall height. The first lateral saddle is broadly rounded, the adventitious lobe is large and pointed.

Taxonomy

Arkanites is possibly derived from Retites and closely related to Quinnites, all which come from the Lower Pennsylvanian (Morrowan). Retites and Quinnites are found together in Arkansas; Arkanites separately in Arkansas and Oklahoma. Retites has also been reported from the southern Urals of Russia and from Inner Mongolia, China.

References

• Arkanites in GONIAT Online 6/6/12
• Arkanites Paleodb 6/6/12.
• W. B. Saunders, D. M. Work, and S. V. Nikolaeva, 1999. Evolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Material. Science Magazine