''Arkanites'' is a
goniatitid ammonite
Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...
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
''Quinnites'' is a genus of goniatitid ammonites included in the gastrioceratoidean family Reticuloceratidae known from the Carboniferous
The Carboniferous ( ) is a Geologic time scale, geologic period and System (stratigraphy), system of the ...
'', 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'' i
GONIAT Online6/6/12
''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
Pennsylvanian ammonites
Goniatitida genera
Reticuloceratidae
Carboniferous ammonites of North America
{{Goniatitida-stub