ammonites
Gastrioceras smithwickense Plummer and Scott 1937 (ammonite)

Cephalopoda - Goniatitida - Gastrioceratidae

Full reference: F. B. Plummer and G. Scott. 1937. Upper Paleozoic ammonites in Texas. The University of Texas Bulletin 3701:1-516

Belongs to Gastrioceras according to F. B. Plummer and G. Scott 1937

Sister taxa: Gastrioceras listeri, Gastrioceras magoffinense, Gastrioceras montgomeryense, Gastrioceras noduliferum, Gastrioceras occidentale, Gastrioceras richthofeni, Gastrioceras williamsi

Type specimen: B.E.G. P-8163. Its type locality is B.E.G. 114-T-46, North of Marble Canyon, Hudspeth County, which is in a Moscovian marine shale in the Smithwick Formation of Texas.

Ecology: fast-moving nektonic carnivore

Average measurements (in mm): shell width 18.0, shell diameter 26.5