''Planitornoceras'' is a genus included in the goniatitid subfamily

Aulatornoceratinae Aulatornoceratinae is one of three subfamilies of the goniatitid family Tornoceratidae, an extinct order of Paleozoic ammonoid cephalopods. ''Aulotornoceratinae'' was established as a subfamily by R.T.Becker, 1993, initially for '' Aulatornocera ...

that lived during the

Famennian The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used b ...

stage at the end of the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

. Its shell is extremely compressed, subinvolute to subevolute with an open umbilicus. Sides are always flat, outer rim (=venter) tabulate to slightly keeled. No constrictions or spiral grooves, but some species have broad spiral depressions. The adventitious lobe of the suture is widely rounded and asymmetric, the ventral lobe and saddle small, the dorsolateral saddle relatively short.

References

*''Planitornoceras'' i
GONIAT Online
6/9/12
The Paleobiology Database ''Planitornoceras'' entry
accessed 9 June 2012 Goniatitida genera Tornoceratidae {{Goniatitida-stub