Wikipedia
Bitaunioceras
Bitaunioceras is a Permian orthocerid with a gradually expanding, straight, orthoconic shell with straight transverse sutures and a small, subcentral siphuncle with staight tubular orthochoamitic necks.
The shell surface of Bitaunioceras has a few, shallow, rounded constrictions and numerous, unequal, prominent transverse wire-like lirae.
Bitaunioceras species have been found in Texas in the United States, Coahuila in Mexico, Sicily, Timor, and the south Urals in Russia.