Arnioceltites
Arnioceltites is a genus of Late Triassic ammonites that has been found in the Alps, Sicily, and possibly in California. The shell is evolute and ribbed, with the outer whorls becoming smooth. Arnioceltities is included in the Tropiceltitidae family of the ceeratitid superfamily Tropitaceae. References 

 

Tropitaceae
Triassic ammonites of Europe
Ceratitida genera
Late Triassic ammonites