Diestoceras Foerste 1924

Genus Diestoceras Foerste, 1924 Type species Gomphoceras indianense Miller & Faber, 1894, Versailles, Indiana, USA, upper part of Hudson River group, Late Ordovician; by original designation. Diagnosis Short diestoceratids with straight or slightly curved shell, and circular conch cross section; conch reaches largest diameter at adoral end of mature phragmocone, contracting to aperture; peristome straight, transverse, with shallow hyponomic sinus; siphuncle positioned near conch margin, cyrtochoanitic; segments subquadrate in longitudinal section; thin annulosiphonate deposits with distinctive irregular linear processes, which extend adapically and adorally without fusing from segment to segment. (Compiled from Sweet 1964b.)