Euaptetoceras

Euaptetoceras is an evolute hildoceratoid ammonite from the lower Middle Jurassic, included in the family Hammatoceratidae and the subfamility Hammatoceratinae. The genus may be a junior synonym for "Eudmetoceras" of Buckman, 1920.
The shell of "Euaptetoceras" has an evolute, compressed, discoidal shape with a whorl section higher than wide. The inner whorls have long primary ribs while the outer whorls become smooth. The venter, which is the outer rim, is narrowly to sharply rounded and its suture is rather complex. "Euaptetoceras" is found in strata of Europe, Iran, and Argentina.