Eotripteroceras

Eotripteroceras is a smooth-shelled michelinocerin orthocerid from the middle Ordovician of the state of New York.

The shell of Eotripteroceras is a depressed orthocone with the underside (the venter) flatter than the upper (the dorsum). The siphuncle is below the center -as viewed in horizontal orientation- and is cylindrical in form. Both siphuncle and chambers are empty.