goniatites

from The Century Dictionary.

• noun A genus of fossil ammonites, giving name to the family Goniatitidæ, having a discoid shell with angu-lated lobed sutures.
• noun Originally (as introduced by de Haan) a genus of Paleozoic ammonoid cephalopods with closely coiled shells, simple septal sutures, and mostly broad lateral saddles and lobes. The genus was later subdivided into other genera of more restricted scope, so that the name, which originally had a value parallel to that of Ammonites, has now, like the latter, disappeared from classification.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun Plural form of goniatite.