Re-evaluation of Procraspedites SPATH, 1930 (Ammonitina) from the Upper Kimmeridgian of Mexico

Abstract

Procraspedites from the Mexican Altiplano, studied with precise stratigraphic control, are coeval with the horizons rich in Glockiceras (Coryceras) carinatum [Del Castillo and Aguilera, 1895]. The interval with Procraspedites is dated as Eudoxus Chron (p.p.) of the Submediterranean late Kimmeridgian. The presence of parabolic structures on the inner whorls, followed by double furcations in Procraspedites, indicates Ataxioceratinae. The type species Procraspedites praecursor [Burckhardt. 1906] is interpreted to be the only valid species of this genus in the Americas.