First occurrence of Haugia cf. variabilis (d’Orbigny) (Ammonoidea) from the Lower Jurassic of the Uminoura area, western Kyushu, Japan

Abstract

Haugia cf. variabitis (d’Orbigny) has been found in the upper part of the Idenohana Formation in the Uminoura area, Kumamoto Prefecture. This species is originally known from the Upper Toarcian H. variabilis Subzone of the Lytoceras jurense Zone in western Europe. This occurrence combined with our analyses of the lithofacies and sequence stratigraphy suggests that the Idenohana Formation is conformably overlain by the Kyodomari Formation.