ON THE FIRST FIND OF APTYCHI IN REPRESENTATIVES OF THE SUBFAMILY PROPLANULITINAE BUCKMAN (PERISPHINCTIDAE, AMMONITIDA)

Abstract

Body chamber molds of representatives of the genus Proplanulites have been found from the lower part of the koenigi Zone (lower Callovian) of the Kursk Region that contain aptychi of Praestriaptychus koenigi parasp. nov. This is the first confirmed find of aptychi in the subfamily Proplanulitinae (family Perisphinctidae, suborder Perisphinctina). Its unusually elongated shape is similar to that of Cornaptychus Trauth and Laevila- mellaptychus Trauth, which are thought to belong to ammonites of the suborder Haploceratina. The new find suggests that at least some elongated aptychi could belong to ammonites of the suborder Perisphinctina.