New Data on Jurassic Cerithiopsidae (Gastropoda) from European Russia

Abstract

The Oxfordian–Kimmeridgian Cerithiopsidae, represented by two genera Cosmocerithium Cossmann, 1906 and Dragonia gen. nov. are re-investigated. Three species (C. renardi (Rouillier, 1849), C. pumilum (Gerasimov, 1992), and C. veliger sp. nov.), representing the same phylogenetic line, are distinguished in the genus Cosmocerithium. These species formed during the gradual morphological evolution, traced from the Middle Oxfordian to Early Kimmeridgian. The diagnosis of all Cosmocerithium species was revised and improved. As a result, the species C. contiae Guzhov, 2002 was included into synonymy of C. pumilum. Two new species are described in the composition of Dragonia: D. minuta sp. nov. (index species) and D. longa sp. nov. It is proposed that Cosmocerithium species were necrophages. It was revealed that Dragoniaminuta belongs to assemblages, which inhabited sunken wood and was able to bore wood fragments.