REVISION OF THE PERMIAN THIN-RIBBED LINOPRODUCTOIDS LINOPRODUCTOIDS OF THE "CANCRINELLA" KONINCKIANA (KEYSERLING, 1846) GROUP

Abstract

Representatives of the Kungurian-Ufimian thin-ribbed linoproductoids are described These forms are known to belong to the genus Cancrinella. A new genus, Striapustula, with the type species S. koninckiana (Keyserling) are established. The following new species are described: S. elongata, S. magna and S. pectiniformis; the characteristics of the type species and S. spitsbergiana (Gobbett) are specified. The described species showed the certain evolutionary trends in the new genus: a general increase of the visceral disc size; a relative decrease of the trail length; the increasing role of the spines on the lateral sides; the beginning of a reduction of the median septum. Considering this, the described species are of great importance for interregional correlations of the Biarmian basins.