The chromosomes of Catinella arenaria (Bouchard-Chantereaux, 1837) with a review of the cytological conditions within the genus Catinella and considerations of the phylogenetic position of the Succineoidea ord. nov. (Gastropoda: Euthyneura)

The cytological conditions in the genus Catinella are discussed. The haploid chromosome number of Catinella arenaria is 6. The karyotype morphology differs from other known Catinellinae by the position of the centromeres and the chiasma frequency. The subgeneric characters of the group are surveyed in detail with respect to their phylogenetic value. The unique phylogenetic position of the Succineidae is pointed out and a new order Succineoidea is proposed.