In this paper some helicoid species from eastern Algeria are investigated using a morphological and molecular approach. The investigation of the genital organs of M. massylaea (Morelet, 1851), the type species of the genus Massylaea Möllendorff, 1898, showed the same autapomorphic character states as are considered typical for Eobania P. Hesse, 1913. These findings are fully supported by the genetic analysis using two mitochondrial and three nuclear markers. Thus, the latter genus has to be considered a synonym of the former. Currently, three species are known to comprise the genus, viz. M. massylaea, M. constantina (E. Forbes, 1838), and M. vermiculata (O. F. Müller, 1774). Several nominal taxa from northern Africa are synonymised with one of the species mentioned here under Massylaea. The generic position of the so-called “Massylaea” species from the High Atlas Mountains in southern Morocco remains unresolved.

Marmorana (Murella) muralis is known as an endemic species of Sicily Island, which is introduced in many European countries. Here, M. (M.) muralis is recorded from the north of Tunisia. In order to confirm the identification of samples collected from several localities, shell morphology, details of genital organs and two mitochondrial markers (COI and 16S) were investigated. The results of the molecular study, as well as the morphological and anatomical studies confirm the identification of all Tunisian samples as M. (M.) muralis. The analysis of mitochondrial markers shows a low divergence between Sicilian and Tunisian samples suggesting a recent introduction of M. (M.) muralis to the North of Tunisia. The comparison of morphological characters of M. (M.) muralis with shell characters of Murella nicollei described by Pallary (1926) confirms that the latter should be considered as synonym of M. (M.) muralis.

In order to clarify the systematic position of Helix latastei Letourneux in Letourneux & Bourguignat, 1887, and Helix latasteopsis Letourneux & Bourguignat, 1887, a comprehensive approach using morphological and molecular methods is presented. The investigation of the genital organs of both species showed that they belong to the genus Xerocrassa Monterosato, 1892 with two very small dart sacs and a few tubiform glandulae mucosae. In our phylogenetic analysis using the mitochondrial markers COI, 16S and the nuclear cluster 5.8-ITS2-28S, the results of the anatomical research were confirmed. Thus, the genus Ereminella Pallary, 1919, which is based on H. latastei, becomes a junior synonym of Xerocrassa. A review of the genus-level taxa Xerobarcana Brandt, 1959, and Xeroregima Brandt, 1959, showed that these should also be considered as synonyms of Xerocrassa. A third species, Helix lacertara Bourguignat, 1863 from Algeria was found to be closely related to X. latastei based on its shell morphology. A map showing the distribution of the three species treated is supplied.

This study presents new insights in the anatomy of genital organs of some large helicid gastropods from northern Africa. The genetic analysis with the markers COI, 16S, H3, and 5.8 S rRNA+ITS2 reveales a high support for Alabastrina and Otala as separate evolutionary lineages within the Otalini. The position of Siretia as another separate lineage within the Otalini is discussed. “Tingitanaminetteidecussata” clusters within the O.xanthodon clade and confirms that the genus Tingitana can be synonymised with Otala. The genus Alabastrina differs from all other known genera by possession of a penial appendix. This character state is also found in topotypic A.tistutensis. Examination of the twin penial papilla system in Otala recovers a reduction of the proximal penial papilla in O.punctata. The position of Helixmurcica as a separate subspecies of O.lactea is not supported, and it is here considered to be a synonym of the latter species.