A molecular phylogeny of apple snails (Gastropoda, Caenogastropoda, Ampullariidae) with an emphasis on African species

Ampullariids are widespread in Africa, Asia, South- and Central America, and the Caribbean Islands. Basal phylogenetic relationships of the African genera Afropomus and Saulea have been inferred based on anatomical evidence. Until recently the Viviparidae was regarded as the sister-group of Ampullariidae, but recent molecular data infer a sister-group relationship with Campanilidae. We have used members of both families as outgroups in the present investigation on ampullariid phylogeny. We have used data from portions of five molecular loci, that is, the nuclear genes 18S rRNA, 28S rRNA and H3, and the mitochondrial genes 16S rRNA and COI. Our data most often infer a basal position of Afropomus. The West African species Saulea is inferred as the basal member of a clade including the South American Marisa and Pomacea. We hypothesize that evolutionary lineages leading to Saulea and the American genera were isolated from each other by vicariance events (Gondwanaland break-up 130-110 Mya). Our individual gene analyses inferred two major clades of the African Lanistes. However, in some analyses they were not inferred as sister-groups making Lanistes paraphyletic. The African and Asian genus Pila is most often inferred to be monophyletic (except for the generally unresolved 28S). Our analyses most often inferred a sister-group relationship between Lanistes and Pila. The very low genetic diversity of the endemic radiation of Lanistes in Lake Malawi suggests that the morphological divergence has happened much faster than the molecular divergence as is also evidenced from the cichlid radiations.