MOLECULAR-GENETIC AND ANATOMICAL RELATIONSHIPS AMONG POMATIOPSID (GASTROPODA, PROSOBRANCHIA) GENERA FROM SOUTHERN CHINA

Allozyme electrophoresis was employed to assess the relationships amon g key genera of Chinese Triculinae and Oncomelania of the Pomatiopsina e, subfamilies of the Pomatiopsidae (Gastropoda: Rissoacea). We assess the degree to which the subfamilies have differentiated genetically, test the congruence of relationships based on anatomical and allozyme data, calibrate genetic distances among triculine genera where the bas is of generic definition is the anatomical data set, and assess interp opulation variation for species widely dispersed throughout China. The interpopulation study was on Oncomelania hupensis from three location s in Zhejiang Province. Interpopulation difference does not exceed Nei 's D of 0.191. The greatest amount of interpopulation D is associated with shell sculpture, not geographic distance. Nei's D ranges from 1.0 to 1.76 for divergence of Oncomelania from the three triculine taxa s tudied. The inter-triculine differences range from 0.69 to 1.24. Pheno grams of relationships based on a UPGMA treatment of Nei's 1972 D, Wri ght's modified Rogers' D, and Cavalli-Sforza and Edwards' Arc distance are congruent with a cladogram based on scoring each locus as a chara cter. Oncomelania is the outlier, but not by much thus showing a close genetic relationship to the triculine taxa. There is a closer relatio nship between Oncomelania and one triculine taxon than between two tri culine taxa. Genetic data support the contention that the Pomatiopsina e and the Triculinae are derived from a common ancestor and are histor ically closely related. The cladistic analysis of anatomical data is c ongruent with the cladogram and phenograms based on allozyme data. The se results support the large-scale cladistic analyses of the Triculina e that are based on anatomical data. The anatomical data, not the allo zymic data, strongly support the subfamily arrangement currently used. A phenetic analysis of the anatomical data indicates that two species provisionally placed in Gammatricula should be placed in separate gen era. The genetic data support this view.