The Giant African Land Snail, Achatina ( = Lissachatina) fulica Bowdich, 1822, is a tropical crop pest species with a widespread distribution across East Africa, the Indian subcontinent, Southeast Asia, the Pacific, the Caribbean, and North and South America. Its current distribution is attributed primarily to the introduction of the snail to new areas by Man within the last 200 years. This study determined the extent of genetic diversity in global A. fulica populations using the mitochondrial 16S ribosomal RNA gene. A total of 560 individuals were evaluated from 39 global populations obtained from 26 territories. Results reveal 18 distinct A. fulica haplotypes; 14 are found in East Africa and the Indian Ocean islands, but only two haplotypes from the Indian Ocean islands emerged from this region, the C haplotype, now distributed across the tropics, and the D haplotype in Ecuador and Bolivia. Haplotype E from the Philippines, F from New Caledonia and Barbados, O from India and Q from Ecuador are variants of the emergent C haplotype. For the non-native populations, the lack of genetic variation points to founder effects due to the lack of multiple introductions from the native range. Our current data could only point with certainty to the Indian Ocean islands as the earliest known common source of A. fulica across the globe, which necessitates further sampling in East Africa to determine the source populations of the emergent haplotypes.

This study represents the first molecular survey of the ichthyofauna of Taal Lake and the first DNA barcoding attempt in Philippine fishes. Taal Lake, the third largest lake in the Philippines, is considered a very important fisheries resource and is home to the world's only freshwater sardine, Sardinella tawilis. However, overexploitation and introduction of exotic fishes have caused a massive decline in the diversity of native species as well as in overall productivity of the lake. In this study, 118 individuals of 23 native, endemic and introduced fishes of Taal Lake were barcoded using the partial DNA sequence of the mitochondrial cytochrome c oxidase subunit I (COI) gene. These species belong to 21 genera, 17 families and 9 orders. Divergence of sequences within and between species was determined using Kimura 2-parameter (K2P) distance model, and a neighbour-joining tree was generated with 1000 bootstrap replications using the K2P model. All COI sequences for each of the 23 species were clearly discriminated among genera. The average within species, within genus, within family and within order percent genetic divergence was 0.60%, 11.07%, 17.67% and 24.08%, respectively. Our results provide evidence that COI DNA barcodes are effective for the rapid and accurate identification of fishes and for identifying certain species that need further taxonomic investigation.

The Streptaxoidea are an ancient and species diverse group that is poorly understood. Examination of the reproductive anatomy of Diaphera showed it to be notably distinct from that of most other streptaxid genera but to exhibit similarities with the reproductive anatomy of Sinoennea (Enneinae), Careoradula (Strepaxinae), Discartemon (Strepaxinae), Augustula (Strepaxinae), and a species of Imperturbatia (Gibbinae). Our molecular phylogenetic analysis placed the two genera with high-spired shells, Sinoennea and Diaphera, in an isolated position as a sister group to the Streptaxidae sensu stricto. This basal divergence within the Streptaxoidea provides support to the proposed recognition of a new family, the Diapheridae. None of the genera possessing low-spired shells, Careoradula, Discartemon, Augustula, and Imperturbatia, were available for inclusion in the molecular analysis and we therefore provisionally restrict the Diapheridae to Diaphera and Sinoennea. However, based on their reproductive anatomy Careoradula, Discartemon, Augustula and a species of Imperturbatia may cluster with the Diapheridae when included in a molecular analysis.