RESUMEN
The West Indian fruit fly, Anastrepha obliqua (Diptera: Tephritidae), is an economically important pest that inhabits areas of South and Central America, Mexico and the Caribbean with occasional infestations in the southern United States. We examine intra-specific relationships within A. obliqua as well as interspecific relationships to other Anastrepha species using a multi-locus data set comprising nine loci (seven nuclear, two mitochondrial) with 105 operational taxonomic units. The results based on a concatenated set of nuclear loci strongly support the monophyly of A. obliqua and most of the other species previously identified by morphology. A split between Peruvian A. obliqua samples and those from other locations was also identified. These results contrast with prior findings of relationships within A. obliqua based on mitochondrial data, as we found a marked discrepancy between nuclear and mitochondrial loci. These analyses suggest that introgression, particularly between A. obliqua and fraterculus species, may be one explanation for the discrepancy and the high mitochondrial diversity reported for A. obliqua could be the result of incomplete lineage sorting.