In this study, Bassaniodes pseudorectilineus (Wunderlich, 1995) (Thomisidae) populations were investigated genetically using the mitochondrial COI gene region. The haplotypes of the populations were determined, network analyses and neutrality tests were performed, and a BEAST (Bayesian evolutionary analysis sampling tree) was created. The populations were not completely separated from each other and that ongoing gene flow was maintained between the populations. The Bassaniodes pseudorectilineus population expanded from south to north and it is thought that the ancestral population is in the south. In addition, the study enabled recording of the taxon in genetic databases for the first time.