Progressive aridification since the mid-Miocene has had a significant influence on the evolution of the biota in the arid zone of central Australia. Especially moisture sensitive groups, such as snails, are often restricted to topographically complex areas, which have acted as refugia in an otherwise inhospitable environment. This historical fragmentation is deemed to be a potent agent of allopatric lineage diversification. Camaenid land snails are amongst only a few terrestrial gastropods that have managed to survive in the arid zone probably due to their ability to escape desiccation through aestivation. In the present study, the authors present the first study of the mitochondrial lineage differentiation in an endemic land snail genus from the Australian ‘Red Centre’, Baccalena Iredale, 1937. Exposing significant incongruence between mtDNA phylogeny and morphology-based taxonomy, the authors completely revise the species and genus level taxonomy of this camaenid group. The authors demonstrate that this genus contains three species, B. grandituberculata, B. adcockiana and B. squamulosa, which have so far been assigned to different genera: Granulomelon Iredale, 1938 (junior synonym of Baccalena), Basedowena Iredale, 1937 and Pleuroxia Ancey, 1887 Two of these species are widespread comprising multiple divergent mitochondrial lineages. Based on a molecular clock estimate, these lineages diverged approximately during the mid-Pleistocene, a period of particularly severe aridification. The phylogeographic patterns are consistent with an isolation-by-distance model in one species but not the other. The authors concluded that these differences can be attributed to their distinctive aestivation behaviour.
Authors: Criscione F, Köhler F. ;Full Source: Molecular Phylogenetics and Evolution. 2015 Aug 31. pii: S1055-7903(15)00252-3. doi: 10.1016/j.ympev.2015.08.021. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][Epub ahead of print] ;[/fusion_builder_column][/fusion_builder_row][/fusion_builder_container]