Morphological evolution of the genus Platynus Bonelli, 1810 in the Italian Western Alps (Coleoptera, Carabidae, Platynini)

The genus Platynus is mainly known for its large Nearctic component, but representatives of these ground beetles can be found worldwide. The species from the North Western Italian Alps are characterized by an extreme morphological similarity among themselves (usually, brown-black in colour, with a flat body), and live in high-altitude habitats, near glaciers, snowfields, or cold streams. Our researches are focused on these alpine species, to evaluate if the region could reveal itself as a hotspot of biodiversity that was not fully highlighted so far. A careful survey was carried on a dataset including specimens ranging from the Lepontine to Maritime Alps, applying the geometric morphometric approach, since the method is an useful tool for taxa examination of morphological traits. The GM method was here coupled to phylogenetic analysis using landmarks data, as implemented in the TNT software. We distinguished three major morphogroups that are endemic of the NW Alps, and evaluated their phylogenetic relationships. We identified at least 21 distinct taxonomic entities of specific rank, whose only seven were already known. The 19 bioclim variables from WorldClim were then used for the climate mapping of the identified species to evaluate any environmental requirements. The results were particularly interesting due to the importance of these ground beetles as bioindicators living in an environment threatened by global warming. Noteworthy, the micro-range species from Italian mountain regions are particularly challenged by the impact of climate changes, thence they must be thoroughly studied to plan effective conservation strategies.