Geometric morphometric characterization of the Balkan alpine grasshopper genus Oropodisma Uvarov, 1942 (Orthoptera, Acrididae, Melanoplinae), with description of two new species

In this study we employ a geometric morphometric approach to quantify morphological differences among taxa of the genus Oropodisma Uvarov, a complex of alpine grasshoppers that includes several narrow endemic species distributed across different mountain ranges of the Balkan Peninsula. The genus was described by Uvarov in 1942 and currently comprises ten recognized species, primarily distinguished by subtle differences in the shape of the phallus apex and furculae of males. Some populations from central Greece exhibit an uncertain taxonomic status, suggesting the possible existence of undescribed species. Quantitative morphological comparisons with specimens collected from the type localities of all currently recognized taxa revealed the presence of two new species in the Pindus Range, Greece: O. tzoumerkae sp. nov. from Mt. Tzoumerka and O. agrafae sp. nov. from Mt. Agrafa. Geometric morphometric analyses indicate that the taxa O. tymphrestosi and O. willemsei, distributed in adjacent mountain ranges from central Greece, do not show statistically significant differences in either of the two studied traits. This finding raises doubts about their taxonomic status but may also reflect the limitations of geometric morphometric approaches in capturing subtle differences in the complex structures that characterize internal male genitalia. Overall, our analyses highlight the importance of quantitative approaches in formally reassessing the taxonomic status of species complexes. The description of two new and geographically restricted species of Oropodisma further emphasizes the role of Mediterranean mountains as key centers of microgeographic speciation for alpine biotas.