Hidden diversity, ancient divergences, and tentative Pleistocene microrefugia of European scorpions (Euscorpiidae: Euscorpiinae) in the eastern Adriatic region

Abstract

The systematics and taxonomy of the scorpion family Euscorpiidae are still unresolved, and, within it, the eastern Adriatic scorpiofauna is largely unknown and under‐researched. Based on two mitochondrial sequences (COI and 16S rRNA) and one nuclear marker sequence (ITS1), we put 107 newly analyzed samples originating from the Alps, the Eastern Adriatic, and the adjacent Dinaric karst area into phylogenetic context. Several species delineation approaches were applied to reveal cryptic diversity. Divergence time dating was used to highlight the major events in the evolutionary history of the genera Euscorpius and Alpiscorpius. The deep intraspecific genetic divergences observed in some clades warrant taxonomic revision of several taxa (Euscorpius tergestinus, Euscorpius hadzii, Euscorpius biokovensis, and Euscorpius (Alpiscorpius) croaticus). In this study, the population of E. hadzii from Lastovo Island (formerly Euscorpius carpaticus lagostae) is elevated to species level as Euscorpius lagostae Di Caporiacco, 1950, stat. nov. Euscorpius croaticus is moved to the genus Alpiscorpius as Alpiscorpius croaticus (Di Caporiacco, 1950) comb. nov. The distribution ranges of several species are revised, and based on the new data, a more detailed revision of species distribution is necessary. We attribute the major divergence events to the impact of the Middle Miocene Climate Transition, the Messinian Salinity Crisis, and the Middle Pleistocene Climate Transition. The observed patterns are therefore a direct consequence of the geological history and complex topography of the region, which provided numerous microhabitats, as well as of the Pleistocene microrefugia that enabled their persistence.

Molecular analyses of pseudoscorpions in a subterranean biodiversity hotspot reveal cryptic diversity and microendemism

“…This agrees with previous studies of many other invertebrate taxa that show the Dinarides as a center of remarkable allopatric diversification 6,73,74 . Additionally, various zoogeographical divisions along the Adriatic coast, including coastal islands, and mountain ranges, can also drive speciation and act as potential microrefugia during periods of environmental change 15 . In our study, species richness was highest in the caves of the Velebit and Biokovo Mountains, and at the margin of karstic areas and alluvial plains in southern Croatia (Fig.…”

“…Most studies on the karstic biota in the Balkans have focused on flagship aquatic taxa such as world’s largest cave amphibian, the olm Proteus anguinus Laurenti, 1768 11 , and subterranean amphipod crustaceans 12 . The status of cryptic taxa 13 , 14 , especially terrestrial invertebrate fauna 15 is often unclear and hampers a deeper understanding of evolutionary processes that lead to high diversity in this biodiversity hotspot.…”

Glacial Relicts? a New Scorpion from Mount Olympus, Greece (Euscorpiidae: Euscorpius)

“…How-ever, subsequent divergence from their respective sister species occurred around 3.2 Mya for E. kinzelbachi and 2.5 Mya for E. aff. sicanus (Podnar et al, 2021), during the Pliocene-Pleistocene. Microallopatry was suggested as a possible explanation for current species distributions across mainland Greece (Parmakelis et al, 2013), as in montane scorpions inhabiting other parts of the world.…”

“…The family Euscorpiidae Laurie, 1896, exhibits a disjunct distribution in the Neotropics (Mexico and Guatemala) and the Palearctic (Europe and northern Africa). It is the most speciose scorpion family in Europe, currently comprising three genera and 94 species (Parmakelis et al, 2013; Fet et al, 2016; Štundlová et al, 2019; Podnar et al, 2021, 2022; Tropea et al, 2022; Kovařík et al, 2023) distributed across a variety of humid to semihumid habitats from the islands and coastlines of the Mediterranean to the high altitudes of the Alps and other mountain ranges (fig. 1A).…”

“…1A). Despite being the most well-studied European scorpion family, the taxonomy of Euscorpiidae remains problematic for several reasons, including the morphological similarity of many species, which requires adult males for accurate diagnosis and delimitation; an inadequate understanding of species distributions that has, in recent years, revealed several cases of sympatry; a general failure to identify adequate diagnostic morphological characters and present comparative diagnoses; the absence of workable taxonomic keys; and different interpretations of species limits, caused in part by the inconsistent application of alternative sources of evidence including morphology, short fragments of mitochondrial DNA, and karyotype (Fet and Soleglad, 2002; Parmakelis et al, 2013; Štundlová et al, 2019; Podnar et al, 2021).…”