Euscorpius Thorell, 1876

(Figures 1–186, Tables 1–4)

Euscorpius Thorell, 1876: 15; Fet & Sissom, 2000: 357–377 (in part, complete reference list until 1998).

TYPE SPECIES. Scorpio carpathicus Linnaeus, 1767

DIAGNOSIS. Total length 20–50 mm. Movable fingers of pedipalp chela with MD aligned in a single straight row in entire length of chelal fingers; ID, IAD (5 in number) and OD present. OD are displaced to outer aspect of fingers. Pedipalp chela flat in appearance. Trichobothrial pattern type C. Two subdistal denticles present on cheliceral movable finger dorsal edge. Ventral edge of cheliceral movable finger smooth; serrula absent. Two pedal spurs present on legs. Tarsal spurs on legs absent. Sternum pentagonal in shape. Hemispermatophore lamelliform in shape with broad trunks. Telson without subaculear tubercle. Metasoma I–IV with single median carina usually absent.

Taxonomic characters.

Characters important for distinguishing species in the genus Euscorpius are: (1) trichobothriotaxy of the pedipalp patella, i. e., number of trichobothria in the external series eb, eb a, esb, em, est, and et, in combination with the number of ventral trichobothria; (2) shape and dimensions of the carapace, pedipalp and metasomal segments; (3) granulation and carination of metasomal segments; (4) coloration; and (5) pectinal tooth count. Two currently valid subgenera can be separated by the number of ventral trichobothria on the pedipalp chela manus, i. e., 4 in Euscorpius sensu stricto, and more than 6 in Polytrichobothrius Birula, 1917 . These characters alone are not always sufficient for distinguishing a total of ca. 60 species, most of which were described or revalidated in the last two decades. Taxonomy of this genus remains complex and challenging. Recently, DNA analysis was suggested to be the only solution to this problem (see e. g. Parmakelis et al., 2013; Fet et al., 2018). Based on our studies of this genus and the application of diagnostic characters to the related genus Megacormus Karsch, 1881 (Euscorpiidae) and to the related family Scorpiopidae Kraepelin, 1905, we here propose application of two additional characters to elucidate taxonomy of Euscorpius .