Reanalysis of Teruelius and Grosphus (Scorpiones: Buthidae) with descriptions of two new species.

The genus Teruelius Lowe &
Kovařík, 2019, was created for a subset of species originally included under Grosphus Simon, 1880, but was subsequently synonymized with Grosphus. We reanalyze Teruelius and Grosphus by scoring 45 discrete characters, and 32 discrete + 17 continuous characters, for all 36 included species, plus 11 related buthids as outgroup taxa. Morphometric analyses are systematically applied to quantify variation in continuous characters, including: carapace length, carapace anterior concavity, carapace preocular length, hemispermatophore posterior lobe length, tibial spur length/ tibia distal depth ratio, metasoma I length/ width ratio, pectine tooth length/ width ratio, pedipalp femur petite ‘trichobothrium’ d2 position, pedipalp fixed finger relative position of trichobothria db vs. est, and pedipalp manus relative position of Eb trichobothria. Elliptic Fourier analyses and principal components analyses are applied to quantify variation in sternite IV spiracle aperture profiles, female basal pectinal tooth shapes and telson lateral profiles. Laser light scattering is applied to quantify differences in optical reflectance of sternite VII arising from cuticular lattice microstructures. Spectral image analysis is applied to quantify differences in granulation of metasoma I ventrosubmedian carinae. The use of UV fluorescence as a quantitative taxonomic character is critically reviewed. Six binary characters are proposed for differential diagnosis of Teruelius vs. Grosphus. Phylogenetic analyses rooting trees with 8 individual outgroup taxa, or with multiple outgroup taxa under morphological and molecular backbone constraints, all yield overwhelming support for the monophyly of Teruelius, and the genus is reinstated. The position of outgroup taxon Microcharmus in a separate family is not supported by any diagnostic characters or phylogenetic analysis, and Microcharmidae is synonymized with Buthidae. Two new species, Grosphus angulatus sp. n. and Teruelius haeckeli sp. n. are described.