New picobuthoid scorpions (Scorpiones: Buthidae) from Oman.

Five new species of diminutive buthid scorpions are described from Oman. Two belong to Microbuthus Kraepelin, 1898, a genus with heavily sclerotized, smooth, strongly pitted posterior metasomal segments, abbreviated telson, and pedipalps with 9 femoral and 6–7 external patellar trichobothria: M. gardneri, sp. nov., from the Al Hajar Mountains, and M. kristensenorum, sp. nov., from the Dhofar Mountains and Hadhramaut of Yemen, which was long misidentified as M. pusillus Kraepelin, 1898. Two additional new species are placed in a new genus Picobuthus, gen. nov., differentiated by granular posterior metasomal segments, elongate telson, pedipalps with 7–9 femoral and 5 external patellar trichobothria: type species P. wahibaensis, sp. nov., from the Wahiba Sands, and P. dundoni, sp. nov., from sand deserts in central Oman. A second new genus, Femtobuthus, gen. nov., is monotypic with type species F. shutuae, sp. nov., from the southern coast and plateau of Jiddat Al Harasis, differentiated by enlarged, granular, dentate metasomal segments, abbreviated telson, and pedipalps with 6 femoral and 5 external patellar trichobothria. The relationship of Microbuthus and the two new genera to other buthid scorpions is discussed, and their trichobothrial homologies are addressed. These three genera are hypothesized to represent a monophyletic ‘picobuthoid’ lineage that originated in the Arabian Peninsula.