Like grains of sand: Ninetis spiders on the Arabian Peninsula (Araneae, Pholcidae)

Ninetinae is a group of small to tiny, short-legged daddy-longlegs spiders (Pholcidae) that has its highest diversity in the New World. Only two genera are known to occur in the Old World: the nominotypical genus Ninetis Simon, 1890 on the Arabian Peninsula and in Africa, and the monotypic genus Magana Huber, 2019 in Oman. Here we redescribe the type species of Ninetis, N. subtilissima Simon, 1890, and describe three new species from the Arabian Peninsula: N. amoud sp. nov. from Saudi Arabia, N. marnif sp. nov. and N. samail sp. nov. from Oman. All species descriptions are based on males and females, supported by CO1 barcodes, and accompanied by SEM photographs. While N. amoud sp. nov. is morphologically and genetically similar to N. subtilissima (and to the known African species, of which no CO1 barcodes are available), the two new Omani species are morphologically very distinct. Intraspecific genetic (K2P) distances are partly very high, in particular in N. amoud sp. nov. (up to 17%) and N. marnif sp. nov. (up to 13%). An exploratory species delimitation analysis suggests that these two nominal species might in fact represent several cryptic species each. No corresponding morphological variation was detected.