Revision of the strongly flattened Megaprosternum Azevedo (Hymenoptera, Bethylidae)

The limno-terrestrial tardigrade fauna of Argentina has been investigated methodically and with modern criteria just in the last two decades, but current knowledge is still incomplete. So far, about 119 limno-terrestrial species are known for the country, of which only 6 belong to the genus Minibiotus R.O. Schuster, 1980. Until 1988, this genus was monotypic, with only Minibiotus intermedius (Plate, 1888), but today the number of species of the genus has risen to 55. In the present contribution, we describe with an integrated approach (PCM, SEM, morphometry and DNA analysis with COI, ITS2, 18S and 28S genes) a new species of Minibiotus from Salta City (Argentina). Minibiotus dispositus sp. nov. has ten transverse bands of variously shaped cuticular pores, arranged in transverse rows, with differences between smaller and larger specimens. Three macroplacoids and a microplacoid are present in the pharynx. The eggs have small conical processes and granulated chorion. The new species is morphologically and morphometrically well differentiated from all other species of the genus, and genetically from the up to date sequenced species. The new species description gave the occasion to broaden knowledge on taxonomy, morphology and faunistics of the genus Minibiotus, and on the tardigrade fauna of Argentina and the Neotropical region.