First description of the male genitalia in a short-tailed whipscorpion (Arachnida: Schizomida), description of the female, and comments on pygidial glands and cuticular ultrastructure of Surazomus algodoal Ruiz & Valente, 2017.

The male genitalia of Surazomus algodoal Ruiz & Valente, 2017 are described. Since this is the first attempt to describe male genitalia in the schizomids, we propose new terminology to describe the sclerites of the male genital chamber in the order. We believe that the male genitalia may provide a large set of characters for taxonomic research in schizomids, as the female genitalia have proven to do. The setae and other cuticular structures were investigated using light and scanning electron microscopy (SEM). The female of S. algodoal is described for the first time, including the genitalia, and we highlight the sexual dimorphism present in the species. We also present descriptions of: 1) microtrichia, with respect to their presence/length/distribution, 2) cuticular sensilla, glandular openings and other cuticular structures, proposing new terminology, 3) setae of the pedipalpal trochanter and tarsus. Some changes on the terminology of setae of pedipalpal tibia are also given. These advances may be useful for description in other schizomids. The pygidial glands, mostly ignored in modern papers, were assessed and commented upon.