Comprising more than 6500 species, Opiliones is the third most diverse order of Arachnida, after the megadiverse Acari and Araneae. The database referred here is part 1 of 12 of a project containing an intended worldwide checklist of species and subspecies of Opiliones as Darwin Core archives, and it includes the superfamilies Travunioidea and Triaenonychoidea. These two superfamilies are often treated together under the denomination of Insidiatores. In this Part 1, a total of 571 species and subspecies are listed. Briggsidae and Cladonychiidae are both downgraded to subfamilies of Travuniidae. Peltonychia Roewer, 1935 is an available name and senior synonym of Hadziana Roewer, 1935 and is herein revalidated. Seven genera of Triaenonychidae described by Lawrence between 1931 and 1933 originally failed to comply ICZN rules for availability (Art. 13.3). All of them only became available when Staręga (1992) designated a type species for each. Therefore, the correct authorships of Austromontia Lawrence, 1931, Biacumontia Lawrence, 1931, Graemontia Lawrence, 1931, Larifugella Lawrence, 1933, Mensamontia Lawrence, 1931, Monomontia Lawrence, 1931 and Rostromontia Lawrence, 1931 are all Staręga, 1992. Fumontana Shear, 1977, originally referred only to subfamily Triaenonychinae (as opposed to Soerensenellinae then and not corresponding to present Triaenonychinae), not to any tribe (which in turn correspond to modern subfamilies) is herein included in the subfamily Triaenonychinae. Picunchenops Maury, 1988 originally not included in any tribe of Triaenonychidae, is herein included in the subfamily Triaenonychinae. Trojanella Karaman, 2005, originally ranked as Travunioidea incertae sedis, is herein included in the Travuniidae Travuniinae. Nuncia ovata Roewer, 1915 (synonymized with Triaenonyx cockayni Hogg, 1920 by Forster (1954), but with inverted precedence) is here combined as Nuncia coriacea ovata Roewer, 1915 as correct senior synonym instead of Nuncia coriacea cockayni (Hogg, 1920), which is current in the literature. Neonuncia enderbei (Hogg, 1909) is reaffirmed as the correct spelling for the species, while the deliberate change to Neonuncia enderbyi by Forster (1954) is an incorrect subsequent spelling.
