All genera of the world: order Opiliones (Animalia: Arthropoda: Arachnida)
Abstract
Opiliones is one of the most diverse orders of Chelicerata, ranking behind Araneae, Acariformes, and Parasitiformes in species richness. The group currently comprises approximately 6,900 valid and 1,500 invalid species, organized in about 1,700 valid and 800 invalid genera, yielding a remarkably low species-to-genus ratio of roughly 4:1 that reflects a history of naming monotypic genera based on a lack of phylogenetic understanding. In this contribution, we present an updated list of all genera of Opiliones, valid and invalid, organized by family-group taxa within each of the four suborders, Cyphophthalmi, Eupnoi, Dyspnoi and Lanitores. We also propose generic reallocations and nomenclatural corrections to improve the consistency of suprageneric classification. Specifically: the fossil genus † Halitherses Giribet & Dunlop, 2005 is placed in the new superfamily † Halithersoidea stat. nov. within Dyspnoi; the family Trionyxellidae Roewer, 1912 is synonymized with Assamiidae Sørensen, 1884; Goniosomoides Mello-Leitão, 1932 is synonymized with Deltaspidium Roewer, 1927, and Deltaspidium viridans (Mello-Leitão, 1932) comb. nov. is treated as a nomen inquirendum ; the East Asian harvestman genus Pseudoliobunum A. Müller, 1914 is resurrected from the synonymy of Leiobunum CL Koch, 1839 under its correct original spelling, correcting the unjustified emendation Pseudoleiobunum Tan, Tsurusaki, Fong & Zhang, 2025 introduced by Tan et al. (2025), and eleven species previously assigned to Nelima Roewer, 1910 or Leiobunum are formally transferred to Pseudoliobunum ; Paralus Roewer, 1949 was incorrectly considered a junior homonym of Paralus Rafinesque, 1815 ( nomen nudum ; Mollusca, Gastropoda) by Özdikmen (2006), who proposed the unnecessary replacement name Neoparalus Özdikmen, 2006—this misinterpretation is recognized and corrected here for the first time; Zalmoxis dentata Thorell, 1891 is herein designated as type species of Zalmoxida Roewer, 1912; and Triaenonyx stewartius Hogg, 1910 is herein designated as type species of Metanuncia Roewer, 1915.
