In many Opiliones (notably the Laniatores) the five most anterior opisthosomal tergites are fused with the carapace forming the so called dorsal scutum (DS) (Latreille 1804; Simon 1879; Hadži 1942) with a highly variable shape arising from multiple factors, such as differential development of musculature (especially of coxa IV), internal organs and influence of appendages (Loman 1903; Winkler 1957). The different degrees of fusion of the tergites were first studied by Hadži (1942), who proposed a terminology for them. This terminology was adopted and enhanced by Kratochvíl (1958) and Martens (1978). A shield formed by the fusion of the carapace with abdominal tergites I to V is called scutum magnum (Hadži 1942). The shield formed by the fusion of carapace with abdominal tergites I to VII is called scutum complexum (Kratochvíl 1958) and occurs in the males of Heteropachylinae Kury, 1994 (Kury 1994) and Paralolidae Kratochvíl, 1958 (Kratochvíl 1958). Finally, the scutum completum (Hadži 1942) is formed by the complete fusion of the carapace and abdominal scutum, formed by tergites I to VIII, and occurs in the Sandokanidae (Martens 1978). In this paper we focus on the different forms of the scutum magnum.

Amendments are made to inconsistencies, mistakes and omissions in the catalogue of American Laniatores by Kury (2003). Discrepancies between dates given in Kury (2003) and Neave’s Nomenclator and the Zoological Record are discussed. Accurate issue dates for relevant publications are used to define priorities. Etymologies are surveyed for generic names, establishing their grammatical gender, so specific names are inflected according to the provisions of the Code. Unavailable generic names are: Messa Sørensen, 1932, Zarax Sørensen, 1932, Prasia Sørensen, 1932, Angistrisoma Roewer, 1932, Angistrisoma Mello-Leitão, 1935, Bunoweyhia Mello-Leitão, 1935, Batomites Mello-Leitão, 1931, Euminua Sørensen, 1932, Minua Sørensen, 1932, Ilhastygnus Roewer, 1943, Fonteboatus Roewer, 1931, Malea Sørensen, 1932, Chersobleptes Sørensen, 1932 and Jimeneziella Avram, 1970. Hernandria Banks, 1909 is unavailable and must be placed as an “incorrect subsequent spelling” of Hernandaria Sørensen, 1884. The valid genus name is Parahernandria Goodnight & Goodnight, 1947 (stat. res.). Zaraxolia Strand, 1942 (stat. res.) is revalidated from the synonymy of Neocynorta Roewer, 1915 with Zarax devians Sørensen, 1932 as type species. Friburgoia Mello-Leitão, 1932 [December] is deemed a junior subjective synonym of Schenkelibunus Strand, 1932 [September] (stat. res.) (inverted precedence between synonyms). Liops Mello-Leitão, 1940 (non Fieber, 1870, nec Gidley, 1906) is a junior homonym and is replaced by its first available synonym, Corcovadesia Soares & Soares, 1954 (stat. res.). The following unavailable generic names are formally described as new: (1) Jimeneziella Kury & Alonso-Zarazaga, gen. nov. (type species: Jimeneziella decui Avram, 1973); (2) Euminua Kury & Alonso-Zarazaga, gen. nov. (type species: Euminua brevitarsa Sørensen, 1932). The following homonym generic names are replaced: (1) Cranellus Roewer 1932, with Narcellus Kury & Alonso-Zarazaga, nom. nov., (2) Metapachylus Pickard-Cambridge, 1905, with Pyropharynx Kury & Alonso-Zarazaga, nom. nov.; (3) Ovalia González-Sponga, 1987, with Oo Kury & Alonso-Zarazaga, nom. nov.; (4) Tiara González-Sponga, 1987 with Mitraia Kury & Alonso-Zarazaga, nom. nov.; (5) Limonia González-Sponga, 1998, with Manuelangelia Kury & Alonso-Zarazaga, nom. nov. Gonyleptes melloleitaoi Kury & Alonso-Zarazaga, nom. nov. is a replacement name for Gonyleptes curvicornis Mello-Leitão, 1932. Discocyrtus confusus Kury, 2003 is unavailable, so this species is here re-described as Discocyrtus confusus Kury n. sp. New combinations are: Parahernandria spinosa (Banks, 1909) (from Hernandaria), Schenkelibunus impar (Mello-Leitão, 1932) (from Friburgoia), Schenkelibunus perditus (Mello-Leitão, 1927) (from Friburgoia), Narcellus balthazar (Roewer, 1932) (from Cranellus), Narcellus montgomeryi (Goodnight & Goodnight, 1947) (from Cranellus), Pyropharynx gracilis (Pickard-Cambridge, 1905) (from Metapachylus), Oo spinosum (GonzálezSponga, 1999) (from Ovalia), Mitraia unispina (González-Sponga, 1987) (from Tiara), Manuelangelia tuberosa (González-Sponga, 1998) (from Limonia), Zaraxolia devians (Sørensen, 1932) (from Zarax), Corcovadesia hexabunus (Mello-Leitão, 1940) (from Liops) and Corcovadesia venefica (H. Soares, 1966) (from Liops). The following genera of Pachylinae, which appeared in conflicting subfamilies in Kury 2003, are formally transferred to the Ampycinae: Ampycella Roewer, 1929, Glysterus Roewer, 1931, Hernandarioides Pickard-Cambridge, 1905, Parahernandria Goodnight & Goodnight, 1947 and Hutamaia Soares & Soares, 1977. A list of taxa described in 2003 is interpolated. A complementary list of the 2004–2009 systematic literature on the subject is given.

Acumontia succinea sp. nov. is described from the Parc national de la Montagne d'Ambre, in the former Antsiranana Pro-vince, Madagascar. Detailed illustrations from all views of the male genitalia of a species of Acumontia are provided forthe first time. Complementary illustrations are provided of the types of the five valid species of Acumontia described by Pocock in the beginning of the 20th century, two of which had never been illustrated before.

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.

For the first time a hypothesis of homology is proposed for the macrosetae which compose the armature of the distal truncus penis of the Gonyleptoidea