Rhaucus Simon 1879
Creators: name: Pinzón-M, Conchita
name: Pinto-Da-Rocha, Ricardo
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Cosmetidae
Rhaucus

description: Rhaucus Simon, 1879
Rhaucus Simon, 1879: 213
Emended diagnosis: Species of the genus Rhaucus can be diagnosed among Metergininae by the following combination of characters: A dorsal scutum α-shaped, shared with species of the genera Arucillus, Erginulus, Rhaucoides, Rhauculanus, and Rhauculus (β-shaped in Meterginus and Poecilaemula, oval-shaped in Trinimontius). Ornamentation on area III among species of Rhaucus may present acuminate tubercles as in Erginulus, Meterginus, Rhaucoides, Rhauculanus, and Rhauculus; dome-shaped tubercles as in Poecilaemula or mammiliform tubercles occurring only within Rhaucus, whereas Arucillus and Trinimontius are unarmed on area III and instead present strong ornamentation on area IV. The Ti of the pedipalp can be spoon-shaped (oval and dorsally well projected, see Fig. 4A–B in García & Kury, 2017), a feature that occurs in species of Erginulus, Poecilaemula, Rhaucoides, and Rhauculus; some species of Rhaucus present Ti elongated almost sub-rectangular (laterally projected and not well projected dorsally, see Figs. 3I and 6H), similar to Meterginus. Chelicerae with basal segment with outstanding ectal projections, as in Poecilaemula, Rhaucoides, Rhauculus, and Rhauculanus, but differing from these genera by the presence of a meso-apical projection (see Figs. 3B and 6A). Ectal projections of the basal segment of the chelicerae are absent in Erginulus, Meterginus, and Trinimontius. Clavi inguines are multi-tuberculated in Rhaucus, being absent in Erginulus, Meterginus, Poecilaemula, and Rhaucoides, and being a single tubercle in Arucillus, Rhauculanus, and Rhauculus. Male Cx IV bears a multi-capitate apical apophysis, present in Rhaucoides and Rhauculus, and is a single triangular apophysis in Erginulus and Meterginus. Fe III and IV are curved and granulated in almost all genera of Metergininae including Rhaucus, except in Poecilaemula which are straight and smooth, and Rhaucoides with sub-straight Fe III and IV. Ornamentation of Fe and Ti III and IV presents ventral rows of tubercles of variable size in Rhaucus and Rhaucoides, differing from Erginulus, Meterginus, and Rhauculanus, where only leg IV is armed. The genital morphology in Rhaucus presents a short VP covered by microsetae T4 on the lateral fields, not reaching the medial field, as well as in Arucillus, Meterginus, Rhaucoides, and Erginulus. Rhaucus can be differentiated from Arucillus by the spoon-shaped or finger-shaped dorsal process of the glans, being sub-triangular in Arucillus; from Rhaucoides by the absence of a ventro-basal protuberance (see Fig. 5c in Medrano et al., 2022); and in general, Rhaucus differs from all remaining Metergininae by the presence of Ventral MS E and B, which are volcano-shaped and/or areolate, being areolate on MS B.
Species included: Rhaucus artifex sp. nov.; R. florezi Garcia & Kury, 2017; R. gaiterus sp. nov.; R. marmoratus (Roewer, 1912) comb. nov.; R. papilionaceus (Simon, 1879); R. quinquelineatus Simon, 1879; R. robustus (Mello-Leitão, 1941); R. serratus (Roewer, 1912) comb. nov.; R. serripes (Simon, 1879); R. trilineatus (Sørensen, 1932) [by implication], and R. vulneratus Simon, 1879 (type species).
description: Published as part of Pinzón-M, Conchita & Pinto-Da-Rocha, Ricardo, 2024, Two new species of Rhaucus Simon, 1879 reveal putative synapomorphies related to the microstructural morphology of male genitalia (Opiliones: Cosmetidae), pp. 35-56 in Zootaxa 5555 (1) on pages 37-38, DOI: 10.11646/zootaxa.5555.1.3, http://zenodo.org/record/14508494