Elpidium F. Muller 1880

GenusElpidiumF. Müller, 1880 Type species (by original designation): Elpidium bromeliarum F. Müller, 1880. Type locality. Itajaí, Santa Catarina state, Brazil. Other species included. E. alarconi sp. nov.; E. chacoense Díaz et al., 2024; E. cordiforme Pereira et al., 2023; E. eriocaularum Pereira et al., 2023; E. heberti Pereira et al., 2019; E. higutiae Pereira et al., 2023; E. inaequivalve Danielopol, 1981; E. laesslei (Tressler, 1956); E. litoreum Pereira et al., 2022; E. littlei Pereira et al., 2019; E. maricaoense (Tressler, 1941); E. martensi Danielopol et al., 2014; E. merendonense Pinto & Jocqué, 2013; E. oxumae Pereira et al., 2023; E. picinguabaense Pereira et al., 2023; E. pintoi Danielopol, 1981; E. purium Pereira et al., 2023; E. purperae Danielopol, 1981; E. wolfi Pereira et al., 2019. Diagnosis. [Modified after Danielopol et al. (2014) and Pereira et al. (2022, 2023)]. Timiriaseviidae of intermediate size (0.6–1.1 mm) with sexually dimorphic carapace, broad and ventrally flat. Females relatively wider than males, due to the presence of a brood pouch, and usually also larger. Valves symmetric or asymmetric in dorsal view, carapace surface of most species with subtle ornamentation of minute and shallow pits (except E. laesslei, which is strongly ornamented). At the mouth part, a funnel structure is internally built in the carapace between both valves. Four apparent adductor muscle scars arranged subvertically (at ~ 15–30 ° oblique from the vertical axis towards the anterior part from top to bottom). Hinge protodont, with a bar on the smaller valve, which may have prototeeth anteriorly and posteriorly, and a groove in the larger one. A 1 apparently six-segmented in most species: with five clearly separated segments, but in most species the fourth segment appears as partially subdivided (4 a + 4 b). A 1 with a dorsal apical expansion in the first segment. A 2 sexually dimorphic; three terminal claws in the last segment, one of which is pectinated only in males. Last segment of A 2 distally with a small hyaline formation. Mx with two spatulate claws and three normal setae in each of the second and third endites. Hp strongly sclerotized, CR reduced to a pair of setae. Distal lobe very apparent and varied in shape, usually subtriangular or subrectangular, but in some species with a small (pointed or digitiform) expansion in its internal border, always with a basal seta. CoP curved (hook-like, curled, U-shaped or L-shaped), with a tip either subdivided or not in ejaculatory glans and duct. Lower ramus varied in shape. Upper ramus absent. Female abdomen rounded, with a dorsal spine-like seta, sclerotized genital lobes, and three setae on each CR lobe.