Oedothorax trilobatus
Creators: name: Lin, Shou-Wang
name: Lopardo, Lara
name: Uhl, Gabriele
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Linyphiidae
Oedothorax
Oedothorax trilobatus

description: OEDOTHORAX TRILOBATUS (BANKS, 1896)
(FIGS 7P, 8B, 9B, 17; SUPPORTING INFORMATION, FIG. S1B)
Dicyphus trilobatus Banks, 1896: 64 (Dm).
Hypomma trilobata Crosby, 1905: 310.
Lophocarenum trilobatum Emerton, 1909: 191, pl. 3, fig. 1 (m).
Oedothorax trilobatus Bishop & Crosby, 1935: 268, pl. 22, figs 7, 8 (m, Df).
Oedothorax trilobatus Paquin & Dupérré, 2003: 115, figs 1190–1193 (mf).
Oedothorax trilobatus Marusik et al., 2010: 287, figs 3–11 (mf).
Type material: Bishop & Crosby (1935) stated that the type locality was Ithaca, New York, but no type designation data was provided by Banks (1896). The original and subsequent descriptions, nevertheless, make the identification of this species unequivocal.
Examined material: USA: New York, McLean 2♂ 8.v.1919 (AMNH); Laborador Pond, 1♂ 14.v.1921, Tarris Sherman, C. Bishop Collection (AMNH); Alaska, Matanuska (61° N, 149° W), 1♂ 20.v.1945, coll. J. C. Chamberlin, det. Wilton Ivie (AMNH); Matanuska (61°32’ N, 149°12’ W), 1♂ v.–vi.1944, coll. J. C. Chamberlin, det. Wilton Ivie (AMNH); Wyoming, Teton Park (Two Ocean Lake), (43° N, 110° W), 1♂ 18.viii.1950, coll. D. C. Lowrie (AMNH); Ontario, Lake Temagami, Island 1024 (46°59’ N, 80°3’ W), 1♂ 8♀ 15.– 25.viii.1946, coll. Gertsch, Ivie, Kurata, det. Wilton Ivie (AMNH); Utah, Smith & Morehouse Canyon (40°47’ N, 111°6’ W), 2♂ 2♀ 3.vi.1934, coll. and det. Wilton Ivie (AMNH). Canada: British Columbia, Terrace, 1♂ 1.–10.vi.1931, leg. Hippisley, Sherman C. Bishop Collection (AMNH).
Diagnosis:
Males: This species can be identified by the shape of post-ocular groove and hump, different from all other species with similar prosomal modifications by the anterior side of the hump having one central and two lateral lobes.
Females: Similar to females of other species in the Oedothorax s.s., but can be identified by its long and maneuvering copulatory ducts in epigyne (Fig. 17E, F); distinguished from Oe. fuscus, Oe. agrestis, Oe. meridionalis and Oe. tingitanus by having one sub- AME seta instead of two.
Description:
Male (Matanuska, 61° N, 149°W): Total length: 2.22. Prosoma: 0.98 long, 0.79 wide, postocular region with transverse hairy groove, posterior to the groove a hump anteriorly divided into three lobs; interocular region with thin, translucent setae directed laterally (Fig. 7P). Eyes: AME-AME: 0.03, AME width: 0.05, AME-ALE: 0.03, ALE width: 0.07, ALE-PLE: 0.01, PLE width: 0.07, PLE-PME: 0.05, PME width: 0.05, PME-PME: 0.14. Clypeus: not hirsute, one sub-AME seta. Sternum: 0.62 long, 0.62 wide. Chelicerae: mastidia absent; stridulatory striae rows widely and evenly spaced (Fig. 8B). Legs: dorsal proximal macroseta on tibia I, II, III and IV 0.21, 0.19, 1.19 and 1.06 times diameter of tibia, respectively; Tm I: 0.68. Pedipalp: TPA long, rod-like and scaly at tip, prolateral side laterally extended, median site with smaller rod-like projection with scaly tip; BT absent (Fig. 17C); PC short, base visible from dorsal view, distal setae at median position (Fig. 17A); T without papillae, PT with papillae; TS short, without papillae (Fig. 17D); DSA tip broad and smoothly serrated (Fig. 17A); EM short, distally oriented, cylindrical, with long papillae (Fig. 17A); TP without small protuberances; E long, prolaterally spiral, not broadened at basal part (Fig. 17B). Opisthosoma: dark brown, evenly coloured (Fig. 9B).
Female (Ontario, Lake Temagami): Total length: 2.74. Prosoma: 1.17 long, 0.91 wide. Eyes: AME-AME: 0.03, AME width: 0.06, AME-ALE: 0.03, ALE width: 0.09, ALE-PLE: 0.01, PLE width: 0.09, PLE-PME: 0.04, PME width: 0.08, PME-PME: 0.07. Clypeus: not hirsute, one sub-AME seta. Sternum: 0.69 long; 0.65 wide. Legs: dorsal proximal macroseta on tibia I, II, III and IV 1.62, 1.64, 1.89 and 2.15 times diameter of tibia, respectively; Tm I: 0.75. Epigyne: Clade 13 characteristic morphology, borders between dorsal and ventral plates parallel, copulatory duct long, curved (Fig. 17E–G). Opisthosoma: brown, evenly coloured.
Variation: The measurements are based on examined material.
Males (N = 10, means in parentheses): Total length 1.91–2.40 (2.17). Prosoma: 0.94–1.04 (0.99) long, 0.76– 0.81 (0.79) wide. Legs: dorsal proximal macroseta on tibia I, II, III and IV 0.11–0.23 (0.18, N = 8), 0.15–0.40 (0.20, N = 7), 0.33–1.24 (0.82, N = 9) and 0.77–1.72 (1.36, N = 7) times diameter of tibia, respectively; Tm I: 0.63–0.69 (0.66, N = 9).
Females (N = 10, means in parentheses): Total length 2.57–3.04 (2.81). Prosoma: 1.07–1.25 (1.19) long, 0.83– 0.98 (0.92) wide. Legs: dorsal proximal macroseta on tibia I, II, III and IV 1.52–1.94 (1.64), 1.52–1.94 (1.64), 1.70–2.06 (1.87) and 1.80–2.44 (2.02) times diameter of tibia, respectively; Tm I: 0.35–0.75 (0.65).
Distribution: USA, Canada, Russia.
Habitat: In vegetation in/next to ponds or swamps.
description: Published as part of Lin, Shou-Wang, Lopardo, Lara & Uhl, Gabriele, 2022, Evolution of nuptial-gift-related male prosomal structures: taxonomic revision and cladistic analysis of the genus Oedothorax (Araneae: Linyphiidae: Erigoninae), pp. 417-584 in Zoological Journal of the Linnean Society 195 on pages 450-451, DOI: 10.1093/zoolinnean/zlab033, http://zenodo.org/record/6967774