Cybaeus consocius, Chamberlin & Ivie, 1932

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae): the consocius species group of the Californian clade, Zootaxa 4965 (3), pp. 401-436 : 402-403

The consocius species group

Diagnosis. The species of the consocius group of the Californian clade are defined by a combination of the following characters: the anterior to medially located undivided ( Figs 5, 13, 30, 37, 46, 52, 64, 74) or divided atrium ( Figs 23, 26), the well-developed, often distinctly looped and/or somewhat membranous copulatory ducts of which the proximal sections (closest to the atrium) do not envelop or loop around the more distal sections (closest to the spermathecal heads) ( Figs 7, 15, 25, 39, 54, 67, 75), and the roughly quadrangular shape of the vulva ( Figs 6, 14, 24, 38, 47, 65, 75).

The members of the devius group are most similar to those of the consocius group but differ in their possession of copulatory ducts in which the proximal sections partially envelop or loop around the more distal sections (e.g., Copley et al. 2009, fig. 9). The other Californian clade species groups are characterized either by transverse ridges or “wrinkles” on the epigynum (aspenicolens and septatus groups; e.g., Copley et al. 2009, figs 6, 12, 65, 95, 101; Bennett et al. 2021, figs 34–35, 38), straight, longitudinally oriented copulatory ducts and a triangular vulva (tardatus group; e.g., Copley et al. 2009, fig. 10), or reduced laterally projecting copulatory ducts and very short spermathecal stalks (adenes group; e.g., Bennett et al. 2019, figs 6, 8, 16–17).

Description. Medium- to large-sized spiders, carapace lengths averaging 2.11–3.0 mm (females), sexes subequal. Abdomen patterned, legs usually unbanded. Two or three complete pairs of ventral tibia I macrosetae; terminal pair absent, incomplete, or present: pattern 2-1p-2-1p-0(or 1p or 2).

Male: Patellar apophysis ( Figs 2, 34, 43, 60, 69, 72) anteriorly or anterolaterally directed, often species specific, length about 1/3 to as long as width of patella. Number and placement of peg setae variable, diagnostic for some species. Retrolateral tibial apophysis ( Figs 33, 59, 68) carinate, nearly as long as tibia. Embolus ( Figs 11, 28, 61, 82) relatively short, somewhat thickened, flattened and ribbon-like in one species ( Figs 70–71). Tegular apophysis with distal arm short, relatively broad but not enlarged or lengthened; proximal arm prolaterally directed, variously developed, species specific ( Figs 3, 11, 18, 35, 44, 61, 70).

Female: Atrium ( Figs 5, 16, 30, 37, 46, 64, 77) usually undivided, variously shaped, anteriorly to medially located on epigynum; distinctly divided in one species ( Figs 23, 26). Copulatory ducts ( Figs 6–7, 14–15, 25, 32, 39, 50, 75) well developed, lightly sclerotized; often broadly attached to atrium but with inconspicuous, somewhat membranous margins. Spermathecal heads small, dorsal lobes ( Figs 7, 25, 67, 32, 54, 79). Spermathecal stalks usually very short, slender, undifferentiated, contiguous or separate in region of Bennett’s glands ( Figs 7, 54, 66– 67); relatively long, slender, and sinuous in two species ( Figs 39, 41). Bennett’s glands close to junction of stalks with rounded bases. Fertilization ducts exiting bases near to junction with stalks.

Composition and distribution. Nine species: Cybaeus consocius Chamberlin & Ivie , C. hesper Chamberlin & Ivie , C. hummeli Bennett spec. nov., C. opulentus spec. nov., C. pan Bennett spec. nov., C. penedentatus Bennett , C. simplex Roth , C. ubicki Bennett spec. nov., and C. vulpinus Bennett. Eight of these species have restricted distributions in California U.S.A. in the north and central Sierra Nevada Mountains from Butte and Plumas Counties south to Tuolumne County and along the coast from southern Mendocino County south to Monterey County; one species ( C. simplex ) is relatively broadly distributed in western Oregon U.S.A.