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.

Figures

FIGURES 5–9. Cybaeus consocius, females from California, copulatory organ (5–7 holotype, 8 from Mount Tamalpais, 9 from near Oakville). 5 Epigynum, ventral. 6–8 Vulva (6, 8 ventral, 7 dorsal). 9 Atria, ventral. BG—Bennett’s gland, CD—copulatory duct, HS—head of spermatheca, SS—stalk of spermatheca. Unlabelled arrows indicate anterior margin of atrium.

FIGURES 13–17. Cybaeus spp., females, copulatory organ (13–15 C. hesper, syntype of C. minor; 16–17 C. consocius, holotype of C. marinensis). 13, 16 Epigynum, ventral; 14–15, 17 Vulva (14, 17 ventral, 15 dorsal). CD—copulatory duct. Unlabelled arrows indicate anterior margin of atrium.

FIGURES 30–32. Cybaeus opulentus spec. nov., female from Riverton, California, copulatory organ. 30 Epigynum, ventral. 31–32 Vulva (31 ventral, 32 dorsal). BG—Bennett’s gland, CD—copulatory duct, HS—head of spermatheca.

FIGURES 37–41. Cybaeus spp., females from California, copulatory organ (37–38 C. pan spec. nov. from near Calpine, 39 C. pan spec. nov. from Sierra City, 40–41 C. vulpinus from Big Trees State Park). 37 Epigynum, ventral. 38–41 Vulva (38, 40 ventral; 39, 41 dorsal). CD—copulatory duct, SS—spermathecal stalk. Unlabelled arrow indicates epigynal notch.

FIGURES 46–51. Cybaeus penedentatus, females from California, copulatory organ (46–48 from Ben Lomond, 49 from Pescadero Creek, 50–51 from Mount Madonna). 46 Epigynum, ventral. 47–51 Vulva (47, 49–50 ventral; 48, 51 dorsal). AT—atrium.

FIGURES 52–54. Cybaeus penedentatus, female from Brookdale, California, copulatory organ. 52 Epigynum, ventral. 53–54 Vulva (53 ventral, 54 dorsal). AT—atrium.

FIGURES 64–67. Cybaeus simplex, females from Cascadia, Oregon, copulatory organ. 64 Epigynum, ventral. 65–67 Vulva (65 ventral, 66–67 dorsal). CD—copulatory duct.

FIGURES 74–79. Cybaeus ubicki spec. nov., females from California, copulatory organ (74–76 from Point Reyes Station, 77– 79 from Anchor Bay). 74, 77 Epigynum, ventral. 75–76, 78–79 Vulva (75, 78, ventral, 76, 79 dorsal). CD—copulatory duct.

FIGURES 23–26. Cybaeus hummeli spec. nov., females from California, copulatory organ (23–25 from Miramar, 26 from San Francisco). 23, 26 Epigynum, ventral. 24–25 Vulva (24 ventral, 25 dorsal). CD—copulatory duct.

FIGURES 1–4. Cybaeus spp., males, left palpus (1 C. simplex from Ashland watershed, Oregon; 2–4 C. consocius from Muir Woods, California). 1 Patella, tibia, and genital bulb, ventral. 2 Patella and tibia, dorsal. 3–4 Genital bulb (3 ventral, 4 retrolateral). DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PS—peg setae, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 33–36. Cybaeus pan spec. nov., male from Calpine, California, left palpus. 33–34 Patella and tibia (33 retrolateral, 34 dorsal). 35–36 Genital bulb (35 ventral, 36 retrolateral). PA—proximal arm of tegular apophysis. PTA—patellar apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrows indicate simple curve of dorsal margin of tegular apophysis.

FIGURES 42–45. Cybaeus penedentatus, male from Holy City, California, left palpus. 42–43 Patella and tibia (42 retrolateral, 43 dorsal). 44–45 Genital bulb (44 ventral, 45 retrolateral). PA—proximal arm of tegular apophysis. PTA—patellar apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrows indicate ventral keel of proximal arm of tegular apophysis.

FIGURES 59–63. Cybaeus simplex, males from Oregon, left palpus (59 from Ashland watershed, 60–63 from H.J. Andrews Experimental Forest). 59 Tibia, retrolateral. 60 Patella and tibia, dorsal. 61–62 Genital bulb (61 ventral, 62 retrolateral). 63 Tip of proximal arm of tegular apophysis, ventral. Arrows indicate diagnostic characters (59 distal extension of retrolateral tibial apophysis, 61 strongly twisted tip and prominent basal projection of proximal arm of tegular apophysis, 62 compound curve of dorsal margin of tegular apophysis).

FIGURES 68–71. Cybaeus ubicki spec. nov., males from California, left palpus (68–69, 71 from Novato, 70 from Anchor Bay). 68–69 Patella and tibia (68 retrolateral, 69 dorsal). 70–71 Genital bulb (70 ventral, 71 retrolateral). E—embolus, PA—proximal arm of tegular apophysis. RTA—retrolateral tibial apophysis. Unlabelled arrows indicate dorsal tibial ridge and dorsal prominence of patellar apophysis.

FIGURES 72–73. Cybaeus ubicki spec. nov., male from Novato, California, left palpus. 72 Patellar apophysis, ventral. 73 Proximal arm of tegular apophysis, ventral. Arrows indicate diagnostic characters (72 dorsal prominence of patellar apophysis, 73 ventral longitudinal groove of proximal arm of tegular apophysis).

FIGURES 10–12. Cybaeus hesper, male from Skyline Boulevard at King’s Mountain, California, right palpus. 10 Patella and tibia, dorsal. 11–12 Genital bulb (11 ventral, 12 retrolateral). PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 27–29. Cybaeus opulentus spec. nov., male from Riverton, California, left palpus. 27 Patella and tibia, dorsal. 28–29 Genital bulb (28 ventral, 29 retrolateral). PA—proximal arm of tegular apophysis. Unlabelled arrows indicate compound curve of dorsal margin of tegular apophysis.

FIGURES 80–83. Cybaeus vulpinus, male from Columbia, California, left palpus. 80–81 Patella and tibia (80 retrolateral, 81 dorsal). 82–83 Genital bulb (82 ventral, 83 retrolateral). Arrows indicate simple curve of dorsal margin of tegular apophysis.

FIGURES 18–19. Cybaeus hummeli spec. nov., male from Skyline Boulevard at King’s Mountain, California, left palpus, genital bulb (18 ventral, 19 retrolateral). E—embolus, PA—proximal arm of tegular apophysis.