Cybaeus opulentus Bennett, 2021

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae): the consocius species group of the Californian clade, Zootaxa 4965 (3), pp. 401-436 : 412-414

Cybaeus opulentus Bennett spec. nov.

Figs 27–32 , 55 , 86

Type material. U.S.A.: California: Holotype male, El Dorado County, 4 mi. W of Kyburz , 15.ix.1959, W.J. Gertsch & V. D. Roth ( AMNH) . Paratypes: Alpine. 1♀, North Fork Mokelumne River at Hwy #4, 7000’, 17.viii.1990, D. Ubick ( CAS) ; 1♂, Woods Lake , 8300’, 16.viii.1990, D. Ubick ( CAS) ; El Dorado. 1♂, Bridal Veil Falls , 10.5 mi. E of Camino, 3400’, 4.ix.1999 (matured), D. Ubick & T. Briggs ( CAS) ; 3♂, Echo Summit , 7377’, 19.ix.1963, W.J. Gertsch ( AMNH) ; 4♂ 3♀, Echo Summit , 7382’, 9.ix.1959, W.J. Gertsch & V. D. Roth ( AMNH) ; 1♂, 2.ix.1961, W.J. Gertsch & W. Ivie ( AMNH) ; 2♂ 3♀, Fallen Leaf Lake , 9.ix.1959, W.J. Gertsch & V. D. Roth ( AMNH) ; 2♂ 1♀, 14.4 km. E of Georgetown , 1300 m., 18.ix.2012, C. Pavla & G. Griswold ( CAS) ; 3♂, 15.2 km. E of Georgetown , 1300 m., 16.ix.2012, C. Pavla & G. Griswold ( CAS) ; 1♂, Kyburz , 15.ix.1959, W.J. Gertsch & V. D. Roth ( AMNH) ; 1♀, Riverton , 22.ii.1958, R. O. Schuster ( CAS) ; 2♂ 8♀, 3 mi. W of Riverton , 9.ix.1959, W.J. Gertsch & V.D. Roth ( AMNH) ; Placer . 1♀, Baxter , 3900’, 12.vii.1990. D. Ubick ( CAS) ; 1♂, 6 mi. NE of Foresthill , 3480’, 27.xii.1986, D. Ubick ( CAS) ; 1♂ 2♀, 9 mi. NE of Foresthill , 3720’, 27.xii.1986, D. Ubick ( CAS) .

Etymology. The specific epithet is from a Latin adjective meaning rich or wealthy and refers to the distribution of this species in eastern California in the vicinity of Lake Tahoe as well as to the central importance of the area to the California gold rush of the mid nineteenth century.

Diagnosis. The male of C. opulentus spec. nov. is unlikely to be confused with the males of the other species in the consocius group and is diagnosed by the unique form of the proximal arm of its tegular apophysis. The base of the proximal arm bears a prominent protrusion and the tip of the proximal arm is slightly twisted ( Figs 28–29 , 55 ). Among the other males in the consocius group only C. simplex is similar. In the male of C. simplex the proximal arm bears a much more prominent basal protrusion and the tip is strongly twisted ( Figs 1 , 61–63 ). In addition, the patellar apophysis in the male of C. opulentus spec. nov. bears more peg setae (30–40 [ Fig. 27 ] versus 15–25 in C. simplex [ Fig. 60 ]) and the retrolateral tibial apophysis does not extend distally beyond the end of the tibia ( Fig. 27 ) (versus retrolateral tibial apophysis with a significant distal extension in C. simplex [ Fig. 59 ]). Among the females of the consocius group, the female of C. opulentus spec. nov. is only likely to be confused with the other species which lack U-shaped copulatory ducts: C. ubicki spec. nov., C. penedentatus , C. vulpinus , C. pan spec. nov., and C. simplex . From those species the female of C. opulentus spec. nov. is distinguished by a combination of atrium wide, occupying about 2/3 the width of the vulva and located on anterior third of the vulva ( Figs 30–31 ) (versus atrium much smaller, about 1/3 the width of the vulva, and usually located on the medial third of the vulva in C. penedentatus [ Figs 46–47 , 52–53 ] or atrium located on medial third of the vulva and wider, nearly as wide as the vulva, in C. ubicki spec. nov. [ Figs 74–75, 77–78 ]); copulatory ducts and spermathecal stalks short and spermathecal stalks noncontiguous along midline of vulva ( Figs 31–32 ) (versus copulatory ducts and spermathecal stalks relatively long and spermathecal stalks contiguous along vulval midline in C. simplex [ Figs 65–67 ]; copulatory ducts contiguous at the atrium as well as partway between the atrium and the spermathecal heads ( Figs 31–32 ) (versus contiguous only at the atrium in C. pan spec. nov. [ Figs 38–39 ] and C. vulpinus [ Figs 40–41 ]).

Description. Ventral tibia I macrosetae 2-1p-2-1p-1p(or 2 or 0).

Male: (n=23). Patellar apophysis ( Fig. 27 ) relatively short, length about 2/3 width of patella. Tip of proximal arm of tegular apophysis ( Figs 28 , 55 ) elongate. Measurements (n=15). CL 2.43–3.3 (2.9±0.2), CW 1.80–2.35 (2.09±0.17), SL 1.25–1.58 (1.40±0.09), SW 1.17–1.45 (1.34±0.08). Holotype CL 2.8, CW 1.93, SL 1.33, SW 1.30.

Female: (n=20).Atrium ( Fig. 30 ) transverse, arched. Copulatory ducts ( Figs 31–32 ) broad at atrium, convergent anteriorly along midline of vulva then turning posteriorly. Measurements (n =18). CL 2.40–3.2 (2.8±0.2), CW 1.60–2.18 (1.94±0.17), SL 1.18–1.50 (1.36±0.09), SW 1.09–1.45 (1.30±0.09).

Distribution and natural history. South central Sierra Nevada region of eastern California south and west of Lake Tahoe in Alpine, El Dorado, and Placer Counties ( Fig. 86 ). Mature males have been collected from August through September and in December.

Figures

FIGURE 86. Distributions of Cybaeus pan spec. nov., C. vulpinus, and C. opulentus spec. nov. AZ—Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California county names capitalized.

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 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 55–58. Cybaeus spp. males from California, left palpus, proximal arm of tegular apophysis (55 C. opulentus spec. nov. from Riverton, 56 C. penedentatus from Holy City, 57 C. vulpinus from Columbia, 58 C. pan from Calpine) (55–56 ventral, 57–58 prolateral). Arrows indicate diagnostic characters (55 slightly twisted tip and prominent basal protrusion; 56 acuminate slightly twisted tip and longitudinal ventral keel; 57 smoothly curved, twisted tip; 58 triangular keel dorsally on tip).

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 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 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 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 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 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.