Cybaeus adenes Chamberlin & Ivie 1932

Bennett, Robb, Copley, Claudia & Copley, Darren, 2019, Cybaeus (Araneae: Cybaeidae): the adenes species group of the Californian clade, Zootaxa 4711 (2), pp. 245-274 : 248-250

Cybaeus adenes Chamberlin & Ivie 1932

Figs 1–11 , 59–60 , 69

Cybaeus adenes Chamberlin & Ivie 1932: 24 , fig. 59 (in part, holotype only). Roewer 1954: 89. Bonnet 1956: 1300. Roth 1956: 178. Roth & Brown 1986: 3. Bennett 2006: 479, Figs 17–20 . Copley et al. 2009: 372, fig. 5. World Spider Catalog 2019.

Cybaeus grizzlyi: Roth 1956: 178 . Roth & Brown 1986: 3.

Cybaeus adenoides: Roth 1956: 178 . Roth & Brown 1986: 3.

Type material. Holotype ♀. U.S.A.: California: Marin County, R. V. Chamberlin ( AMNH), examined but subsequently lost. Neotype ♂ designated by Bennett (2006) from U.S.A.: California: Marin County, San Geronimo (37°59'N 122°42'W), 19 September 1963, J. Ivie & W. Ivie ( AMNH), examined. See discussion of type material and synonymy in Bennett (2006).

Other material examined. Specimens and locality data in Bennett (2006). (Note: Green Valley locality, considered by Bennett (2006) to be “probably Sonoma Co.”, could be in Solano Co.)

Diagnosis. The male of C. adenes is diagnosed by the morphology of the proximal arm of the tegular apophysis: tip bifid with the two tips slightly divergent ( Figs 1 , 59–60 ). Known males of the other species of the adenes group have either a single ( C. amicus : Fig. 56 ; C. auburn : Fig. 63 ; C. grizzlyi : Fig. 61 ) or trifid ( C. reducens : Fig. 57 ) tip on the proximal arm of the tegular apophysis. Males of some species also have a bifid tip of the proximal arm of the tegular apophysis but in those males there are fewer peg setae on the patellar apophysis and the bifid tips are more or less convergent ( C. sanbruno : Figs 45 , 67 ; C. schusteri : Figs 51 , 65 ).

The female of C. adenes is distinguished from all other females of the adenes group except C. grizzlyi by the form of the atrium. The atrium in females of C. adenes and C. grizzlyi is inverted U-shaped or lyriform, relatively narrow (length from epigastric groove to anterior margin> width between lateral margins), and widest anteriorly ( C. adenes : Figs 4, 7 , 9 ; C. grizzlyi : Fig. 30 ). The atrium in females of all other species of the adenes group either has its lateral ends strongly curved anteriorly ( C. sanbruno : Figs 47–48 ), is inverted U- or vase-shaped (but not lyriform) and widest posteriorly ( C. schusteri : Fig. 53 ; C. amicus : Figs 15–16 ; C. torosus : Fig. 54 ; C. pearcei : Fig. 33 ), or is relatively broad with length <width ( C. reducens : Figs 38, 41, 43 ; C. auburn : Figs 21–22 ). (Most females of C. schusteri are distinguished by the inverted vase-shaped atrium ( Fig. 53 ) but the atrial morphology of some specimens may resemble that of females of C. adenes and C. grizzlyi . Collection of males with females may be the only way to ensure reliable identification in such instances.) Females of C. grizzlyi and C. adenes apparently are morphologically indistinguishable but can be separated by their respective distributions: both are found in the San Francisco Bay area of California but C. grizzlyi appears to be restricted to Contra Costa and Alameda Counties to the east of San Francisco Bay ( Fig. 70 ) while C. adenes is more widespread and found to the north and east of the Bay area in Marin, Napa, Sonoma, San Francisco, and possibly Solano Counties ( Fig. 69 ).

Description. Femora unbanded.

Male: (n=9). Patellar apophysis ( Fig. 2 ) with variable number of peg setae (most specimens have about two dozen) on concave or convex antero-dorsal surface. Very small retrolateral ridge anteriorly on tibia dorsal to carinate retrolateral tibial apophysis ( Fig. 3 ). Dorsal keel ( Figs 59–60 ) present on proximal arm of tegular apophysis, usually inconspicuous but occasionally prominent.

(n=8). CL 2.15–2.6 (2.5), CW 1.60–2.00 (1.83), SL 1.08–1.29 (1.22), SW 1.00–1.26 (1.17). Neotype CL 2.45, CW 1.80, SL 1.22, SW 1.17.

Female: (n=39). Atrium ( Figs 4, 7 , 9 ) usually conspicuous, occasionally indistinct such that atrium may appear divided, anterior margin often sinuous, length of atrium (from epigastric groove to anterior margin) 1.5–2 times width (between lateral margins). Copulatory ducts ( Figs 5–6, 8 , 10–11 ) well separated, attached to lateral margins of atrium.

(n=22). CL 1.58–2.8 (2.2±0.3), CW 1.12–1.90 (1.49±0.23), SL 0.86–1.35 (1.10±0.14), SW 0.79–1.28 (1.02±0.13). Holotype (lost) CL 2.20, CW 1.55, SL 1.12, SW 1.05.

Distribution and natural history. West central California: Marin, Napa, San Francisco, Sonoma, and possibly Solano Counties in the San Francisco Bay area ( Fig. 69 ). Males have been collected from mid-September to mid- November. Cybaeus adenes and C. grizzlyi are the most commonly encountered species of the adenes group.

Figures

FIGURE 69. Distributions of Cybaeus adenes (●), C. amicus. (), C. grizzlyi (○). CA—California, OR—Oregon, NV—Nevada.

FIGURE 70. Distributions of Cybaeus auburn spec. nov. (▪), C. reducens (□), C. sanbruno (), C. schusteri spec. nov. (●). CA—California, OR—Oregon, NV— Nevada.

FIGURES 1–3. Cybaeus adenes, male from San Francisco, California, left palpus (1 genital bulb, ventral; 2 patella and tibia, dorsal; 3 patella and tibia, retrolateral). DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RR—retrolateral ridge dorsal to retrolateral tibial apophysis, RTA—retrolateral tibial apophysis. Scale bars: 0.1 mm.

FIGURES 4–8. Cybaeus adenes, females (4–6 holotype; 7–8 from San Geronimo, California), copulatory organ (4 epigynum, ventral; 5 vulva, ventral; 6 same, dorsal; 7 atrium, ventral; 8 vulva, dorsal). AT—atrium, BG—Bennett’s gland, BS—base of spermatheca, CD—copulatory duct, HS—head of spermatheca, SS—stalk of spermatheca. Scale bars: 0.1 mm.

FIGURES 9–11. Cybaeus adenes, females from vicinity of St. Helena, California, copulatory organ (9 epigynum, ventral; 10 vulva, ventral; 10 same, dorsal). Scale bars: 0.1 mm.

FIGURES 56–60. Cybaeus spp., male left palpi, detail of tegular apophysis. 56 C. amicus from San Mateo County, California. 57–58 C. reducens from Santa Clara County, California. 59 C. adenes from San Francisco, California. 60 C. adenes from San Geronimo, California (56–57 proximal arm, ventral; 58 tegular apophysis, retrolateral; 59–60 proximal arm, ventral). Red arrows indicate single (Fig. 56) and trifid (Fig. 57) tips of proximal arm. Red lines indicate divergence of tips of proximal arm. DA—distal arm of tegular apophysis, DK—dorsal keel of proximal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis. Scale bars: 0.05 mm (Figs 56–57, 59–60), 0.1 mm (Fig. 58).

FIGURES 15–17. Cybaeus amicus, females (15 from Stanford University, California; 16–17 from Holy City, California), copulatory organ (15 epigynum, ventral; 16 vulva, ventral; 17 same, dorsal). CD—copulatory duct. Scale bars: 0.1 mm.

FIGURES 18–20. Cybaeus auburn spec. nov., male holotype, left palpus (18 genital bulb, ventral; 19 patella and tibia, dorsal; 20 patella and tibia, retrolateral). PA—proximal arm of tegular apophysis. Scale bars: 0.1 mm.

FIGURES 61–64. Cybaeus spp., male left palpi, detail of tegular apophysis. 61–62 C. grizzlyi from Berkeley, California. 63–64 C. auburn spec. nov. holotype (61 proximal arm, ventral; 62 tegular apophysis, retrolateral; 63 proximal arm, ventral; 64 tegular apophysis, retrolateral). Red arrows indicate single tips of proximal arm. DK—dorsal keel (Figs 61–62) or blunt process (Figs 63–64) of proximal arm of tegular apophysis, E—embolus. Scale bars: 0.05 mm (Figs 61, 63), 0.1 mm (Figs 62, 64).

FIGURES 44–46. Cybaeus sanbruno, male from San Bruno Mountain, California, left palpus (44 genital bulb, ventral; 45 patella and tibia, dorsal; 46 patella and tibia, retrolateral). DK—dorsal keel of proximal arm of tegular apophysis, RR—retrolateral ridge dorsal to retrolateral tibial apophysis. Scale bars: 0.1 mm.

FIGURES 65–68. Cybaeus spp., male left palpi, detail of tegular apophysis. 65–66 C. schusteri spec. nov. holotype. 67–68 C. sanbruno from San Bruno Mountain, California (65 proximal arm, ventral; 66 tegular apophysis, retrolateral; 67 proximal arm, ventral; 68 tegular apophysis, retrolateral). Red lines indicate convergence of tips of proximal arm. DK—dorsal keel of proximal arm of tegular apophysis, E—embolus. Scale bars: 0.05 mm (Figs 65, 67), 0.1 mm (Figs 66, 68).

FIGURES 50–53. Cybaeus schusteri spec. nov. (50–52 male holotype, left palpus; 53 female from south of Monticello, California), copulatory organ (50 genital bulb, ventral; 51 patella and tibia, dorsal; 52 patella and tibia, retrolateral; 53 vulva, ventral). DK—dorsal keel of proximal arm of tegular apophysis, RR—retrolateral ridge dorsal to retrolateral tibial apophysis. Scale bars: 0.1 mm.

FIGURES 28–30. Cybaeus grizzlyi, females (28 from hills above Berkeley, California; 29 lectotype of C. adenoides; 30 from Orinda, California), copulatory organ (28 teneral vulva, dorsal; 29 vulva, dorsal; 30 atria, ventral). CD—copulatory duct, HS—head of spermatheca. Scale bar: 0.1 mm.

FIGURES 47–49. Cybaeus sanbruno, females from San Bruno Mountain, California, copulatory organ (47 epigynum, ventral; 48 vulva, ventral; 49 same, dorsal). Scale bars: 0.1 mm.

FIGURES 54–55. Cybaeus torosus spec. nov., female holotype, copulatory organ (54 epigynum, ventral; 55 vulva, dorsal). Scale bars: 0.1 mm.

FIGURES 33–34. Cybaeus pearcei spec. nov., female holotype, copulatory organ (33 epigynum, ventral; 34 vulva, dorsal). CD—copulatory duct, HS—head of spermatheca. Scale bar: 0.1 mm.

FIGURES 38–43. Cybaeus reducens, females (38–40 from Carmel, California; 41–43 from south of Big Sur, California), copulatory organ (38 epigynum, ventral; 39 vulva, ventral; 40 same, dorsal; 41 epigynum ventral; 42 vulva, ventral; 43 same, dorsal). Scale bars: 0.1 mm.

FIGURES 21–24. Cybaeus auburn spec. nov., females from vicinity of Nashville, California, copulatory organ (21 epigynum, ventral; 22 vulva, ventral; 23–24 same, dorsal). CD—copulatory duct, EP—epigynal pit. Scale bars: 0.1 mm.