Cybaeus cribelloides Chamberlin & Ivie, 1932

Bennett, Robb, Copley, Claudia & Copley, Darren, 2022, The Californian clade of Cybaeus (Araneae: Cybaeidae) in the Nearctic: the septatus species group and three unplaced species, Zootaxa 5100 (2), pp. 189-223 : 204-210

Cybaeus cribelloides Chamberlin & Ivie

Figs 51–62 , 85

Cybaeus cribelloides Chamberlin & Ivie 1932: 26 , fig. 62. Chamberlin & Ivie 1942: 18, figs 45, 46. Roewer 1954: 90. Bonnet 1956: 1301. Roth & Brown 1986: 3. Bennett 2006: 482, figs 26–27. World Spider Catalog 2021.

Cybaeus consocius Gertsch & Ivie 1936: 22 , fig. 48. Misidentification.

Cybaeus hystrix Chamberlin & Ivie 1942: 18 , fig. 47. Roewer 1954: 91. Roth & Brown 1986: 4.

Type material examined. U.S.A.: California: Holotype female of C. cribelloides from Marin County, no date, R . V . Chamberlin ( AMNH) . Holotype female of C. hystrix from Marin County, Redwood Highway , 38°N / 123°W, April, Cockerell ( AMNH) .

Localities of other material examined. U.S.A.: California: Contra Costa. S of Byron; Humboldt. Humboldt Redwoods State Park, N of Piercy; Marin. Audobon Canyon Ranch, vicinity of Muir Woods; Mendocino. Albion, Big River Camp, Dimmick State Park, Dunlap Camp, Hwy. 1 nr. Usal Road; Napa. Howell Mountain; Sonoma. vicinity of Camp Meeker, Cazadero, vicinity of Healdsburg, Monte Rio, Pine Flat Rd., Santa Rosa. Other localities data in Bennett 2006.

Diagnosis. The male of C. cribelloides is distinguished from other species of Californian clade Cybaeus by a combination of palpal tegular apophysis characters. The distal arm of the tegular apophysis ( Fig. 53 ) is large, broad, angular, and truncated while the tip of the proximal arm is bifurcate in retrolateral view ( Figs 54 , 56 ), appearing trifurcate in ventral view( Figs 53 , 55 ).

The female of C. cribelloides is diagnosed by the morphology of the epigynal atrium and the form of the spermathecal heads and stalks and Bennett’s glands. The atrium ( Figs 57, 60 ) features a pair of longitudinal atrial openings spanned anteriorly by a transverse hood. The heads, stalks, and Bennett’s glands ( Figs 58–59, 61–62 ) are, respectively, anteriad and usually bilobed (occasionally trilobed), long and convoluted (and often looped anteriorly), and usually strongly protruding. Furthermore, the stalks are usually distinctly visible through the integument of the uncleared epigynum in ventral view ( Figs 57, 60 ).

Also of some diagnostic use, most specimens of C. cribelloides are dark and heavily pigmented with a distinctly patterned abdomen and strongly banded femora while other Californian clade Cybaeus are generally pale, only weakly patterned, and with at best only very lightly banded femora.

Description. As in diagnosis. Other descriptive characters are presented here. Ventral tibia I macrosetae variable, usually two complete pairs with pattern 2–1p–2–1p–0(or 1p).

Male (n=56). Patellar apophysis ( Figs 51–52 ) about as long as width of patella with about 20 dorsal peg setae often with one or two slightly isolated at tip of apophysis. Retrolateral tibial apophysis about as long as palpal tibia ( Fig. 51 ). Embolus ( Figs 53–54 ) long, slender, smoothly curved. Distal arm of tegular apophysis ( Fig. 53 ) about as long as or slightly longer than wide. Tips of proximal arm of tegular apophysis ( Figs 53–56 ) bluntly acuminate in ventral view, sharply acuminate in retrolateral view.

Measurements (n=21). CL 2.15–3.2 (2.7+0.3), CW 1.58–2.28 (1.99+0.20), SL 1.08–1.48 (1.30+0.11), SW 1.05–1.40 (1.26+0.10).

Female (n=166). Epigynum ( Figs 57, 60 ) with small, arched hood anterior to well defined, central concave area between atrial openings. Copulatory ducts ( Figs 58–62 ) proceeding very short distance anteriorly from atrial openings then turning posteriorly and slightly converging before turning anteriorly and diverging to lead into the junction with the spermathecal heads and stalks. Bennett’s glands ( Figs 59, 61–62 ) located near junction of stalks with spermathecal bases, often strongly protruding.

Measurements (n=22). CL 1.96–2.8 (2.5+0.2), SW 1.39–2.13 (1.74+0.17), SL 0.94–1.33 (1.20+0.10), SW 0.91–1.29 (1.15+0.10). Holotypes: C. cribelloides CL 2.56, CW 1.78, SL 1.22, SW 1.21; C. hystrix CL 1.96, CW 1.39, SL 0.94, SW 0.91.

Distribution and natural history. North and central coastal California from Humboldt County south to San Francisco and Contra Costa Counties ( Fig. 85 ). Within this area C. cribelloides is one of the most commonly collected species of Cybaeus . One female was collected in the Sierra Nevada Mountains in El Dorado County and two other specimens are from Los Angeles. These specimens may be mislabelled (see discussion under C. consocius Chamberlin & Ivie in Bennett 2006 and Bennett et al. 2021b) and the localities have not been included in the map. Males have been collected from early October to mid-February.

Figures

FIGURES 51–54. Cybaeus cribelloides, males from California (51–52 from near Woodacre, 53–54 from Humboldt Redwoods State Park), left palpus. 51–52 Patella and tibia (51 retrolateral, 52 dorsal). 53–54 Genital bulb (53 ventral, 54 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrows indicate furcate tip of proximal arm.

FIGURES 55–56. Cybaeus cribelloides, male from Humboldt Redwoods State Park, California, left palpus. 55–56 Proximal arm of tegular apophysis (55 ventral, 56 retrolateral). Unlabelled arrows indicate furcate tip of proximal arm.

FIGURES 57–62. Cybaeus cribelloides, females from California (57–59 holotype of C. hystrix, 60–62 from S.P. Taylor State Park), copulatory organ. 57, 60 Epigynum, ventral. 58–59, 61–62 Vulva (58, 61 ventral, 59, 62 dorsal). AT—Atrial opening, BG—Bennett’s gland, HS—head of spermatheca.

FIGURES 85–87. Distributions of unplaced Californian clade Cybaeus spp. (85 C. cribelloides, 86 C. gidneyi, 87 C. irreverens spec. nov.) AZ—Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California and Oregon county names capitalized.