Cybaeus somesbar Bennett, 2009

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 : 201

Cybaeus somesbar Bennett

Figs 33–36 , 40–42 , 49

Cybaeus somesbar Bennett in Copley et al. 2009: 393, figs 99–101, 113. World Spider Catalog 2021.

Type material examined. U.S.A.: California: Holotype female. Siskiyou County, 1 mile south of Somes Bar , 22.viii.1959, V. D. Roth & W.J. Gertsch ( AMNH) . Paratypes. Specimens and locality data in Copley et al. 2009.

Other material examined. U.S.A.: California: Humboldt. 1♂, Slide Creek, 7.4 mi. W of Hwy. 96, Six Rivers National Forest , 2400′, 9.ix.1992, D. Ubick & J. Boutin ( CAS). One other non-paratype specimen and its locality data are in Copley et al. 2009 .

Diagnosis. The male of C. somesbar is unlikely to be confused with any of the known males of the other species in the septatus group. It is distinguished from the male of C. viator spec. nov. by the slightly angular but rounded profile of its patellar apophysis ( Fig. 34 ), the angular truncated tip of the distal arm of the tegular apophysis and the strongly concave posterior margin of the proximal arm of the tegular apophysis ( Figs 35–36 ) (versus in the male of C. viator spec. nov. the patellar apophysis has a strongly angular profile [ Figs 43–44 , 47 ], the tip of the distal arm of the tegular apophysis is rounded, and the posterior margin of the proximal arm is angular [ Figs 45 , 48 ]). Separating the male of C. somesbar from those of C. chauliodous and C. septatus is discussed in the diagnoses of those two species.

The female of C. somesbar is unique among septatus group females in having long convoluted spermathecal stalks which make three 180° bends between the spermathecal heads and bases ( Figs 41–42 ). It shares very small inconspicuous atrial openings ( Fig. 40 ) with the female of C. viator spec. nov. ( Fig. 37 ) but the spermathecal stalks in that species are very short and almost linear ( Figs 38–39 ). Distinguishing the female of C. somesbar from those of C. chauliodous , C. lockeae spec. nov., and C. septatus is discussed in the diagnoses of those three species.

Description. As in diagnosis. Other descriptive characters are presented here. Ventral tibia I macrosetae 2–1p– 2–1p–1p(or 0, or 2). Femora unbanded in females, very lightly banded ventrally in the single known male.

Male (n=1). Patellar apophysis ( Figs 33–34 ) antero-prolaterally directed, length about equal to width of palpal patella, with solitary large medially located peg seta isolated from three setae arranged around the tip of the apophysis. Embolus ( Figs 35–36 ) very thin, describing a simple curve. Tip of proximal arm of tegular apophysis ( Figs 35–36 ) sharply acuminate in ventral view, angular in retrolateral view

Measurements (n=1). CL 2.28; CW 1.58; SL 1.14; SW 1.09.

Note: We have associated the Slide Creek male with the previously described females of C. somesbar because it was collected in the same general area as the other California specimens, only 20 to 50 km separate the Slide Creek locality from the other California localities for this species, and no other species of Cybaeus in the area is known only from females.

Female: See Copley et al. 2009.

Distribution and natural history. ( Fig. 49 ) Northwestern California (Klamath Mountains and lower Klamath/Salmon Rivers drainage) and adjacent southwestern Oregon. Apparently absent from the coast. The single male was collected in September.

Figures

FIGURE 49. Distributions of Cybaeus chauliodous, C. septatus, and C. somesbar. AZ—Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California and Oregon county names capitalized.

FIGURES 33–36. Cybaeus somesbar, male from Slide Creek, California, left palpus. 33 Patella, tibia, and genital bulb, ventral. 34 Patella and tibia, dorsal. 35–36 Genital bulb (35 ventral, 36 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrows indicate diagnostic characters (34 single isolated peg seta medially on PTA, 35 strongly concave posterior margin of PA).

FIGURES 37–42. Cybaeus spp., females, copulatory organ (37–39 C. viator spec. nov. from Fouts Springs, California; 40–42 holotype of C. somesbar). 37, 40 Epigynum, ventral. 38–39, 41–42 Vulva (38, 41 ventral, 39, 42 dorsal). AT—Atrial openings, HS—head of spermatheca.

FIGURES 43–46. Cybaeus viator spec. nov., male from Fouts Springs, California, left palpus. 43–44 Patella and tibia (43 retrolateral, 44 dorsal). 45–46 Genital bulb (45 ventral, 46 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 47–48. Cybaeus viator spec. nov., male from Fouts Springs, California, left palpus. 47 Patellar apophysis, dorsal. 48 Proximal arm of tegular apophysis, ventral. Unlabelled arrows indicate diagnostic characters (47 pointed angular tip of patellar apophysis with three peg setae, single isolated peg seta medially; 48 angular posterior margin of proximal arm of tegular apophysis).