Cybaeus septatus Chamberlin & Ivie, 1942

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 : 196-198

Cybaeus septatus Chamberlin & Ivie

Figs 22–32 , 49

Cybaeus septatus Chamberlin & Ivie 1942: 17 , figs 41–42. Roth 1952: 219, fig. 29. Roewer 1954: 92. Roth & Brown 1986: 4. Bennett, 2006: 478, figs 7–10. Copley et al., 2009: 373, figs 11–12. World Spider Catalog 2021.

Type material examined. U.S.A.: California: Holotype female. Shasta County, Potter Creek Cave [approximately 2 km south of Shasta Lake Caverns], 40° 47' N, 122° 17' W, 1.vii.1937, R. V . Chamberlin ( AMNH). Allotype male. Siskiyou County, Weed , 8.ix.1935, R. V . Chamberlin & W. Ivie ( AMNH) .

Other material examined. U.S.A.: California: Glenn . 1♀, Ivory Mill Rd , 0.9 mi W of County Rd. 308, 19.i.1997, J. Schweikert & J. Vindum ( CAS) ; Shasta . 1♀, Dekkas Rock at Gilman Rd. , 122° 14.2' N, 40° 52.6' W, 9.v.1995, D. Ubick ( CAS) ; 1♀, Madrone Camp , 7.5 mi. E of Samwel Cave, 7.viii.1989, D. Ubick ( CAS) ; 1♀, Potter Creek Cave , 8.vi.1995, D. Ubick ( CAS) ; 1♂ 2♀, Samwel Cave [about 9 mi. E of Lakehead nr. Nosoni Creek ], 30.vi.1989, D. Ubick ( CAS) ; Siskiyou . 1♀, Bartle , 5.vii.1952, W.J. Gertsch ( AMNH) ; 2♂ 1♀, Bartle , 18.ix.1961, W. Ivie & W.J. Gertsch ( AMNH) ; 1♀, Dead Horse Summit, Hwy 89, 5500', 18.ix.1961, W. Ivie & W.J. Gertsch ( AMNH) ; 10♂ 6♀, 3 mi. E of McCloud , 2.ix.1959, V. D. Roth & W.J. Gertsch ( CAS) ; 6♂ 9♀, Mt. Shasta, Panther Meadow Rd. [Everitt Memorial Hwy.], 7000', 17.ix.1961, W. Ivie & W.J. Gertsch ( AMNH) ; 1♀, Mt. Shasta, Everitt Memorial Hwy. , 6520', 6.viii.1968, R. E. Leech ( REL) . Oregon: 1♀, Josephine, Grants Pass , 9.ix.1935, R. V. Chamberlin & W. Ivie ( AMNH) .

Diagnosis. The male of C. septatus is most likely to be confused with the male of C. somesbar . The males are distinguished by characters of the tegular apophysis in ventral view: in C. septatus the proximal arm has a bluntly acuminate tip and a weakly concave posterior margin and the distal arm has a rounded tip ( Figs 23–24 , 26 ) (versus in C. somesbar the proximal arm has a sharply acuminate tip and an angular posterior margin and the tip of the distal arm is distinctly truncated [ Figs 33, 35–36 ]). Separating the males of C. septatus and C. chauliodous is discussed in the diagnosis of the latter.

The female of C. septatus is distinguished from those of C. somesbar and C. viator spec. nov. by its large, shepherd’s-crook-shaped atrial openings ( Fig. 27 ) and relatively long and sinuous spermathecal stalks ( Figs 29–30 ) (versus atrial openings very small and crook shaped [ Figs 40–41 ] or parenthesis-like [ Figs 37–38 ] and spermathecal stalks long and convoluted [ Figs 41–42 ] or short and nearly linear [ Fig. 38 ] in C. somesbar and C. viator spec. nov.). Separating the female of C. septatus from those of C. chauliodous and C. lockeae spec. nov. is discussed in the diagnoses of the latter two species.

Description. As in diagnosis. Other descriptive characters are presented here. Ventral tibia I macrosetae usually 2–1p–2–1p– 1p.

Male (n=20). Patellar apophysis ( Figs 22 , 25 ) about as long as width of palpal patella; five to 12 peg setae located around margin of apophysis with proximal medial one slightly larger than the remainder. Embolus describing a compound curve ( Figs 23–24 ).

Measurements (n=20). CL 2.05–2.6 (2.3+0.2), CW 1.53–2.03 (1.75+0.15), SL 1.04–1.34 (1.19+0.08), SW 0.99–1.25 (1.11+0.07). Allotype CL 2.05, CW 1.58, SL 1.04, SW 0.99.

Female (n=27).Atrial openings ( Figs 27–28 ) inconspicuous. Copulatory ducts as long as or slightly shorter than spermathecal stalks; stalks contiguous or separated near bases; fertilization ducts with large lumina ( Figs 28–32 ).

Measurements (n=21). CL 1.95–2.7 (2.3±0.2), CW 1.33–1.85 (1.60±0.14), SL 1.01–1.35 (1.18±0.10), SW 0.96–1.23 (1.09±0.08). Holotype largest specimen examined.

Notes: The examined specimens of the population at Samwel Cave are pale and unpatterned with reduced eyes. A blind male and female from this locality roughly figured by Roth (drawings examined) and listed by Rudolph et al. (unpublished data) as " Cybaeus n. sp. near septatus " have not been seen but we presume are specimens of C. septatus . Bennett (2006) described the ontogeny of the female copulatory organ of C. septatus from subadult with lightly sclerotized ducts, prominent spermathecal heads, and no Bennett’s glands ( Fig. 30 ) through teneral with light sclerotization and Bennett’s glands now present ( Fig. 31 ) to fully mature with increasingly heavy sclerotization and well-developed spermathecal heads and Bennett’s glands ( Figs 29, 32 ).

Distribution and natural history. North-central California (Shasta and Siskiyou Counties) with one record from southwestern Oregon ( Fig. 49 ). The single Oregon female is possibly a misidentified specimen of C. chauliodous ; Bennett originally examined this specimen in the late 1980s and we have been unable to recheck this specimen subsequently. Collection data suggest C. septatus is most common in montane pine ( Pinus L.) forests. At lower elevations around Shasta Lake it has been collected mostly in and around caves. One female (Glenn County) was collected in a low elevation oak ( Quercus L.) woodland (circa 250 m). Males have been collected in late June and 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 22–24. Cybaeus septatus, male from Mt. Shasta, California, left palpus. 22 Patella, dorsal. 23–24 Genital bulb (23 ventral, 24 retrolateral). DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis. Unlabelled arrows indicate diagnostic characters (22 single slightly enlarged peg seta on patellar apophysis, 23 weakly concave posterior margin of PA).

FIGURES 25–26. Cybaeus septatus, male from Mt. Shasta, California, left palpus. 25 Patellar apophysis, dorsal. 26 Proximal arm of tegular apophysis, ventral. Unlabelled arrows indicate diagnostic characters (25 single slightly enlarged peg seta on patellar apophysis; 26 weakly concave posterior margin of proximal arm of tegular apophysis).

FIGURES 27–32. Cybaeus septatus, females from California (27 from Mt. Shasta, 28–29 holotype, 30–32 from McCloud), copulatory organ. 27 Epigynum, ventral. 28–29, 32 Vulva (28, 32 ventral, 29 dorsal). 30 Subadult vulva, dorsal. 31 Portion of teneral vulva (Bennett’s gland and base of spermatheca), dorsal. AT—Atrial opening, BG—Bennett’s gland, BS—base of spermatheca, HS—head of spermatheca, W—epigynal “wrinkle”.

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.