Cybaeus devius, Chamberlin & Ivie, 1942

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae) in the Nearctic: the devius and tardatus species groups of the Californian clade, Zootaxa 5026 (4), pp. 451-479 : 452-453

The devius species group

Diagnosis. The devius group is diagnosed through the females by the long, convoluted copulatory ducts with the basal sections at least partially enveloping or looped about the more apical sections ( Figs 9–10, 12–13 , 15–16, 18–19 , 21–22 ). Within this group two subgroups are definable: one comprised of C. devius , C. echo spec. nov., and C. wilsonia spec. nov., and the other including C. bilectus spec. nov. and C. bryoncavus spec. nov. The devius subgroup is characterized by distinctly bipartite copulatory ducts (a basal, very lightly sclerotized region enveloping an apical, relatively straight, heavily sclerotized section) and very short stalks ( Figs 15–16, 18–19 , 21–22 ). The bilectus subgroup has the copulatory ducts gradually becoming more heavily sclerotized apically and longer stalks which take a single turn around the medial part of the copulatory ducts ( Figs 9–10, 12–13 ).

Description. Medium-sized spiders: carapace lengths ranging 2.0– 2.8 mm (females). Males subequal to slightly larger. Abdomen patterned. Legs usually unbanded (femora occasionally lightly banded). Two or occasionally three complete pairs of ventral tibia I macrosetae (distal pair sometimes present or incomplete).

Male: Patellar apophysis ( Figs 1–2 , 5 , 23 , 26–28 ) laterally to disto-laterally directed, length 1/2 to nearly as long as width of tibia, 12–30 peg setae, number is species specific. Retrolateral tibial apophysis ( Figs 1–2 , 5 ) carinate, nearly as long as tibia. Embolus long and narrow ( Figs 3 , 6–7 ) or long and slightly ribbon-like and broadened ( Figs 24–25 ). Tegulum ( Figs 3 , 24 ) conspicuous in ventral view, partially obscuring basal part of embolus. Distal arm of tegular apophysis prominent, elongate and either narrow ( Fig. 24 ) or broad ( Figs 3 , 6 ); proximal arm ( Figs 3 , 6 , 25 , 29–31 ) simple, prolaterally directed, slightly twisted.

Female: Simple undivided transverse atrium ( Figs 8, 11 , 14, 17 , 20 ) medially located on epigynum. Vulva ( Figs 9–10, 12–13 , 15–16, 18–19 , 21–22 ) with basal sections of copulatory ducts completely or partially enveloping apical sections of the ducts or spermathecal stalks; spermathecal heads small, dorsolateral lobes; spermathecal stalks undifferentiated, relatively long or very short; lumina narrow throughout heads and stalks; Bennett’s glands large, prominent, near junction of stalks and spermathecal bases; bases large, rounded; fertilization ducts exit bases near entrance of stalks.

Composition and distribution. ( Fig. 32 ). Cybaeus bilectus Bennett spec. nov., C. bryoncavus Bennett spec. nov., C. devius Chamberlin & Ivie , C. echo Bennett spec. nov., and C. wilsonia Bennett spec. nov. All are rarely encountered species with restricted ranges within the central and southern Sierra Nevada Mountains of eastern California from the Lake Tahoe area south to Tulare County.

Figures

FIGURE 32. Distributions of Cybaeus bilectus spec. nov., C. bryoncavus spec. nov., C. devius, C. echo spec. nov., and C. wilsonia spec. nov. AZ—Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California county names capitalized.

FIGURES 8–13. Cybaeus spp., females from California, copulatory organ (8–10 C. bilectus spec. nov., from Double Bunk Meadows; 11–13 C. bryoncavus spec. nov., from Pine Grove). 8, 11 Epigynum, ventral. 9–10, 12–13 Vulva (9, 12 ventral, 10, 13 dorsal). BG—Bennett’s gland, CD—copulatory duct, HS—head of spermatheca, SS—stalk of spermatheca.

FIGURES 14–19. Cybaeus spp., females, copulatory organ (14–16 C. devius, holotype; 17–19 C. wilsonia spec. nov., from Wilsonia, California). 14, 17 Epigynum, ventral. 15–16, 18–19 Vulva (15, 18 ventral, 16, 19 dorsal). BG—Bennett’s gland, HS—head of spermatheca. Unlabelled solid arrows indicate basal lightly sclerotized sections of copulatory ducts which envelop apical more heavily sclerotized sections (indicated by unlabelled dashed arrows).

FIGURES 20–22. Cybaeus echo spec. nov., holotype female, copulatory organ. 20 Epigynum, ventral. 21–22 Vulva (21 ventral, 22 dorsal). Unlabelled solid arrows indicate basal lightly sclerotized sections of copulatory ducts which envelop apical more heavily sclerotized sections (indicated by unlabelled dashed arrows).

FIGURES 1–4. Cybaeus bilectus spec. nov., male from Double Bunk Meadows, California, left palpus. 1–2 Patella and tibia (1 retrolateral, 2 dorsal). 3–4 Genital bulb (3 ventral, 4 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, E— embolus, PA—proximal arm of tegular apophysis, PS—peg setae, PTA—patellar apophysis, RTA—retrolateral tibial apophysis, TG—tegulum.

FIGURES 5–7. Cybaeus bryoncavus spec. nov., holotype male, left palpus. 5 Patella and tibia, dorsal. 6 Genital bulb (embolus tip apparently missing; base of embolus, part of tegulum obscured in specimen, ventral. 7 Tegular apophysis and embolus (part), retrolateral. CY—cymbium, DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrow indicates basal projection of PA.

FIGURES 23–25. Cybaeus wilsonia spec. nov., holotype male, left palpus. 23 Patella and tibia, dorsal. 24–25 Genital bulb (24 ventral, 25 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, E—embolus. Unlabelled arrows indicate length and width of DA (Fig. 24) and swollen base of proximal arm of tegular apophysis (Fig. 25).

FIGURES 26–28. Cybaeus spp. males, left palpus, patellar apophysis, dorsal (26 C. bilectus spec. nov., from Double Bunk Meadows, California, 27 C. bryoncavus spec. nov., holotype, 28 C. wilsonia spec. nov., holotype). Arrows indicate diagnostic characters (26 concave distal margin; 28 concave dorsal surface).

FIGURES 29–31. Cybaeus spp. males, left palpus, proximal arm of tegular apophysis, ventral (29 C. bilectus spec. nov., from Double Bunk Meadows, California, 30 C. bryoncavus spec. nov., holotype, 31 C. wilsonia spec. nov., holotype). Arrows indicate diagnostic characters (29 bluntly hooked tip, 30 inconspicuous basal projection).