Allocybaeina littlewalteri Bennett, 2020

Bennett, Robb, Copley, Claudia & Copley, Darren, 2020, Allocybaeina littlewalteri (Araneae: Cybaeidae): a new genus and species endemic to northwestern California, Zootaxa 4845 (3), pp. 436-446 : 438-442

Allocybaeina littlewalteri Bennett spec. nov.

Figs 1–13

Type material. Holotype male. U.S.A.: California: Mendocino County, Navarro River, 39°12'N, 123°48'W, six miles south of Albion , 13.9.1961, W.J. Gertsch & W. Ivie ( AMNH) . Paratypes. U.S.A.: California: Humboldt. 1 ♀, 5 mi. N Piercy, 6.4.1960, W.J. Gertsch, W. Ivie, & Schrammel ( AMNH); Mendocino. 15 ♀, Albion , 17.2.1967, V.D. Roth ( CAS); 8 ♂ 11 ♀, Caspar Creek, 1 mi. SE Caspar, 39°21′N, 123°48′W, 13.9.1961, W.J. Gertsch & W. Ivie ( AMNH); 1 ♂ 1 ♀, Caspar Creek, 1 mi. SE Caspar , 39°21′N, 123°48′W, 13.9.1961, W.J. Gertsch & W. Ivie ( CAS); 1 ♀, 7–10 mi. W Comptche, 15.2.1967, V. D. Roth ( CAS); 1 ♀, Elk , 16.2.1967, V.D. Roth ( CAS); 1 ♀, Fort Bragg , 5.1.1957, J. R. Helfer ( AMNH); 1 ♀, Navarro River, 39°12'N, 123°48'W, 6 mi. S Albion, 13.9.1961, W.J. Gertsch & W. Ivie ( AMNH); 2 ♀, 1 mi. N Piercy , 1.10.1959, V.D. Roth ( CAS); 3 ♀, 4.2 mi. S Piercy , 17.2.1967, V.D. Roth ( CAS); 1 ♀, Rockport, 39°43′N, 123°48′W, 14.9.1961, W.J. Gertsch & W. Ivie ( AMNH); 1 ♀, Rockport , 39°43′N, 123°48′W, 16.7.1962, V.D. Roth ( CAS) .

Other material examined. U.S.A.: California: Mendocino . 1 ♂, Big River Camp, ~ 2mi. W James Creek, 21.8.1990, D. Ubick ( CAS) ; 6 ♀, Big River Camp, ~ 2 mi. W James Creek, 5.5.1991, D. Ubick ( CAS) ; 4 ♂ 8 ♀, Big River Camp, Jackson State Forest , 400′, 15.9.1990, D. Ubick ( CAS) ; 1 ♀, 1 km. S Caspar , 15.7.2005, N. Dupérré & P. Paquin ( CAS) ; 2 ♂ 1 ♀, 4 mi. W Comptche , 21.7.1990, D. Ubick ( CAS) ; 2 ♀, Dunlap Camp, Jackson State Forest , 2.7.2006, J. Ledford & S. Synhorst ( CAS) ; 1 ♂ 3 ♀, Dunlap Camp, Jackson State Forest , 2.8.2006, R. Carlson, C. Griswold, V. Knutson, J. Ledford, C. Vo, & D. Ubick ( CAS) ; 2 ♂ 2 ♀, Dunlap Camp, Jackson State Forest , 2.8.2006, D. Ubick ( CAS) ; 1 ♀, Dunlap Camp area, Jackson State Forest , 400′, 16.9.1990, D. Ubick ( CAS) ; 6 ♂ 2 ♀, 0.5 mi. W Dunlap Pass along Big River , 19– 20.7.1990, D. Ubick ( CAS) ; 2 ♀, 0.5 mi. W Dunlap Pass along Big River , 16.9.1990, D. Ubick ( CAS) ; 1 ♀, Hwy 1, 9.8 mi. SW Hwy 101, 1000′, 20.9.1990, D. Ubick ( CAS) ; 5 ♂ 7 ♀, Hwy 1, 1 mi. NE Usal Rd, 200′, 20.9.1990, D. Ubick ( CAS) ; 1 ♀, Hwy 128, 2.7 mi. E Hwy 1, 10.10.1993, D. Ubick ( CAS) ; 2 ♂ 4 ♀, S end Mendocino Woodlands State Park, near Big River , 80′, 16.9.1990, D. Ubick ( CAS) ; 4 ♀, Tranquility , 1.5 mi. S Caspar, 300′, 17– 18.9.1990, D. Ubick ( CAS) ; 2 ♀, 2 mi. S Usal Campground , 19.9.1990, D. Ubick ( CAS) .

Etymology. The specific epithet is a patronym honouring the late musician “Little” Walter Jacobs whose ground-breaking approach to blues harmonica in the 1950s and 1960s set the standards for all subsequent players; noun (name) in genitive case.

Diagnosis. Specimens of Allocybaeina littlewalteri Bennett spec. nov. are distinguished by the characters discussed in the genus diagnosis section.

Description. Male (n=30). Pedipalpal patellar apophysis with retrolatero-distal origin, tapering, extending distally ( Figs 1–2 , 6–8 ); length about 1/2 width of patella; one large peg seta on ( Figs 6–7 ) or dorsally near ( Fig. 8 ) tip, one or a few others scattered on dorsal surface. Pedipalpal tibial apophysis ( Figs 2 , 6, 8 ) bipartite with a flattened scale-like plate dorsally in addition to retrolateral component typical of many Cybaeinae : an elongate longitudinal carina nearly as long as tibia, slightly extended distally. Embolus ( Figs 1 , 3–5 ) very long, thin, ribbon-like (especially apically), and usually medially and apically enveloped within folds of the tegular apophysis ( Fig. 5 ). Tegular apophysis large ( Figs 1–5 ); distal arm broadly triangular; medial portion with retrolateral margin deflected to position dorsal to ventral surface of tegular apophysis; proximal arm a large, plate-like structure narrowing to a variable bluntly pointed tip curving dorsally; medial portion and proximal arm collectively resemble the stalk and cap, respectively, of an inverted mushroom.

Measurements (n=10). CL 2.38–2.7 (2.5+0.1), CW 1.65–2.00 (1.82+0.11), SL 1.26–1.43 (1.33+0.07), SW 1.09–1.27 (1.17+0.06). Holotype CL 2.50, CW 1.85, SL 1.35, SW 1.16.

Female (n=83). Epigynum with single medially located, inverted U-shaped atrium ( Fig. 9 ) of variable width. Copulatory ducts ( Figs 10–12 ) proceeding posteriorly (and usually contiguously) from atrium, separating at posterior margin of vulva and turning anteriorly, becoming heavily sclerotized before joining with spermathecal heads anterior of anterior margin of atrium. Spermathecal heads, stalks, and bases ( Figs 10–12 ) are convoluted ducts with lumina of similar diameter throughout, undifferentiated from each other except for simple pores ( Fig. 11 ) marking position of spermathecal heads; heads are anterior-most component of vulva; stalks embrace anterior portions of copulatory ducts, passing back and forth across ventral (but not dorsal) surfaces. Bennett’s glands not observed.

Measurements (n=21). CL 1.98–2.7 (2.4+0.2), CW 1.35–1.90 (1.67+0.15), SL 1.07–1.40 (1.26+0.09), SW 0.92–1.26 (1.11+0.09).

Variation. The proximal arm of the male’s tegular apophysis exhibits minor variation and, perhaps, fragility. In coastal males, including the holotype, the tip of the proximal arm of the tegular apophysis is strongly curved dorsally in an approximately 90° angle from the main axis of the proximal arm ( Fig. 3 ). The tip is entirely absent, apparently broken off, in one specimen from Caspar Creek. Males from the slightly inland location of Dunlap Camp show a smoothly curved dorsal trajectory of the tip of the proximal arm ( Figs 1 , 5 ).

Females share generally similar epigynal and vulval morphology across the known range of this species. The most noticeable variation in female characters appears to be the width of the atrial area—some specimens have narrower atria than is shown in Fig. 9 . There is also minor variation in the convoluted paths of the spermathecal ducts. Intraspecific variability of sexual and other characters is common among a range of spider taxa, including Cybaeinae ( Bennett 1987, 2006; Higgins 1989).

Perhaps the morphological variation we have observed among male and female specimens of A. littlewalteri Bennett spec. nov. indicates that at least 2 species are encompassed by our concept of the species. In the absence of a suitable sample of specimens (especially males) from throughout the known range of this species for molecular analysis and (or) further morphological analysis, we prefer to recognize the observed differences as intraspecific variability.

Natural history. As with most Cybaeinae , this species is found in a variety of forest floor habitats including redwood ( Sequoia sempervirens ), tanoak ( Notholithocarpus densiflorus ), Bishop pine ( Pinus muricata ), and riparian litter as well as under logs and loose bark. Males have been collected from mid-July to mid-September.

Figures

FIGURES 1–2. Allocybaeina littlewalteri Bennett spec. nov., male from Dunlap Camp, California, left palpus (1 ventral; 2 dorsal). Unlabelled arrow indicates dorsal plate of tibial apophysis. DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 3–5. Allocybaeina littlewalteri Bennett spec. nov., males, (3–4 from Caspar Creek, California; 5 from Dunlap Camp, California), left palpus (3 genital bulb, ventral; 4 tegular apophysis and embolus, retrolateral; 5 same, ventral). Embolus dislodged from usual resting position in folds of tegular apophysis in Figs. 3–4. DA—distal arm of tegular apophysis, E—embolus, MP—medial portion of tegular apophysis, PA—proximal arm of tegular apophysis.

FIGURES 6–8. Allocybaeina littlewalteri Bennett spec. nov., males, (6–7 from Caspar Creek, California; 8 from Dunlap Camp, California), left palpus (6 tibia, retrolateral; 7 patella, dorsal; 8 tibia and patella, dorsal). DTA—dorsal plate of tibial apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 9–11. Allocybaeina littlewalteri Bennett spec. nov., female from Caspar Creek, California, copulatory organ (9 epigynum, ventral; 10 vulva, ventral; 11 same, dorsal). Numerals in Fig. 10 indicate trajectory of lumina of vulva components from copulatory duct near its junction with atrium (“1”) to end of spermathecal base near fertilization duct (“18”). Bracketed numerals indicate where the copulatory duct lies underneath (dorsal to) loops of the spermathecal stalk (“(3)”, “(4)”) and the spermathecal base lies underneath (dorsal to) the copulatory duct (“(16)”, “(17)”). AT—atrium, CD—copulatory duct, FD—fertilization duct, HS—head of spermatheca, SP—simple spermathecal pores, SS—stalk of spermatheca.

FIGURE 12. Allocybaeina littlewalteri Bennett spec. nov., female from Dunlap Camp, California, copulatory organ (12 vulva, ventral). CD—copulatory duct, HS—head of spermatheca, SS—stalk of spermatheca.

FIGURE 13. Distribution of Allocybaeina littlewalteri Bennett spec. nov. (●). AZ—Arizona, CA—California, ID—Idaho, NV—Nevada, OR—Oregon, UT—Utah.