Cybaeus fraxineus Bennett, 2021

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae): the aspenicolens species group of the Californian clade, Zootaxa 4926 (2), pp. 224-244 : 233-237

Cybaeus fraxineus Bennett spec. nov.

Figs 25–28 , 32 , 34–37 , 42

Type material. Holotype male. U.S.A.: California: Tulare County, Sequoia National Park, seven miles northeast of Ash Mountain Entrance , matured 4.10.1959, W.J. Gertsch & V. D. Roth ( CAS).

Paratypes. U.S.A.: California: Tulare, 2³ (incompletely moulted to maturity) 1♀, Sequoia National Park , 7 miles NE Ash Mountain Entrance, matured 4.10.1959, W.J. Gertsch & V . D. Roth ( CAS); 1³ 1♀, Soda Creek, near Nelson Camp , 14.9.1959, W.J. Gertsch & V . D. Roth ( AMNH); 1³, Sequoia National Park, Ash Mountain, “Pwr. Sta. #3”, 17.2.1985, D.J. Burdick (D. Ubick); 1♀, Sequoia National Park , near Ash Mountain Entrance , 5.7.1956, W.J. Gertsch & V . D. Roth ( CAS); 1³, Sequoia National Park , 7 mi. NE of Ash Mountain Entrance, matured 25.9.1959, W.J. Gertsch & V . D. Roth ( CAS); 1³, Sequoia National Park , 7 mi. NE of Ash Mountain En-trance, matured 30.9.1959, W.J. Gertsch & V . D. Roth ( CAS); 1♀, Sequoia National Park, 7 mi. NE of Ash Moun-tain Entrance , matured 15.10.1959, W.J. Gertsch & V . D. Roth ( CAS); 1♀, Sequoia National Park, Clough Cave, 50–100’ from cave entrance, 5.4.1990, Tyson, Brigman & Jeffery ( CAS); 1♀, Sequoia National Park , Clough Cave , 27.4.2004, J. Krejca, P. Sprouse, S. Fryer, P. Paquin, & D. Ubick ( CAS); 1♀, Sequoia National Park , Kaweah Cave , 17.11.2003, V . Krejca & S. Taylor ( CAS); 1♀, Sequoia National Park, Kaweah Cave , 13.8.2003, V . Krejca & V . Loftin ( CAS); 1³, Sequoia National Park, Overhang Cave , 16.9.2003, V . Krejca & V . Loftin ( CAS); 3♀, Sequoia National Park, Overhang Cave, outside cave, 29.4.2004, D. Ubick & P. Paquin ( CAS); 2♀, Sequoia National Park , Paradise Cave , 30.4.2004, V . Krejca, P. Paquin, & D. Ubick ( CAS); 1³, Sequoia National Park, South Fork Ranger Station , 4.11.2004, D. Ubick ( CAS) .

Etymology. The specific epithet is from the Latin adjective “fraxineus, -a, -um” for “of ash” and refers to the type locality; adjective.

Diagnosis. Cybaeus fraxineus spec. nov. is grouped with C. thermydrinos in the informal fraxineus subgroup. Distinguishing the aspenicolens and fraxineus subgroups is discussed in the aspenicolens species group diagnosis. The males of C. fraxineus spec. nov. and C. thermydrinos can be separated by the form of the proximal arm of the tegular apophysis. In males of C. fraxineus spec. nov. the proximal arm in ventral view ( Figs 26 , 32 ) is comprised of two distinct components: the ventral component is a simple, broad, convex arch tapering to a dull or rounded point while the dorsal component is smaller with an angular tip of slightly variable morphology. In ventral view the proximal arm of the tegular apophysis in males of C. thermydrinos is a single concave process ( Figs 30 , 33 ), keeled ventrally and with a simple pointed dorsal tip. The females of C. fraxineus spec. nov. and C thermydrinos are dif-ficult to separate. In C. fraxineus spec. nov. the copulatory ducts, spermathecal heads, and spermathecal stalks ( Figs 35–37 ) are broadly contiguous along the midline of the vulva versus in C thermydrinos the anterior portions of the copulatory ducts as well as the spermathecal heads and stalks are separated and only the posterior portions of the copulatory ducts are contiguous ( Figs 39–40 ).

Description. All Gertsch and Roth paratypes (5 males, 4 females) are teneral, incompletely moulted, or in poor condition. Ventral tibia I macrosetae 2–1p–2–1p– 1p.

Male: (n=7). Patellar apophysis ( Fig. 25 ) gradually tapering to dull point with 30–40 large peg setae along dorsal and lateral margins of distinct concavity on anterior margin of apophysis. Proximal arm of tegular apophysis (Figs 266–28, 32) prolaterally directed, bifurcate; ventral component large, broad, convex, tapering to dull or rounded point; dorsal component smaller with angular apex; proximal margin of proximal arm smoothly curved in retrolateral view.

Measurements (n=5). CL 2.7–3.6 (3.2), CW 2.00–2.7 (2.4), SL 1.33–1.63 (1.48), SW 1.30–1.55 (1.43). Holotype CL 3.3, CW 2.43, SL 1.48, SW 1.43).

Female: (n=5). Atrium ( Fig. 34 ) partially obscured anteriorly by large but inconspicuous, transverse epigynal ridge. Copulatory ducts (figs 35–37) heavily sclerotized.

Measurements (n=2). CL 2.6, 2.8; CW 1.78, 1.90; SL 1.26, 1.30; SW 1.20, 1.23.

Distribution. Western slopes of the southern Sierra Nevada in and around Sequoia National Park, Tulare County, California ( Fig. 42 ).

Figures

FIGURE 42. Distributions of Cybaeus fraxineus spec. nov. (purple circles), C. thermydrinos (white triangles). AZ—Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah.

FIGURES 25–28. Cybaeus fraxineus spec. nov., males from vicinity of Ash Mountain, California, left palpus. 25 patella and tibia, dorsal; 26 genital bulb, ventral; 27 tegular apophysis and embolus, ventral prolateral; 28 genital bulb, retrolateral.Arrows indicate bifurcate tip of proximal arm of tegular apophysis.

FIGURES 32–33. Cybaeus spp, males, left palpus, proximal arm of tegular apophysis (32 C. fraxineus spec. nov. from vicinity of Ash Mountain, California. 33 C. thermydrinos from near Johnsondale, California). Arrows indicate bifurcate tip of proximal arm of tegular apophysis.

FIGURES 34–40. Cybaeus spp, females, copulatory organ (34–36 C. fraxineus spec. nov. from vicinity of Ash Mountain, California. 37 C. fraxineus spec. nov. from Clough Cave, California. 38–39 C. thermydrinos from near Johnsondale, California. 40 C. thermydrinos from California Hot Springs, California). 34, 38 epigynum, ventral; 35, 39–40 vulva, ventral; 36–37 vulva, dorsal. CD—copulatory duct, ER—epigynal ridge or hood.

FIGURES 29–31. Cybaeus thermydrinos, male from near Johnsondale, California, left palpus. 29 patella and tibia, dorsal; 30 genital bulb, ventral; 31 genital bulb, retrolateral.