Cybaeus consocius Chamberlin and Ivie

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae): the consocius species group of the Californian clade, Zootaxa 4965 (3), pp. 401-436 : 404-406

Cybaeus consocius Chamberlin and Ivie

Figs 2–9 , 16–17 , 20 , 84

Cybaeus consocius Chamberlin and Ivie 1932: 25 , fig. 61. Roewer 1954: 90. Bonnet 1956: 1301. Roth and Brown 1986: 3. Bennett 2006: 481, figs 23–25. Copley et al. 2009: 372, fig. 7. World Spider Catalog 2021.

Cybaeus marinensis Chamberlin and Ivie 1932: 25 , fig. 60. Roewer 1954: 91. Bonnet 1956: 1302.

Cybaeus angelus Chamberlin and Ivie 1942: 16 , fig. 50. Roewer 1954: 9. Roth and Brown 1986: 3.

Cybaeus mariensis: Roth and Brown 1986: 4 (incorrect subsequent spelling of C. marinensis ).

Type material examined. U.S.A.: California: Holotype female of C. consocius, Marin County , no date, R . V . Chamberlin ( AMNH), subsequently lost . Neotype male of C. consocius , designated by Bennett (2006), Marin County, south end of S.P. Taylor State Park, 1.xi.1953, V . D. Roth & G. Marsh ( AMNH) . Holotype female of C. angelus . Los Angeles County, Los Angeles , no date, no collector ( AMNH) . Holotype female of C. marinensis . Marin County, no date, R . V . Chamberlin ( AMNH) .

See discussion of type material and synonymy in Bennett (2006).

Other material examined. U.S.A.: California: Marin. 1♀, E slope Mt Tamalpais, 14.v.1952, H.S. Dybas ( FMNH); 2♂ 3♀, Muir Woods, 5.ix.1927 ( AMNH); 1♀, Muir Woods , 24.x.1953, V.D. Roth ( CAS); 1♀, Ring Mountain Preserve , S of Corte Madera, 18.xii.1982, V.F. Lee ( CAS); 3♀, Ross Bald Hill , 1.iii.1991, D. Ubick & T. Briggs ( CAS); 1♀ San Anselmo, San Rafael Ridge, 19.ix.1995, L.G. Freihofer ( CAS); Mendocino. 4♀, near Lake Mendocino , P. R. Craig & C. Kirsch ( CAS); Napa. 3♀, 2mi. W Oakville, 31.xii.1953 ( AMNH); 1♀, 3 mi W Oakville , 15.ii.1954, V.D. Roth & R. O. Schuster, ( AMNH); 1♀, 7 mi. W Oakville, 15.ii.1954 ( AMNH); 2♀, 7 mi. W Oakville , 13.xii.1957, L.M. Smith & R.O. Schuster ( CAS); 3♀, Skyline Park, Camp Coombs , 22.i.1999, T. Briggs, W. Rauscher & D. Ubick ( CAS); San Francisco. 1♀, San Francisco, Marx ( MCZ); Santa Clara. 2♀, Alum Rock Park , 22.ii.2013, I.M. Sokolov ( CAS); Solano. 1♀, Cordelia , 14.9 mi N of Benicia, 9.ii.1964, P. R. Craig & D.L. Craig ( CAS) .

Diagnosis. The male of C. consocius is unlikely to be confused with the males of the other species in the consocius group and is diagnosed by the unique forked tip of the proximal arm of the tegular apophysis ( Figs 3–4 , 20 ). In ventral view the two forks are at right angles to each other with the larger, ventral-most fork directed prolaterally and featuring a sharp-edged longitudinal ridge medially along the ventral surface while the smaller fork is directed proximally and resembles the keel of a sailboat. The female of C. consocius is only likely to be confused with the females of C. hesper or C. hummeli spec. nov.; those three species have similar vulval morphology featuring, in dorsal view, a distinctive U-shaped proximal loop of each copulatory duct ( Figs 7 , 15 , 25 ). In C. consocius and C. hesper the atrium is undivided and of an inverted U-shaped form ( Figs 5–14, 16–17 ); in C. hummeli spec. nov. the atrium is divided into a pair of longitudinal slits or depressions separated by a medial convex septum ( Figs 23–24, 26 ). The females of C. consocius and C. hesper can be separated by differences in atrial and copulatory duct morphology. The medial area of the atrium between the lateral arms of the inverted “U” in C. consocius is smoothly concave ( Figs 5, 9 , 16 ) versus laterally concave and medially convex ( Fig. 13 ) in C. hesper . The copulatory ducts in C. consocius are attached to the lateral margins of the atrium and extend at best only slightly anterior of the anterior margin of the atrium ( Figs 6–8 , 17 ); in C. hesper the copulatory ducts are attached to the anterolateral margins of the atrium and extend well anterior of the anterior margin of the atrium ( Figs 14–15 ).

Description. Ventral tibia I macrosetae: 2-1p-2-1p-0.

Male: (n=3). Length of patellar apophysis about 3/4 width of patella, six small peg setae dorsally and around tip ( Fig. 2 ). Measurements (n=3). CL 2.20, 2.25, 2.6; CW 1.58, 1.68, 1.85; SL 1.11, 1.13, 1.27; SW 1.05, 1.07, 1.21. Neotype is largest specimen.

Female: (n=31). Copulatory ducts ( Figs 6–8 , 17 ) somewhat membranous, contiguous or separate at atrium. Spermathecal stalks well separated ( Fig. 7 ). Measurements (n=14). CL 1.60–2.43 (2.11±0.23), CW 1.09–1.57 (1.44±0.15), SL 0.88–1.17 (1.08±0.08), SW 0.81–1.10 (1.01±0.08). Holotypes: C. consocius CL 2.20, CW 1.53, SL 1.12, SW 1.04; C. angelus CL 2.30, CW 1.57, SL 1.13, SW 1.04; C. marinensis CL 2.43, CW 1.70, SL 1.17, SW 1.10.

Distribution and natural history. Coastal California from southern Mendocino County to northern Santa Clara County ( Fig. 84 ). Most records are from the San Francisco Bay area. Following Bennett (2006), we believe the record from the Los Angeles area (a single specimen, the holotype of C. angelus ) to be erroneous: no other species of the consocius group is known to range that far south and no further specimens of C. consocius have been recorded from the Los Angeles area subsequent to the original description of C. angelus . This record is not included on the distribution map. Also see distribution discussion under C. hesper . Mature males have been collected in September and November.

Figures

FIGURE 84. Distribution of Cybaeus consocius, C. hesper, C. hummeli spec. nov., C. penedentatus, and C. ubicki spec. nov. AZ—Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California county names capitalized.

FIGURES 1–4. Cybaeus spp., males, left palpus (1 C. simplex from Ashland watershed, Oregon; 2–4 C. consocius from Muir Woods, California). 1 Patella, tibia, and genital bulb, ventral. 2 Patella and tibia, dorsal. 3–4 Genital bulb (3 ventral, 4 retrolateral). DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PS—peg setae, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 5–9. Cybaeus consocius, females from California, copulatory organ (5–7 holotype, 8 from Mount Tamalpais, 9 from near Oakville). 5 Epigynum, ventral. 6–8 Vulva (6, 8 ventral, 7 dorsal). 9 Atria, ventral. BG—Bennett’s gland, CD—copulatory duct, HS—head of spermatheca, SS—stalk of spermatheca. Unlabelled arrows indicate anterior margin of atrium.

FIGURES 13–17. Cybaeus spp., females, copulatory organ (13–15 C. hesper, syntype of C. minor; 16–17 C. consocius, holotype of C. marinensis). 13, 16 Epigynum, ventral; 14–15, 17 Vulva (14, 17 ventral, 15 dorsal). CD—copulatory duct. Unlabelled arrows indicate anterior margin of atrium.

FIGURES 20–22. Cybaeus spp., males from California (20 C. consocius from Muir Woods, 21 C. hesper from Skyline Boulevard at King’s Mountain, 22 C. hummeli spec. nov. from Skyline Boulevard at King’s Mountain). 20, 22 Left palpus, proximal tip of tegular apophysis, ventral. 21 Right palpus, proximal tip of tegular apophysis, ventral. Unlabelled arrows indicate diagnostic characters (20 right angle forked tip, 21 inconspicuous bifid tip, 23 small acuminate tip and central longitudinal concavity).

FIGURES 23–26. Cybaeus hummeli spec. nov., females from California, copulatory organ (23–25 from Miramar, 26 from San Francisco). 23, 26 Epigynum, ventral. 24–25 Vulva (24 ventral, 25 dorsal). CD—copulatory duct.