Cybaeus tardatus (Chamberlin)

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 : 470-472

Cybaeus tardatus (Chamberlin)

Figs 46–51 , 60 , 62

Parauximus tardatus Chamberlin 1919: 3 , fig. 2.

Namopsilus pletus Chamberlin 1919: 14 , fig. 1.

Cybaeus tardatus Chamberlin 1924: 669 . Chamberlin and Ivie 1932: 23, fig. 56. Chamberlin and Ivie 1937: 225. Roewer 1954: 92. Bonnet 1956: 1304. Roth and Brown 1986: 4, 12. World Spider Catalog 2021.

Type material. U.S.A.: California: Holotype male. Los Angeles County, Claremont, no date, R.V. Chamberlin ( MCZ), examined . Holotype female of Namopsilus pletus . Los Angeles County, Claremont, iv.1913, R.V. Chamberlin ( MCZ), examined .

Other material examined. U.S.A.: California: Los Angeles. 1♂, Claremont , no date, no collector ( MCZ); 1♀ Pasadena, vi.1945, S.C. Bishop ( AMNH) .

Diagnosis. The male of C. tardatus is readily diagnosed by the form of the proximal and distal arms of the tegular apophysis ( Figs 48 , 60 ); these characteristics are discussed under the diagnosis of C. piazzai spec. nov.

Distinguishing the females of C. orarius spec. nov. and C. tardatus is discussed under the diagnosis of the former. From the other females in the tardatus species group with rounded spermathecal bases ( C. piazzai spec. nov., C. topanga spec. nov.) the female of C. tardatus is distinguished by the nearly parallel-sided atrial area, the copulatory ducts contiguous over much of their length, as well as the general simplicity of the vulval ducts ( Figs 50–51 ) (versus atrial area inverted vase-shaped with sides diverging posteriorly [ Figs 42 , 52–53 ], copulatory ducts non-contiguous [ Fig. 43 ] or contiguous only along anterior-most section [ Figs 42 , 54 ], and vulval ducts complex [ Figs 42–43, 45 , 53–54 ] in C. piazzai spec. nov. and C. topanga spec. nov.).

Description. Ventral tibia I macrosetae: 2-1p-2-1p-2. Femora and tibia lightly banded.

Male: (n=2). About 40 peg setae on strongly anteriorly directed patellar apophysis ( Fig. 47 ). Retrolateral tibial apophysis about 2/3 the length of the tibia, not extending to anterior margin of tibia ( Fig. 46 ).

Measurements (n=2). CL 3.2, 3.3; CW 2.50, 2.50; SL 1.55, 1.53; SW 1.48, 1.48. Holotype listed first.

Female: (n=2). Atrium ( Fig. 50 ) with area between atrial openings slightly raised and convex, largely parallelsided but slightly widening posteriorly. Vulva ( Figs 50–51 ) with copulatory ducts opening into atria from midline of vulva, well sclerotized posteriorly, less so anteriorly; heads of spermathecae undifferentiated from adjacent ducts (i.e. not distinct lobes), located near posterior margin of vulva, visible in dorsal view; spermathecal stalks short, thick walled; Bennett’s glands visible in dorsal view on small, thick walled, rounded spermathecal bases.

Measurements (n=2). CL 2.9, 3.3; CW 2.03, 2.38; SL 1.33, 1.48; SW 1.30, 1.48. Holotype of N. pletus listed second.

Distribution. ( Fig. 62 ). Los Angeles County, California. Male specimens listed in Chamberlin and Ivie (1932) from Ensenada, Baja California have not been found. We consider Ensenada to be outside the range of C. tardatus and have not included that locality in the distribution map.

Figures

FIGURE 62. Distribution of Cybaeus orarius spec. nov., C. piazzai spec. nov., C. tardatus, and C. topanga spec. nov. AZ— Arizona, CA—California, ID—Idaho, OR—Oregon, NV—Nevada, UT—Utah, WA—Washington. California county names capitalized.

FIGURES 46–49. Cybaeus tardatus, male from Claremont, California, left palpus. 46–47 Patella and tibia (46 retrolateral, 47 dorsal). 48–49 Genital bulb (48 ventral, 49 retrolateral). DA—distal arm of tegular apophysis, E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis.

FIGURES 50–54. Cybaeus spp., females, copulatory organ (50–51 C. tardatus, holotype of Namopsilus pletus; 52–54 C. topanga spec. nov., from San Ysidro, California). 50–51, 53–54 Vulva (50, 53 ventral, 51, 54 dorsal). 52 Atrium (anterior portion), ventral. BG—Bennett’s gland, CD—copulatory duct, SS—stalk of spermatheca.

FIGURES 59–61. Cybaeus spp. males from California, left palpus, proximal arm of tegular apophysis, ventral (59 C. piazzai spec. nov. from Santa Barbara, 60 C. tardatus from Claremont, 61 C. topanga spec. nov., holotype). Solid arrows indicate ventral tip of proximal arm, dashed arrows indicate dorsal tip of proximal arm.

FIGURES 42–45. Cybaeus piazzai spec. nov., females from California, copulatory organ (42–43 from Santa Barbara Natural History Museum grounds, 44–45 from “W119/N34”). 42–43 Vulva, ventral. 44 Epigynum, ventral. 45 Vulva, dorsal). CD— copulatory duct.