Cybaeus piazzai Bennett, 2021

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 : 466-468

Cybaeus piazzai Bennett spec. nov.

Figs 39–45 , 59 , 62

Type material. U.S.A.: California: Holotype male. Santa Barbara County, grounds of Santa Barbara Natural History Museum , 7.ii.1967, V.D. Roth ( CAS) . Paratypes. Ventura. 1♀, “N34 W119” no date, no collector, ( AMNH) ; Santa Barbara. 1♀, N end of Lk. Cachuma, 8.ii.1967, V.D. Roth ( CAS) ; 1♂ 7♀, grounds of Santa Barbara Natural History Museum , 7.ii.1967, V.D. Roth ( CAS) .

Etymology. The specific epithet is a patronym honouring the prominent Los Angeles area blues harmonicist Rod Piazza.

Diagnosis. The male of C. piazzai spec. nov. is distinguished by the form of the distal and proximal arms of the tegular apophysis; the female by the form of the copulatory ducts ( Fig. 45 ). The males of C. tardatus and C. piazzai spec. nov. ( Figs 40 , 59 ) are distinguished by the concave distal prolateral margin of the elongate distal arm of the tegular apophysis ( Fig. 40 ) and the acuminate ventral and dorsal tips of the proximal arm of the tegular apophysis ( Figs 40 , 59 ) in C. piazzai spec. nov. (versus a short, broad, and angular distal arm [ Fig. 48 ] and the rounded ventral tip and acuminate dorsal tip of the proximal arm [ Figs 48 , 60 ] in C. tardatus ). The males of C. topanga spec. nov. and C. piazzai spec. nov. can be distinguished by the ventral and dorsal tips of the proximal arm of the tegular apophysis being approximately at right angles to each other with the dorsal tip about twice as long as the ventral tip ( Figs 40 , 59 ) in C. piazzai spec. nov. (versus the ventral and dorsal tips are oriented in the same direction and of similar lengths ( Figs 57 , 61 ) in C. topanga spec. nov.). Furthermore, the dorsal tip of the proximal arm is sharply acuminate in C. piazzai spec. nov. (versus bluntly acuminate in the male of C. topanga spec. nov.). This difference can be difficult to resolve, however, because of the small size of these structures.

Distinguishing the females of C. piazzai spec. nov. and C. orarius spec. nov. is discussed under the diagnosis of the latter species. From the other females in the tardatus species group with rounded spermathecal bases ( C. tardatus and C. topanga spec. nov.) the female of C. piazzai spec. nov. is distinguished by the posteriorly broadened copulatory ducts which obscure the Bennett’s glands in cleared dorsal view of the vulva ( Fig. 45 ) (versus copulatory ducts of similar narrow diameter throughout their length and not obscuring the Bennett’s glands in dorsal view in C. tardatus [ Fig. 51 ] and C. topanga spec. nov. [ Fig. 54 ]).

Description. Ventral tibia I macrosetae variable: 2-1p-2-1p-1p(or 2 or 0). Femora and tibiae lightly banded or not (larger individuals are more likely to have banded legs than are smaller specimens).

Male: (n=2). About 30–35 peg setae on anteriorly directed patellar apophysis ( Fig. 39 ). Carinate retrolateral tibial apophysis nearly as long as tibia. Distal arm of tegular apophysis ( Fig. 40 ) very broad, elongate; proximal arm ( Figs 40 , 59 ) appearing trifid in ventral view with ventral tip triangular, bluntly acuminate, prolaterally directed; dorsal tip triangular, sharply pointed, basally directed.

Measurements (n=2). CL 2.7, 2.9; CW 1.98, 2.10; SL 1.30, 1.33; SW 1.23, 1.33. Holotype larger specimen.

Female: (n=9). Atrium ( Figs 42, 44 ) slightly hooded anteriorly with area between atrial openings inverted vase-shaped, widest posteriorly, concave. Copulatory ducts ( Figs 42–45 ) opening into atrium laterally from vulva, contiguous or separated anteriorly, gradually broadening posteriorly, turning anteriorly and narrowing at posterior margin of vulva. Spermathecal heads small dorsal lobes medially on vulva, visible in dorsal view. Stalks narrow, relatively long. Bennett’s glands located dorsolaterally on small, rounded bases.

Measurements (n=9). CL 2.13–3.4 (2.6+0.4), CW 1.40–2.30 (1.80+0.30), SL 1.04–1.55 (1.26+0.17), SW 0.99– 1.45 (1.20+0.16).

Distribution and natural history. ( Fig. 62 ). Known only from Ventura and Santa Barbara Counties, California. The two males were collected in February.

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 39–41. Cybaeus piazzai spec. nov., male from Santa Barbara, California, left palpus. 39 Patella and tibia, dorsal. 40–41 Genital bulb (40 ventral, 41 retrolateral). CY—cymbium, DA—distal arm of tegular apophysis, E—embolus, PA— proximal arm of tegular apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrow indicates concave distal prolateral margin of DA.

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.

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 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 55–58. Cybaeus topanga spec. nov., holotype male, left palpus. 55–56 Patella and tibia (55 retrolateral, 56 dorsal). 57–58 Genital bulb (57 ventral, 58 retrolateral).E—embolus, PA—proximal arm of tegular apophysis, PTA—patellar apophysis, RTA—retrolateral tibial apophysis. Unlabelled arrow indicates concave distal prolateral margin of DA.

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.