Cybaeus auburn Bennett,

Bennett, Robb, Copley, Claudia & Copley, Darren, 2019, Cybaeus (Araneae: Cybaeidae): the adenes species group of the Californian clade, Zootaxa 4711 (2), pp. 245-274: 254-256

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Cybaeus auburn Bennett

spec. nov.

Cybaeus auburn Bennett  spec. nov.

Figs 18–24View FIGURES 18–20View FIGURES 21–24, 63–64View FIGURES 61–64, 70View FIGURE 70

Type material. Holotype ♂. U.S.A.: California: Placer County, Elders Corner, five miles north of Auburn , 27 December 1986, D. Ubick ( CAS). 

Paratypes. U.S.A.: California: El Dorado. 2♀, near Nashville , 5.iii.1958, L.M. Smith & R  . O. Schuster ( CAS); Placer. 1♀, Auburn , 12.iii.1958, R  . O. Schuster & V  . D. Roth ( CAS)  .

Etymology. The specific name is a noun in apposition taken from the type locality.

Diagnosis. The lightly banded femora of male and female C. auburn  may often be sufficient to separate them from specimens of other adenes  group species except for C. amicus  and C. torosus  .

In addition, the male of C. auburn  is diagnosed by the relatively short patellar apophysis ( Fig. 19View FIGURES 18–20) and, more reliably, the morphology of the proximal arm of the tegular apophysis ( Figs 18View FIGURES 18–20, 63–64View FIGURES 61–64). The length of the patellar apophysis is about 2/3 the width of the patella; in the known males of all other adenes  group species the length of the patellar apophysis is nearly equal to the width of the patella. However, this difference is slight and difficult to determine. The tip of the proximal arm of the tegular apophysis is single, slender, and slightly corkscrewed while dorsal to the tip there is a relatively large, blunt, proximo-ventrally directed process ( Figs 63–64View FIGURES 61–64) which gives the proximal arm the appearance of being bifid. In the other males of the adenes  group with a single pointed tip of the proximal arm, the tip is untwisted and the prominent blunt dorsal process is lacking ( C. amicus  : Fig. 56View FIGURES 56–60) or sharply pointed ( C. grizzlyi  : Figs 61–62View FIGURES 61–64). The remaining adenes  group males have a distinctly bifid ( C. adenes  : Figs 59–60View FIGURES 56–60; C. sanbruno  : Fig. 67View FIGURES 65–68; C. schusteri  : Fig. 65View FIGURES 65–68), or trifid tip ( C. reducens  : Fig. 57View FIGURES 56–60).

The female of C. auburn  is distinguished by the form of the atrium and, when present, the small epigynal pit. The atrium is broad, weakly concave, and located antero-medially on the epigynum ( Figs 21–22View FIGURES 21–24). No other female in the adenes  group has this combination of characters; in particular, the atrium in all other species is anteriorly located on the epigynum. As well, most females of C. auburn  have a small pit located postero-medially on the epigynum (discernible in cleared specimens: Figs 22–23View FIGURES 21–24), lacking in females of all other adenes  group species.

Description. Femora very lightly banded.

Male: (n=1). Patellar apophysis (Fig. 240) with about 25 peg setae on dorsal surface. No retrolateral ridge anteriorly on tibia dorsal to carinate retrolateral tibial apophysis.

Holotype CL 2.45, CW 1.83, SL 1.20, SW 1.16.

Female: (n=3). Length of atrium (from epigastric groove to anterior margin) about 3/4 width (between lateral margins). Posterior epigynal pit lacking in Auburn specimen.

CL 1.83, 1.93, 2.6; CW 1.35, 1.35, 2.00; SL 0.98, 0.99, 1.26; SW 0.92, 0.92, 1.18 (Auburn specimen listed second).

Distribution. Western lower slopes of the Sierra Nevada of Placer and El Dorado Counties in east central California ( Fig. 70View FIGURE 70).


California Academy of Sciences


Departamento de Geologia, Universidad de Chile


Royal British Columbia Museum - Herbarium