Cybaeus reducens Chamberlin & Ivie 1932,

Bennett, Robb, Copley, Claudia & Copley, Darren, 2019, Cybaeus (Araneae: Cybaeidae): the adenes species group of the Californian clade, Zootaxa 4711 (2), pp. 245-274: 259-262

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Cybaeus reducens Chamberlin & Ivie 1932


Cybaeus reducens Chamberlin & Ivie 1932 

Figs 35–43View FIGURES 35–37View FIGURES 38–43, 57–58View FIGURES 56–60, 70View FIGURE 70

Cybaeus reducens Chamberlin & Ivie 1932: 23  , fig. 57. Roewer 1954: 91. Bonnet 1956: 1303. Roth & Brown 1986: 4. Bennett 2006: 479, Figs 13–16. World Spider Catalog 2019.

Type material. Holotype ♀. U.S.A.: California: Monterey County, Pacific Grove , 17 August 1931, W. Ivie ( AMNH), examined. 

Other material examined. U.S.A.: California: Monterey. 6♀, 14 mi. S of Big Sur , 22.xii.1953, V  . D. Roth ( CAS); 3♀, 17 mi. S of Big Sur , 22.xii.1953, V  . D. Roth ( AMNH); 1♀, Carmel , 6.iv.1954, no collector data ( AMNH); 3♀, 1 mi. N of Carmel, 21.xii.1953, V  . D. Roth ( CAS); 2♀, Pacific Grove , 1913, R  . V  . Chamberlin ( AMNH); 2♀, 6.viii.1931, R  . V  . Chamberlin ( AMNH); 6♀, 17.viii.1931, W. Ivie ( AMNH); 5♀, 1.ix.1931, W. Ivie ( AMNH); 2♀, Pebble Beach, Crest Road, 19.ix.1959, L.M. Smith ( AMNH); Santa Clara. 1♂, 3.6 mi. from San Felipe Road on Silver Creek Road [SE of San Jose], 2.i.1983, T  . S. Briggs, D.Ubick & V  . F. Lee ( DU)  .

Diagnosis. The near absence of peg setae on the patellar apophysis and the morphology of the proximal arm of the tegular apophysis diagnose the male of C. reducens  . The patellar apophysis ( Fig. 36View FIGURES 35–37) in the single known male has only two small peg setae located dorsally near the tip of the apophysis. The proximal arm of the tegular apophysis ( Figs 35View FIGURES 35–37, 57–58View FIGURES 56–60) has a trifid tip and, dorsally, a prominent angular keel. No other males in the adenes  group have this combination of characters.

The female is distinguished by the combination of the broad, slightly to moderately concave atrium located anteriorly on the epigynum ( Figs 38, 41View FIGURES 38–43) and the compact, apparently strongly reduced vulva ( Figs 39–40, 42–43View FIGURES 38–43). The females of all other adenes  group species have narrow, strongly concave atria and “normal” (well-developed and not apparently reduced) vulvae ( C. adenes  : Figs 4–6View FIGURES 4–8, 9View FIGURES 9–11 –111; C. amicus  : Figs 15–17View FIGURES 15–17; C. grizzlyi  : Figs 28–32View FIGURES 28–30View FIGURES 31–32; C. pearcei  : Figs 33–34View FIGURES 33–34; C. sanbruno  : Figs 7–49View FIGURES 4–8View FIGURES 9–11View FIGURES 15–17View FIGURES 18–20View FIGURES 21–24View FIGURES 25–27View FIGURES 28–30View FIGURES 31–32View FIGURES 33–34View FIGURES 35–37View FIGURES 38–43View FIGURES 44–46View FIGURES 47–49; C. schusteri  : Fig. 53View FIGURES 50–53; C. torosus  : Figs 54–55View FIGURES 54–55). The atrium and vulva of female C. auburn  are antero-medially located on the epigynum ( Figs 21–22View FIGURES 21–24) and “normal” ( Figs 23–24View FIGURES 21–24), respectively.

Description. Femora unbanded.

Male: (n=1). Proximal arm of tegular apophysis ( Fig. 57View FIGURES 56–60) with trifid tip: anterior-most termination rounded and prominent, two others smaller and pointed. Very small inconspicuous retrolateral ridge anteriorly on tibia dorsal to carinate retrolateral tibial apophysis ( Fig. 36View FIGURES 35–37).

CL 2.28, CW 1.65, SL 1.16, SW 1.11.

Note. This male has been paired with the females of C. reducens  because of the similarity of all specimens in size, coloration, and range (although the females were all collected in a small area along the coast and the male from about 70 km away and 35 km inland).

Female: (n=31). Length of atrium (from epigastric groove to anterior margin) 0.7–1.0 times width (between lateral margins) ( Figs 38, 41View FIGURES 38–43). Vulva ( Figs 39–40, 42–43View FIGURES 38–43) usually very small, compact.

(n=23). CL 1.98–3.1 (2.5+0.3), CW 1.35–2.05 (1.70+0.20), SL 0.99–1.43 (1.21+0.12), SW 0.90–1.30 (1.14+0.11). Holotype CL 2.8, CW 1.98, SL 1.29, SW 1.26.

Distribution and natural history. West central California from coastal northern Monterey County inland to central Santa Clara County ( Fig 70View FIGURE 70). The male was collected in early January at an elevation of 70 meters.


American Museum of Natural History


Royal British Columbia Museum - Herbarium


California Academy of Sciences


Departamento de Geologia, Universidad de Chile


Tavera, Department of Geology and Geophysics


Duke University Vertebrate Collection














Cybaeus reducens Chamberlin & Ivie 1932

Bennett, Robb, Copley, Claudia & Copley, Darren 2019

Cybaeus reducens

Bennett, R. G. 2006: 479
Roth, V. D. & Brown, W. L. 1986: 4
Bonnet, P. 1956: 1303
Roewer, C. F. 1954: 91
Chamberlin, R. V. & Ivie, W. 1932: 23