Cybaeus hesper 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: 407-409

publication ID

publication LSID


persistent identifier

treatment provided by


scientific name

Cybaeus hesper Chamberlin and Ivie


Cybaeus hesper Chamberlin and Ivie 

Figs 10–15View FIGURES 10–12View FIGURES 13–17, 21View FIGURES 20–22, 84View FIGURE 84

Cybaeus minor Banks 1904: 341  , figs 4, 44 (preoccupied by Chyzer 1897, in Chyzer & Kulczyński, 1897). Chamberlin and Ivie 1932: 27, fig. 63 (not 64 = C. hummeli  spec. nov.).

Cybaeus hesper Chamberlin and Ivie 1932: 27  , figs 65–66. Chamberlin and Ivie 1937: 225. Roewer 1954: 90. Roth and Brown 1986: 3. Copley et al. 2009: 372, fig. 8. World Spider Catalog 2021.

Cybaeus minoratus Gertsch 1936: 14  (replacement name for C. minor Banks  ).

Cybaeus hesperus: Bonnet 1956: 1301  (unjustified emendation).

Nomenclatural notes. Cybaeus minor Banks  is a junior homonym of C. minor Chyzer  and therefore unavailable. Cybaeus hesper  has age precedence over C. minoratus  , Gertsch’s (1936) replacement name for C. minor Banks. Chamberlin and Ivie (1932)  were unable to examine Bank’s specimens and based their redescription of C. minor  upon a single female from Stanford. The genitalic morphology of their specimen agrees well with Banks’ female syntype but is not the specimen they used for the purpose of illustrating the epigynum of C. minor  ( Chamberlin and Ivie 1932, fig. 64). That figure is almost certainly of the epigynum of a previously undescribed species of the consocius  group described below as C. hummeli  spec. nov.

Chamberlin and Ivie (1932) provided no etymological explanation for the species name hesper  . We assume it is a shortened version of the Latin noun hesperus  (translated as evening star, evening, or west) and was intended to reflect the western California distribution of this species. If so, then, as suggested by Bonnet (1956: “Il vaut mieux ecrire hesperus  ”), the correct spelling should be hesperus  . No provision of the Code suggests emending the spelling of a Latin noun lacking its expected suffix, however, and subsequent authors have used the original spelling without commenting upon Bonnet’s emendation. Following Roth and Brown (1986), Copley et al. (2009), and World Spider Catalog (2021) we accept the original spelling, hesper  , as correct and consider Bonnet’s emendation to be unjustified.

Type material examined. U.S.A.: California: Holotype male of C. hesper, Santa Clara County, Stanford  University, spring 1921, J.C. Chamberlin ( AMNH). 1 male, 1 female, syntypes of C. minor, Los Angeles County, Claremont  , no date, Baker, ( MCZ). 

Other material examined. U.S.A.: California: San Mateo. 1♀, Page Mill Rd. at Skyline Blvd., ~ 7.2 km E of La Honda, 2.iv.1994, D. Ubick & J. Boutin ( CAS);  1♀, Redwood City, 22.i.1946, P.H. Arnaud ( CAS);  1♂ (palpus only), Skyline Blvd . at King’s Mtn., 18.viii.1928, J.C. Chamberlin ( AMNH);  Santa Clara. 1♀, Page Mill Rd. , 0.3 mi. E of Skyline Blvd., 24.v.1992, D. Ubick & J. Boutin ( CAS);  1♀, Stanford [University], no date, R. V. Chamberlin ( AMNH)  .

Diagnosis. The male of C. hesper  is unlikely to be confused with the males of the other species in the consocius  group and is diagnosed by the unique form of the proximal arm of the tegular apophysis ( Figs 11–12View FIGURES 10–12, 21View FIGURES 20–22), in particular the small terminal indentation producing a distinct (but inconspicuous) bifid tip ( Fig. 11View FIGURES 10–12, 21View FIGURES 20–22). The female of C. hesper  is only likely to be confused with the females of C. consocius  or C. hummeli  spec. nov.; distinguishing the females of these three species is discussed under C. consocius  .

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

Male: (n=3). Patellar apophysis ( Fig. 10View FIGURES 10–12) nearly as long as width of patella, with less than ten peg setae dorsally. Proximal arm of tegular apophysis ( Fig. 11–12View FIGURES 10–12, 21View FIGURES 20–22) with a rounded ridge anteriorly and extending posterolaterally). Measurements (n=2). Holotype of C. hesper  , male syntype of C. minor  respectively: CL 2.16, 2.33; CW 1.64, 1.73; SL 1.02, 1.13; SW 0.99, 1.12.

Female: (n=5). Atrium ( Fig. 13View FIGURES 13–17) with inconspicuous anterior border. Copulatory ducts ( Figs 14–15View FIGURES 13–17) somewhat membranous, extending anteriorly beyond the anterior margin of the atrium a distance of up to approximately 2/5 the distance between the anterior atrial margin and the epigastric groove. Spermathecal stalks well separated ( Fig. 15View FIGURES 13–17). Measurements (n=3). Female syntype of C. minor CL  2.05, CW 1.40, SL 1.04, SW 1.00. Redwood City and Stanford females: CL 2.13, 2.7; CW 1.48, 1.83; SL 1.12, 1.30; SW 1.01, 1.24.

Distribution and natural history. Apparently restricted to San Mateo and Santa Clara Counties southwest of San Francisco Bay, California ( Fig. 84View FIGURE 84). We believe the record from the Los Angeles area (two syntypes of C. minor  ) to be mislabeled: no other species of the consocius  group is known to range that far south and no further specimens of C hesper  have been recorded from the Los Angeles area subsequent to the original description of C. minor  over 100 years ago. It is not included on the distribution map. Mature males have been collected in “spring” and August.


American Museum of Natural History


Museum of Comparative Zoology


California Academy of Sciences


Departamento de Geologia, Universidad de Chile


Royal British Columbia Museum - Herbarium














Cybaeus hesper Chamberlin and Ivie

Bennett, Robb, Copley, Claudia & Copley, Darren 2021

Cybaeus hesperus: Bonnet 1956: 1301

Bonnet, P. 1956: 1301

Cybaeus minoratus

Gertsch, W. J. 1936: 14

Cybaeus hesper

Copley, C. R. & Bennett, R. & Perlman, S. J. 2009: 372
Roth, V. D. & Brown, W. L. 1986: 3
Roewer, C. F. 1954: 90
Chamberlin, R. V. & Ivie, W. 1937: 225
Chamberlin, R. V. & Ivie, W. 1932: 27

Cybaeus minor

Chamberlin, R. V. & Ivie, W. 1932: 27
Banks, N. 1904: 341