Cybaeus schusteri 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: 264-265

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Cybaeus schusteri Bennett

spec. nov.

Cybaeus schusteri Bennett  spec. nov.

Figs 50–53View FIGURES 50–53, 65–66View FIGURES 65–68, 70View FIGURE 70

Type material. Holotype ♂. U.S.A.: California: Napa County, 10 miles south of Monticello , 6 January 1957, R. O. Schuster ( AMNH). 

Paratypes. U.S.A.: California: Napa. 1♀, 5 mi. S of Monticello , 6.i.1957, R  . O. Schuster ( AMNH); 2♀, 10 mi. S of Monticello , 16.iii.1956, R  . O. Schuster ( AMNH); 1♀, 10 mi. S of Monticello , 17.ii.1957, R  . O. Schuster ( AMNH)  .

Etymology. The specific name is a patronym honouring the late R.O. Schuster who collected the holotype and paratypes of this species.

Diagnosis. The male of C. schusteri  is diagnosed by the combination of about ten small peg setae arranged linearly along the dorsal surface and tip of the patellar apophysis ( Fig. 51View FIGURES 50–53) and, on the proximal arm of the tegular apophysis ( Figs 50View FIGURES 50–53, 65–66View FIGURES 65–68), the bifid tip with the terminations small, not pincer-like, and only slightly convergent and the presence of a small but prominent angular dorsal keel. Although no other male of the adenes  group has this combination of characters, the males of C. schusteri  and C. sanbruno  can be confused; see the diagnosis of C. sanbruno  for further discussion.

The female is distinguished by the inverted vase-shaped atrium which is narrowest anteriorly and widest posteriorly ( Fig. 53View FIGURES 50–53). It may be difficult to differentiate some females of this species from females of C. adenes  and C. grizzlyi  . See the diagnosis of C. adenes  for further discussion.

Description. Femora unbanded.

Male: (n=1). Small inconspicuous retrolateral ridge anteriorly on tibia dorsal to carinate retrolateral tibial apophysis ( Fig. 51View FIGURES 50–53).

Holotype. CL 1.73, CW 1.30, SL 0.94, SW 0.86.

Female. (n=4). Length of atrium (from epigastric groove to anterior margin) about twice width (between lateral margins) ( Fig. 53View FIGURES 50–53). Vulva ( Fig. 53View FIGURES 50–53) as for C. adenes  .

CL 1.75–2.10 (1.94), CW 1.26–1.45 (1.35), SL 0.94– 1.09 (1.02), SW 0.85–0.99 (0.93).

Note. The female of C. adenes  from near St. Helena, Napa County ( Figs 9–11View FIGURES 9–11), may prove to be a specimen of C. schusteri  . Males and a larger sample of females from that area are needed to determine if one or both of C. adenes  and C. schusteri  occur in the St. Helena area.

Distribution. Monticello area near south end of Lake Berryessa, Napa County, in west central California ( Fig. 70View FIGURE 70).


Departamento de Geologia, Universidad de Chile


American Museum of Natural History