Cybaeus aspenicolens, Chamberlin & Ivie, 1932

Bennett, Robb, Copley, Claudia & Copley, Darren, 2021, Cybaeus (Araneae: Cybaeidae): the aspenicolens species group of the Californian clade, Zootaxa 4926 (2), pp. 224-244: 225-226

publication ID

https://doi.org/10.11646/zootaxa.4926.2.4

publication LSID

lsid:zoobank.org:pub:FDAE3465-979C-482F-908F-D0CF4A15000E

DOI

http://doi.org/10.5281/zenodo.4506085

persistent identifier

http://treatment.plazi.org/id/676A6A74-B100-3879-F8A1-F85FFC34FC66

treatment provided by

Plazi

scientific name

Cybaeus aspenicolens
status

 

The aspenicolens  species group

Diagnosis. Differentiating the species groups of the Holarctic and Californian clades of Cybaeus  is discussed in Copley et al. (2009). The species of the aspenicolens  group of the Californian clade are defined by the atrium usually divided and with longitudinal copulatory openings leading into the midline of the vulva ( Figs 16, 18View FIGURES 14–19, 38View FIGURES 34–40) and the greatly reduced and linearly oriented copulatory ducts and spermathecal stalks ( Figs 19View FIGURES 14–19, 22View FIGURES 20–24, 37View FIGURES 34–40). Other Californian clade species groups are characterized either by a divided atrium but a more complex vulva with the copulatory ducts and spermathecal stalks not so reduced or linear ( septatus  group–Copley et al. 2009: figs 12, 95, 101), an undivided atrium and simple but sinuous copulatory ducts and spermathecal stalks ( adenes  group–Bennett et al. 2019: figs 6, 8, 11, 17, 24, 29, 31, 32, 34, 40, 48, 55), or the atrium divided or not and relatively long and complex copulatory ducts ( consocius  , devius  , and tardatus  groups–Copley et al. 2009: figs 8–10, 72, 75, 78, 84).

Two informal subgroups are definable within the aspenicolens  group: the aspenicolens  subgroup ( C. aspenicolens  , C. blasbes  , and C. coylei  spec. nov.) and the fraxineus  subgroup ( C. fraxineus  spec. nov. and C. thermydrinos  ). Males of the aspenicolens  subgroup are characterized by their possession of a large, broad, blunt patellar apophysis with dimorphic peg setae in two groups ( Figs 2View FIGURES 1–4, 5View FIGURES 5–7, 8View FIGURES 8–10, 11–13View FIGURES 11–13) and the large, C-shaped proximal arm of the tegular apophysis with a retrolaterally directed uncinate tip ( Figs 3View FIGURES 1–4, 6View FIGURES 5–7, 9View FIGURES 8–10), Males of the fraxineus  subgroup can be distinguished by their narrower and tapered patellar apophysis with monomorphic peg setae in a single group ( Figs 25View FIGURES 25–28, 29View FIGURES 29–31) and the proximal arm of the tegular apophysis smaller with a prolaterally directed bifurcate tip ( Figs 26View FIGURES 25–28, 30View FIGURES 29–31, 32–33View FIGURES 32–33). Females of the aspenicolens  subgroup are characterized by their conspicuous epigynal concavity or depression and atrial openings without a transverse hood ( Figs 14, 16, 18View FIGURES 14–19). Females of the fraxineus  subgroup have an epigynum with a “normal”, relatively convex surface and atrial openings partially obscured anteriorly by a transverse epigynal ridge or hood ( Figs 34–35, 38–39View FIGURES 34–40).

Description. Medium- to large-sized spiders, carapace lengths averaging 2.6–3.3 mm (males) and 2.4–3.4 mm (females). Abdomen patterned, femora usually at least lightly banded. Two or three complete pairs of ventral tibia I macrosetae (terminal pair absent, incomplete, or present): pattern 2–1p–2–1p–0 (or 1p, or 2).

Male: Patellar apophysis distally directed, species specific; massive, blunt, broader than long, length about 3/4 patellar width, with dimorphic peg seta separated in two groups retrolaterally and dorsally ( Figs 2View FIGURES 1–4, 5View FIGURES 5–7, 8View FIGURES 8–10, 11–13View FIGURES 11–13); or slenderer, gradually tapering to blunt point, longer than broad, length about equal to width of patella, with monomorphic peg setae in single group dorsally along posterior margin of distinct concavity ( Figs 25View FIGURES 25–28, 29View FIGURES 29–31). Palpal tibia about as long as wide; retrolateral tibial apophysis carinate, nearly as long as tibia ( Figs 1–2View FIGURES 1–4, 25View FIGURES 25–28). Embolus relatively short, thick ( Figs 3View FIGURES 1–4, 5View FIGURES 5–7, 9View FIGURES 8–10, 26View FIGURES 25–28, 30View FIGURES 29–31). Distal arm of tegular apophysis short, not enlarged or lengthened; proximal arm species specific, retrolaterally or prolaterally directed ( Figs 3–4View FIGURES 1–4, 6–7View FIGURES 5–7, 9–10View FIGURES 8–10, 26–28View FIGURES 25–28, 30–31View FIGURES 29–31).

Female: Epigynum usually ridged anteriorly; atrium inconspicuous with medial paired, longitudinal openings ( Figs 14, 18View FIGURES 14–19, 38View FIGURES 34–40). Vulva ( Figs 19View FIGURES 14–19, 22View FIGURES 20–24, 39View FIGURES 34–40) simple with reduced, nearly linear copulatory ducts and spermathecal heads and stalks. Copulatory ducts very short, exiting atria towards midline of vulva, often contiguous along midline. Heads of spermathecae on small dorsal lobes near midline of vulva; often not differentiated from rest of vulva except for presence of primary pores. Stalks very short, not differentiated. Bennett’s glands near junction of stalks with rounded, relatively large spermathecal bases. Fertilization ducts exit bases near junction with stalks.

Composition and distribution. Cybaeus aspenicolens Chamberlin & Ivie  , C. blasbes Chamberlin & Ivie  , C. coylei Bennett  spec. nov., C. fraxineus Bennett  spec. nov., and C. thermydrinos Bennett. All  species have very restricted distributions on the western slopes of the central and southern Sierra Nevada mountain range in California from Tuolumne County south to northern Kern County ( Figs 41–42View FIGURE 41View FIGURE 42).

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Araneae

Family

Cybaeidae

Genus

Cybaeus