Cybaeus septatus, Chamberlin & Ivie, 1942

Bennett, Robb, Copley, Claudia & Copley, Darren, 2022, The Californian clade of Cybaeus (Araneae: Cybaeidae) in the Nearctic: the septatus species group and three unplaced species, Zootaxa 5100 (2), pp. 189-223 : 190-191

publication ID

https://doi.org/ 10.11646/zootaxa.5100.2.2

publication LSID

lsid:zoobank.org:pub:1D783E41-8DF8-4D3C-9853-38C41CCEBB30

DOI

https://doi.org/10.5281/zenodo.6313355

persistent identifier

https://treatment.plazi.org/id/39264D0A-FFE5-AD0E-FF6F-658BFD2DFBE3

treatment provided by

Plazi

scientific name

Cybaeus septatus
status

 

The septatus View in CoL species group

Diagnosis. Unique among the members of the Californian clade of Cybaeus , the species group affiliation of the males of the septatus group is relatively easily to determine. The males of the septatus group are diagnosed by a combination of the prolaterally to slightly anteriorly directed patellar apophysis which is as long as or longer than the width of the palpal patella and bears four to 12 peg setae one of which is in a proximal medial position isolated from, or slightly to noticeably larger than, the remainder of the peg setae ( Figs 1–2 View FIGURES 1–4 , 5–7 View FIGURES 5–9 , 22 View FIGURES 22–24 , 25 View FIGURES 25–26 , 34 View FIGURES 33–36 , 44 View FIGURES 43–46 , 47 View FIGURES 47–48 ). To our knowledge, no males of other Californian clade Cybaeus species groups ( adenes , aspenicolens , consocius , devius , and tardatus ) or unplaced Californian species ( C. cribelloides Chamberlin & Ivie , C. gidneyi Bennett , C. irreverens Bennett spec. nov.) show this combination of characters.

The females of the septatus group are diagnosed by a combination of features of the epigynum, atrium, and copulatory ducts. The epigynum is marked anteriorly by one or more “wrinkles” in the integument ( Figs 10, 13 View FIGURES 10–15 , 27 View FIGURES 27–32 ) and the atrium features paired longitudinal atrial openings medially ( Figs 10, 13 View FIGURES 10–15 , 16 View FIGURES 16–21 , 27 View FIGURES 27–32 , 37, 40 View FIGURES 37–42 ). The copulatory ducts ( Figs 11–12, 14–15 View FIGURES 10–15 , 18–19 View FIGURES 16–21 , 28–29 View FIGURES 27–32 , 38, 41 View FIGURES 37–42 ) are short and lead from the atrial openings medially to the midline of the vulva where they are contiguous prior to diverging and leading laterally to the spermathecal heads. As with the septatus group males, no females of other Californian clade Cybaeus species groups or unplaced Californian species are known which possess this combination of characters.

Description. As in diagnosis. Medium-sized spiders: carapace lengths averaging 2.15–2.5 mm (females). Males subequal. Abdomen usually patterned. Legs unbanded (femora rarely lightly banded). Two or occasionally three complete pairs of ventral tibia I macrosetae (distal pair present, absent, or incomplete).

Male: Retrolateral tibial apophysis ( Figs 1 View FIGURES 1–4 , 33 View FIGURES 33–36 , 43 View FIGURES 43–46 ) carinate, nearly as long as tibia. Embolus relatively short and thin, describing a compound ( Figs 3 View FIGURES 1–4 , 23 View FIGURES 22–24 , 45 View FIGURES 43–46 ) or simple ( Fig. 35 View FIGURES 33–36 ) curve. Tegular apophysis ( Figs 3 View FIGURES 1–4 , 23 View FIGURES 22–24 , 35 View FIGURES 33–36 , 45 View FIGURES 43–46 ) with distal arm short, unmodified, with rounded or angular terminus; proximal arm prolaterally directed, slightly swollen basally, and tip slightly twisted and swollen ( Figs 3–4 View FIGURES 1–4 , 8–9 View FIGURES 5–9 ), bluntly acuminate ( Figs 23–24 View FIGURES 22–24 , 26 View FIGURES 25–26 ), or sharply acuminate ( Figs 35 View FIGURES 33–36 , 45 View FIGURES 43–46 , 48 View FIGURES 47–48 ).

Female: Atrial openings ( Figs 10, 13 View FIGURES 10–15 , 16 View FIGURES 16–21 , 27 View FIGURES 27–32 , 37, 40 View FIGURES 37–42 ) conspicuous or not. Spermathecal heads ( Figs 12, 15 View FIGURES 10–15 , 20–21 View FIGURES 16–21 , 29–30 View FIGURES 27–32 , 38–39, 41–42 View FIGURES 37–42 ) small dorsolateral lobes; spermathecal stalks short ( Figs 12, 14 View FIGURES 10–15 , 20 View FIGURES 16–21 , 38 View FIGURES 37–42 ) or relatively long ( Figs 29–30 View FIGURES 27–32 , 42 View FIGURES 37–42 ); Bennett’s glands near junction with spermathecal bases ( Figs 12, 14 View FIGURES 10–15 , 20–21 View FIGURES 16–21 , 39 View FIGURES 37–42 , 32 View FIGURES 27–32 , 39, 42 View FIGURES 37–42 ); bases large, rounded; fertilization ducts exit bases posteriorly.

Composition and distribution. Cybaeus chauliodous Bennett , C. lockeae Bennett spec. nov., C. septatus Chamberlin & Ivie , C. somesbar Bennett , and C. viator Bennett spec. nov. Cybaeus septatus and C. chauliodous are relatively common within their known distributions; the other species are uncommon. All have restricted ranges within an area encompassing southwestern Oregon (Jackson and Josephine Counties) and northern California south to Alameda and Sierra Counties ( Figs 49–50 View FIGURE 49 View FIGURE 50 ).

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Araneae

Family

Cybaeidae

Genus

Cybaeus

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