Psilochorus apicalis Banks, 1921

Slowik, Jozef, 2009, A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae), Zootaxa 2144, pp. 1-53 : 8-10

Psilochorus apicalis Banks, 1921

Figs. 15–27, 188

Psilochorus gertschi Schenkel, 1950 . New synonymy.

Types. P. apicalis : ɗ syntype from Sierra Madre (33.38 N, 119.68W), Los Angeles County, California, USA; Coll: J. I. Carlson, CAS 737. Not Examined. ɗ and seven Ψ syntypes, from Colfax (39.10 N, 120.95 W), Placer County, California, USA; no collector, Jun-1888, MCZ. Examined.

P. gertschi Schenkel, 1950 , one Ψ and two juveniles from San Diego (32.71 N, 117.15 W), San Diego County, California, USA; no collector, no date, NHMB. Examined.

Specimens examined. 9 ɗ, 23 Ψ; USA, Arizona, Coconino County, 1 Ψ, Grand Canyon National Park, 30-Dec-1899, AMNH; California, Butte County, 1 Ψ Chico, 05-Jan-1956, EM; Calaveras County, 1 Ψ, Hanging Gardens Cave, R E Graham, 17-Aug-1962, AMNH; Contra Costa County, 1 Ψ, Briones Reservoir, J B Fraser, 20-Jul-1979, EM; Del Norte County, 1 ɗ 1 Ψ, Klamath, 05-Jul-1968, AMNH [odd spur]; El Dorado County, 1 ɗ 1 Ψ, Browns Ravine, Folsom L, 04-Apr-1981, EM; 1 Ψ, Georgetown, 29-May-1971, EM; Inyo County, 1 Ψ, Panamint Mtns., Sourdough Canyon, I. LaPre, 13-Aug-1971, EM; Maricopa County, 1 Ψ, Yosemite N P, Yosemite Lodge, D Boe, 16-Aug-1979, EM; Mono County, 1 ɗ, H M Hall Natural Area, Inyo N F, 18-Jul–1-Aug-1973, EMEM; Napa County, 1 ɗ, N Side Mt Howell, 3 km NSE of Angwin, H B Leech, 28-Feb-1977, CAS; 1 Ψ, North Side Mt. Howell, 3 km NSE of Angwin, H B Leech, 05-Apr-1980, CAS; San Benito County, 1 Ψ, Mercy Hot Springs, W of Panoche, S C Williams, 25-Oct-1970, CAS; San Diego County, 1 Ψ, Tijuana Estuary Array 14, USGS San Diego, Sept-2002, DMNS; 1 Ψ, Tijuana Estuary Array 14, USGS San Diego, Nov-2002, DMNS; 1 Ψ, San Diego Mission Gorge, D Boe, 26-May-1979, EM; San Francisco County, 2 Ψ, San Francisco, Cal Nat Maritime, 26-Jan-1931, CAGG; Santa Cruz County, 1 Ψ, Santa Cruz, D Boe, 12-Aug-1979, EM; Stanialaus County, 1 ɗ, 1 Ψ, Salt Grass canyon, 24 km W of Petterson, W E Azeredo, C L Mollinex, V F Lee, 02-Feb-19, CAS; 1 ɗ, 1 Ψ, Del Puerto Cyn, 12-Apr-1974, EM; 1 Ψ, Patterson, W fork Del Puerto Crk, 19-Jun-1980, EM; 1 ɗ, Lot B, Schick (37.94 N, 122.637 W), no date, NHMLA.

Diagnosis. Specimens may be distinguished by: male spur is very distal on the chelicerae as well as lying low and extending to or past the fang (Figs. 15, 17), bulb apophysis is singular, centered with a large retrolateral tab (Figs. 19, 20), MEP ridges are massive and project anteriorly creating an overhang when viewed laterally (Figs. 26, 27). This species may also have a clear sternal pattern (Fig. 22).

Male: (N=4) Total length: 2.32 ± 0.10; carapace length: 0.98 ± 0.09; carapace width: 1.00 ± 0.15; leg 1: 17.23 ± 2.43 (5.01 ± 0.85 + 0.33 ± 0.03 + 4.90 ± 0.63 + 5.83 ± 0.93 + 1.17 ± 0.06); tibia 2: 3.39 ± 0.37; tibia 3: 2.74 ± 0.32; tibia 4: 3.46 ± 0.37. 19–22 leg I tarsal segments; femur1/carapace length: 5.18 ± 1.05; RT at 7.4–10.3%; DT at 5.1–8.0%. Carapace and abdomen color pattern typical for genus. Sternum dusky except for a light median diamond shape extending almost the entire length and a light rectangular mark at each coxal joint (Fig. 22). Cheliceral spur located distal on the chelicera, extending past the fang in lateral view (Fig. 17), narrow in dorsal view, ending in a fine point (Fig. 15). Procursus thick, distal area lanceolate, end rounded (Fig. 21). Bulb apophysis singular, narrow, remaining almost the same thickness its entire length. Embolic tab on the retrolateral side almost extending to the bulb apophysis tip (Figs. 19, 20).

Female: (N=4) Total length: 2.53 ± 0.29; carapace length: 0.95 ± 0.06; carapace width: 0.95± 0.06; leg 1: 12.76 ± 0.70 (3.60 ± 0.25 + 0.33 ± 0.03 + 3.73 ± 0.22 + 4.15 ± 0.14 + 0.96 ± 0.06); tibia 2: 2.4 ± 0.16; tibia 3: 2.00 ± 0.17; tibia 4: 2.63 ± 0.16. 16–22 leg I tarsal segments; femur1/carapace length: 3.78 ± 0.12; RT at 11.0–14.2%; DT at 6.0–6.7%. Color pattern same as male. Epigynum lacking AEP. MEP forming two large lateral bulbs which extend anteriorly creating an overhang appearance in lateral view (Figs. 26, 27). PEP lower with shallow ridges conforming to general shape of MEP in posterior view (Fig. 25).

Variation. One male collected from Klamath, CA showed variation in the location and shape of the cheliceral spur (Figs. 16, 18). The spur was more proximal and projected further from the chelicera than usual. The procursus and bulb apophysis conformed to the type as well as the specimens were collected with a conspecific female. The sternal pattern was also faint in several specimens.

Remarks. Banks apparently designated two type sets for this species, the male examined from the MCZ type set matches the description and subsequent specimens examined confirm that the females associated with it are correct. Upon comparing the type specimens of P. gertschi it has been found that it is a misidentified P. apicalis . Apparently W. Gertsch examined the specimens in the 1980’s and made note of this (Ambros Haenggi, NHMB pers. comm.), however his observation was never published. This species can be separated from all other species by the cheliceral spur shape in the males and the overhanging MEP in the females. The sternal pattern is also distinctive.

Distribution. California

PLATE 3. Figures 15–27. Psilochorus apicalis Banks. 15– 22 Male. 15–16. Dorsal view of chelicerae. 17–18. Lateral view of chelicera. 19–20. Dorsal view of bulb apophysis. 21. Lateral view of procursus. 22. Sternum. 23–27. Epigynum. 23. Anterior view. 24. Ventral view. 25. Posterior view. 26–27. Lateral view.