Aptostichus hesperus Chamberlin, 1919

Bond, Jason E., 2012, Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae), ZooKeys 252, pp. 1-209 : 93-98

Aptostichus hesperus Chamberlin, 1919 Figures 188-196Maps 20, 21

Nemesoides hespera Chamberlin, 1919: 2. Male holotype (379), California, Los Angeles County, Claremont, 34.0968, -117.7195 5, coll. W. Hilton, in MCZ, examined.

Aptostichus hesperus - Bond and Opell 2002: 518.

Diagnosis.

Female (Figs 188-191) and male (Figs 192-196) Aptostichus hesperus can be distinguished from all other Aptostichus species by having posterior sternal sigilla that are positioned mid - ventrally and are either very closely positioned, or contiguous (Fig. 188). The sigilla of other Aptostichus species are distinctly separated and tend to be positioned more posteriorly. A longer palpal bulb length and greater PTw/PTl ratio (Figs 195, 196) also help to distinguish this species from Aptostichus atomarius , Aptostichus cahuilla and Aptostichus icenoglei that potentially occur sympatrically with Aptostichus hesperus . All Hesperus group taxa have an offset rastellar spine (Fig. 189).

Descriptions.

Described by Chamberlin (1919: 1-2).

Material examined.

United States: California: Orange Co.: S Limestone Canyon, N The Sinks, 33.7231, -117.6663 1, 378m, USGS-BRD San Diego Sta. 1.v.2001 [AP1054, 1♀, CAS]; Loma Ridge, W Limestone Canyon, 33.7358, -117.6877 1, 327m, USGS-BRD San Diego Field Sta. 1.xi.2000 [AP1056, 2♂, CAS], 1.xi.1998 [AP1055, 1♂, CAS]; NE Lemon Heights, Lomas de Santiago, E Peters Canyon, 33.7672, -117.7637 1, 295m, USGS-BRD San Diego Sta. 1.iv.1999, [AP960, 1♂, CAS]; Weir Canyon, 33.8155, -117.7471 1, 232m, USGS-BRD San Diego Field Sta. 1.iv.2000 [AP1124, 1♂, CAS]; Anaheim, 33.8197, -117.8963 7, 50m, F Handsfield 1.vii.1962 [AP618, 1♀, AMNH]; Ridge NE Weir Canyon, 33.8376, -117.7219 1, 354m, USGS-BRD San Diego Sta. 1.i.2000 [AP1097, 1♂, CAS], 1.iv.1999 [AP1098, 1♂, CAS]; Chino Hills, ridge S Telegraph Canyon, 33.9116, -117.7887 1, 355m, USGS-BRD San Diego Field Sta. 1.x.1998 [AP1039, 1♂, CAS]; Riverside Co.: S Santa Margarita River, NW Royal Oak ranch, 33.4463, -117.1719 1, 353m, USGS-BRD San Diego Sta. 1.v.2000 [AP896, 1♂, CAS]; between Squaw Mountain & Redonda Mesa, N Tenaja Rd., 33.5025, -117.3386 1, 1020m, USGS-BRD San Diego Sta. 1.ii.2000 [AP968, 1♂, CAS]; between Squaw Mountain & Redonda Mesa, N Tenaja Rd, 33.5028, -117.3406 1, 690m, USGS-BRD San Diego Sta. 1.vi.1999 [AP966, 1♂, CAS]; SE Skinner Reservoir, 33.5766, -117.0316 1, 482m, USGS-BRD San Diego Sta. 1.viii.1999 [AP1023, 1♂, CAS]; S Skinner Reservoir, 33.5774, -117.0545 1, 469m, USGS-BRD San Diego Field Sta. 1.iv.1999 [AP1020, 1♂, CAS]; E Skinner Reservoir, 33.5819, -117.0189 1, 488m, USGS-BRD San Diego Field Sta. 1.ii.2000 [AP1006, 1♂, CAS], 1.iv.1999 [AP1003, 1♂, CAS]; E Skinner Reservoir, 33.585, -117.0236 1, 514m, USGS-BRD San Diego Field Sta. 1.ii.2000 [AP1013, 1♂, CAS]; E Skinner Reservoir, 33.5869, -117.0212 1, 501m, USGS-BRD San Diego Sta. 1.iv.1999 [AP1005, 1010, 1011, 3♂, CAS], 1.v.1999 [AP1004, 1008, 2♂, CAS]; E Skinner Reservoir, 33.5898, -117.0233 1, 452m, USGS-BRD San Diego Sta. 1.iv.1999 [AP1002, 1♂, CAS]; E Skinner Reservoir, 33.5947, -117.0253 1, 468m, USGS-BRD San Diego Sta. 1.ii.2000 [AP1030, 1♂, CAS], 1.iv.1999 [AP1031, 1♂, CAS]; E Skinner Reservoir, 33.5977, -117.024 1, 464m, USGS-BRD San Diego Field Sta. 1.ii.2000 [AP1029, 1♂, CAS], 1.iv.1999, [AP1028, 1♂, CAS]; E Skinner Reservoir, 33.5989, -117.0235 1, 467m, USGS-BRD San Diego Field Sta. 1.ii.2000 [AP1024, 1025, 2♂, CAS]; E Rawson Canyon, S Crown Valley, 33.631, -117.0086 1, 655m, USGS-BRD San Diego Sta. 1.v.2000 [AP1119, 1♂, CAS]; E Rawson Canyon, S Crown Valley, 33.6369, -117.0022 1, 677m, USGS-BRD San Diego Field Sta. 1.v.2000 [AP1117, 1♂, CAS]; just S Winchester on Leona Rd, ~1.6km S intersection w/Patton Avenue, 33.6771, -117.1157 1, 444m, J Bond 1.ii.2004 [MY2510, 2516 2♀, AUMNH]; Winchester, 33.7138, -117.0915 1, 470m, W Icenogle 7.ii.1972 [AP143, 1♂, AUMNH], 28.i.1973 [AP146, 1♂, AMNH], W Icenogle 14.vi.1980 [AP145, 1♂, AUMNH], 26.i.1983 [AP144, 1♂, AUMNH]; 1.6km NW Winchester Town Center, 33.7148, -117.0921 1, 470m, W Icenogle 11.i.1998 [AP358, 1♂, CAS]; Winchester, 1.6km NW of town center, vicinity of Double Butte, 33.7149, -117.0922 1, 478m, W Icenogle 21.iii.1977 [AP107, 1♂, AMNH], 26.xii.1977 [AP100, 1♂, AMNH], 28.xii.1977 [AP139, 1♂, AMNH], 18.v.1988 [AP129, 1♂, AMNH], 29.xii.1968 [AP140, 2♂, AMNH], 12.ii.1967 [AP112, 1♀, CAS], 19.iii.1967 [AP617, 1♀, AMNH], 28.v.1967 [AP118, 1♀, 10juv, CAS], 11.vi.1967 [AP124, 1juv, AMNH], 6.viii.1967 [AP123, 1♀, AMNH], 23.viii.67 [AP125, 1♀, 45juv, AMNH], 23.viii.1967 [AP126, 1♂, CAS], 15.x.1967 [AP111, 1♀, 35juv, AMNH], 15.x.1967 [AP113, 1♀, AMNH], 12.xi.1967 [AP114, 1♀, 49juv, AMNH], 12.xi.1967 [AP117, 1♀, 46juv, AMNH], 22.xi.1967 [AP120, 1♂, AMNH], 12.xii.1967 [AP099, 1♂, AMNH], 17.viii.1968 [AP108, 1♀, 35juv, AMNH], 29.xii.1968 [AP135, 1♂, AMNH], 16.i.1969 [AP133, 3juv, AMNH], 6.ii.1972 [AP098, 1♂, AMNH]; Winchester, 1.6km NW of town center, vicinity of Double Butte, 33.7156, -117.0936 1, 465m, J Bond 29.i.2004 [MY2496, 1♀, AUMNH]; ravine NW Icenogle residence, 33.72, -117.0922 1, 523m, J Bond 26.iii.1996 [AP725, 2♀, AUMNH]; Winchester, deep ravine NW Icenogle residence Grand Ave, 33.7222, -117.0913 1, 600m, J Bond 7.xi.1998 [AP690, AP733, 1♀, AUMNH]; N of Perris, E of Mayer Farms, 33.8049, -117.254 1, 559m, USGS-BRD San Diego Field Sta. 1.ii.1999 [AP1101, 1♂, CAS]; N of Perris, E of Mayer Farms, 33.8115, -117.257 1, 588 m, USGS-BRD San Diego Field Sta. 1.i.2000 [AP1104, 1♂, CAS]; E of Perris, E of Mayer Farms, 33.8136, -117.2587 1, 577m, USGS-BRD San Diego Field Sta. 1.i.2000 [AP1105, 1♂, CAS]; Lake Matthews, 33.82667, -117.438 1, 446m, J Bond 22.xi.1998 [AP692, 1♀, AUMNH]; NE Perris Reservoir, 33.8666, -117.1938 1, 533m, USGS-BRD San Diego Sta. 1.ii.1999 [AP925, 1♂, CAS]; Hwy 79, ~6km S Beaumont, N facing slope small ravine, 33.87, -116.9963 1, 655m, J Bond 19.i.1997 [MY2286, 1juv, AUMNH]; 9.65 road km S of Banning, 33.8797, -116.8458 6, 1221m, W Icenogle 7.x.1968 [AP103, AP104, 2♂, AMNH], [AP137, 2♀, 2juv, CAS]; E Perris Reservoir, between Bernasconi Hills & Mount Russell, 33.8864, -117.1349 1, 507m, USGS-BRD San Diego Sta. 1.i.2000 [AP926, 1♂, CAS]; University of California Riverside, 33.9533, -117.3953 6, 252m, D Bixler 10.v.1968 [AP119, 1juv, AMNH], E Schlinger 6.vii.1957 [AP134, AP142, 5♀, 7juv, AMNH]; University of California, Riverside Campus, 33.9742, -117.3251 3, 327m, W Icenogle 17.xii.1969 [AP619, 2♀, CAS], 13.ix.1967 [AP110, AP136, 1♀, 26juv, AMNH], 17.ix.1967 [AP101, 1♂, AMNH], 19.ix.1967 [AP109, 1♀, 25juv, AMNH], 25.ix.1967 [AP116, AP616 2♀, 105juv, AMNH], 5.x.1967 [AP127, 1juv, AMNH], 10.x.1967 [AP106, 115, 128, 1♂, 2♀, 51juv, AMNH], 20.xi.1967 [AP105, 1♂, AMNH], 27.x.1967 [AP121, 130, 138, 141, 147, 5♂, AMNH], 31.x.1968 [AP131, 1♀, AMNH], H Nakakihara 11.iv.1974 [AP584, 1♂, UCR]; San Bernardino Co.: Yucaipa, bluffs behind city municipal office, 34.035, -117.0597 2, 737m, J Bond 19.i.1997 [MY2287, MY2289, MY2291, 3juv, AUMNH]; Yucaipa, Jct Yucaipa Blvd & 7th Street, 34.0362, -117.0638 3, 722m, W Icenogle 3.xii.1995 [AP102, 1♂, CAS]; Yucaipa, Bluff behind city municipal office on barren eroded bank, 34.0362, -117.0598 1, 737m, J Bond 19.i.1997 [AP1206, 1juv, AUMNH]; Yucaipa, Oak Glen Creek, just N jct 6th St & Yucaipa Blvd, 34.0382, -117.0599 1, 792m, W Icenogle 29.x.1995 [AP352, 1♂, CAS]; Yucaipa, 0.8km W junction Grape Ave & Bryant St, 34.0641, -117.0425 1, 853m, W Icenogle 3.ii.2000 [AP363, 1♂, CAS]; Yucaipa, Grape Rd, housing development, 34.065, -117.0422 1, 852m, J Bond 17.xii.1997 [AP703, 005, 708, 1♂, 2♀, AUMNH]; Yucaipa, Grape St, 0.6km from intersection Grape & Bryant, 34.0653, -117.0425 1, 863m, J Bond, W Icenogle 28.i.2004 [MY2526, 1♀, AUMNH].

Variation, males (10). Cl 5.25-5.90, 5.54 ± 0.05; Cw 4.38-4.88, 4.61 ± 0.05; STRl 3.00-3.57, 3.23 ± 0.05; STRw 2.46-2.79, 2.65 ± 0.03; LBw 0.78-0.96, 0.88 ± 0.02; LBl 0.42-0.68, 0.54 ± 0.03; leg I: 4.81-5.56, 5.24 ± 0.07; 3.45-3.88, 3.67 ± 0.05; 3.33-3.81, 3.56 ± 0.05; 2.10-2.37, 2.25 ± 0.03; 1.86-2.16, 2.01 ± 0.03; leg IV: 4.88-5.56, 5.25 ± 0.07; 2.19-2.88, 2.60 ± 0.06; PTl 2.25-2.52, 2.38 ± 0.03; PTw 0.99-1.05, 1.03 ± 0.01; Bl 1.20-1.38, 1.31 ± 0.02; TSp 3-6, 3.30 ± 0.30; TSr 1-2, 1.70 ± 0.15; TSrd 4-6, 5.00 ± 0.26.

Variation, females (10). Cl 5.38-7.50, 6.60 ± 0.25; Cw 4.13-6.13, 5.33 ± 0.22; STRl 3.27-5.06, 4.08 ± 0.19; STRw 2.46-3.69, 3.29 ± 0.13; LBw 0.92-1.37, 1.11 ± 0.05; LBl 0.50-0.78, 0.65 ± 0.03; Leg I: 12.01-17.13, 15.02 ± 0.53; ANTd 6-8, 6.80 ± 0.20; PTLs 7-14, 10.60 ± 0.56; TBs 3-5, 3.90 ± 0.28.

GenBank accessions.

16S-tRNAval-12S: JX103313-JX103318

Distribution and natural history.

Aptostichus hesperus is distributed in the Santa Ana, San Jacinto, San Bernardino Mountains, and intervening areas. County records include Orange, the western extent of Riverside, and a few localities in San Bernardino (Map 20). The primary habitat type throughout this area comprises chaparral forest and shrub, open woodland shrub, and coniferous forest. Aptostichus hesperus is particularly prevalent in chaparral habitat and is often collected from burrows at the base of large boulders and along steep inclines of north facing slopes. The DM (Map 21) corresponds well with the known distribution but indicates that Aptostichus hesperus should be more prevalent throughout open woodland shrub habitat in the southwestern extent of San Bernardino County; the species has not been collected in the areas of higher probability to the south in San Diego County. Although a few males have been recovered from pitfall traps in the spring and summer, the majority of wandering males have been collected during late fall and winter months (October-February).

Conservation status.

This species is relatively abundant across its range thus the conservation status of Aptostichus hesperus is likely secure.

Species concept applied.

Morphological/Phylogenetic.

Remarks.

Aptostichus hesperus is one of the easier species to identify because of its unique sternal sigilla morphology and its range is relatively restricted in Orange and Riverside Counties. However, all male specimens collected as part of the USGS survey in the southernmost extent of the species distribution in Riverside County lack a foveal groove. Although this form seems anomalous, the fact that multiple individuals from a number of populations share it suggests that it may be a diagnostic feature that would set these populations aside as a separate species. However, I have conservatively included these specimens as part of the Aptostichus hesperus hypothesis until molecular data are available to confirm that these morphological distinct populations are an exclusive lineage.