Aptostichus stephencolberti Bond, 2008

Bond, Jason E., 2012, Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae), ZooKeys 252, pp. 1-209 : 38-43

Aptostichus stephencolberti Bond, 2008 Figures 82-90Maps 4, 5

Aptostichus stephencolberti Bond, 2008: 646. Male holotype (MY3515, EU570029) and female paratype (MY3513, EU570028), California, San Mateo Co., Pescadero State Beach, 37.26598, -122.41219 1, elev. 3m, coll. A. Stockman & P. Marek, 29.i.2008, in CAS, examined.

Diagnosis.

Individuals of this species are difficult to distinguish from other Atomarius Sibling Species Complex members on the basis of morphological features (Figs 82-90) alone but can be diagnosed on the basis of a set of unique mtDNA site substitutions (see Bond and Stockman 2008). The species is restricted in distribution to the coastal dune habitats of Monterey, Santa Cruz, San Mateo, and San Francisco Counties (California; Maps 4, 5) and is much lighter in coloration (Figs 88-90) than species found in inland habitats (e.g., Aptostichus atomarius , Aptostichus angelinajolieae , and Aptostichus stanfordianus ).

Descriptions.

Described by Bond (2008).

Material examined.

United States: California: Monterey Co.: Asilomar St Beach, 36.6221, -121.9391 3, 8m, W Icenogle 14.x.1971 [AP463-64, 3♀, 7juv, CAS]; Asilomar St Beach, 36.6236, -121.9405 1, 3m, J Bond 15.v.1997, [AP800-802, 812-13, 2♀4juv, AUMNH]; 2.5km S Marina Ranger Station, 36.6969, -121.8088 1, 14m, J Bond 16.v.1997 [AP803, 814-16, 4juv, AUMNH]; end Dunes Rd, N Marina St Beach, 36.7068, -121.807 1, 8m, J Bond, W Bond 27.vii.2008 [MY3750-51, 2♀, AUMNH]; dunes Marina Beach, 36.705, -121.8077 1, 3m, J Bond 4.v.1997 [AP772-74, 13♀, AUMNH]; Marina Beach (dunes across from RV park), 36.7033, -121.8063 1, 7m, J Bond 2-3.iv.1996 [AP711 722, 739-40, 748,, 4♀, 1juv, AUMNH]; Marina Beach dunes, 36.703, -121.808 1, 13m, J Bond 2.iv.1996 [AP736, 1♀, AUMNH]; Marina State Beach, 36.6973, -121.8092 4, 12m, M Ramirez 16.v.1983 [AP278, 1juv, AMNH], 28.x.1984 [AP468, 1♀, AMNH], E Schlinger 23.iv.1970 [AP485, 2♀, SCW]; Marina Dunes Natural Preserve, 36.6905, -121.8105 2, 3m, J Bond, D Beamer, A Stockman 17.iii.2005 [MY3069-70, 1♀ 1juv, AUMNH]; Moss Landing St Beach, 36.8086, -121.7883 1, 3m, J Bond 14.iv.1997 [AP1265, 1♀, AUMNH]; Moss Landing St Beach, 36.8155, -121.79 1, 0m, M Hedin, M Lowder 28.vi.2000 [AP1267, 1♀, AUMNH], J Bond 21.xii.1997 [AP706, 1♀, AUMNH]; Point Sur Lighthouse, 36.3062, -121.8971 1, 0m, M Hedin, M Lowder 29.vi.2000 [AP1252, MY699-MY701, 3♀, 2juv, AUMNH]; Salinas River St Beach, 36.7823, -121.7939 1, 9m, W Icenogle 14.x.1999 [MY0713, 1♀, CAS]; Salinas River St Beach, 36.7831, -121.7944 1, 3m, J Bond 17.v.1997 [AP758-60, AP804, 4juv, AUMNH], 6.v.1997 [AP778, 1juv, AUMNH]; Salinas River St Beach, Molera Rd Parking Lot, 36.7752, -121.796 4, 6m, M Ramirez 16.iv.1983 [AP258, AP306, 2♀, AMNH]; Salinas River St Beach, 36.7855, -121.7945 3, 3m, A Stockman, P Marek 28.i.2006 [MY3489-91, 3juv, AUMNH]; Salinas River St Beach, 36.7907, -121.7919 1, 3m, J Bond 8.xii.2005 [MY3455-57, 2♀, 1juv, AUMNH]; Zmudowski St Beach, 36.8436, -121.8041 2, 3m, J Bond 15.v.1997 [AP797-99, 809-11, 5♀, 1juv, AUMNH]; Zmudowski St Beach, 36.8358, -121.802 1, 3m, J Bond 8.xii.2005 [MY3461-63, 2♀, 1juv, AUMNH]; Pfeiffer Beach, 36.2384, -121.8154 2, 6m, J Bond 7.xii.2005 [MY3451, 1juv, AUMNH]; San Francisco Co.: Ft Funston National Recreation Area, 37.7231, -122.5043 3, 31m, M Ramirez 23.vi.1988 [AP196, 1♀, CAS]; Ft Funston National Recreation Area, 37.7121, -122.5014 1, 48m, A Stockman, P Marek 30.i.2006 [MY3517-20, 1♀, 3juv, AUMNH]; San Francisco, near jct Lincoln Way & 46 Ave, 37.7642, -122.5062 3, 16m, L Trautz 1.x.1969 [AP1273, 1♀, SCW)]; Petrel Bluff, 37.6978, -123.0017 7, 3m, M Ramirez 30.vii.1986 [AP156, 1♂, CAS]; San Francisco, Baker Beach, 37.792, -122.484 4, 7m, D Ubick 8.iii.1980 [AP301, 3♀, CAS]; San Francisco, Sunset District, 37.7601, -122.4877 5, 71m, J McNally 3.x.1969 [AP255, 1♀, CAS]; San Mateo Co.: Gazos Creek Coastal Access off HWY 1, 37.1659, -122.3625 3, 10m, M Thompson 17.ix.1976 [AP1278, 2♀, 1♂, CAS]; Ano Nuevo St Reserve, 37.1165, -122.3277 1, 1m, M Hedin, M Lowder 28.vi.2000 [MY698, AP1253, 1♀, 3juv, AUMNH]; Ano Nuevo St Reserve, Cascade Creek Trail, 37.139, -122.3403 2, 3m, A Stockman, P Marek 29.i.2006 [MY3509, 1♀, AUMNH]; Ano Nuevo St Reserve, Franklin Point Trail, 37.1551, -122.3555 1, 7m, A Stockman, P Marek 29.i.2006 [MY3510-12, 2♀, 4juv, AUMNH; 1juv, AUMNH]; Pescadero St Beach, 37.2659, -122.4121 1, 4m, A Stockman, P Marek 29.i.2006 [MY3513-16, 2♀, 2♂, AUMNH]; San Luis Obispo Co.: S Morro Bay, 0.64km N parking lot, 35.3136, -120.7679 4, 24m, W Icenogle 16.x.1999 [MY712, 1♀, CAS]; Santa Cruz Co.: Younger Lagoon, 36.9508, -122.0658 4, 11m, M Ramirez 27.vii.1987 [AP437, 1juv, CAS]; Bonny Doon Beach W Bonny Doon Rd, 37.0003, -122.181 1, 8m, A Stockman, P Marek 29.i.2006 [MY3501-04, 2♀ 2juv, AUMNH]; Sunset St Beach, 36.878, -121.8261 1, 1m, A Stockman, P Marek 28.i.2006 [MY3492-97 1♀, 5juv, AUMNH]; Waddell Creek Beach, 37.0953, -122.277 1, 11m, A Stockman, P Marek 29.i.2006 [MY3505, 08, 3♀ 1juv, AUMNH]; Wilder Ranch St Park, parking area N main entrance, 36.9668, -122.1228 1, 4m, A Stockman, P Marek 29.i.2006 [MY3498-500, 3♀, AUMNH; MY3499, 1♀, AUMNH].

Variation, males (3). Cl 5.65-6.38, 6.09 ± 0.22; Cw 4.85-5.63, 5.37 ± 0.26; STRl 3.10-3.60, 3.28 ± 0.16; STRw 2.76-3.25, 3.00 ± 0.14; LBw 0.85-0.94, 0.91 ± 0.03; LBl 0.51-0.53, 0.52 ± 0.01; leg I: 5.10-5.50, 5.33 ± 0.12; 3.25-3.75, 3.53 ± 0.15; 3.25-3.75, 3.53 ± 0.15; 2.00-2.35, 2.23 ± 0.12; 1.75-2.25, 2.08 ± 0.17; leg IV: 5.00-5.25, 5.15 ± 0.08; 2.35-3.00, 2.70 ± 0.19; PTl 2.25-2.50, 2.42 ± 0.08; PTw 0.85-1.00, 0.93 ± 0.04; Bl 1.05-1.45, 1.29 ± 0.12; TSp 3-6, 4.33 ± 0.88; TSr 0-6, 3.00 ± 1.73; TSrd 4-8, 5.67 ± 1.20.

Variation, females (5). Cl 7.20-9.00, 7.98 ± 0.32; Cw 6.56-7.90, 7.39 ± 0.23; STRl 3.90-5.15, 4.63 ± 0.22; STRw 3.70-4.75, 4.31 ± 0.17; LBw 1.28-1.70, 1.50 ± 0.07; LBl 0.85-1.02, 0.94 ± 0.04; Leg I: 14.05-20.51, 17.74 ± 1.08; ANTd 6-10, 7.60 ± 0.81; PTLs 16-29, 20.40 ± 2.38; TBs 5-11, 7.20 ± 1.11.

GenBank accessions.

16S-tRNAval-12S: EU569930-EU569939, EU570008-EU570021, EU570028-EU570031, JX103357- JX103366; 18S (partial)-ITS1-5.8S-ITS2: EU569888-EU569892.

Distribution and natural history.

Aptostichus stephencolberti is distributed throughout the coastal dune habitats of San Francisco, San Mateo, Santa Cruz, and Monterey Counties with a single population recorded from San Luis Obispo County (Map 4). Individuals are found in relatively deep burrows on the steep faces of sand dunes and at the base of coastal vegetation. Burrows comprise a thick silk lining and are covered by a very cryptic trapdoor constructed of silk and sand. Dune habitats disturbed by high concentrations of the invasive Carpobrotus edulis (ice plant) tend to lack Aptostichus stephencolberti individuals entirely. The DM for this species (Map 5) follows closely with the known distribution to include the southernmost-recorded locality for the species. Wandering males (2) have been collected in August and September; two males have been collected from burrows in January.

Conservation status.

Aptostichus stephencolberti is generally abundant at localities along the California coast (Map 4). However, the species is particularly vulnerable to invasive plant species (e.g., ice plant, Carpobrotus edulis ) and is highly structured genetically across its distribution thus many populations contain unique alleles ( Bond and Stockman 2008). Moreover, divergent populations at the southernmost extent of the distribution comprise very few individuals (specimens are rare, despite extensive searching). Consequently, I would consider this species to be apparently secure or vulnerable, contingent upon future delimitation of divergent lineages as nominal taxa.

Species concept applied.

Cohesion. Aptostichus stephencolberti is considered to be ecological non-interchangeable from other closely related lineages–it is restricted to coastal dune habitat and has psammophilic features (e.g., lighter coloration).