Aptostichus simus
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Ordo: Araneae
Familia: Euctenizidae
Genus: Aptostichus
Name
Aptostichus simus Chamberlin, 1917 – Wikispecies link – Southern Coastal Dune Trapdoor Spider’ ZooBank link – Pensoft Profile
Diagnosis
Males of Aptostichus simus can be distinguished from species in the Simus species group by having a serrated embolus (Figs 50, 277) and lacking both elongate ventral tibia I spines and ventral tarsal spines (Figs 275, 276, 279). Females can be easily recognized by having a very large (> 150), sharply delineated patch of endite cuspules (Fig. 39, 283). The species is the only member of the Simus group that has been collected from coastal dune habitat.
Descriptions
Described by Chamberlin (1917[1]: 36).
Material examined:
Mexico: Baja California: El Descanso, Descanso Dunes, 32.2074, -116.91255, 22m, D Weissman, V Lee 3.iii.1992 [AP63, 89, 2♀, CAS]; United States: California: Los Angeles County: San Clemente Island, 32.878, -118.4646, 500m, J Scott 1.vi.1938 [AP093, 1♀, CAS]; S Huntington Beach, 33.6354, -117.96563, 3m, W Gertsch, W Ivie 28.ix.1961 [AP628, 1♀, 1♂, AMNH]; Dunes on beach just W Los Angeles Airport, 33.9361, -118.43915, 10m, W Icenogle 30.viii.1973 [AP073, 1♀, AMNH]; Los Angeles, El Segundo Sand Dunes, 33.939, -118.4394, 35m, J George 9.xii.1987 [AP441, 442, 2♂, CAS]; Playa Del Rey Beach, sand dunes between intersection 66th & Pacific & Pacific & Argonaut St, 33.959, -118.44913, 4m, M Ramirez, H David 6.xi.1982 [AP58, 78, 611, 2juv, 1♀, 1♂, AMNH]; Malibu, Broad Beach, 34.0338, -118.85173, 4m, M Ramirez [AP622, 626, 2♀, CAS]; Monterey Co.: Salinas River St Beach, 36.7831, -121.79441, 3m, J Bond 6.v.1997 [AP757, 1♀, AMNH], [AP777, 1264, 1♀, 1juv, AUMNH]; Moss Landing St Beach, 36.8086, -121.78831, 3m, J Bond 14.v.1997 [AP624, 794, 807, 808, 3♀, 1juv, AUMNH], [AP796, 1♀, AMNH]; Moss Landing St Beach, beachside dunes, 36.8091, -121.78831, 1m, J Bond, W Bond 27.vii.2008 [MY3749, 1♀, AUMNH]; Moss Landing St Beach, 36.8109, -121.78941, 6m, J Bond 17.iii.2005 [MY3080, 1♀, AUMNH], [MY3081, 1♀, FMNH], 8.xii.2005 [MY3466, 1♀, AUMNH], A Stockman, P Marek 30.i.2006 [MY3534, 1♀, FMNH]; San Diego Co.: Border Field St Park, S Monument Blvd, just N international border, 32.5351, -117.11911, 16m, USGS-BRD San Diego Sta. 16.i.2003 [AP917, 1♂, CAS], 1.ii.2000 [AP918, 1♀, CAS]; Border Field St Park, S Monument Blvd., 32.5422, -117.12341, 2m, R Fisher 2.x.1997 [AP819, 1♀, 4♂, CAS]; Border Field St Beach, 32.5436, -117.12271, 3m, J Bond 19.x.1998 [AP699, 701, 707 3♀, AUMNH]; Borderfield St Beach, 32.5453, -117.12493, 2m, W Icenogle 26.viii.1971 [AP054, 94, 2♀, 96juv, CAS], M Ramirez. H David 21.viii.1982 [AP071, 2 eggsacs, AMNH]; Tijuana Estuary, N Monument Blvd., E of beach, 32.5457, -117.12431, 2m, USGS-BRD San Diego Field Sta. 1.x.1998 [AP1188-1190, 4♂, CAS]; Tijuana Estuary, N of Monument Blvd., E beach, 32.5479, -117.12491, 2m, USGS-BRD San Diego Sta. 26.ix.2002 [AP1182, 3♂, CAS], 1.vii.2002, [AP1183, 1♂, CAS], 1.ix.2002 [AP1184, 3♂, CAS], 1.viii.1998 [AP1185, 1♀, CAS], 1.x.1998 [AP1186, 2♂, CAS], 1.xi.2002 [AP1187, 3♂, CAS]; Tijuana Estuary, N of Monument Blvd., E beach, 32.5503, -117.12611, 1♂, USGS-BRD San Diego Sta. 1.x.1998 [AP1181, 2♂, CAS]; Otay Mesa, E Spring Canyon, N Wruck Canyon, 32.5515, -116.99981, 150m, R Fisher 1.viii.2002 [AP820, 2♂, CAS]; Imperial Beach, 32.5805, -117.13253, 0m, S Johnson 5.x.1978 [AP087, 4♀, AMNH], W Icenogle 2.x.1978 [AP091, 1♀, 62juv, AMNH], [AP097, 1♀, 58j, AMNH], 1.xi.1978 [AP598, 1♀, UCR]; N end Imperial Beach, just N YMCA Camp, 32.5871, -117.13192, 0m, M Hedin 12.xi.2005 [AP1209, 1♂, CAS]; N end Imperial Beach, ~0.8km N YMCA surf camp, 32.5929, -117.13212, 1m, M Hedin 23.ix.2002 [MY667, 1♂, AUMNH]; 0.4km N Imperial Beach, 32.59351, -117.13213, 3m W Icenogle 1.x.1977 [AP201, 657, 2♂, CAS]; Silverstrand St Beach, 32.6265, -117.1393, 4m, M Ramirez, H David 4.xi.1982 [AP064, AP1260, 2♀, AMNH]; Silver Strand St Beach, 32.6267, -117.13913, 2m, Parrish 11.v.1963 [AP088, 1♀, AMNH]; J Bond 27.iii.96, [AP1256, 1257, 3♀, AUMNH]; 0.4km S Ponto St Beach, 33.0608, -117.30273, 3m, W Icenogle 22.x.1970 [AP056, 1♀, 41juv, AMNH], 8.v.1970 [AP095, 2♀, CAS]; Encinitas, Ponto St Beach, 33.0668, -117.30653, 4m, B Kaston 22.x.1970 [AP096, 1♀, 40juv, CAS]; Leucadia, sand dunes on beach, 33.0655, -117.30513, 3m, B Kaston 30.i.1971 [AP065, 1♀, AMNH], 26.ix.70 [AP651, 1♀, 50+juv, AMNH]; Encinitas, Ponto St Beach, 33.0668, -117.30653, 4m, B Kaston 22.x.1970 [AP055, 1♀, 20juv, CAS], W Icenogle 28.x.1970 [AP059, 28juv, AMNH], [AP067, 1♀, 15juv, CAS], [AP069, 1♀, CAS], [AP075, 1♀, 32juv, AMNH], 26.ix.1970 [AP082, 1♀, 83juv, CAS], [AP090, 1♀, 6juv, AMNH]; S Carlsbad St Beach, 33.1038, -117.31911, 3m, J Bond 19.x.1998 [AP698, 709, 2♀, AUMNH]; San Luis Obispo Co.: Oso Flaco Lake, 35.0305, -120.62413, 6m, M Irwin 22.vi.1965 [AP061, 4juv, AMNH]; Montana de Oro St Park, 35.2854, -120.88091, 29m, A Stockman, A Bailey 8.vii.2009 [MY3704-3706, 3juv, AUMNH]; Morro Dunes, S end Morro Bay, 35.3058, -120.87281, 20m, J Bond 6.xii.2005 [MY3436-3440, 4♀, 1juv, AUMNH]; N end Morro Bay, 35.3748, -120.86311, 4m, J Bond 6.xii.2005 [MY3441-3443, 3♀, AUMNH]; Baywood, 35.3083, -120.86833, 3m, P Sullivan 26.xi.1977 [AP621, 1♂, AMNH]; Morro Bay, beach N Morro Rock, 35.3739, -120.86131, 0m, M Hedin, S Foldi 3.iv.2005 [AP1208, 1♀, AUMNH]; Estcro Bay, 35.3453, -120.86246, 10m, 1.vi.1975 [AP068, 1♀, CAS]; isolated dune field just N San Simeon Bay, 35.6466, -121.2111, 3m, J Bond 6.xii.05 [MY3447, 3449, 2♀, AUMNH]; Santa Barbara Co.: Santa Rosa Island E of marsh road to E Pt, 33.9572, -119.97845, 14m, M Ramirez, H David 9.viii.1994 [AP079, 80, 594, 3♀, 1juv, AMNH]; Santa Rosa Island, SE Anchorage, 33.9787, -120.00345, 19m, M Ramirez, H David 30.viii.1988 [AP053, 1♀, 29juv, AMNH], [AP081, 1♀, AMNH], 9.viii.1994 [AP083, 1♀, AMNH], 1.vii.1987 [AP092, 1♀, CAS]; Santa Rosa Island, dunes Skunk Pt, 33.9821, -119.97934, 15m, M Ramirez, H David 11.viii.1994 [AP050, 57, 1261, 2♀, 3juv, AMNH]; Santa Rosa Island, dunes E Sandy Pt, 34.0003, -120.2434, 24m, M Ramirez, H David 8.viii.1994 [AP052, 3juv, AMNH]; N Carpinteria St Beach, 34.393, -119.52393, 3m, W Gertsch, W Ivie 27.ix.1961 [AP659, 1♀, 1♂, AMNH]; Coal Oil Pt, 34.4072, -119.87721, 3m, J Bond, B Opell 21.xi.1998 [AP689, 697, 702, 3♀, AUMNH], [AP695, 700, 2♀, FMNH], [AP696, 1♀, AMNH], M Ramirez, H David 24.vi.82 [AP070, 72, 76, 86, 623, 4♀, 1eggsac, AMNH], J Bond 5.iv.1996 [AP721, 735, 744, 2♀, 1juv, AUMNH], [AP743, 1♀, FMNH]; Ocean Beach Co Park, W of Lompoc, W end HWY 246, 34.69, -120.60313, 2m, W Icenogle 12.viii.1978 [AP074, 1♀, 62juv, AMNH]; Vandenberg Air Force Base, dunes mouth San Antonio Creek, 34.7989, -120.61994, 11m, 25.v.1976 [AP051, 1juv, CAS]; Jalama Co Park, 34.5098, -120.50111, 4m, J Bond, A Stockman, D Beamer 17.iii.2005 [MY3422-24, 2♀, 1juv, AUMNH]; Ocean Park Dunes, 34.69, -120.60311, 2m, J Bond, A Stockman, D Beamer 17.iii.2005 [MY3425-27, 3♀, AUMNH]; Guadalupe-Nipomo Dunes Preserve, 34.9624, -120.64971, 11m, J Bond, A Stockman, D Beamer 17.iii.05 [MY3428, 1♀, 15juv, AUMNH]; J Bond, A Stockman, D Beamer 17.iii.05 [MY3429, 1♀, AMNH]; J Bond, A Stockman, D Beamer 17.iii.05 [MY3430, 1juv, AUMNH]; Oso Flaco Lake Preserve, 35.0341, -120.63261, 6m, J Bond 17.iii.2005 [MY3431-34, 4♀, AUMNH], [MY3435, 1♀, AMNH]; Santa Cruz Co.: Santa Cruz Island, Johnson’s Lee Beach, 33.9684, -119.82913, 3m, 12.ix.1982 [AP077, 1♀, 7juv, AMNH], M Ramirez 15.i.1983 [AP653, 1♂, AMNH], 3.x.1987 [AP658, 1♀, 2♂, CAS]; Ventura Co.: Pt Mugu St Park, Sycamore Cove Beach, 34.0742, -119.02073, 3m, M Ramirez [AP625, 627, 629, 3♀, CAS]; Pt Mugu, 34.0863, -119.055625, 25m, D Boe 16.vi.1979 [AP596, 1♀, UCR]; McGrath St Beach, 34.2264, -119.26143, 7m, M Ramirez, H David 25.vi.1982 [AP062, 1♀, 2juv, AMNH].
Variation, males (5). Cl 4.88-6.19, 5.61±0.21; Cw 4.31-5.19, 4.76±0.16; STRl 2.79-3.25, 3.01±0.09; STRw 2.40-2.85, 2.64±0.08; LBw 0.80-0.92, 0.84±0.02; LBl 0.45-0.63, 0.54±0.03; leg I: 5.00-5.22, 5.13±0.04; 3.69-4.06, 3.81±0.07; 3.13-3.50, 3.30±0.06; 2.06-2.44, 2.26±0.07; 1.50-1.86, 1.70±0.08; leg IV: 4.75-5.25, 5.03±0.08; 2.69-3.38, 3.10±0.12; PTl 1.68-1.95, 1.79±0.04; PTw 1.02-1.14, 1.09±0.02; Bl 0.80-0.86, 0.83±0.01; TSp 14-29, 20.20±2.62; TSr 12-21, 16.4±1.72; TSrd 0-0, 0±0.
Variation, females (32). Cl 4.81-8.75, 6.91±0.19; Cw 3.66-7.06, 5.70±0.15; STRl 2.64-4.88, 3.87±0.10; STRw 2.31-4.31, 3.39±0.09; LBw 0.81-1.64, 1.19±0.04; LBl 0.60-1.04, 0.82±0.02; Leg I: 10.53-19.50, 15.65±0.41; ANTd 4-5, 4.22±0.07; PTLs 15-29, 20.75±0.69; TBs 2-8, 5.66±0.32.
GenBank accessions
16S: AF307955-AF307969; 16S-tRNAval-12S: EU570038, JX103367-JX103400.
Distribution and natural history
Like Aptostichus stephencolberti and Aptostichus miwok, Aptostichus simus is distributed throughout the California coastal dune habitats. Specimens are known from Baja California Norte, northward along beaches in San Diego, Orange, Los Angeles, Ventura, Santa Barbara, and San Luis Obispo Counties; their distribution ends just north of Point Conception with two disjunct populations in Monterey County and on the Channel Islands just off the California coast (Map 32). Like other coastal dune species, Aptostichus simus is 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 simus.
Conservation status
Aptostichus simus is generally abundant at some localities along the California coast but has been almost entirely extirpated from many beaches in Southern California. For example, the species is very rare at the type locality, Silver Strand State Beach. Moreover, 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 et al. 2001[2]). Consequently, I would consider this species to be vulnerable or imperiled due to its low abundance at many localities and extreme structuring.
Species concept applied
Morphological/Phylogenetic.
Remarks
As discussed by Bond et al. (2001)[2] the species hypothesis presented here likely represents 2-3 additional species, however, further work is needed before we fully understand the composition and limits of this taxon.
Taxon Treatment
- Bond, J; 2012: Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae) ZooKeys, 252: 1-209. doi
Other References
- ↑ Chamberlin R (1917) New spiders of the family Aviculariidae. Bulletin of the Museum of Comparative Zoology 61: 25-75.
- ↑ 2.0 2.1 Bond J, Hedin M, Ramirez M, Opell B (2001) Deep molecular divergence in the absence of morphological and ecological change in the Californian coastal dune endemic trapdoor spider Aptostichus simus. Molecular Ecology 10: 899-910. doi: 10.1046/j.1365-294X.2001.01233.x
Images
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![Figures 274–280. Aptostichus simus Chamberlin, 1917 male specimens from San Diego County; scale bars = 1.0mm. 274 habitus (AP1209) [806521] 275–278 secondary sexual characteristics (AP819) 275 retrolateral aspect, leg I [806525] 276 prolateral aspect, leg I [806529] 277 ventral view, pedipalp bulb [806531] 278 retrolateral aspect, pedipalp [806533] 279, 280 line drawings, leg I articles 279 retrolateral and prolateral aspect of specimen from San Diego County, Imperial Beach 280 retrolateral aspect, tibia and patella, in descending from San Diego County, Imperial Beach and Santa Barbara County, Carpinteria State Beach.](/wiki/File:ZooKeys-252-001-g072.jpg)
![Figures 281–283. Aptostichus simus female specimens. 281 habitus, from San Diego County (AP067) 282 cleared spermathecae (MY3447), from San Luis Obispo County [806538]; scale bar = 0.1mm 283 cephalothorax, ventral aspect, from San Diego County (AP095) [806542].](/wiki/File:ZooKeys-252-001-g073.jpg)
