Aptostichus dantrippi, Bond, Jason E., 2012

Bond, Jason E., 2012, Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae), ZooKeys 252, pp. 1-209 : 55-59

Aptostichus dantrippi sp. n. Figures 115-119Maps 12, 13

Types.

Male holotype (AP179) and female paratype (AP173) from California, Kern Co., Bakersfield, South Bank of Kern River, 35.3947, -119.0313 5, elev. 137m, coll. W. Icenogle 6.x.1971, deposited in AUMNH.

Etymology.

The specific epithet is patronym in honor of Daniel Tripp in recognition of the Tripp family support of biodiversity research and scholarship at East Carolina University, Greenville, North Carolina.

Diagnosis.

Morphological differences, particularly secondary sexual characteristics (Figs 115-119), between Aptostichus dantrippi and other geographically proximate species of the Atomarius Sibling Species Complex are subtle. First, Aptostichus dantrippi male and female individuals are found only in far inland habitats but tend to be much lighter in coloration (Fig. 118) than other inland species ( Aptostichus atomarius , Aptostichus angelinajolieae , and Aptostichus stanfordianus ) and thus superficially resemble coastal dune species Aptostichus miwok and Aptostichus stephencolberti . Spermathecae have a very elongate lateral lobe that is directed anteriorly whereas the secondary lobe in other taxa is directed more posterior-laterally (Fig. 119). The species is restricted in distribution to Kern County (California) and does not overlap with any closely related Atomarius Sibling Species Complex taxa (Map 12).

Description of male holotype.

Specimen preparation and condition. Specimen collected live from burrow, preserved in 70% ethanol. Coloration moderately faded. Pedipalp, leg I left side removed, stored in vial with specimen. General coloration. Carapace, chelicerae, legs dark yellowish brown 10YR 4/6. Abdomen uniform dark reddish gray 5YR 5/2 dorsally. Very light diminutive abdominal color pattern comprising 3 patches along dorsal midline (Fig. 118). Cephalothorax. Carapace 6.32 long, 5.44 wide, clothed in light white hairs, stout black bristles along fringe; surface smooth, pars cephalica elevated slightly. Fringe, posterior margin lacks black bristles. Foveal groove deep, straight. Eyes on low mound. AER slightly procurved, PER slightly recurved. PME, AME subequal diameter. Sternum moderately setose, STRl 3.45, STRw 3.00. Posterior sternal sigilla moderate sized, positioned centrally, not contiguous, anterior sigilla pairs small, oval, marginal. Chelicerae with distinct anterior tooth row comprising 6 teeth, posterior margin with single row of small denticles. Palpal endites with patch of small cuspules on proximal, inner margin, labium lacks cuspules, LBw 1.02, LBl 0.42. Rastellum consists of 5 very stout spines not on a mound. Abdomen. Setose, sparse heavy black setae intermingled with fine lighter colored setae. Legs. Leg I: 6.10, 4.19, 4.13, 2.68, 2.40; leg IV: 6.10, 3.30. Light scopulae on legs I, II tarsus, metatarsus. Tarsus I with single, slightly staggered row of 14 trichobothria. Leg I spination pattern illustrated in Figures 115, 116; TSp 3, TSr 5, TSrd 5. Metatarsus I anteverted retrolaterally, modified with mid-ventral mating apophysis terminating in triangular mound. Pedipalp. Articles slender (Fig. 117). PTw 1.40, PTl 2.50, Bl 1.36. Embolus slender, tapering sharply toward tip, slightly curved, lacking serrations (Fig. 117).

Variation.Known only from the type specimen.

Description of female paratype.

Specimen preparation and condition. Female collected live from burrow, prepared in same manner as male holotype. Genital plate removed stored in microvial with specimen. General coloration. Carapace, legs, chelicerae, yellowish brown 10YR 5/6. Abdomen uniform dark yellowish brown dorsally 10YR 4/4, ventrum, spinnerets pale yellow; narrow small dusky stripes on dorsal surface. Cephalothorax. Carapace 6.90 long, 6.00 wide, glabrous; generally smooth surface, pars cephalica moderately elevated. Fringe lacks setae. Foveal groove deep, slightly procurved. Eye group slightly elevated on low mound. AER slightly procurved, PER slightly recurved. PME-AME subequal diameter. Sternum widest at coxae II/III, moderately setose, STRl 4.20, STRw 3.60. Three pairs of sternal sigilla anterior pairs small, oval, marginal, posterior pair much larger, oval, mesially positioned. Chelicerae anterior tooth row comprising 7 teeth with posterior margin denticle patch. Palpal endites with 10 cuspules concentrated at inner (promargin) posterior heel; labium with 8 cuspules, LBw 1.40, LBl 0.80. Rastellum consists of 8 very stout spines not positioned on mound; fringe of short spines along distal promargin extending upward from rastellum. Abdomen. Moderately setose. PLS all 3 segments with spigots. Terminal segment 1/2 length of medial segment, 2 enlarged spigots visible at tip. PMS single segment, with spigots, short with rounded terminus. Legs. Anterior two pairs noticeably more slender than posterior pairs. Leg I: 5.60, 3.40, 3.40, 2.80, 1.60. Tarsus I with single staggered row of 19 trichobothria. Legs I, II with moderately heavy scopulae on tarsus, metatarsus. PTLs 14, TBs 3. Rudimentary preening comb on retrolateral distal surface (at tarsus - metatarsus joint) of metatarsus III, IV. Spermathecae. 2 simple spermathecal bulbs that lack an elongate neck, basal lateral extension of bulb enlarged, directed anteriorly (Fig. 119).

Variation (5). Cl 5.90-7.60, 6.79+0.28; Cw 5.05-6.56, 5.98+0.26; STRl 3.60-4.56, 4.16+0.16; STRw 3.00-3.68, 3.46+0.12; LBw 1.19-1.40, 1.32+0.04; LBl 0.77-0.95, 0.84+0.03; Leg I: 14.50-18.00, 16.69+0.58; ANTd 5-7, 6.20+0.37; PTLs 11-17, 14.60+1.29; TBs 3-5, 3.60+0.40.

Material examined.

United States: California: Kern Co.: Bakersfield, South Bank Kern River, 35.3947, -119.0313 5, 137m, W Icenogle 6.x.71 [AP173, 1♀, 10juv, CAS; AP178, 179, 182, 2♀ 1♂ 20juv, AMNH], 16.x.70 [AP175, 1♀, AMNH], 22.vi.70 [AP180, 2♀, CAS], 23.vi.70 [AP545, 1♀, CAS]; Cedar Creek, Cedar Creek Campground, 35.7493, -118.5816 1, 1495m, F Moore, R Berry 22.v.69 [AP443, 1♀, AMNH]; NE edge El Paso Mountains, hills ~ 1 mile W hwy 395, 35.5288, -117.7636 4, 900m, W Icenogle 11.x.68 [AP257, 1♀, CAS]; S bank Kern River ~1/4mi from Manor St Bridge, 35.4067, -119.0118 1, 127m, J Bond 31.iii.96 [AP713, 716, 741, 746 3♀ 1 juv, AUMNH]; Tehachapi Mountains, Antelope Canyon, 34.9005, -118.6406 5, 1524m, S Frommer 12.xi.75 [AP595, 1♀, CAS]; Tehachapi Mountains, Water Canyon, 35.0848, -118.4934 5, 1372m, W Icenogle 22.vi.70 [AP194, 2♀, CAS]; San Emigdio Mountain, San Emigdio Creek, NE of Pine Mountain Club, off Mill Potrero Hwy, 34.8624, -119.1275 1, 1380m, M Hedin, J Satler, D Carlson 27.vii.2010 [MY3808, 3806 2juv, AUMNH]; Breckenridge Rd, 33km E int w Comanche Dr, NE Edison, 35.4843, -118.6477 1, 1527m, J Satler, S Derkarabetian, C Richart, P van Niekerk 28.iii.2011 [MY3817, 1♀, AUMNH]; Hwy 178, ~100m W of Walker Pass, 35.66343, -118.02767 1, 1067m, M Hedin, P Paquin, J Starrett 29.iii.2003 [MY0730, 1♀, AUMNH]; San Luis Obispo.: Temblor Range, Hwy 58, Pee Wee Park, 35.3494, -119.8174 1, 900m, M Hedin, J Starrett, D Leavitt, D Carlson, B Keith 29.iii.2010 [MY3792, 1♀, AUMNH]; Hwy 58, Temblor Range, 35.3452, -119.8107 1, 860m, M Hedin, J Starrett, D Leavitt, D Carlson, B Keith 25.iii.2010 [MY3807 3809, 1juv, 1♀, AUMNH].

GenBank accessions.

16S-tRNAval-12S: EU569911, EU569912, JX103294-JX103300.

Distribution and natural history.

Aptostichus dantrippi as currently defined is distributed primarily throughout Kern County with a few specimens taken from the Temblor Range along the western border with San Luis Obispo County (Map 12). The distribution essentially “rings” the ranges that bound the southernmost extent of the Central Valley and includes the San Emigdio, Tehachapi, and Greenhorn Mountains. The species is mostly restricted to the south valley alluvium and basins, Sierran steppe and mixed and coniferous forests ecoregions of Kern County (Map 12). The only known male specimen was collected during late fall (October). The DM prediction corresponds closely to the known distribution but predicts a high probability of occurrence along the Transverse Ranges. Conversely, the Bakersfield locality along the banks of the Kern River is located in an area of relatively low probability of occurrence; it is likely that this population is relictual given the nature and paucity of the habitat at this location.

Conservation status.

The status of Aptostichus dantrippi appears to be relatively secure; the species is widespread and abundant. However, the type locality, along the banks of the Kern River, in Bakersfield, California is disturbed and has been highly impacted by proximal development of the last quarter century and thus the species is likely to be locally vulnerable.

Species concept applied.

Morphological/phylogenetic. As noted below the molecular data support the hypothesis that these populations constitute a single evolutionary lineage that has subtle morphological differences that distinguish it from sibling species.

Remarks.

I have included additional Kern County specimens from the El Paso Mountain and Tehachapi Mountains as part of the Aptostichus dantrippi species hypothesis. Specimens from both of these outlying populations appear to be mostly consistent, morphologically, with those specimens collected from the type locality with the exception of the two specimens collected from Water Canyon; they appear to have more prominent abdominal markings and a slightly darker cephalothorax than the type specimens. Molecular data to date obtained from specimens collected just west of the Tehachapi’s corroborate the hypotheses that these populations be included as Aptostichus dantrippi despite their somewhat divergence coloration.