Aptostichus sinnombre, 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 : 131-132

Aptostichus sinnombre sp. n. Figures 266-273Map 30

Types.

Male holotype (MY3761) from California, San Diego County, Anza-Borrego Desert State Park, Indian Gorge, 0.4km W mouth of Torote Canyon, 32.86923, -116.23740 1, 350m, coll. M. Hedin 20.ii.2009; male paratype (MY3823) from near type locality, mouth of canyon Sin Nombre, 32.8584, -116.1473 1, 200m, coll. M. Hedin 13.iii.2010; deposited in AUMNH.

Etymology.

The specific epithet is a noun in apposition taken from name of canyon near the type locality, Sin Nombre.

Diagnosis.

Males can be differentiated from all other Aptostichus species on the basis of a unique conformation of the retrolateral distal-most spination pattern of tibia I, which comprises 3-6 spines arranged in a distinct cluster, a low rounded metatarsal mating apophysis that bears a single strong spine, and a convex shaped (curved) tarsus (Figs 266, 269, 272); all other known species lack this combination.

Description of male holotype.

Specimen preparation and condition. Specimen collected live, wandering, preserved in 80% EtOH. Coloration and specimen in relatively good condition. Pedipalp, leg I left side removed, stored in vial with specimen; legs right side removed for tissue storage. General coloration. Carapace, chelicerae, yellowish brown 10YR 5/4. Abdomen light yellowish brown 10YR 6/4, light dorsal chevron markings (Fig. 273). Cephalothorax. Carapace 5.75 long, 5.05 wide, very hirsute with intermingled thin white, black setae; stout black bristles along fringe; surface smooth, pars cephalica elevated. Fringe, posterior margin lacks black bristles. Foveal groove deep, straight. Eyes elevated on low mound. AER slightly procurved, PER strongly recurved. PME’s smaller in diameter than AME’s. Sternum moderately setose, STRl 3.10, STRw 2.67. Posterior sternal sigilla moderate in size, positioned towards center, not contiguous, anterior sigilla pairs small, oval, marginal. Chelicerae with distinct anterior tooth row comprising 7 teeth, posterior margin with patch of small denticles. Palpal endites with patch of small cuspules on proximal, inner margin, labium lacks cuspules, LBw 0.97, LBl 0.65. Rastellum consists of 3 spines not on prominent mound. Abdomen. Setose, heavy black setae intermingled with fine black setae. Legs. Legs long; Leg I: 6.88, 5.19, 4.35, 2.88, 1.90; leg IV: 6.19, 3.05. Tarsus I, swollen distally, tarsus IV straight. Heavy short scopulae on tarsi I, II; lighter on legs III, IV. Tarsus I with single, slightly staggered row of 13 trichobothria. Leg I spination pattern illustrated in Figures 266, 267, 269, 270, 272; TSp 4, TSr 4, TSrd 3. Knob-like metatarsal apophysis bearing a single large spine. Pedipalp. Articles slender (Fig. 268), distal prolateral spine on tibia (Fig. 271). PTw 0.85, PTl 2.57, Bl 1.45. Embolus slender, tapering sharply toward tip, lacking serrations (Fig. 271).

Variation (2). Cl 5.25-5.75, Cw 4.70-5.05, STRl 3.10-3.13, STRw 2.57-2.67, LBw 0.90-0.97, LBl 0.56-0.65, leg I: 6.38-6.88, 4.70-5.19, 4.15-4.35, 2.67-2.88, 1.75 -1.90; leg IV: 5.88-6.19, 2.92-3.05; PTl 2.38-2.57, PTw 0.85-0.85, Bl 1.45-1.53, TSp 2-4, TSr 4-4, TSrd 3-6.

Description of female.

Known only from male specimens.

Material examined.

Known only from the type material.

Distribution and natural history.

Aptostichus sinnombre is known from only two specimens from the Anza-Borrego Desert State Park, Colorado Desert habitat, in San Diego County and is sympatric with Aptostichus anzaborrego . Males appear to disperse during late winter months (February, March), based on the limited data available.

Conservation status.

The conservation status of Aptostichus sinnombre is likely imperiled given its restricted distribution and rarity in collections.

Species concept applied.

Morphological/Phylogenetic.

The Simus species group

Included Species.

Aptostichus simus Chamberlin, 1917

Aptostichus satleri sp. n.

Aptostichus elisabethae sp. n.

Aptostichus fornax sp. n.

Aptostichus lucerne sp. n.

Aptostichus bonoi sp. n.

Aptostichus fisheri sp. n.

Aptostichus cajalco sp. n.