Aptostichus isabella, 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 : 84-85

Aptostichus isabella sp. n. Figures 165-168Map 1

Types.

Male holotype (MY3824), from California, Kern County, Erskine Creek Rd., 5.6km E or intersection with Lake Isabella Blvd., E of Bodfish, 35.5689, -118.4383 1, 925m, coll. J. Satler 8-29x.2010; deposited in AUMNH.

Etymology.

The specific epithet is a noun taken in apposition from the type locality, Lake Isabella.

Diagnosis.

Males can be diagnosed on the basis of a unique conformation of the tibia I mating apophysis and TSrd spination pattern (Figs 165-167. Like Aptostichus icenoglei , the Aptostichus isabella tibial I apophysis (Figs 165, 167) is rectangular in shape and bears a distal spine. In all other Aptostichus species the tibial I apophysis is triangular, rounded, or absent, with the exception of Aptostichus cabrillo which has a similar rectangular apophysis. Aptostichus isabella males can be differentiated from Aptostichus icenoglei and Aptostichus cabrillo males on the basis of the TSr (Figs 165, 167) spination pattern. The TSr of Aptostichus isabella consists of a number of spines offset proximally with no TSrd spines whereas Aptostichus icenoglei and Aptostichus cabrillo have 2-4 non–overlapping TSrd spines.

Description of male holotype.

Specimen preparation and condition. Specimen collected in pitfall trap, preserved in 80%. Coloration in relatively pristine condition. Pedipalp, leg I left side removed, stored in vial with specimen. General coloration. Carapace, chelicerae, legs very dark brown 10YR 2/2. Abdomen yellowish brown 10YR 5/4 with dark distinct chevron striping dorsally. Cephalothorax. Carapace 5.60 long, 4.50 wide, very hirsute with white setae, stout black bristles along fringe; surface smooth, pars cephalica elevated. Fringe, posterior margin with black bristles. Foveal groove deep, straight. Eyes on relatively high mound. AER slightly procurved, PER slightly recurved. PME, AME subequal diameter. Sternum moderately setose, STRl 3.13, STRw 2.38. Posterior sternal sigilla small, widely separated, anterior sigilla pairs small, oval, marginal. Chelicerae with distinct anterior tooth row comprising 6 teeth, posterior margin with patch of small denticles. Palpal endites with very small patch of small cuspules on proximal, inner margin, labium lacks cuspules, LBw 0.92, LBl 0.44. Rastellum consists of 6 stout spines not on mound. Abdomen. Setose, heavy black setae intermingled with fine black setae. Legs. Leg I: 5.69, 4.20, 3.88, 2.79, 2.33; leg IV: 6.00, 3.13. Light scopulae on tarsi, metatarsi legs I, II. Tarsus I with single, slightly staggered row of 10 trichobothria. Leg I spination pattern illustrated in Figures 165-167; TSp 10, TSr 3, TSrd 0. Pedipalp. Articles slender, lacking distinct spines (Fig. 168). PTw 0.80, PTl 2.58, Bl 1.26. Embolus long, very slender, tapering gradually toward tip, lacking serrations (Fig. 168).

Variation. Known only from the type specimen.

Description of female.

Known only from male specimens.

Material examined.

Known only from the type specimen.

Distribution and natural history.

Aptostichus isabella is known only from a single specimen collected from the type locality (Map 1) in Kern Co., Piute Mountains; the habitat in the region is primarily classified as Sierran steppe, mixed coniferous forest.

Conservation status.

Undetermined.

Species concept applied.

Morphological.

Remarks.

Although based on a single specimen, the morphology of this hypothesized species is significantly divergent, and represents an interesting form such that recognizing it as a nominal taxon is warranted.