Aptostichus muiri, 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 : 85-87

Aptostichus muiri sp. n. Figures 169-173Map 1

Types.

Male holotype (AP409) from California, Mariposa County, 3.2km SE of Mariposa, 37.4668, -119.9384 5, 640m, coll. M. Bentzien 20.ix.1972, deposited in CAS. Female paratype (AP1263) from California, Mariposa County, Yosemite National Park, west facing slope of valley off of "4 Mile" trailhead, 37.7226, -119.5943 1, 1128m, coll. J. Bond 10.v.1997, deposited in AUMNH.

Etymology.

The specific epithet is a patronym in honor of John Muir, one of the first European explorers to visit Yosemite Valley, and to subsequently fight for its preservation.

Diagnosis.

Males of this species are similar to those of Aptostichus atomarius complex individuals, however Aptostichus muiri has fewer TSrd spines and a more slender palpal tibia (Figs 169-172). They can be distinguished from all other species of Aptostichus by their unique tibia I spination pattern. The female paratype of this species, collected not far from the type locality, is tentatively placed as a conspecific with the male holotype. This female specimen can be distinguished from Aptostichus atomarius by having fewer labial cuspules and a secondary spermathecal bulb (Fig. 173) that is much smaller than that observed for most putative Aptostichus atomarius specimens.

Description of male holotype.

Specimen preparation and condition. Specimen collected live, preserved in 80%. Coloration faded. Pedipalp, leg I left side removed, stored in vial with specimen. General coloration. Carapace, chelicerae, legs strong brown 7.5YR 4/6. Abdomen brown 10YR 4/3 dorsally with distinct mottled striping, ventrum, spinnerets pale yellow. Cephalothorax. Carapace 5.70 long, 4.70 wide, glabrous, stout black bristles along fringe; surface hirsute with light white spines, pars cephalica elevated. Fringe, posterior margin with black bristles. Foveal groove deep, straight. Eyes on low mound. AER slightly procurved, PER slightly recurved. PME, AME subequal diameter. Sternum moderately setose, STRl 2.91, STRw 2.53. Posterior sternal sigilla moderate size, 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 0.85, LBl 0.51. Rastellum consists of 5 very stout spines not on mound. Abdomen. Setose, heavy black setae intermingled with fine black setae. Legs. Leg I: 5.10, 3.50, 3.50, 2.33, 2.05; leg IV: 5.40, 2.75. Light tarsal scopulae on legs I, II. Tarsus I with single, slightly staggered row of 11 trichobothria. Leg I spination pattern illustrated in Figures 171, 172; TSp 3, TSr 3, TSrd 3. Pedipalp. Articles slender, lacking distinct spines (Fig. 170). PTw 0.94, PTl 2.18, Bl 1.21. Embolus slender, sinuous, lacking serrations (Fig. 170).

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, cleared in trypsin, stored in microvial with specimen. General coloration. Carapace, legs, chelicerae, brown 7.5YR 4/4. Abdomen black dorsally 7.5YR 2.5/1 with light mottled striping, ventrum, spinnerets pale yellow. Cephalothorax. Carapace 5.00 long, 4.08 wide, lightly hirsute with thin black spines; generally smooth surface, pars cephalica moderately elevated. Fringe lacks setae. Foveal groove deep, procurved. Eye group slightly elevated on low mound. AER slightly procurved, PER slightly recurved. PME’s larger in diameter than AME’s. Sternum widest at coxae II/III, moderately setose, STRl 2.83, STRw 2.40. Three pairs of sternal sigilla anterior pairs small, oval, marginal, posterior pair larger, oval, mesially positioned. Chelicerae anterior tooth row comprising 6 teeth with posterior margin denticle patch. Palpal endites with 17 cuspules concentrated at the inner (promargin) posterior heel; labium with 3 cuspules, LBw 0.94, LBl 0.58. Rastellum consists of 6 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 11.44 long. Tarsus I with single staggered row of 15 trichobothria. Legs I, II, III with moderately light scopulae on tarsi only. PTLs 12, TBs 3. Rudimentary preening comb on retrolateral distal surface at tarsus-metatarsus joint) of metatarsus III, IV. Spermathecae. Median stalk lightly sclerotized, basal extension lacks a well-developed bulb that does not extend below lateral plane of base (Fig. 173)

Variation. Known only from the paratype specimen.

Material examined.

Known only from the type material.

Distribution and natural history.

Aptostichus muiri is known only from Mariposa County in the Sierra Nevada Mountains (Map 1); the habitat from which the single female was collected from a shallow burrow is classified as mixed coniferous forest.

Conservation status.

Undetermined.

Species concept applied.

Morphological.