Acuclavella quattuor Shear, 1986

Richart, Casey H. & Hedin, Marshal, 2013, Three new species in the harvestmen genus Acuclavella (Opiliones, Dyspnoi, Ischyropsalidoidea), including description of male Acuclavella quattuor Shear, 1986, ZooKeys 311, pp. 19-68 : 52-56

Acuclavella quattuor Shear, 1986 Figure 11 and 12, Appendix VIII: Figure 1, Figure 2

Material examined.

Males (AMNH; CAS, CASENT9039220; UWBM, ID0013/5661) from the type locality: Slate Creek Road 10.2 miles east of US 95, Nez Perce National Forest, Idaho County, Idaho.

Diagnosis.

Diagnosed from all Acuclavella species except for Acuclavella cf. quattuor by having two pairs of erect spines on tergites I and II; similar morphologically to Acuclavella cf. quattuor, and is best diagnosed using molecular data: basepair 23 of the EF-1α intron cytosine in Acuclavella cf. quattuor, adenine in Acuclavella quattuor ; basepair 44 guanine in Acuclavella quattuor , thymine or adenine in Acuclavella cf. quattuor (thymine if sequences aligned due to a 3 basepair deletion in 40% of Acuclavella cf. quattuor at basepair 39-41).

Description.

Description of male. Body arched and convex dorsally (Figure 11); sides parallel or slightly broader posteriorly. Nearly all of body heavily sclerotized, black, with densely scattered hemispherical warts which irregularly house short setae apically or posteriorly. Total length 4.22 mm (n=3, 4.06-4.45 mm); carapace length 1.35 mm (n=14, 1.25-1.50 mm), width 2.60 mm (n=3, 2.56-2.64 mm); scutum length 2.84 mm (n=3, 2.56-3.25 mm), width 2.80 mm (n=3, 2.69-2.88 mm); length fused tergites I-V 2.69 mm (n=14, 2.50-3.10 mm).

Eye tubercle at anterior edge of carapace, erect, spine-like, standing 0.98 mm above the surface of the carapace (n=3, 0.94-1.05 mm), distance from ventral edge of eye to tip of spine 0.84 mm (n=14, 0.65-0.93 mm). Eye color brown, on basal part of ocularium. Surface of carapace evenly curved, posterior margin arcuate. Metapeltidial paramedian sensory cones acute or blunt spines standing 0.28 mm (n=14, 0.18-0.38 mm) above surface of carapace.

Scutum of opisthosoma rounded anteriorly, squared of posteriorly. All fused tergites with paramedian pair of tubercles, these in the form of erect spines on areas I and II. Spines of tergites I and II curve posteriad, stand 0.82 mm (n=14, 0.65-1.05 mm) and 0.91 (n=14, 0.70-1.12 mm) above the surface of the tergite respectively; tubercles lateral to spines as small raised wart mounds; one of 14 males with lateral spines on area II. Tergites III, IV, and V with four pairs of tubercles as raised areas adorned with warts; paramedian tubercles of area III height 0.06 mm (n=14, 0.03-0.20 mm); area IV paramedian tubercle height 0.05 mm (n=14, 0.03-0.08 mm); two individuals with one of paramedian tubercles of area III spine-like, left side on one, right side on other. First free tergite (VI) with small median tubercles in the form of enlarged shiny wart; remaining free tergites without discernable tubercles.

Abdominal sternite warty sculpturing strongest laterally and on posterior margin; sternites brown or dark brown. Genital operculum tongue-shaped, clearly delineated by transverse furrow, lateral ends of furrow membranous suture, distal margin rebordered, glossy. Prosomal sternum wider than long; length 0.18 mm (n=3, 0.17-0.21 mm), width 0.29 mm (n=3, 0.26-0.31 mm); pale brown or brown; without setae. Labium moderately sclerotized, wider than long or dimensions subequal; length 0.11 mm (n=3, 0.09-0.13 mm), width 0.14 mm (0.13-0.16 mm); brown or dark brown; without setae. Palpal endites setose; brown. Leg II endites bearing 2 (AMNH, CAS) or 3 setae (UWBM), other leg endites glabrous. Horn-shaped process of epistome strongly decurved; projecting 0.43 mm (n=4, 0.41-0.44 mm) from sulcus.

Chelicerae light brown or brown; darker dorsally; article II with darker, more sclerotized striations on prolateral and retrolateral surfaces (Figure 12). Article I length 1.21 mm (n=3, 1.18-1.25 mm), width 0.44 mm (n=3, 0.42-0.45 mm); article II length 1.38 mm (n=3, 1.35-1.40 mm), width 0.41 mm (n=3, 0.38-0.45 mm); article III length 0.59 mm (n=3, 0.58-0.60 mm). Article I dorsal surface with raised, glandular area densely setose (Figure 12). Prolateral side of article II with dark sclerotization at cleavage of corpus and fixed finger housing 6, 6, 5, 5 setae; ventral surface of article with 19, 20, 16, 23 setae; these patches discrete in three of four individuals examined. Palpal measurements given in Table 7. Palpal coxae light brown or brown (Figure 12), with 2 seta-bearing tubercles. Palpal trochanters light brown, brown, or dark brown; with 4 seta-bearing tubercles. Femora and patella white or yellow-brown; patella without distal prolateral tubercle, without diffuse dark band, bearing small setae and microtrichia distally. Tibia white or pale yellow, with scattered setae and dense microtrichia. Tarsi white or pale yellow, darkening distally; with setae and dense microtrichia. Claw rudiment very small.

Leg measurements given in Table 7. Microsculpture of femora, patellae, and tibiae scattered, distally elevated scales, bilobed scales not observed; scales infrequently house seta apically or distally. Trochanters, femora, patellae, and tibiae dark brown to black; metatarsi of leg III with proximal one-quarter brown or black, leg IV with proximal one-half brown or black, proximal end of metatarsi of I and II brown or black, remaining metatarsal areas brown; tarsi brown, darkening distally. Leg claws single, black, not toothed, evenly curved.

Penis length 2.49 mm (n=4, 2.35-2.55 mm); shaft evenly tapered, broadening slightly at glans. Glans bearing scattered small setae; glans length 0.32 mm (n=3, 0.29-0.36 mm). Stylus length 0.18 mm (n=3, 0.16-0.19 mm); stylus spirally twisted, decurved.

For female description see Shear (1986).

Distribution and habitat.

Acuclavella quattuor populations are bracketed by the Salmon River to the south and the South Fork Clearwater River to the north, whereas Acuclavella cf. quattuor is found north of the Selway River and south of the Lolo Trail Ridge. Acuclavella quattuor habitats are dominated by Abies grandis and Picea englemannii ; microhabitat in litter, moss, and moist woody debris adjacent to headwater streams.