The simple, distally tapering penis (Appendix VIII, Figure I) and short ovipositor (Appendix III, Figure 2) morphologies are conserved across species, with intraspecific variation seemingly as great as interspecific variation. Penis sheath with two sclerotized bands. Metatarsus of leg II with or without false leg articulations (Appendix IX). Distitarsi with three segments on legs I and II; distal end of legs III and IV with two constrictions, each comprised of two segments. All males with raised, glandular (Shear 1986), setose mound dorsally on basal article of chelicerae, setae often capped with secretions (MorphBank image 822802); mounds lacking in females. Chela teeth diaphanous, with two heavily sclerotized teeth distally on fingers (MorphBank image 822817). All leg coxae with prolateral and retrolateral tubercles in the form of distended clusters of warts (MorphBank image 828524). Epistome of stomotheca horn-like, projecting outward (MorphBank image 828520) to strongly decurved (MorphBank image 822815), without apparent interspecific trends. Pseudotrachea of pedipalpal coxaphysis sclerotized ctenoid (MorphBank image 822798).

This dichotomous key should allow users to identify the new species described herein. However, discovery of new morphologies in northern Idaho not described by Shear (1986), and not ascribed to species herein, are currently of uncertain placement at the species level. These morphologies include females with pairs of spines on scute areas I-IV, individuals with three pairs of spines on scute areas I-III, and individuals with pairs of spines on scute areas I-II which are geographically and genetically distinct, but morphologically similar to Acuclavella quattuor. For the purposes of this work, the four species named by Shear (1986) are treated sensu stricto, and follow his diagnoses.

Male holotype (AMNH), and male (CAS, CASENT9039218) and female (AMNH) paratypes from a tributary of Iron Creek, Forest Service Rd 25 4.6 miles south of FS Rd 300, Gifford Pinchot National Forest, Lewis County, Washington; male paratype (UWBM, WA2392/6319) and female paratype (CAS, CASENT9039224) from upper Iron Creek, FS Rd 28 0.1 miles E of FS 25, Gifford Pinchot National Forest, Skamania County, Washington; female paratype (UWBM, WA2391/6027) from a tributary of Goble Creek, Cowlitz County, Washington. Further information on type localities can be found in Appendix I with the exception of female paratype from Goble Creek. This specimen was collected by the first author 3 August 2005 and deposited in a research collection; this specimen was not used in morphometric analyses, but is used to characterize the species in the description below. This specimen was collected at a location accessed via S Goble Creek Rd; 2.0 miles east of Rose Valley Rd turn right, 1.6 miles turn right, 0.6 miles park; 46.0963°N, 122.7607°W, elevation 227 meters.

The specific epithet is a patronym in honor of the naturalist and careful observer William P. Leonard for his work on litter-dwelling organisms in the poor-person’s rainforest of the Pacific Northwest.

Distinguished from all Acuclavella except Acuclavella makah by the combination of having paramedian tubercles as enlarged spines on area II only, and having light, strongly contrasting ends to sclerotized leg segments, giving the appearance of banding. Also distinguished from these taxa in that false leg articulations on the metatarsi of legs II are present, or single dark prolateral tubercles on the palpal patellae are present, but these features are not consistently found in Acuclavella leonardi. Scutes posterior to spines containing many raised mounds bearing warty tubercles, more distinct than in Acuclavella makah. Though the height of scutal spines is similar, the base of the spines in Acuclavella leonardi appears broader than in Acuclavella makah. Diagnostic COI sequences have been uploaded to the Barcode of Life Data Systems (BOLD: ACUOP005-13).

Body arched and convex dorsally (Figure 5); sides parallel or nearly so when broader posteriorly. Nearly all of body heavily sclerotized black or brown, with densely scattered hemispherical warts which irregularly house short setae apically or posteriorly. Total length 4.18 mm (n=3, 3.88–4.35 mm), carapace length 1.22 mm (n=7, 1.10–1.35 mm), carapace width 2.53 mm (n=3, 2.44–2.65 mm), length of fused tergites I-V 2.24 mm (n=7, 2.10–2.41 mm), scutum length 2.73 mm (n=3, 2.65–2.85 mm), scutum width 2.63 mm (n=3, 2.55–2.75 mm).

Eye tubercle at anterior edge of carapace prolonged into an acute spine lacking hemispherical warts on distal half; standing 1.25 mm above the surface of the carapace (n=3, 1.13–1.35 mm), 1.05 mm (n=7, 0.88–1.19 mm) from the ventral edge of the eye to the tip of the tubercle. Eye color brown, brown-gray, or gray, located basally on tubercle. Metapeltidial paramedian sensory cones raised into a sharp, acute spine standing 0.26 mm (n=7, 0.23–0.28 mm) above surface of the carapace, curving slightly towards the midline; lateral to these spines clusters of warts form tubercles.

All scutal tergites with pairs of median tubercles, these prolonged into large spines on area II only; lateral tubercles distinct. Tergite I with paired median tubercles as raised mounds adorned with warts standing 0.09 mm (n=7, 0.08–0.13 mm) above the scutal surface; two additional pairs of warty mounds reduce in size laterally. Median tubercles on area II tergite greatly enlarged into erect spines standing 1.04 mm (n=7, 0.85–1.16 mm) above the surface of the scutum; lateral to these tubercles are raised mounds adorned with warts. Area III tergite with three pairs of relatively large tubercles in the form of raised mounds adorned with warts; these not decreasing in size laterally; apical setae on each mound; median pair 0.06 mm above scutum (n=7, 0.03–0.08 mm). Tergite areas IV and V with three or four (UWBM) pairs of tubercles in the form of raised mounds adorned with warts, these not decreasing in size laterally or posteriorly; setae as previous; area IV median tubercle height 0.06 mm (n=7, 0.05–0.08 mm). First free tergite (VI) with relatively large and numerous tubercles in the form of raised warty mounds. Second free tergite (VII) as previous in the holotype and paratype (CAS); paratype (UWBM) without tubercles. Free tergite VIII without distinguishable tubercles, or with a median pair only (CAS paratype).

Abdominal sternite warty sculpturing strongest laterally and on posterior margins; sternites brown. Sclerotized areas of genital operculum relatively setose. Prosomal sternum (n=1) length 0.19 mm, width 0.37 mm; brown; without setae. Labium weakly to moderately sclerotized, wider than long or longer than wide (CAS); lengths: 0.14, 0.20, 0.08 mm, widths: 0.28, 0.16, 0.18 mm; light brown to brown; without setae. Palpal endites setose, light brown or brown. Leg II endites bearing 1 or 2 (UWBM) setae, leg IV bearing 1 setae in paratype only, all other endites without setae. Horn-shaped process of epistome decurved, projecting 0.40 mm from sulcus (n=1).

Chelicerae brown or light brown (Figure 6); darker dorsally; article II with prolateral and retrolateral striations of darker, more sclerotized cuticle; weakly so in paratypes. Cheliceral measurements (n=3): article I length 1.14 mm (1.03–1.34 mm), width 0.41 mm (0.40–0.44 mm), article II length 1.32 mm (1.20–1.38 mm), width 0.38 mm (0.35–0.38 mm), article III length 0.56 mm (0.53–0.60 mm). Dorsal surface of article I with raised, glandular area dense with setae, these capped with a white secretion in the CAS paratype; proximal end of article I with boss-like tubercles on retrolateral and proventrolateral surfaces. Palpal coxae brown or light brown (UWBM paratype), with 2 seta-bearing tubercles. Palpal measurements given in Table 4. Trochanter (Figure 6) brown, light brown, or pale brown, with 3 or 4 (UWBM paratype) seta-bearing tubercles. Palpal femora brown or white; patella white without a dark diffuse band, with dark, prolateral tubercles distally, bearing small trichia and setae distally; tibia white, with scattered setae and dense microtrichia; tarsus white, darkening distally, with vestiture of microtrichia and setae. Claw rudiment very small.

Leg measurements given in Table 4. Microsculpture of femora, patellae, and tibiae scattered, distally elevated scales, bilobed scales not observed; scales subtend setae, occasionally housing seta apically. Leg trochanters, femora, patellae, tibiae light brown, dark brown, or black, lighter at joints; metatarsi of leg III with proximal one-third to one-half light brown, brown, or black; leg IV with proximal three-quarters light brown, brown, or black; proximal end of metatarsi of legs I and II pale brown, brown, or black; remaining metatarsal areas pale brown; tarsi pale brown, darkening distally. Scaled microsculpture subequal to darkened areas, remainder with setae and microtrichia. Metatarsi of leg II with false leg articulations (n=7).

Penis length 2.48 mm (n=1), glans plate 0.37 mm, stylus 0.09 mm, stylus slightly twisted, not decurved.

Similar to male for nearly all characters. Total length 4.71 mm (n=3, 4.45–5.06 mm); carapace length 1.35 mm (n=5, 1.25–1.44 mm); carapace width 3.01 mm (n=3, 2.81–3.13 mm); scutum length 3.63 mm (n=3, 3.19–4.30 mm); scutum width 3.70 mm (n=3, 3.12–3.50 mm); length of fused sternites I-V 2.96 mm (n=5, 2.81–3.06 mm).

Eye tubercle height above surface of carapace 1.18 mm (n=3, 1.00–1.28 mm); distance from ventral edge of eye to tip of spine 1.06 mm (n=5, 0.90–1.13 mm). Eye color dark brown, pink-gray, or light brown. Metapeltidial spine 0.22 mm (n=5, 0.18–0.25 mm).

Paramedian tubercles or tergite I height 0.08 mm (n=5, 0.05–0.13 mm) above surface of tergite; median tubercles raised mounds adorned with warts, two additional pairs of warty mounds reducing in size laterally. Tergite II paramedian tubercles greatly enlarged into erect spines standing 0.94 mm (n=5, 0.78–1.03 mm) above tergite surface; lateral to these are raised mounds adorned with warts. Paramedian tubercles of tergite III 0.07 mm (n=5, 0.03–0.10 mm); IV 0.06 mm (n=5, 0.03–0.10 mm). Tergite areas III, IV, and V with three pairs of relatively large tubercles in the form of raised mounds adorned with warts; these not decreasing in size laterally, decreasing slightly posteriorly across tergites. First free tergite (VI) adorned with raised warty mounds; tergites VII and VIII without discernable tubercles in paratypes (AMNH, CAS), tergite VII of paratype (UWBM) with tubercles as in VI.

Sternites brown. Transverse furrow and membranous lateral sutures of genital operculum less distinct than in other species. Prosomal sternum (n=1) length 0.18 mm, width 0.39 mm; pale-brown; without setae. Labium wider than long or subequal; lengths: 0.10, 0.19, 0.13 mm; widths: 0.16, 0.18, 0.19 mm; moderately or weakly sclerotized; brown; without setae. Palpal endites light brown. Leg II endites adorned with 2 setae.

Horn-shaped process of epistome decurved, projecting 0.42 mm from sulcus. Chelicerae brown or light brown; article I length 1.18 mm (n=3, 1.16–1.21 mm), width 0.43 mm (0.42–0.44 mm); article II length 1.39 mm (1.34–1.42 mm), width 0.41 mm (0.38–0.43 mm); article III length 0.59 mm (0.58–0.62 mm). Article I without raised glandular mound (Figure 6). Article II with 6 setae on prolateral dark area at cleavage of corpus and fixed finger of chela; 15 setae on ventral surface of article II; these patches discrete. Palpus dimensions in Table 4; coxae light brown or brown with two seta-bearing tubercles; trochanters brown or pale brown with 4 or 5 seta-bearing tubercles; only paratype (CAS) with tubercle on patella, only paratype (UWBM) with partial diffuse band on patella.

Leg measurements given in Table 4. Leg trochanters, femora, patellae, and tibiae brown to dark brown, lighter at joints; metatarsi of legs III with proximal one-half brown, of leg IV with proximal three-quarters light brown to brown, proximal ends of legs I and II light brown to brown, remaining metatarsal areas pale brown; tarsi pale brown, darkening distally.

Ovipositor length 0.80 mm, width 0.44 mm; corona of setae at furcal base surrounding lobes, apical setae on lobes; furca without dorsoventral differentiation.

Acuclavella leonardi is found in the southern Cascade Mountains of Washington State in the Cowlitz River (includes Iron Creek) and Coweeman River (includes Goble Creek) watersheds in Lewis, Cowlitz, and Skamania Counties (Appendix I). Found in coniferous forests with small perennial water-features such as side-slope seeps, springs, and headwater streams; underneath stream-side woody debris.

Male holotype and female paratype (AMNH), and male and female paratypes (CAS, CASENT9039219) from Brownes Creek, Clallam County, Washington; male and female paratypes (UWBM, WA2393/7641) from Yahoo Lake Road 1.4 miles east of Hoh-Clearwater Road, Jefferson County, Washington (Appendix I). An additional specimen is housed at UWBM (WA0973/8147): Ahlstroms Prairie, Olympic National Park, Clallam County, Washington, (NAD 1927) 48.157°N, 124.704°W, elevation 40 meters; Rod Crawford (collected under permit), 16–17 July 1984.

The specific epithet refers to the Makah Nation, which historically occupied much of the known distribution of the species. The name Makah was given to these people by their neighbors; it means “generous with food”. These people have shared with many people access to their beautiful land, next to the rocks and gulls. For more information on the Makah Nation see: http://www.makah.com.

Distinguished from all Acuclavella except Acuclavella leonardi by the combination of having paramedian tubercles on area II only, having light, and strongly contrasting ends to sclerotized leg segments, giving the appearance of banding at joints. Though not always present, false leg articulations on the metatarsi of legs II, and single dark prolateral tubercles on the palpal patellae also diagnose it from these species. Scutal tubercles lateral to paramedian tubercles tend to be on more distinctive raised mounds in Acuclavella leonardi. Area II spines more narrow at base than in Acuclavella leonardi. Best diagnosed from Acuclavella leonardi using molecular data. Diagnostic COI sequences have been uploaded to the Barcode of Life Data Systems (BOLD: ACUOP007-13).

Body arched and convex dorsally (Figure 7), sides parallel with equal scutum and carapace widths; nearly all of body heavily sclerotized, black, with densely scattered hemispherical warts which irregularly house short setae apically or posteriorly. Total length 4.11 mm (n=3; 4.05–4.20 mm), carapace length in midline 1.26 mm (n=10; 1.05–1.44 mm), greatest carapace width 2.57 mm (n=3; 2.50–2.72 mm); length of fused scutes I-V in midline 2.33 (n=10; 2.20–2.48 mm), scutum length in midline 2.74 (n=3; 2.60–2.90 mm) greatest scutum width 2.57 mm (n=3; 2.50–2.72 mm).

Eye tubercle at anterior edge of carapace, prolonged anteriad into a sharp conical spine 1.27 mm (n=10; 1.05–1.45 mm) from ventral edge of eye to tip of spine; 1.58 mm above the carapace (n=3; 1.53–1.64 mm). Eyes light-brown to brown, located basally on tubercle. Surface of carapace evenly curved, posterior margin arcuate. Metapeltidial paramedian sensory cones short, acute spines standing 0.19 mm (n=10; 0.13–0.25 mm) above the surface of the metapeltidium, shiny, lacking warts.

All scutal areas with pairs of paramedian tubercles. Area I paramedian tubercles cluster of cuticular warts standing 0.04 mm above the surrounding scute (n=10; 0.025–0.075 mm), two additional pairs of warty tubercles reduce in size laterally. Paramedian tubercles of area II rise to form large acute spines standing 1.37 mm above the scutum surface (n=10; 1.13–1.75 mm); lateral to spines a pair of tubercles typically small cluster of warts, though one individual (CHR1536) with lateral pair of short spines. Scute areas III, IV, and V with three pairs of wart-clustered tubercles each; paramedian pair largest, diminishing in size laterally along scute, and posteriorly across scute areas. Paramedian tubercles of area III stand 0.03 mm (n=10, 0.03–0.05 mm) above surface of the tergite; area IV tubercle height 0.04 mm (n=10, 0.03–0.08 mm). Holotype and paratype (CAS) with first free tergite (area VI) with barely distinguishable tubercle as median pair of enlarged warts, tergites VII and VIII without tubercles; paratype (UWBM) tergite VI with median and lateral pair of enlarged warty tubercles, tergite VII with barely distinguishable tubercles, these lacking on tergite VIII. Tergite IX divided, triangular, bracketing tergite X, which forms the anal operculum.

Abdominal sternites with infrequent setae; warty sculpturing strongest on posterior and lateral margins; brown to dark brown. Prosomal sternum length 0.14 mm (n=2, 0.13–0.16 mm), width 0.28 mm (0.26–0.30 mm); brown; without setae. Labium weakly sclerotized, wider than long, length 0.08 mm (n=3; 0.05–0.11 mm), width 0.15 mm (0.13–0.17 mm); light brown to yellow-brown, without setae. Palpal endites brown to yellow-brown, large, free, bearing many setae; leg II endite bearing 3 setae in holotype and paratype (CAS), 2 in paratype (UWBM); legs I, III, IV endites without setae. Epistome with horn-like anteriad projection, decurved or slightly decurved, projecting 0.34 mm (n=2, 0.33–0.36 mm) from sulcus. Chelicerae basal article (I) dark brown dorsally, middle article (II) with prolateral and retrolateral striations of darker, more sclerotized striations. Article I length 1.18 mm (n=3, 1.06–1.30 mm), width (I) at widest point 0.41 mm (0.38–0.43 mm), article II length 1.40 mm (1.34–1.46 mm), width (II) at widest point 0.40 mm (0.38–0.43 mm), article III length 0.53 mm (0.50–0.57 mm). Article I with raised, setose glandular area on dorsal surface (Figure 8). Article I with boss-like tubercles proximally on proventrolateral and retrolateral surfaces, one individual with proventrolateral tubercles bilobed; proventrolateral tubercle may function to macerate food or manipulate food items in conjunction with the epistome process. Cleavage of corpus and fixed finger housing 5 or 6 setae on prolateral side of article II; 12 or 15 setae on ventral surface of article II; these patches discrete. Palpal coxae yellow-brown to brown, with two seta-bearing tubercles ventrally (Figure 8). Palpal measurements given in Table 5. Trochanter brown to dark-brown with 3 (holotype) or 4 seta-bearing tubercles; femur white; patella white without dark band medially, with prolateral, distal darkened tubercles; bearing microtrichia and small setae distally; tibia white with scattered setae and dense microtrichia; tarsus white, usually darkening distally. Claw rudiment very small.

Leg measurements given in Table 5. Trochanters, femora, patellae, tibiae black, lighter at joints, with scattered, distally elevated scales which subtend short setae, scales occasionally house setae apically or posteriorly. Metatarsi of leg III with proximal half black or darkened; leg IV proximal three-quarters black or darkened; legs I and II with proximal end darkened; remaining metatarsal areas pale-brown to yellow-brown. Scaled-microsculpture subequal to darkened areas. Metatarsi and tarsi without tubercles. Six of ten males with false leg articulations on metatarsi of leg II, including holotype. Leg claws single, black, not toothed, evenly curved.

Penis 2.39 mm in length (n=2, 2.38–2.40 mm); glans plate length 0.34 mm (n=2, both 0.34 mm); stylus length 0.16 mm (0.14–0.17 mm). Shaft evenly tapered, broadening slightly at glans; glans with scattered small setae; stylus spirally twisted, very slightly decurved.

Similar to male for nearly all characters. Total length 5.14 mm (n=3; 5.00–5.31 mm); carapace length 1.37 mm (n=14; 1.25–1.81 mm); carapace width 3.16 mm (n=3; 3.00–3.31 mm); scutum length 3.82 mm (n=3; 3.63–3.94 mm); scutum width 3.33 mm (n=3; 3.19–3.50 mm); length of fused sternites I-V 2.96 mm (n=14; 2.75–3.19 mm).

Eye tubercle height above surface of carapace 1.37 mm (n=3; 1.31–1.46 mm); distance from ventral surface of eye to tip of spine 1.21 mm (n=14; 1.08–1.33 mm). Eye color brown. Metapeltidial spine 0.16 mm (n=14; 0.10–0.23 mm).

Paramedian tubercles of tergite I height 0.06 mm (n=14; 0.03–0.10 mm) above surface of tergite. Tergite II paramedian tubercles greatly enlarged spines standing 1.10 mm (n=14; 0.93–1.28 mm) above tergite surface; tubercles lateral to spines warty mounds. Paramedian tubercle height of tergite III 0.07 mm (n=14; 0.05–0.10 mm); IV 0.06 mm (n=14; 0.03–0.08 mm). Tergites III, IV, V with three pair of tubercles with median pair largest, reducing in size laterally along tergite and posteriorly across tergites; the right median tubercle of tergite III of paratype (CAS) enlarged into mound with diminished frequency of warts standing 0.22 mm above carapace. First free tergite (IV) with median and lateral pair of enlarged warty tubercles, or barely distinguishable median pair of enlarged warts; tergite VII without tubercles, or tubercles barely distinguishable, or more noticeable; tergite VIII without distinguishable tubercles.

Sternites brown. Prosomal sternum length 0.17 mm (n=2, 0.17–0.18 mm), width 0.32 mm (0.30–0.33 mm); dark brown. Labium wider (0.17 mm, 0.16 mm, 0.14 mm) than long (0.09 mm, 0.09 mm, 0.14 mm), or nearly equal; yellow-brown to light brown. Palpal endites brown, yellow-brown, or light brown. Paratypes (AMNH, CAS) with 3 setae on leg II endite; paratype (UWBM) with 2 setae. Horn-shaped process of epistome decurved or projecting downward; length 0.48 mm (n=2, 0.47–0.50 mm).

Chelicerae article I length 1.35 mm (n=3; 1.20–1.47 mm), width 0.45 mm (n=3, 0.44–0.46 mm); article II length 1.49 mm (n=3; 1.48–1.50 mm), width 0.42 mm (0.42–0.43); article III length 0.59 mm (n=3; 0.56–0.60 mm). Article I without raised glandular mound (Figure 8); prolateral side of cheliceral article II with 2 or 4 setae at cleavage of corpus and fixed finger; 12 setae on ventral surface of article II; these patches discrete. Palpus dimensions in Table 5; coxae brown with two seta-bearing tubercles; trochanter brown to dark brown with 4 seta-bearing tubercles; only paratype with tubercle on patella.

Leg measurements given in Table 5. Leg trochanters, femora, patellae, and tibiae black, lighter at joints; metatarsi of leg III with proximal half black or darkened, leg IV with proximal three-quarters black or darkened, proximal end of legs I and II black or darkened, remaining metatarsal areas yellow-brown or pale brown; tarsi yellow-brown or pale brown, darkening distally.

Ovipositor length 0.74 mm (n=2, 0.72–0.77 mm), width 0.46 mm (0.44–0.47 mm); furca without dorsoventral differentiation; corona of setae at furcal base surround lobes; apical setae on lobes.

Known from the northwest areas of the Olympic Peninsula in Clallam and Jefferson Counties, Washington State (Appendix I). Found in coniferous or riparian forests along small, perennial water-features such as headwater streams, springs, and seeps; underneath woody debris and moss.

Male holotype (AMNH) and female paratypes (AMNH; CAS, CASENT9039225; UWBM) from Burgdorf Road 12.4 miles northwest of Warren Wagon Rd, tributary of Fall Creek, Payette National Forest, Idaho County, Idaho; two male paratypes (CAS, CASENT9039217; UWBM, ID0016/5360) from Burgdorf Road 16.6 miles northwest of Warren Wagon Road; otherwise as previous (Appendix I).

The specific epithet honors Dr. William A. Shear, eminent milliped and opilionid taxonomist. His influence has been important to the authors’ aspirations to be systematic biologists, and we thank him sincerely, and with pleasure.

Generally reduced dimensions overall. Males with one pair of scutal spines on area II only; scutal spines ≤ 0.50 mm, distance from ventral edge of eye to tip of ocularium ≤ 0.60 mm distinguishes it from other males with single pair of spines. Females lack scutal spines. Diagnosed from spine-less Acuclavella shoshone (Shear, 1986 sensu stricto) females by having palpal femora ≤ 0.88 mm, leg II tarsi ≤ 3.92 mm, leg II femora ≤ 2.75 mm.

Body arched and convex dorsally (Figure 9); sides broader posteriorly. Nearly all of body heavily sclerotized black or dark brown, with densely scattered hemispherical warts which irregularly house short setae apically or posteriorly; bilobed warts sporadic in holotype. Total length 3.90 mm (n=3, 3.68–4.06 mm), carapace length 1.24 mm (n=4, 1.15–1.32 mm), carapace width 2.34 mm (n=3, 2.31–2.36 mm); length of fused tergites I-V 2.26 mm (n=4, 2.16–2.31 mm), scutum length 2.61 mm (n=3, 2.32–2.81 mm), scutum width 2.60 mm (n=3, 2.55–2.63 mm).

Eye tubercle at anterior edge of carapace, hemispherical warts cover entirety of ocular spine, prolonged into an acute spine standing 0.67 mm above the surface of the carapace (n=3, 0.64–0.70 mm), 0.53 mm (n=4, 0.48–0.60 mm) from the ventral edge of the eye to the tip of the tubercle, eye spine less acute than in other species of Acuclavella. Eyes dark brown to brown, located basally on tubercle. Surface of carapace evenly curved, posterior margin arcuate. Metapeltidial paramedian sensory cones raised into sharp, acute spines standing 0.21 mm (n=4, 0.17–0.24 mm) above surface of the carapace, curving slightly towards the midline, lacking warty microsculpture, shiny; lateral to spines, clusters of warts form tubercles, missing in paratype (UWBM).

All scutal tergites with pairs of paramedian tubercles; relatively short, pointed spines on area II only. Fused tergite I with paramedian tubercles as raised mounds, relatively tall but not spike-like, standing 0.125 mm above the surrounding scute (n=4, all 0.125), these adorned with warts; lateral to these, two additional raised mounds become smaller away from the midline, these lacking in holotype. Paramedian tubercles of area II form acute spine 0.39 mm above the scutum surface (n=4, 0.34–0.43 mm), curved slightly posteriad; lateral to these are raised tubercles adorned with warts. Fused tergites III, IV, and V with paramedian tubercles in the form of raised mound adorned with warts; lateral to these, area III with 2 or 3 additional pairs of tubercles, area IV with 1 or 2 additional tubercles, area V with 0 or 2 additional tubercles; these tend to diminish in size away from the midline and posteriorly across tergites. Area III tubercle height above tergite 0.081 mm (n=4, 0.075–0.10 mm); area IV tubercle height 0.075 mm (all 0.075 mm). Free tergites without discernable tubercles, or tubercles occur in single pairs as small warty mounds.

Abdominal sternites with infrequent setae; warty sculpturing strongest laterally and on posterior margin; sternites brown, dark brown, or black. Sclerotized areas of genital operculum relatively setose. Prosomal sternum (n=1) wider than long: length 0.19 mm, width 0.29 mm; dark brown; without setae. Labium weakly to well-sclerotized, wider than long (n=3):, length 0.09 mm (0.08-0.10 mm), width 0.16 mm (0.13-0.19 mm), light brown to dark brown, darkness commensurate to sclerotization, without setae. All coxae with endites. Palpal endites setose, light brown, dark brown, or black. Leg II endite bearing 2 setae, other leg endites unadorned. Horn-shaped process of epistome decurved, projecting 0.34 mm from sulcus.

Chelicerae light brown, dark brown, or black; lighter individuals with article I darker dorsally, article II with darker, more sclerotized striations on prolateral and retrolateral surfaces (Figure 10). Article I length 1.11 mm (n=3, 1.00-1.18 mm), width 0.39 mm (0.36-0.42 mm), article II length 1.21 mm (1.12-1.27 mm), width 0.40 mm (all 0.40 mm), article III length 0.54 mm (0.52-0.56 mm). Dorsal surface of article I with raised, glandular area dense with setae. Palpal coxae pale-brown, light brown, or black, with 2 or 1 (UWBM) seta-bearing tubercles. Palpal measurements given in Table 6. Trochanter (Figure 10) pale-brown or dark brown, with 2 (CAS), 3 (holotype), or 4 (UWBM) seta-bearing tubercles; these reduced on later individual; femur pale-brown, brown, or dark brown; patella pale-brown or brown, with (CAS) or without a diffuse dark band on middle third, without darkened tubercle distally, bearing small setae and microtrichia distally; tibiae pale brown or white (holotype), with scattered setae and dense microtrichia; tarsus pale-brown or white (holotype), darkening to brown distally. Claw rudiment very small to absent.

Leg measurements given in Table 6. Microsculpture of femora, patellae, and tibiae scattered, distally elevated scales, bilobed scales not observed; scales subtend setae, occasionally housing seta apically. Trochanters, femora, patellae, tibiae black, or in holotype, trochanters light brown, femora, patellae, and tibiae brown; metatarsi of leg III proximal one-third to one-quarter brown or black; leg IV with proximal half black or brown; proximal end of metatarsi on legs I and II black or brown, remaining metatarsal areas pale brown or brown; all tarsi pale brown or brown, darkening distally. Scaled microsculpture subequal to darkened areas, remainder with setae and microtrichia. False leg articulations not observed. Leg claws single, black, not toothed, evenly curved.

Penis length 2.94 mm (n=1); glans plate 0.31 mm, scattered small setae; stylus 0.13 mm, slightly spirally twisted and decurved.

Similar to male, differing in dimensions, secondary sexual characteristics, and dorsal armature. Total length 4.25 mm (n=3; 4.05-4.65 mm); carapace length 1.325 mm (n=4, 1.05-1.45 mm), width 2.62 mm (n=3, 2.35-3.05 mm); scutum length 3.03 (n=3, 2.90-3.25 mm), width 3.23 mm (n=3, 2.85-3.55 mm); fused tergites I-V length in midline 2.81 mm (n=4, 2.20-3.10 mm).

Eye tubercle height above surface of carapace 0.67 mm (n=3, 0.56-0.73 mm), distance from ventral surface of eye to tip of spine 0.54 mm (n=4, 0.46-0.60 mm). Eye color brown or gray. Metapeltidial spine 0.11 mm (n=4, 0.08-0.15 mm), curving slightly posteriad and towards the midline, lateral to these spines clusters of warts form tubercles.

Dorsal armature lacking. Dorsal adornment generally with median tubercles as raised mounds adorned with warts, decreasing in size away from midline and posteriorly across tergites. Two lateral pairs of warts on areas III and IV, area V with median pair of tubercles barely discernable, two pairs of lateral tubercles, or shallowly raised mounds adorned with warts. Free tergites with tubercles in the form of clusters of warts, or without discernable tubercles. Paramedian tubercles heights above the surface of the tergite (n=4): of area I 0.07 mm (0.05-0.08 mm); area II 0.10 mm (0.08-0.15 mm); area III 0.06 mm (0.05-0.08 mm); area IV 0.05 mm (0.03-0.08 mm).

Sternites brown, black, or light brown. Prosomal sternum (n=1) length: 0.26 mm, width 0.31 mm; light brown, without setae. Labium wider (0.13, 0.17, 0.16 mm) than long (0.08, 0.09, 0.08 mm); light brown or pale brown. Palpal endites brown or pale brown. Endites of leg II adorned with two or one (CAS) setae.

Chelicerae article I length 0.98 mm (n=3, 0.92-1.06 mm), width 0.41 mm (0.37-0.44 mm); article II length 1.31 mm (1.14-1.40 mm), width 0.43 mm (0.40-0.46 mm); article III length 0.57 mm (0.52-0.62 mm). Article I without raised glandular mound (Figure 10). Article I darker dorsally, chelicerae light brown or black with areas of dark brown. Palpus dimensions in Table 6; coxae light brown, dark brown, or white, with two seta-bearing tubercles; trochanters light brown, dark brown, or white, with three (AMNH) or four (CAS, UWBM) seta-bearing tubercles; femora and patella pale brown, brown, or white, patella without both distal tubercles and diffuse bands; tibiae white or pale-brown; tarsus white or pale-brown, fading to brown distally. Claw rudiment very small (AMNH, UWBM), or absent.

Leg measurements given in Table 6. Leg trochanters brown, black, or pale-brown; femora, patellae, and tibiae dark brown, back, or pale brown; metatarsi of legs III with proximal third brown, black, or pale-brown; leg IV metatarsi with proximal half brown, black, or pale-brown; proximal end of legs I and II metatarsi brown, black, or pale-brown; remaining metatarsal areas pale-brown, brown, or white; tarsi pale brown or white, darkening distally.

Ovipositor length 0.82 mm, width 0.46 mm (n=1); otherwise as Acuclavella makah.

Known from north-facing, horizontal band of Abies grandis forest above south shore of Salmon River. This habitat is mainly roadless, though intersected by FS 592 and Burgdorf Road in Payette National Forest, Idaho County, Idaho. Adults collected in June and September. Abies grandis, Pseudotsuga menziesii, and Picea engelmannii associated canopy cover; collected under woody debris adjacent to headwater streams.

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.

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).

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).

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.

For species descriptions see Shear 1986. Discriminated from other Acuclavella having a single pair of paramedian spines on tergite II by having relatively homogenously colored leg segments, not giving the appearance of banding at leg joints (from Acuclavella makah and Acuclavella leonardi) or by having scutal spines > 0.50 mm and ocularium height from ventral edge of eye to tip of spine > 0.60 mm (from Acuclavella sheari).

Acuclavella merickeli populations are bracketed to the south by the South Fork Clearwater River and to the north by the Selway River; all localities in Nez Perce National Forest, Idaho County, Idaho. Coniferous habitat dominated by Picea englemannii or Thuja plicata and Pseudotsuga menziesii; microhabitats include moist woody debris and moss adjacent to small perennial water features such as side-slope seeps and headwater streams.