Figs. 15–26
Types: Male holotype and male paratype from Prairie Creek Redwoods State Park, 41.3729833°, 124.0138833°, 252’ asl, Humboldt Co., California, collected 21 December 2006 by C. H. Richart, A. Fusek (Richart collection number CHR 1041). Parts of these specimens are mounted on SEM stubs: WAS33-18, WAS34-1, WAS34-2 and WAS34-3.
Diagnosis: Distinct from A. rykkenae, the other species in the group, in having the femora of the second pair of legs of the males much enlarged, nearly as wide as long (Fig. 15).
Etymology: The species name is a noun in apposition and refers to the nearby town of Arcata, where the species was also collected
Description: Male paratype. Length about 10.5 mm, width about 1.0 mm. Seven or eight black ommatidia in triangular patch. Labrum with long, sinuate hooks; mandible not modified (Fig. 15). Legpairs 1 and 2 subequal, legs 1 without long setae, tarsi ventrally with twisted, spatulate setae (Figs. 15–17). Trochanters of second legs with short ventral process with patch of specialized setae, femora enlarged, oval, inflated. Coxal flasks of third legs (Figs. 18, 21) evenly curved, tapering, pleurotergal bars of third ring narrow, not meeting in midline (Fig. 18). Legpairs 4–7 enlarged, with flattened podomeres, coxae unmodified except for lobes on coxae 7. Metazonital crests prominent, more so posteriorly, posterior part of crests raised on rings 21–27 (Fig. 20). Pygidium elongate (Fig. 19, 20), divisions between lobes deep, narrow. Color medium tan, crests darker, posterior edge of each crest outlined in purplish brown.
Gonopods (Figs. 25, 26) similar to those of A. rykkeni, but with fewer spiculate processes on posteriodistal part of anterior angiocoxites, which bear large, blunt lateral lobes. Ninth legs (Fig. 24) also similar to those of A. rykkeni, articulating loosely with depressions in pleurotergal margins of ring 7.
Female similar to males in nonsexual characters.
Distribution: In addition to type locality known from CALIFORNIA: Humboldt Co.: Arcata, Community Forest east of Humboldt State University, 40.8699°, -124.0725°, collected 31 March 2011 by C. H. Richart et al. mmff.