Taracus timpanogos Shear, new species
Creators: name: Shear, William A.
name: Warfel, Joseph G.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Taracidae
Taracus
Taracus timpanogos

description: Taracus timpanogos Shear, new species (Utah)
Figs. 94–105, Map 6
Types. Male holotype and male paratype from Timpanogos Cave, Timpanogos Cave National Monument, American Fork Canyon, Utah Co., Utah (CAS). No further data is given on the label. The identities of the collectors and the date of collection are suggested by the label with a juvenile specimen (UWBM), undoubtedly this species, collected in Timpanogos Cave by C. R. Nelson and B. K. Kowallis, on 9 June 2004. This was confirmed by Brandon Kowallis (pers. comm. 2013) and the labels with the types have been amended accordingly. Two female paratypes from North Madhouse Cave, near Provo, Utah Co., Utah, 7500’ asl, collected 27 May 1965 by S. Moulton (AMNH).
Diagnosis. This is the only Utah species and is clearly related to T. taylori and T. spesavius. It differs from both species in having a much shorter, broader penis, much less prominent seta-tipped tubercles on the palpal trochanter, and from taylori in having unreduced, pigmented eyes. The legs of spesavius are significantly longer than those of timpanogos, though the lengths of their bodies are similar.
Etymology. The species epithet is a noun in apposition, after the type locality.
Description. Male from Timpanogos Cave. Total length, 4.6 mm. Carapace medium to dark chestnut brown, more lightly sclerotized laterally, with distinct “hash marks” posteriolateral to ocularum; central region strongly domed; midline sulcus closed, reaching anterior margin of ocularium. Ocularium as wide as long, rounded, higher behind, with few small setae; eyes only slightly smaller than those of epigean species. Metapelitidium unsclerotized, with few scattered small setae; sensory cone long, white, acute, with distinctly bulbous base, margin of carapace not indented to receive cone. Abomen soft, white, unsclerotized, set with scattered, small, black setae; setae not on sclerotized plaques or tubercles, lightly pigmented areas median on first two abdominal segments but no sclerotization (Figs. 100, 101). Ventrally, coxae white to tan, unmarked. Palpal and first leg coxae light brown, with stout setae on distinct tubercles, second to fourth leg coxae somewhat lighter, with strong, black setae not on tubercles. Five or six setae in two groups on lightly sclerotized patches mark presumed position of thoracic sternum. Second coxal endites long, narrow, separate from coxae. Genital operculum apically rounded, heavily setose, pale tan, unspotted. Venter of abdomen with setae in irregular rows; abdominal sternites entirely unsclerotized.
Chelicerae (Figs. 104–105) 9.68 mm long, slender, black. Basal article 4.48 mm long, 0.40 mm wide (L/W = 11.2); second article 5.20 mm long, 0.52 mm wide (L/W = 10). Basal article with prominent, acute seta-tipped tubercles extending three-quarters of length, dorsal tubercles much smaller; second article with relatively low, rounded seta-tipped tubercles densely scattered over anterior surface, tubercles more widely spaced distally. Fixed and movable fingers with paired, articulating triangular teeth, narrow, acute tips of fingers cross each other at rest.
Palpi (Fig. 95) brown, total length 12.23 mm, typical for genus; trochanter with prominent scattered setatipped tubercles. Lengths of articles as given in Table 16. Legs long, thin; first leg brown, becoming lighter distally, other legs yellowish tan without markings. Basal autospasy articulations clear on all femora. Tibiae without false articulations, metatarsus of leg 2 with about 9–10 very faint false articulations; otherwise false articulations absent. Total lengths in mm of legs 1–4: 17.19, 25.69, 19.76, 22.26. Measurements of leg articles given in Table 16.
Penis (Figs. 96, 97) 1.68 mm long, 0.30 mm wide (L/W = 5.6), sides of shaft straight, tapering gradually to straight, relatively long aculeus; glans not set off by suture; aculeus subtended by crown of few small, acute setae; shaft with similar setae sparsely scattered on either side below glans.
Female from Professor Buss Cave: As for the male holotype, except as follows. Total length, 5.33 mm (Figs. 98, 99). Cheliceral (Figs. 102, 103) basal article 4.92 mm long, 0.54 mm wide (L/W = 8.93); second article 6.04 mm long, 0.58 mm wide (L/W = 10.41). Total length of palpus (Fig. 94), 13.71 mm. Abdomen without sclerotization. Total lengths in mm of legs 1–4: 16.84, 26.92, 16.33, 22.44; lengths of palpal and leg articles as given in Table 17. Ovipositor typical.
Distribution. In addition to the type localities: UTAH: Utah Co.: Professor Buss Cave, south of BYU campus, Slide Canyon, 15 September 1966, ƋƋ ♀♀ (CAS). Professor Buss and the Madhouse Caves are close together, about 60 miles south of Timpanogos Cave National Monument, also in the Wasatch Mountains and the Uinta- Wasatch-Cache National Forest.
Notes. Based on photographs and a scan via Google Earth, it appears that potentially suitable Taracus habitat, a dense forest of Douglas fir and white fir, occurs on the north-facing side of American Fork Canyon near Timpanogos Cave. With increasing elevation, aspen predominates, followed by alpine meadow habitats. By analogy with the habitat of T. packardi, surface populations could be present but if so, remain unsampled. The harvestman species Hesperonemastoma packardi (Verhoeff 1914) was originally described from a cave in Salt Lake Co., Utah, but unpublished records in AMNH establish that it is abundant in Wasatch Range canyons in Salt Lake and Utah Cos (Shear 2010b). However, there are no samples in AMNH or elsewhere of surface populations of T. timpanogos, which one would expect if such populations actually exist in and around a national monument. Thus the ecological status of this species remains unclear. Vegetation in the immediate vicinity of Madhouse and Professor Buss caves near Provo appears to be treeless scrub, but dense, moist forest occurs at higher elevations, and the Wasatch Mountains receive abundant winter snowfall. Madhouse Cave is the type locality for the troglomorphic travunioid harvestman Cyptobunus ungulatus madhousensis Briggs (Briggs 1971; Dekarabetian et al. 2010). The higher, forested elevations of the Wasatch Mountains should be searched for Taracus.
Specimens from Professor Buss Cave are somewhat darker than the type series, have some spotting on the legs and genital operculum, and males have a sclerotized strip across the first abdominal segment at the base of the genital operculum.
description: Published as part of Shear, William A. & Warfel, Joseph G., 2016, The harvestman genus Taracus Simon 1879, and the new genus Oskoron (Opiliones: Ischyropsalidoidea: Taracidae), pp. 1-71 in Zootaxa 4180 (1) on pages 47-50, DOI: 10.11646/zootaxa.4180.1.1, http://zenodo.org/record/164222