Taracus pallipes Banks 1894
Creators: name: Shear, William A.
name: Warfel, Joseph G.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Taracidae
Taracus
Taracus pallipes

description: Taracus pallipes Banks 1894
Figs. 16–31, Maps 2, 3
Taracus pallipes Banks 1894a:161. Banks 1901:676 (Fig. 5), 678 (in key). Banks 1904:362. Cokendolpher & Lee 1993:7 (list). Schönhofer 2013:21 (list).
Types. The holotype of Taracus pallipes is in the collection of the Museum of Comparative Zoology (MCZ), Harvard University, Cambridge, MA (examined 1971, 2012). The specimen is an adult female, and was collected in Olympia, Thurston Co., Washington (No further data, but Banks stated he had the specimen from T. Kincaid of Olympia. This is Banks’ original label, therefore Roewer [1914] was correct in giving the type locality as Olympia, not in error as stated by Schönhofer [2013]). In addition to the specimen, missing its fourth legs, four extra legs of another Taracus specimen are also in the vial. These may have come from the male Banks (1894b) said was in the collection, but which could not be located in 1971 when WAS took notes on the specimen, and which remains missing.
Diagnosis. Taracus pallipes is potentially or actually sympatric/syntopic with five of the species described below: Taracus marchingtoni, T. silvestrii, T. ubicki, Oskoron brevichelis and O. crawfordi, but is considerably larger than all but silvestrii. The long, thin chelicerae and highly reduced eyes of T. marchingtoni serve to distinguish it from T. pallipes. In Oskoron brevichelis, the chelicerae are either shorter than or about as long as the body, while in O. crawfordi they are about one-fourth longer than the body. T. pallipes typically has chelicerae up to 50% longer than the body length. The closest resemblance is between T. pallipes and T. silvestrii, but pallipes has much shorter legs, palpi and chelicerae. Taracus pallipes males from the region just east of Puget Sound are dimorphic; the less common form has massive second cheliceral segments studded with rows of cylindrical projections (Figs. 30, 31) and cannot be mistaken for any other sympatric Taracus species. See the discussion below under the description of T. ubicki for possible confusion between that species and pallipes. All known males of T. audisioae have the massive chelicerae, but this species occurs in the southern Sierra Nevada in California, far to the south.
Description. Male from near Randle, Lewis Co., Washington: Total length, 5.16 mm. Carapace dark brown to near black, with paired lighter areas behind ocularium, margins well-defined; strongly domed; midline sulcus extends from anterior margin to ocularium, continues partially over ocularium as faint line. Ocularium as wide as long, rounded, with five or six stout, curved setae on low tubercles above each eye; eyes large, black, ringed with black pigment. Metapelitidium unsclerotized, long, without setae; sensory cone small, white, tipped brown, acute (Fig.), distinct from posterior margin of carapace. Abdomen soft, white or pale tan base color (live specimens ofen have unsclerotized membranes bright pink [Rod Crawford, pers. comm.. 2015]), heavily shaded with purplish gray pigment in band behind carapace (metapeltidium), also in central area; with scutum parvum but lateral margins of scutum irregular; scutum set with rows of small black setae on prominent, more heavily sclerotized plaques, these rows distinct anteriorly, becoming irregular posterior on scutum; first two areas with central pair or trio of plaques coalesced into small sclerites, thereafter six large plaques in distinct rows, with many smaller ones scattered between (Figs. 22, 23). Ventrally, coxae pale yellowish tan, unspotted. Palpal coxae with numerous stout setae on distinct tubercles, leg coxae with strong, black setae, not on tubercles. No indication of thoracic sternum. Genital operculum apically rounded, heavily setose, pale yellowish tan, unspotted, with sclerotized distal lip. Abdominal sternites sclerotized along anterior margin, posteriorly with scattered black setae.
Chelicerae (Figs. 26, 27) 10.08 mm long, black. Basal article 4.40 mm long, 0.52 mm wide (L/W = 8.46); second article 5.68 mm long, 0.72 mm wide (L/W = 7.89). Basal article with prominent mediobasal knob, only with numerous seta-tipped tubercles in basal third, ventral row of tubercles extends two-thirds length of article, fewer tubercles dorsally; second article with more prominent, rounded seta-tipped tubercles ranged in about four irregular rows, tubercles more widely spaced and smaller distally. Fixed and movable fingers with paired, articulating triangular teeth, narrow, acute tips of fingers cross each other at rest. See Notes below for discussion of male dimorphism in chelicerae.
Palpi (Fig. 17) brown, shaded darker distally, total length 10.08 mm, relatively slender; trochanter with five or more prominent, seta-tipped tubercles, femur with regularly spaced slender setae, not set on tubercles. Patella not swollen. Lengths of articles as given in Table 3. Legs long, thin; yellowish tan, unspotted. Autospasy suture of femur distinct on all legs. Tibiae without false articulations, metatarsal false articulations 7, 15, 0, (3?) respectively (false articulations, if present on fourth leg, poorly indicated). Total lengths in mm of legs 1–4: 12.66, 20.78, 12.06, 17.40. Measurements of leg articles given in Table 3.
Penis (Figs. 18, 19) 2.06 mm long, 0.32 mm wide (L/W = 6.44), sides of shaft straight; glans slightly swollen, abruptly tapering to harpoon-like aculeus subtended by shorter, acute process; distal glans with subtending crown of setae incomplete ventrally; densely setose dorsally; shaft with many scattered small setae distally. Ventrally, glans with distinct triangular ventral plate.
Female from near MacKenzie Bridge: Total length, 6.12 mm. Carapace dark brown to black, paired lighter areas behind ocularium. Metapeltidium not sclerotized; two to four small setae on either side of sensory cone. Abdomen pale tan, heavily shaded purplish brown, with prominent raised, sclerotized plaques bearing single or multiple setae; plaques of first two or three abdominal areas coalesced in midline, on more posterior areas two larger plaques on either side of midline, between these, irregularly arranged smaller plaques (Figs. 20, 21). Genital operculum with heavily sclerotized lip, sclerotized ventral plate.
Chelicerae (Figs. 24, 25) stouter than in male, 9.67 mm long, basal article 4.23 mm long, 0.48 mm wide (L/W = 8.8); second article 5.44 mm long, 0.68 mm wide (L/W = 8.0). Total length of palpus, 9.75 mm; patella of palpus not swollen, femoral setae not on tubercles. Total lengths in mm of legs 1–4: 12.17, 18.70, 11.54, 16.40; lengths of leg and palpal articles as given in Table 4. Second leg metatarsus with 18 false articulations, none in other legs. Legs sometimes heavily spotted. Ovipositor typical. Other characters as in male.
Distribution. Samples marked (*) contained crassichelis-form males (see Notes, below). OREGON: Benton Co.: Clemens Park, Seeley Creek Road, 0.3 mi SR34, North Fork of Alsea River, N44.24.55, W123.34.07, 400’asl, 4 December 2005, W. Leonard, C. Richart, Ƌ (WAS); Junction of Rds. S-709/S-70, 39 mi E Estacada, 2000’ asl, 3 October 1971, E. M. Benedict, Ƌ (WAS); Colton, December 1934, E. S. Ross, Ƌ (CAS). Coos Co.: 9 miles northeast of Bandon, 29 November 1971, C. Mason, Ƌ (AMNH). Douglas Co.: 5 mi E, 4 mi N Tiller, South Umpqua River, 11 November 1972, E. M. Benedict, Ƌ (WAS); 12 mi E, 9 mi N Tiller, South Umpqua Falls Campground, 11 November 1972, E. M. Benedict, Ƌ (WAS); 4 mi E Camas Valley, 27 November 1966, C. W. O’Brian, ♀ Ƌ (CAS). Jackson Co.: French Gulch, Forest Service Road 420, 3 mi N Copper, 1900’ asl, 13 November 1971, E. M. Benedict, Ƌ (WAS).; Pinehurst, 9 September 1935, W. Ivie, R. V. Chamberlin, ♀♀ (AMNH) Lane Co., Alder Springs Campground, McKenzie Pass Highway 242, 3400’ asl, 16 October 1971, E. M. Benedict, Ƌ (WAS). Lincoln Co:, 0.6 mi NW Elk City, Yaquina River, 200’ asl, 20 December 1971, E. M. Benedict, Ƌ (WAS). Tillamook Co.: 23 mi E US 101 on OR22 at Hebo, Siuslaw National Forest, N45.12.18, W123.50.30, 250’ asl, 10 December 2005, W. Leonard, C. Richart, Ƌ ♀ (WAS). WASHINGTON: Clallam Co.: Lake Aldwell, shore west of dam, 48.0949°N, 123.5592°W, 220’ asl, 16 January 2008, R. Crawford, ♀ (UWBM); south side of Cape Alava, 48.159°N, 124.728°W, 10’ asl, 17 July 1984, R. Crawford, juv. (UWBM); Olympic National Park, 3.1 mi S Port Angeles, road to Hurricane Ridge, N48.04.406, W123.25.951, 1100’asl, 10 November 2003, W. Leonard, Ƌ (WAS). Clark Co.: Vancuver, northwest of town, 45°40’N, 122°45N, 24 September 1964, J. and W. Ivie, ♀♀ (AMNH). Cowlitz Co.: Cougar Camp, 46.053°N, 122.286°N, 500’ asl, 24 August 1982, R. Crawford, juv (UWBM); Delameter Road, 10.1 mi SW Castle Rock, N46.13.052, W123.01.069, 400’asl, 22 November 2003, W. Leonard, C. Richart, ♀ (WAS); Germany Creek, 5.5 mi N SR14, N46.15.65, W123.08.06, 350’asl, 8 December 2003, W. Leonard, ♀♀ (WAS); Germany Creek, 5.3 mi N SR14, 11 November 2004, W. Leonard, ♀ (WAS). Grays Harbor Co.: Blue Slough Road, 0.7 m W US 101, N46.56.094, W123.42.145, 29 November 2004, W. Leonard, ♀ (WAS). Jefferson Co.: Camp Collins, 47.683°N, 123.018°W, 275’ asl, 15 October 1977, R. Crawford, ♀ (UWBM); Dosewallips River, 7 mi W US 101, N47.45.961m W123,01.213, W. Leonard, 10 November 2003 (WAS). King Co.: *Woodinville (vicinity), 47.75– 47.77°N, 122.12–122°W, 30–200’ asl, 25 November 1975, P. Huffman, ƋƋ (UWBM) *Matthews Beach, 47.696°N, 122.227°W, 75’ asl, 9–16 April (?) 1991, D. Bivins, Ƌ ♀ (UWBM); southeast of Black Diamond, 47.291°N, 121.985°W, 720’ asl, 1 November 2006, R. Crawford, ♀ (UWBM); Bridle Trails State Park, 47.653°N, 122,173°W, 500’ asl, 15 March 1985, R. Crawford, ♀ (UWBM); Tokul Creek, 47.556°N, 121.817°W, 520’ asl, 21 November 1979, R. Crawford, Ƌ (UWBM); Discovery Park, Seattle, 47.664°N, 122.410°W, 150’ asl, 22 October 1977, R. Crawford, ♀ (UWBM); 14 March 1981, R. Crawford, ƋƋ ♀♀ (UWBM); Seattle, 17.5–6°N, 122.3°W, 15 November 1933, H. Exline, ♀; *Kincaid Ravine, University of Washington campus, 47.661°N, 122.301°W, 75’ asl, 20 January 1977, D. Mann, Ƌ (UWBM); Denny Creek, 47.432°N, 121.452°W, 3500’ asl, 20 December 1976, D. Mann, Ƌ (UWBM); West Fork Miller River, 47.661°N, 121.407°W, 1740–1850’ asl, 28 November 2005, R. Crawford, ♀♀ (UWBM); Snoqualmie River, 0.5 mi N I–90 exit 38, N47.25.977, W121.37.869, 300’asl, 21 January 2005, W. Leonard, ♀ Ƌ; Skunk Creek, four overwinter pitfalls, 47.571°N, 121.863°W, 520’ asl, 21 November 1979 – 13 April 1980, R. Crawford, ƋƋ ♀♀ (UWBM); southwest base of Tiger Mountain, four overwinter pitfalls, 47.475°N, 121.987°W, 900; asl, 14 November 1996 – 13 April 1997, J. Bergdahl, Ƌ ♀♀ (UWBM); *south slope of Tiger Mountain, six overwinter pitfalls, 47.471°N, 121.945°W, 1940’ asl, 13 October 1996 – 5 April 1997, J. Bergdahl, mmff (UWBM); four overwinter pitfalls, 47.472°N, 121.936°W, 1650’ asl, J. Bergdahl, ff; *west side of Tiger Mountain, five overwinter pitfalls, 47.490°N, 121.955°W, 2530’ asl, 13 October 1996 – 5 April 1997, J. Bergdahl, ƋƋ ♀♀ (UWBM); seven overwinter pitfalls, 47.488°N, 121.964°W, 2280’ asl, 13 October 1996 – 5 April 1997, J. Bergdahl, ƋƋ ♀♀; northwest slope of Tiger Mountain, 5 overwinter pitfalls, 47.499N, 121.959°W, 2080’ asl, 13 October 1996 – 5 April 1997, J. Bergdahl, ƋƋ; west of Deep Creek, 6 overwinter pitalls, 47.468°N, 121.934°W, 1450’ asl, 17 November 1996 – 20 April 1997, J. Bergdahl, Ƌ ♀♀ (UWBM); *Holder Creek Valley, 12 overwinter pitfalls, 47.467°N, 121.954°W, 1375–1400 ’ asl, 12 December 1996 – 20 April 1997, J. Bergdahl, ƋƋ ♀♀ (UWBM); *12 overwinter pitfalls, 47.469°N, 121.954°W, 1460’ asl, 12 December 1996 – 29 April 1997, J. Bergdahl, Ƌ ♀♀ (UWBM); Asahel Curtis Trail, 55 forest pitfalls, 47.391°N, 121.465°W, 2040–2240’ asl, 13 September 1995 – 21 April 1996, J. Bergdahl, Ƌ ♀♀ (UWBM). Kitsap Co.: *northwest of Suquamish, 47.744°N, 122.566°W, 130’ asl, 7 January 2008, D. Chernick, Ƌ (UWBM); south of Rude Road, 47.748°N, 122.674°W, 380’ asl, 8 July 2010, R. Crawford, juv (UWBM). Lewis Co.: 8 mi S Randle, 6 December 2003, W. Leonard, C. Richart, Ƌ; SR 508 at Bremer, N46.35.30, W122.25.55, 750’asl, 6 December 2003, W. Leonard, C. Richart, Ƌ ♀ (WAS); FR#25 8.5 mi S Randall, Gifford Pinchot National Forest, N46.26.456, W121.59.796, 1050’asl, 6 December 2006, W. Leonard, C. Richart, ♀ (WAS); East of Lone Tree Mountain, 46.48N, 121.80°W, 3680’ asl, 5–23 August 1983, K. Johnson, ♀ (UWBM). Mason Co.: Mt. Rose trailhead at Lake Cushman, Olympic National Forest, N47.29.733, W123.15.933, 805’ asl, 7 November 2001, W. Leonard (WAS). Pacific Co.: 1.1 m S Rt. 6 on Trap Creek Road, N46.32.591, W123.36.908, 19 November 2005, W. Leonard, C. Richart, f; Ellsworth Creek Preserve, N46.23.887, W123.53.391, 50’asl, 23 November 2003, W. Leonard et al., ♀ (WAS); Pierce Co.: below Tahoma Vista, 46.794N, 121.880°W, 3200’ asl, 12 December 1996, J. Gosnell, Ƌ IUWBM); *Little Mashel River, 46.853°N, 122.276°W, 770’ asl, 13 November 1976, R. Crawford & C. Stoner, ♀ (UWBM); east of Edna Creek,, 46.831°N, 122.364°W, 760–820’, 8 December 1991, G. Matos, m (UWBM); Virginia Peak, southeast slope, in stomach of Ambystoma gracile, 46.940°N, 121.902°N, 4100’ asl, 21 October 1985, D. Converse, ♀ (UWBM); Puyallup, 47.15–25°N, 122.25–35°, 5 October 1931, W. Baker, ♀ (UWBM); west of Puyallup, 47.184°N, 122.349°W, 360’ asl, 3 February 2003, J. Austin, ♀ (UWBM); near Twenty-Five-Mile Creek, 46.932°N, 122.164°W, 1680’ asl, 8 January 1981, R. Nelson, Ƌ ♀ (UWBM); Eagle Peak Trail, from stomach of Ambystoma gracile, 46.748°N, 121.804°W, 2960’ asl, 1 November 1985, D. L. Converse, Ƌ; Tahoma Creek, Mount Ranier National Park, 46.741°N, 121.894°W, 2160’ asl, D. Converse, Ƌ; Tipsoo Lake, Mount Ranier National Park, 46°52’N, 121°31’W, 5 July 1938, J. and W. Ivie, Ƌ (AMNH). Skagit Co.: Rubbish Cave, near entrance in twilight zone, 48.552°N, 121.720°W, 1200’ asl, 2 October 1973, R. Crawford, decomposed juv (UWBM); north side of Grandy Lake, 48.566°N, 121.804°W, 850’ asl, 18 October 1984, R. Crawford, Ƌ (UWBM); Rockport State Park, 11 pitfalls in old growth forest, 48.490°N, 121.613°W, 540’ asl, 19 September–21 November 1992, J. Bergdahl, Ƌ ♀♀ (UWBM); 47 pitfalls in old growth forest, 48.490–493°N, 121.609–613°W, 540–700’ asl, 2 September–10 January 1991, J. Bergdahl, ƋƋ ♀♀ (UWBM); Skamania Co.: Cook-Underwood Road, 1.4 mi NE Cook, N45.43.434, W121.38.859, 30 November 2003, W. Leonard, ♀ (WAS). Snohomish Co: Young’s Creek, 47.808°N, 121.829°W, 580’ asl, 28 November 1976, B. Vogel, ♀ (UWBM); Skykomish River, 47.837°N, 121.657°W, 265’ asl, 25 October 1980, R. Nelson, ♀ (UWBM); Mother Nature’s Window Park, 48.083°N, 122.153°W, 80’ asl, 11 October 1997, R. Crawford, ♀ (UWBM); east of Boulder River, 48.279°N, 121,778°W, 350’ asl, 8 October 2009, ♀ (UWBM); Deer Creek Road, 48.085°N, 121.551°W, 1580’ asl, 30 November 2011, R. Crawford, Ƌ (UWBM); east of Mission Beach, 48.050°N, 122.261°W, 130’ asl, 21 November 2007, R. Crawford, ♀ (UWBM); Lynndale Park, 47.828°N, 122.332°W, 380’ asl, 29 December 2006, R. Crawford, ♀; Thurston Co.: Centralia Canal, 46.940°N, 122.567°W, 320’ asl, 23 October 2007, R. Crawford, Ƌ ♀ (UWBM); Hospital Creek, 5mi S, 3 mi E Vail, 12 October 2003, W. Leonard, Ƌ (WAS); Hospital Creek above confluence with Skookumchuck River, N46.46.396. W122.35.133, 15 December 2003, W. Leonard, K. McAllister, ♀ (WAS); Allison Springs, Olympia, N47.2.73, W122.48.93, 50’ asl, 4 December 2005, W. Leonard, C. Richart, ♀ (WAS). Whahkiakum Co.: Tributary of McDonald Creek, Skamokawa Watershed, N46.20.5785, W123.05.62, C. Richart, Ƌ (WAS). Whatcom Co.: * Sehome Hill, 48.73°N, 122.47°W, 300–600’ asl, October 1978, C. Senger, Ƌ (UWBM).
Banks (1904) gave a record from Shasta Co., California, but the specimen or specimens could not be located; they are not in the MCZ with other Banks material. It is likely they were in the California Academy of Sciences collections, and were destroyed in the 1906 earthquake. Given the presently known distribution of pallipes, it is possible (Pinehurst in Jackson Co., Oregon, is only about 10 miles from the California border) that it occurs in northern California, but less likely that it would be found as far east as Shasta Co; Banks’ specimens may have been Oskoron spinosus, which has been recorded from Shasta Co, or T. ubicki n. sp., which is somewhat similar to T. pallipes.
In summary, T. pallipes is widely distributed in the Cascade and Coast Ranges from east of Puget Sound to southern Oregon. It would appear to be the most widespread and common species of Taracus in the Pacific Northwest, with other species often sympatric but with much narrower distributions. However, we did not attempt to analyze geographic variation in morphology, nor do we have any genetic data. The possibility remains that pallipes could be a complex of closely related species, as appears to be the case with Sabacon occidentalis (Schönhofer et al. 2012). In particular, the distribution gap in west central Oregon may suggest isolation of northern and southern populations and possible speciation. According to Rod Crawford (pers. com. 2015), while pallipes was common in the Tiger Mountain pitfall samples collected by Bergdahl (see above), a significantly greater collecting effort on the San Juan Islands of northwest Washington produced neither pallipes nor carmanah (described below), despite the finding of most of the other soil and litter-dwelling harvestmen of the region. This suggests that the dispersal ability of at least Taracus pallipes may be limited.
Notes. Males are smaller, more slender, and with relatively longer legs. The chelicerae show noticeable sexual dimorphism with those of the males longer and more slender, except for the ‘crassichelis’ form described below. Males show scutum parvum but this is in the form of only slightly more sclerotization and heavier pigmentation in older, darker animals. The sclerotized plaques bearing small setae remain prominent in the scutum. Males also have (rather poorly indicated) false articulations in the first and fourth metatarsi; these are absent in most females, but some poorly defined false articulations may sometimes be seen in legs one and four of females. The legs of most specimens are unspotted or have only a few basal spots, but some are heavily dappled with purplish brown. The degree of sclerotization of the abdominal sternites, especially in females, is variable and may depend on age since maturity, ranging from little or no sclerotization to well-developed brown plaques extending across the width of the venter. Similarly, age seems likely to increase the overall cuticular sclerotization and pigmentation of males. Females also vary in size due to expansion of the abdomen by eggs; the largest measured was 8.20 mm long. Not enough specimens were measured to confirm, but our impression is that southern Oregon males are smaller in general than those from further north.
Surveying collections early in this study, we set aside specimens that occurred syntopically with typical males of pallipes as representatives of a striking new species with massive, spiny chelicerae and heavier overall sclerotization. However, as more specimens were examined, particularly the large collection of the Burke Memorial Museum, facts emerged that militated against considering these males as representing a species distinct from pallipes. Aside from the enormous chelicerae and the more extensive sclerotization (Figs. 28, 29) other characters were within the range of variation of pallipes. With few exceptions (solitary specimens) the form was collected only in company with other specimens referable to pallipes. And finally, despite the examination of 24 UWBM samples each containing more than three individuals of pallipes, no corresponding females were found. Our conclusion is that, as with a number of other harvestman species (see Taylor 2004), Taracus pallipes males are dimorphic. For ease of reference, we call the form with massive chelicerae ‘crassichelis,’ an informal designation since the ICZN does not recognize infrasubspecific names published after 1960 (ICZN Art. 45.5). The crassichelis form is quite distinct in the massive second cheliceromere and hypertrophied teeth on the cheliceral fingers, as well as an interesting depressed area on the lateral surface which is free of seta-tipped tubercles (Figs. 30, 31). It stands distinct from the variation in size found in normal males, the larger of which have correspondingly (and perhaps allometrically) larger chelicerae. The form seems to occur only around Puget Sound, mostly in King and Thurston Cos., Washington (Map 3; with a single isolated record considerably to the north, from Whatcom Co.), and is much less common than the normal form. In the distribution section above, samples that included at least one crassichelis male are marked with an asterisk (*). Determining the significance of this dimorphism will require studies of live animals of both forms; the chelicerae may be used in male-male conflicts over mates or used in some way to subdue reluctant females.
Alternatively, the form may actually be a syntopic undescribed species in which the females are not notably distinct from those of T. pallipes. Genetic data and morphometrics will resolve this question.
A female from Hoquiam, Grays Harbor Co., Washington (MCZ), collected in 1904 (probably by Nathan Banks) is definitely not pallipes, having an altogether different pattern of abdominal sclerotization, more gracile, smoother chelicerae and much longer legs. It is not a member of Oskoron, nor is it referable to T. carmanah. Further collecting is needed to clarify the identity of this specimen. A number of other specimens (UWBM) centered around Skamania Co. have similar differences, but more collecting is needed.
The numerous samples of this species allow some conclusions to be drawn about its ecology and development. Specimens were taken at elevations from sea level to about 2500’, with a single record at 3680’ asl in Lewis Co., Washington. Notes on labels indicate that specimens were collected in association with both broadleaf and conifer litter, from moss and from beneath rocks and logs. As far as can be determined, all samples are from forested areas and many were collected near streams. A large series of pitfall traps left over winter on Tiger Mountain, King Co., Washington, accumulated substantial numbers of both males and females, and crassichelis males were included in many of them, as were specimens of Oskoron crawfordi. The earliest date mature individuals were collected was in late October (but a single female was taken at 3680’ asl in Lewis Co., Washington, in August; the early maturation may have been due to the high elevation), and by April at the latest mature specimens disappear from the records, indicating that T. pallipes is a winter-maturing and winter-active species; at least one specimen was collected walking over snow. Summers can be warm and dry in the area, while winters are moist and mild. Two specimens were taken from the stomachs of Ambystoma salamanders.
While adults have striking black chelicerae, juveniles are more uniform in coloration, with the chelicerae white or pale yellow, as is the dorsum of the body. It appears the spininess of the chelicerae develops quickly over the penultimate and last instars, those of younger individuals being setose but generally lacking pronounced spines. There is variation in pigmentation with darker individuals being collected later in the winter and in early spring, presumably because sclerotization and the deposition of waste in the cuticle goes on with age. There appears to be no differential survival of males and females and both sexes mature at about the same time.
MAP 1. Parts of Colorado, New Mexico and Wyoming, with ecoregions indicated. Green area, Colorado Rocky Mountain Forest Ecoregion. Filled circles, localities for Taracus packardi Simon.
MAP 2. Parts of the states of Washington and Oregon, and the province of British Columbia. Filled circles, localities for Taracus pallipes Banks (includes localities for ‘crassichelis’ form); filled triangle, type locality of T. carmanah, n. sp.
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 20-27, DOI: 10.11646/zootaxa.4180.1.1, http://zenodo.org/record/164222