Taracus packardi Simon 1879
Creators: name: Shear, William A.
name: Warfel, Joseph G.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Taracidae
Taracus
Taracus packardi

description: Taracus packardi Simon 1879
Figs. 4–15, Map 1
Taracus packardi Simon 1879:LXX. Cokendolpher & Lee, 1993:7 (list). Schönhofer 2013:21 (list).
Taracus nigripes Goodnight & Goodnight 1943:647. Cokendolpher & Lee, 1993:7 (list). New synonymy.
Types. The holotype of Taracus packardi is conserved in the Muséum national d’Histoire naturelle in Paris (examined 2012). The only locality given is “ Colorado. ” It is an early instar juvenile, so tells us little about its identity in comparison to T. nigripes. The holotype of Taracus nigripes Goodnight & Goodnight is a mature female from Wolf Creek Pass, 10,000 ft asl, Mineral Co., Colorado, in the San Juan Mountains (AMNH; examined 2012). We have seen large collections of Taracus specimens from numerous localities in Colorado, including mature specimens of both sexes and a range of juveniles. Some of these juveniles, presumably the same instar and at least similar size, had body lengths and cheliceral measurements nearly identical to the type specimen of T. packardi, and the lengths of the leg femora and palpi were likewise very close. Since there appears to be but one species of Taracus in Colorado (though sampling has not been exhaustive), the best course seems to be to use the older name and relegate nigripes to synonymy, though its type comes from a defined locality, to which the type locality of packardi is hereby restricted.
Diagnosis. Taracus gertschi and T. timpanogos also occur in the Rocky Mountains, but well to the north (gertschi) or west (timpanogos) of the distribution of T. packardi, and can be distinguished from that species by their much longer chelicerae and legs. Taracus packardi is quite short-legged, with the first femur about half the length of the body in males.
Description. Male from near Divide, Teller Co., Colorado: Total length, 4.43 mm. Carapace dark chestnut brown to black, lacking “hash marks” (diagonal dark lines lateral to the ocularium), all carapace edges welldefined, anterior and posterior margined; midline sulcus extends from anterior margin to ocularium. Ocularium about as long as wide, rounded, with few small setae above eyes; eyes small, black, ringed with black pigment. Metapelitidium lightly sclerotized but clearly distinct from carapace, without setae; sensory cone white, acute, arising from soft cuticle between carapace and metapeltidium. Abdomen unsclerotized, or weakly so, irregularly set with small black setae slightly raised on bumps, but these not as sclerotized plaques (Figs. 10, 11). Ventrally, coxae pale yellowish, unspotted. Palpal and first leg coxae and trochanters with numerous stout setae on strong tubercles, other leg coxae with strong, black setae, not on tubercles. No indication of thoracic sternum. Genital operculum apically rounded, heavily setose, pale yellowish tan, unspotted. Abdominal sternites not sclerotized, with scattered black setae.
Chelicerae (Figs. 14, 15) 6.05 mm long, black. Basal article 2.80 mm long, 0.33 mm wide (L/W = 8.48); second article 3.25 mm long, 0.45 mm wide (L/W = 7.22). Basal article with prominent mediobasal knob, with long, seta-tipped tubercles relatively few in number, in mesal view only three or four of these nearly equally spaced; second article with more numerous, but more rounded, much lower seta-tipped tubercles ranged in obscure rows, tubercles more densely spaced over anterior face of article but diminishing before base of fixed finger. Fixed and movable fingers with paired, articulating triangular teeth, narrow, acute tips of fingers cross each other at rest.
Palpi (Fig. 5) dark brown, shaded darker distally, tibia, tarsus black; total length 4.77 mm, rather stout; trochanter with six or seven prominent low, seta-tipped tubercles, femur with regularly spaced slender setae, not set on tubercles. Patella not swollen. Lengths of articles as given in Table 1. Legs short relative to body length; dark brown to black, darker distally. Autospasy sutures of femora distinct on all legs. Tibiae without false articulations, metatarsal false articulations 7, 11, 8, 9 respectively. Total lengths in mm of legs 1–4: 7.39 11.24, 7.41, 9.85. Measurements of leg articles given in Table 1.
Penis (Figs. 6, 7) 1.72 mm long, 0.13 mm wide (L/W = 13.46), sides of shaft tapering evenly to aculeus; glans only slightly swollen, distal portion of glans with array of small, short setae; shaft without setae.
Female from near Divide, Teller Co., Colorado: Total length, 4.00 mm. Carapace dark brown to black, lacking “hash marks.“ Metapeltidium unsclerotized, nearly without setae (two small setae on either side of sensory cone); sensory cone in slight embayment in posterior margin of carapace. Abdomen white, unsclerotized, with two or three vaguely indicated sclerotized patches along midline and few scattered, very small, black setae not set on cuticular plaques (Figs. 8, 9).
Chelicerae (Figs. 12, 13) black, 4.85 mm long; cheliceral basal article 2.10 mm long, 0.30 mm wide (L/W = 7.0); second article 2.75 mm long, 0.45 mm wide (L/W = 6.1). Total length of palpus, 4.97 mm; trochanter with four or five seta-tipped tubercles, femoral setae not on tubercles. Total lengths in mm of legs 1–4: 6.40, 9.70, 6.69, 9.09; lengths of leg and palpal articles as given in Table 2. Metatarsal false articulations 5, 11, 5, 7 respectively. Ovipositor typical. Other characters as in male.
Distribution. COLORADO: Boulder Co., Boulder, no date, N. Banks, Ƌ (MCZ). Chaffee Co., Sawatch Mtns., Monarch Pass, 10,800 ft asl, 5 July 1952, H. Levi, juv. (MCZ); Garfield, 9000 ft asl, 7 July 1952, H. Levi, ♀ (MCZ). Clear Creek Co., Mt. Evans, 11,500 ft asl, 19 July–1August 1967, R. Schmoller, mm (MCZ); Idaho Springs, 24 August 1935, W. Ivie, ♀ (AMNH); Berthoud Pass, 24 August 1935, W. Ivie, ♀♀ (AMNH). Dolores Co.: near Fish Creek, 27 mi northeast of Dolores, 8200’ asl, 24 July 1976, L. & N. Herman, Ƌ, ♀ (AMNH). Gunnison Co., Elk Mtns., Gothic Natural Area, 2900 m asl, spruce-fir forest, 27 July 1969, H., L., and F. Levi, ƋƋ ♀♀ (MCZ), 25 July 1954, H. Levi, Ƌ (MCZ), 12–13 July 1956, H., L. Levi, ƋƋ ♀♀ (MCZ); Gothic, 9500 ft asl, August 1957, H., L. Levi, juv (MCZ), 4 June 1959, H. Levi, ♀ (MCZ); Copper Lake, 3500m asl, 26 July 1969, H. and F. Levi, ♀ (MCZ); East River Valley, 10,000 ft asl, 11 July 1954, H. Levi, Ƌ (MCZ); Rustler’s Gulch, 3000– 3300m asl, 22 July 1969, H., L. and F. Levi, Ƌ (MCZ); Copper Creek Valley, 10,500 ft asl, 11 July 1954, H. Levi, juv. (MCZ); below Queen Basin, 10,300–11,000 ft asl, 7 August 1956, H. and L. Levi, juvs (MCZ), 21 July 1969, H., L. Levi, mm ff (MCZ); Damphier Creek near Fossil Ridge, north of Ohio, 3500–3800m asl, 28 July 1960, H. Levi, A. Kostinsky, ♀ (MCZ); Schofield Pass, 10,500 ft asl, 11 July 1954, H. Levi, Ƌ (MCZ); north slope of Ohio Peak, 10,500–11,700 ft asl, 10 August 1957, H., L. Levi, Ƌ (MCZ); 2 mi north of Gothic, 3500m asl, 14 June 1960, H. Levi, Ƌ (MCZ); Gothic, near Crested Butte, 12 July 1956, W. J. Gertsch, V. Roth, mm ff (AMNH). Hinsdale Co., San Juan Mtns., Slumgullion Pass, 3700m asl, 5 July 1959, H., L. Levi, juvs. (MCZ), 2 August 1957, H., L. Levi, Ƌ ♀ (MCZ). Jackson Co.: Cameron Pass, 10,000’ asl, 8 August 1941, S. Mulaik, ♀ (AMNH). Lake Co., Sawatch Mtns., Independence Pass, 3700m asl, 24 July 1961, H., L. Levi, Ƌ (MCZ). Larimer Co.: Rocky Mountain National Park, Trail Ridge Road. 11,500’ asl, at tree-line, 5 August 1966, R. Schmoller, mm (CAS); Cameron Pass, 10,000’ asl, 8 August 1941, S. Mulaik, jv (AMNH). Mesa Co.: Kannah Creek, 20 mi north of Cedaredge, 28 July 1976, L. & N. Herman, Ƌ (AMNH). Teller Co., 8 mi S of Divide on Cripple Creek Road, 9500’ asl, 26 July 1977, S. B. Peck, ƋƋ ♀♀ (WAS); Glen Cove, Pike’s Peak, 3500m asl, 20 June 1969, H. and L. Levi, ♀, juvs (MCZ). NEW MEXICO: San Miguel Co.: Spirit Lake Trail near Cowles, no date, C. C. Hoff, Ƌ (AMNH). Santa Fe Co.: 4 mi SE Glorieta Baldy Lookout, 8000’ asl, 14 August 1968, T. Briggs, K. Hom, D. Owyang, ƋƋ (CAS); Lake Peak, no date, C. C. Hoff, ♀ (AMNH). Taos Co.: northwest side of Wheeler Peak, no date, C. C. Hoff, ♀ (AMNH). WYOMING: Albany Co.: Centennial, 9500’ asl, 17 August 1939, R. Voris, ♀ (AMNH).
Banks (1901) likewise reported this species from New Mexico, but his specimens could not be located. They may have been in the California Academy collection and destroyed in the 1906 earthquake and fire.
Notes. According to Goodnight & Goodnight (1943), T. nigripes differs from T. packardi in having darker legs, but the Goodnights did not say that they examined the holotype of the latter species, which is an early instar, long-preserved, and would be expected to have pale coloration. There is nothing in Simon’s original description of packardi aside from this that would allow the two to be distinguished.
Some specimens from Gunnison Co. have noticably more slender chelicerae, but these are mixed in with more typical ones, so probably represent variation or perhaps a less distinct form of male dimorphism as seen in T. pallipes (see below). Also, a few specimens, both males and females, show indications of scutum laminatum, with small, faint, midline sclerotized patches. These are likely older individuals. The two males from New Mexico are lighter in color, lacking the dark legs seen in Colorado specimens; they show definite scutum laminatum and small sclerotized plaques on the abdomen, but otherwise conform to Colorado packardi. Additional specimens from New Mexico should be examined if and when they become available because the localities there are some distance from the central and western Colorado records. They may not be conspecific with Colorado packardi. The single Wyoming female is smaller and paler than Colorado packardi, but it seems best presently to include it under this species. For the benefit of future research, an altitude of 9500’ is not reached until some 10 miles east of Centennial on Rt. 130, in the Snowy Range of the Medicine Bow Mountains. WAS collected there several days in August, 1972, but did not find any Taracus.
Noting the morphological similarity to Ischyropsalis hellwigi hellwigi, H. W. Levi tried to get captive Taracus packardi to feed on snails local to Crested Butte, Colorado, but they would not do so; the same captives readily devoured local insects (H. W. Levi, pers. comm., 1971). Samples of T. packardi tend to contain numerous individuals, indicating that the species is quite common and abundant in the right habitat, which from label notes would seem to be spruce-fir forest, aspen groves and alpine meadows above 7000’ up to 11,000’ elevation. Thus T. packardi is ecologically similar to T. gertschi in being a high-altitude, summer-active species. Given the abundance of T. packardi in the region of the Rocky Mountain Biological Laboratory in Gothic, Colorado, this would be an ideal species for extended ecological and behavioral study. In a broader perspective, it would appear from present records that T. packardi is entirely endemic to the Colorado Rocky Mountain Forest Ecozone (Map 1), which suggests a potential for further range extensions north into Wyoming and south into New Mexico.
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 17-20, DOI: 10.11646/zootaxa.4180.1.1, http://zenodo.org/record/164222