Desoria rosea Fjellberg, 2010, sp. n.

Desoria rosea sp. n.

(Figs. 64–70)

Type material. Holotype (alc.) and 9 paratypes (3 in alc., 6 in two slides) from " Canada, B.C., Sparwood, 49o43'N, 114o57'W, 09.VI.1983. Plant debris in moist avalanche track, 1,900 m., A. Fjellberg 119/83" (INHS).

Other material: Canada, B.C., Garibaldi Park, Panorama Ridge, 1.IX.1983. Wet moss at snow edge, 1,900 m. A. Fjellberg 387/83; Canada, Alberta, Kananaskis, Marmot Creek at Twin Fork, 29.VI.1983. Litter in spruce Krummholtz at tree line, 2,300 m. A. Fjellberg 193/83; Canada, Alberta, Kananaskis, French Creek, 16.V 1.1984, Moss & litter at stream bank, A. Fjellberg leg.; USA. Alaska, Juneau, mountains. between Mendenhall Glacier and Montana Creek Trail, 13.VII.1980. On ponds at snow bed, 950 m. alt., A. Fjellberg leg; USA, Washington, Wenatchee Mountains, Ingalls Lake, 23.VIII.1980. Hemlock litter, A. Fjellberg 181/ 80.

Description. Size up to 1.2 mm. Colour white or faintly pinkish grey, eye-spots black. Ocelli 6+6, G and H absent. PAO elongated, slightly longer than diameter of nearest ocellus, with three associated setae (Fig. 64). Body shape normal, head not prognathous or hypognathous. Last two abdominal segments weakly separated. Ant. 2–3 with an increased number of additional sensilla, erect ventral sensilla present in full grown specimens (Figs. 65–66). Ant. 4 with bifurcated pin seta and a small globular organite. Basomedian field of labium usually with five setae (Fig. 67). Details of labrum, frontoclypeal field, maxillary palps, labial palps, mandibles and maxillae as in previous species. Body integument smooth; setal cover open and clearly "double" in anterior part of the body (short ordinary setae, longer dagger-like mesochaetae). Longest macrochaetae on tip of abdomen clearly serrated; median macrochaetae on abd. 5 more than three times as long as inner edge of last claw. Spine-like microsensilla as 11/001, rarely 11/101. Number of ordinary sensilla as 55/44456. Ventral tube on each side with 3 frontal and 5 lateral setae. Posterior side with 6–8 setae. Retinaculum with 3–4 setae. Manubrium with blunt apical teeth and 3+3 short ventroapical setae; ventromedian field densely pilose. Mucro 5-toothed, apical tooth smaller than subapical (Fig. 68). Legs long and slender, inner side of tib. 1–2 with 3–4 pairs of setae along median line. Subcoxa 1 with 1–2 setae. Claw structures as in previous species. Males present, reproductive individuals with unmodified setal cover.

Etymology. The pinkish colour of the animal is reflected in the name.

Discussion. Similar to cryophila, but differs most sharply in number of lateral setae on the ventral tube which is 5+ 5 in rosea and up to 15 on each side in cryophila. Also number of dorsal setae on dens is never more than 8 in rosea, while 12–14 in adult cryophila. In general the setal cover of the body is more open and abd. 5-6 less fused than in cryophila. Although variable, rosea usually has five basomedian setae on labium (Fig. 67) while cryophila has four. Erect ventral sensilla on ant. 2–3 are present in full grown rosea (Figs. 65- 66), not in cryophila. PAO is more elongate in rosea, slightly longer than diameter of nearest ocellus (Fig. 64). The serrated macrochaetae on tip of abdomen are slightly longer in rosea, median macrochaetae on abd.5 often more than 3 times as long as inner edge of last claw (less than 3.0 in cryophila). Apical tooth of mucro is relatively smaller in rosea than in cryophila (compare Figs. 59 and 68).

Distribution and ecology. Judging from present records the species is widely distributed in the Rockies from Alaska to Washington and Alberta, appearing in damp plant litter close to cold water and snowfields.