Desoria pilifrons Fjellberg, 2010, sp. n.

Desoria pilifrons sp. n.

(Figs. 50–56)

Type material. Holotype: One specimen (slide, not sexed) labelled " Canada, B.C. Vancouver Island, Comox Glacier, 49o33'N, 125o21'W, 26.VIII.1983. Wet moss in melt water, 1.850 m. A. Fjellberg 375/83". Paratypes: Four specimens in two slides, same data as holotype (INHS).

Description. Body size up to 1.6 mm. Body shape slender, with pear-shaped abdomen. Abd. 5–6 fused, but with a gap in setal cover. Head distinctly prognathous (Fig. 50). Colour pale bluish grey, darkest in anterior part of the body. Ocelli 8+8, G & H smaller. PAO oval, about 1.3 times as long as diameter of nearest ocellus. Three setae associated with PAO (Fig. 51). Ant. 1 with 4–5 short ventroapical sensilla and a few curved setaceous sensilla. Ant. 2 with two small setaceous sensilla in lateral position near apex. Ant. 3 organ normal, with several additional small setaceous sensilla (Fig. 54). One or two erect setaceous sensilla ventrally on ant. 2–3 in some individuals. Ant. 4 apically with two blunt lobes and a bifurcate pine seta; subapical organ with a globular organite (Fig. 52). Labrum with 4/554 strong curved setae. Apical edge with 4 sharp lobes and a composite ventral ciliation. Frontoclypeal area with more than 30 setae in adults (Fig. 53). Maxillary palp bifurcate, 4 sublobal setae. Labial palps complete, guard e7 present, 4 proximal setae. Terminal sensilla on labial papillae longer than guards. Basal fields of labium with 5 median and 5 lateral setae. Hypostomal papilla with H longer than h1/h2. Head with 5–7 postlabial setae on each side of ventral line. Mandibles normal, strong. Maxillae unmodified, with 3-toothed capitulum and 6 short lamellae covered with fine denticles. Body integument smooth. Ground cover of setae dense, markedly "double" all over the body with short microchaetae and dagger-like mesochaetae (as Fig. 30). Macrochaetae strong, those on abd. 5–6 finely serrated in apical half. Median macrochaeta on abd. 5 2.5–3.0 times as long as inner edge of last claw. Sensillary equipment on the tergites unclear, but numbers apparently low with five setaceous sensilla on each side of th. 2–abd. 2; spine-like microsensilla as 11/111. On abd. 5 one sensillum in anterior position. Ventral tube on each side with 8–10 frontal and 8–9 lateral setae; posterior side with more than 10 setae in large individuals. No ventral setae on thorax. Retinaculum with 4+4 teeth and 7–9 setae. Manubrium with blunt apical teeth and 3+3(2) short ventroapical setae, ventral field densely pilose, with more than 50 setae. Dens dorsally crenulated, with about 20 dorsal setae in the basal half; ventral subapical seta not prolonged. Mucro 4-toothed, rather slender with relatively large apical tooth (Fig. 55), inner lateral lamella ending at the subapical tooth without forming a secondary tooth; lateral seta absent. Tibiotarsi with 11 apical setae, all acuminate. Inner side of tib.1–2 with more than 3+3 setae along median line. Claws normal, with distinct lateral teeth; inner tooth present on anterior pairs of claws; unguiculus on two last pairs of claws with a high dorsal lamella bearing a small corner tooth (Fig. 56). Males present, reproductive individuals not seen.

Etymology. The name reflects the unusually dense setal vestiture in the frontoclypeal field.

Discussion. Differs from the other species with a 4-tothed mucro (ater and garibaldii) by prognathous head with increased number of setae in frontoclypeal area (>30), the marked "double" setal cover, long macrochaetae and increased number of setae on ventral tube (Table 1).

Distribution and ecology. Only known from the type locality at Comox Glacier, Vancouver Island where it occurred along a melt water stream near the glacier.