Desoria pilifrons, Fjellberg, Arne, 2010

Fjellberg, Arne, 2010, Cryophilic Isotomidae (Collembola) of the Northwestern Rocky Mountains, U. S. A., Zootaxa 2513, pp. 27-49 : 37

publication ID	https://doi.org/ 10.5281/zenodo.196078
DOI	https://doi.org/10.5281/zenodo.3509393
persistent identifier	https://treatment.plazi.org/id/504F2D6C-FFD3-FF83-97BE-F08EFCCA1B45
treatment provided by	Plazi
scientific name	Desoria pilifrons
status	sp. nov.

Treatment

Desoria pilifrons sp. n.

( Figs. 50–56 View FIGURES 30 – 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 View FIGURES 30 – 56 ). 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 View FIGURES 30 – 56 ). 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 View FIGURES 30 – 56 ). 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 View FIGURES 30 – 56 ). 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 View FIGURES 30 – 56 ). 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 View FIGURES 30 – 56 ). 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 View FIGURES 30 – 56 ), 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 View FIGURES 30 – 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 View 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.