Paranura oregonensis sp. nov.

Figs 16–26, Tables 3–4

Etymology. Named after its terra typica, Oregon state.

Diagnosis. Body bluish grey. 3+3 eyes on head. Tubercles slightly developed on dorsal side of abdomen, reticulations absent. Head with chaetae O, A and E. Head with three ocular chaetae. Thorax I with 2 chaetae De. Thorax II–III with 3 chaetae Di. Thorax II–III with 3 and 4 ordinary chaetae De respectively. Abdomen V with 2+2 chaetae Di. Abdomen V slightly longer than VI. Abdomen without clavate chaetae. Furca rudimentary with microchaetae. Male ventral organ absent. Tibiotarsi with chaetae M.

Description. Habitus typical for Paranura Axelson, 1902 genus. Buccal cone slightly elongated. Body length (without antennae) 0.45–0.85 mm (holotype: 0.75 mm). Colour of body when alive and in alcohol bluish grey. Tubercles not developed except on two last abdominal segments (Figs 20, 22). Ordinary dorsal chaetae (Figs 20, 22, 25) differentiated into short, thin, acuminate microchaetae, medium size, smooth, acuminate mesochaetae and long, nearly smooth (with hardly visible denticles), relatively thick, acuminate macrochaetae Ml and Mc. No plurichaetosis on body.

Head. Antennae slightly shorter than head (fig. 20). S-chaetae of ant. IV relatively short and thick, S2 distinctly smaller than others (Fig. 21). Apical bulb bilobate (Fig. 21). Chaetotaxy of antennae as in Fig. 21 and Tab. 3. Buccal cone relatively long and rounded at apex (Fig. 17). Maxilla needle-like, mandible with four teeth (Fig. 19).

Chaetotaxy of labium as in Fig. 16, labial papillae x absent. Labrum chaetotaxy 4/2,4 (Fig. 18). Group Vi with 6+6 chaetae (Fig. 16). Groups Vea, Vem and Vep with 4, 3–4 and 4 chaetae respectively. Dorsal chaetotaxy of head as in Tab. 3. and Fig. 20. Chaetotaxy of central area on head complete, with 3 chaetae Oc and chaetae A, B, C, D, E, F, G, O (Fig. 20). Line of chaetae Di2–De2 crosses line Di1–De1 on head (cross-type, Deharveng 1983). 3+3 relatively large eyes, their diameter about three times as large as the diameter of chaeta Ocm socket (Fig. 20), pigmented in black.

Thorax, abdomen, legs. Dorsal chaetotaxy as in Figs 20, 22 and in Tab. 4. Ventral chaetotaxy as in Tab. 4. Schaetae long, slightly longer than nearby macrochaetae (Figs 20, 22, 24). S-chaetae formula of body: 022/11111, smicrochaeta on Dl of th. II present. Tubercles well developed on abd. V and VI. Tubercles Di of abd. V fused with 2+2 chaetae (Fig. 22). Furcal remnant with 6 microchaetae and 3–5 mesochaetae (Figs 23, 26). Male without ventral modified chaetae (“male ventral organ”). Claw without internal tooth. Chaeta M present on tibiotarsus. Chaetotaxy of legs as in Tab. 4.

Types. Holotype: female on slide, United States of America: Oregon, Blue River Ranger District of Willamette National Forest, neighborhood of H. J. Andrews Experimental Forest, “Wolf Rock” site, old-growth forest of Tsuga heterophylla Zone (tree species: Douglas fir Pseudotsuga menziessi, western red-cedar Thuja plicata), litter, 25.IX. 2006, leg. A. Smolis. Holotype deposited in DIBEC. Paratypes: 11 females and 3 juveniles on slides, same data as holotype. Two paratypes are housed in MNHN, other ones in DIBEC.

Remarks. See remarks of Paranura reducta sp. nov.

Biology. The species was found only in litter from upper elevation forest of Tsuga heterophylla Zone (Fig. 27). Despite intensive field investigations it was not collected at lower elevation forests (below 700 m) of the Zone. Considering sex of analyzed specimens it cannot be excluded that the species is parthenogenetic.

a) Cephalic chaetotaxy––dorsal side.

b) Chaetotaxy of antennae.

Terga Legs

Di De Dl L Scx2 Cx Tr Fe TT th. I 1 2 1 – 0 3 6 13 19 th. II 3 3+s 3+s+ms 3 2 7 6 12 19 th. III 3 4+s 3+ s 3 2 8 6 11 18

Sterna

abd. I 2 3+ s 2 3 VT: 4

abd. II 2 3+ s 2 3 Ve: 4–6; Vel present

abd. III 2 3+ s 2 4 Ve: 4–5; Fu: 3–5 me, 6 mi

abd. IV 2 1+ s 3 6 –8 Vel: 4; Vec: 2 Vei: 2; Vl: 4

abd. V (2+2) 5–6+s Ag: 3; chaetae L‘ and Vl present

abd. VI 7 Ve: 11–12; An: 2 mi