Jacekaphorura sakhaensis Pomorski & Babenko, 2010, sp. nov.

Jacekaphorura sakhaensis sp. nov.

Figs 1–9

Type material. Holotype, female, Russia, Yakutia (Sakha), Suntar–Khayata Mt. Range, upper current of Kyubyume River [63 0 13’N 139 0 32’E], ca. 1800 m alt., stony terrace, Salix tschuktschorum, Cassiope tetragona, Cetraria spp., 9.vii.2002, O. Makarova leg. Paratype, juvenile, same region, but ca. 2000 m alt., alpine tundra with Salix polaris, Dryas punctata, Carex ensifolia arctisibirica, 15.vii.2002, O. Makarova leg. The types are deposited in MSPU collection.

Description. Holotype length without antennae 2.9 mm. Colour of specimens preserved in alcohol white. Body shape cylindrical, abdominal tip broadened, Abd.6 small, poorly separated from and partly hidden under Abd.5.

Antennae thin, slightly longer than head, antennal base not well marked. Ant.4 with cauliflower-like apical papilla, subapical organite and microsensillum present (Figs 1–2). AO consists of 5 long and narrow papillae, two smooth sensory rods, two sensory clubs, straight and granulated [or “morel-like” according to Weiner (1996)], 5 guard setae, and lateral microsensillum (Figs 2–3). Ant.1–2 with 26–27 and ca. 70 setae, correspondingly, other antennal segments also with increased number of setae clearly differentiated in size.

PA O long with 34–38 simple vesicles (Fig. 4). Labrum with 9 setae and 4 prelabral setae. Labium of A - type, with all 5 usual papillae (A–E), 7 long guards, and 9–10 proximal setae, basal fields with 4+5 setae (Fig. 5). Maxillary palp simple with two sublobal hairs.

Dorsal pseudocellar formula (pso) as 42/133/33333 (holotype) or 32/133/33333 (paratype, juvenile), antennal pseudocelli in a form of triangle, medial hind pseudocellus on head moved slightly forward (Figs 6, 8). Number of ventral pso 2/000/0111, but holotype with 1+2 ventral pso on Abd.4; ventral pseudocelli on head in usual position: medial and postero-lateral; ventral pso on abdomen as Fig. 9. Accurate number of parapseudocelli (psx) is undetectable because of lack of material, but psx present on VT base, inner side of femora, and questionably ventrally on Abd.4. Upper subcoxae with 2–2–2 pso, correspondingly.

Granulation fine and uniform with 15–17 granules around a pseudocellus. Dorsal chaetotaxy plurichaetotic and asymmetric, all setae pointed and clearly differentiated into macro- and microsetae, especially laterally and on abdominal tip (Fig. 6). Both Th.2 and Th.3 with lateral microsensilla. Unpaired dorsal seta d 0 on head absent (Fig. 8). Thorax without setae along linea ventralis.

Furca in the single known juvenile specimen reduced to finely granulated area with 2+2 small posterior setae arranged in two rows (Fig. 9), no traces of furca detected in adult (holotype), but with 2+2 small setae arranged asymmetrically (posterior one moved forward). Ventral tube with ca. 40 distal setae on each flap, frontal and proximal setae at corpus base absent. Each subcoxa with 15–16 setae, all tibiotarsi with additional proximal setae (ca. 30 as a whole), distal row complete with 11 setae. Unguis rather long with clear tooth on basal third of inner edge (invisible in juvenile) and a pair of lateral ones, unguiculus with distinct basal lamella, shorter than inner edge of unguis (Fig. 7). Anal spines absent.

Etymology. The species is named after Sakha, a native name of Yakutia.

Distribution and ecological preferences. The species seems to be rare in the study area (found in only two from more than 100 soil samples). This may be considered as evidence that the type locality does not fully reflect its real distributional range or biotopic preference.

Concluding remarks (Anatoly Babenko). This is probably the last paper prepared by the senior author. The study was initiated in October, 2007 when R. Jacek Pomorski visited Moscow and a draft version was ready as early as the end of March, 2008, a week before a tragic accident interrupted his fruitful scientific activity. I dared to finalize it changing a tentative name of the genus before the publication.