Subisotoma cruda, Potapov, Mikhail, Babenko, Anatoly, Fjellberg, Arne & Greenslade, Penelope, 2009

Potapov, Mikhail, Babenko, Anatoly, Fjellberg, Arne & Greenslade, Penelope, 2009, Taxonomy of the Proisotoma complex. II. A revision of the genus Subisotoma and a description of Isotopenola gen. nov. (Collembola: Isotomidae), Zootaxa 2314, pp. 1-40 : 23-24

Subisotoma cruda sp. nov.

Figs 61–63 , Tab. 2

Type material. Holotype, male, Turkmenistan, 18 km from Ashkhabad, Bagyr (Novaya Nisa), soil under wormwood and spurge, 20.iv.1990, leg. S. Iordansky ( MSPU). Two paratypes, subadult female and male, the same data as the holotype.

Description. Size about 0.9 mm. Body slender. Colour greyish-black. Cuticle with fine and relatively regular orthogonal primary granulation, pits absent. Ocelli 8+8, G and H smaller. PAO large, not constricted, about three times as long as ocellus or slightly longer than inner unguis (1.1: 1). Maxillary outer lobe with 4 sublobal chaetae, maxillary palp simple. Labral formula as 2/554. Labium with a complete set of papillae and only 4 e-guard chaetae (studied in two specimens), papillae A, B and D with 1, 4, 4 guards, respectively. Proximal chaetae 3, basomedian field with 4 chaetae. Ventral side of head with 4(5)+4(5) postlabial chaetae. Ant.1 with 2 basal microsensilla (bms) (dorsal and ventral) and 2 ventral sensilla (s). Ant.2 with 3 bms and one laterodistal s. Ant.3 without bms and with 5 distal s (including one lateral), inner sensilla small and roundish, additional sensilla in the middle part of Ant.3 absent ( Fig. 61 ). Sensilla on Ant.4 poorly differentiated, subapical organite minute, microsensillum present.

Tergal sensilla well differentiated, shorter and finer than ordinary chaetae. Sensillar formulas 33/22224 (s) and 10/000 (ms). Medial sensilla on Abd.I–III set slightly in front of the p-row. Sensilla of lateral group on Abd.V shorter and thicker than medial ones ( Fig. 63 ). Macrochaetae not differentiated even on Abd.V–VI. Largest chaetae on Abd.V about 0.2 times as long as tergal length. Axial chaetom of Th.II–Abd.III as 7,6–7/ 6,6,6–7. Thorax without ventral axial chaetae.

Unguis curved, without inner tooth, empodial appendage thin. Tibiotarsi 1–3 with 21, 21, 24–27 chaetae. Tibiotarsal tenent chaetae pointed, approximately as long as unguis. Chaetae x and B5 on Ti. 3 in males do not differ from other chaetae. Ventral tube 4–5+4 –5 laterodistal and 6–7 posterior chaetae. Tenaculum with 3+3 teeth and 1–2 chaeta. Anterior furcal subcoxa with 5–6 chaetae, posterior with 6–7. Furca short, hardly passing the posterior border of Abd.III sternum. Anterior side of manubrium without chaetae, posterior side with 9+11 chaetae and 4+4 additional chaetae on its laterobasal lobes. Dens rather plump without anterior chaeta, posterior side with 3 strong chaetae (two type specimens have only 2 on one side). Mucro not clearly set off from dens, with two teeth. Ratio of manubrium: dens: mucro as about 8: 3: 1. Furcal area shown on Fig. 62 . Each anal lobe with three minute setulae.

Affinity. Differs from all species of the genus by microsensillar set and chaetotaxy of anterior side of dens (see also remarks to S. asiatica ).

Distribution. Three known specimens of the new species came from a semi-desert Inner Asian region. It was already listed as Subisotoma sp. (Turkmenian SSR, Iordansky leg.) in Fjellberg’s (1993) revision of Folsomides where it was erroneously characterized as having a bifurcate maxillary palp.

Name derivation. The name refers to the small number of microsensilla on the species (Latin ‘ crudus ’ denotes lacking in sensitivity).

Figures

FIGURES 61 – 63. Subisotoma cruda sp. n.: 61, Ant. 3, dorsal view; 62, ventral chaetotaxy of posterior part of abdomen and furca; 63, chaetotaxy of Abd. V.