Subisotoma guzeriplica, 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 : 17-18

Subisotoma guzeriplica sp. nov.

Figs 2 , 38–45 , Tab. 2

Type material. Holotype, female, Russia, Northern Caucasus, Adygeya, vicinity of Guzeripl' [43° 50’N, 40° 11’E], beech litter, 30.i.–03.ii.2003, leg. D. Shitikov ( MSPU). Paratypes: 2 females and 2 males, the same data as the holotype ( MSPU).

Description. Size up to 0.9–1.1 mm. Colour dark, almost-black, with numerous colourless spots, ventral side also intensely pigmented. Cuticle with medium sized pits densely scattered all over the body. Ocelli 6+6, subequal, ocelli C and H absent, G present ( Figs 44–45 ). PAO wide elliptic, without constriction, about twice as long as ocellus diameter and slightly shorter than inner unguis (0.9: 1). Maxillary palp simple with 4 sublobal chaetae. Labrum with 2/554 chaetae. Labium with all papillae A–E present, papilla E with 6 guard chaetae (e7 absent) ( Fig. 43 ), proximal chaetae 3. Basomedial and basolateral fields of labium with 4 and 5 chaetae. Ventral side of head with 4+4(5) postlabial chaetae. Ant.1 with 2 bms (dorsal and ventral) and 2 ventral sensilla (s), Ant.2 with 3 bms and 1 distal s, Ant.3 with 1 bms and 5 distal s, including one lateral in АО. Inner sensilla of АО clearly broadened, the number of additional sensilla on dorsal side of the segment varies from 1 to 3 ( Figs 39–40 ). Ant.4 with numerous poorly differentiated sensilla, subapical organite small, microsensillum present.

All terga with dense cover of short, uniform chaetae, macrochaetae poorly developed. On Abd.V longest chaetae about 0.2 times as long as tergite length. Dorsal axial chaetom as 8–10,7–9/5–7,5–6,6–7. Tergal sensilla shorter and more slender than ordinary chaetae, medial ones on Abd.I–III set slightly in front of prow. Sensillar formulas 33/22234 (s) and 10/101 (ms) ( Figs 2 , 38 ). Only 1+1 ventral chaetae present on Th.III. Unguis usually toothless. Ti.1–3 with 22–23–24 chaetae. Tibiotarsal tenent chaetae 1–2–2, clearly clavate, longer than inner edge of unguis (U3: t.ch. = 0.7–0.8). Modified chaetae x and B5 on Ti. 3 in males truncate and slightly thickened. Ventral tube with 4+4(5) lateral and usually with 4 posterior chaetae. Tenaculum with 3+3 teeth and one chaeta. Anterior furcal subcoxae with 7–11, posterior ones with 6–9 chaetae. Manubrium without anterior chaetae, posterior side with 10–12+10–12 chaetae, laterobasal lobes usually with 4 chaetae ( Fig. 42 ). Dens with one anterior and 4 posterior chaetae ( Fig. 41 ). Mucro narrow and rather long, with 2 teeth and lateral lamella. Ratio of manubrium: dens: mucro = 4–7: 3–5: 1. Each anal lobe with 3 tiny equal setulae.

Affinity. The unusual reduction of ocelli C and H and the number of abdominal macrosensilla easily identify the species. In the family Isotomidae ocelli G and H are usually lost at the first step of reduction. Distribution. Known only from the type locality in Northern Caucasus.

Name derivation. Named after the village Guzeripl' because of their hospitality to a group of MSPU students when collecting the new species.

Figures

FIGURES 1 – 6. Sensillar chaetotaxy of Subisotoma: 1, Subisotoma tenuis, Subisotoma bisensillata sp. nov. (3,3 / 2,2,2,2,4); 2, Subisotoma guzeriplica sp. nov. (3,3 / 2,2,2,3,4); 3, Subisotoma pomorskii sp. nov. (3,3 / 2,2 – 3,3,3,4); 4, Subisotoma homonomica sp. nov. (3,3 / 3,3,3,3,4); 5, Subisotoma quadrisensillata (3,3 / 3,3,3,4,4); 6, Subisotoma pusilla (4,4 / 3,3,3,3,4).

FIGURES 38 – 45. Subisotoma guzeriplica sp. nov.: 38, chaetotaxy of Abd. III and IV; 39 – 40 – Ant. 3, dorsolateral view (variation); 41, dens and mucro, lateral view; 42, ventral chaetotaxy of abdomen; 43, labial palp (only e-guard chaetae shown in details); 44 – 45, ocelli and PAO (two views).