Folsomia maximovi, Potapov, Mikhail & Gulgenova, Ayuna, 2013

Potapov, Mikhail & Gulgenova, Ayuna, 2013, Isotomidae (Collembola) of Buryat Republic. II. A revision of the genus Folsomia, Zootaxa 3682 (2), pp. 305-330 : 314-316

Folsomia maximovi sp. nov.

Figs 16–17

Type material. Holotype: adult female. Russia (East Siberia), S Buryat Republic, Zagansky Range, northern slope, near Shibertuy, 813 m alt., 50.82321°N, 107.87671°E, birch forest, 21.viii.2011, leg. A.Gulgenova & L.Vanyavina. 10 paratypes from the same locality. Holotype and 5 paratypes in MSPU; 5 paratypes in BSU.

Description. Body size about 0,8 mm (for two adult females). Body without pigmentation, of normal shape. Cuticle with thin hexagonal primary granulation. Ocelli absent. PAO, slightly constricted, 1.3–1.6 as long as width of Ant I and 1.5–1.8 as long as inner unguis length. Maxillary outer lobe with 4 sublobal hairs, maxillary palp bifurcate. Labral formula as 4/5,5,4. Labium with 5 usual papillae (А–Е), guard chaetae e7 present, proximal, basomedian, and basolatera chaetae as common for the genus. Ventral side of a head with 4–5+4–5 chaetae. Ant.I with 2 ventral sensilla (s) and 2 small basal microsensilla (bms), dorsal and ventral, the former set together with a long chaetaceous microsensillum, Ant.II with 3 bms and 1 latero-distal s, Ant.III with 1 bms and with 6 distal s (including 2 lateral), without additional sensilla. Sensilla on Ant.4 weakly differentiated. Organite stick-form, small.

Sensillary formula as 4,3/2,2,2,3,5 (s), 1,0/1,0,0 (ms). Tergal sensilla thin, as long as or longer than common chaetae. Medial sensilla on Th.II–Abd.III situated in mid-tergal position, on Abd.I–III between Mac1 and Mac2. Abd.V with 5 sensilla arranged with 3 dorsal ones (al, accp1, accp2), long and slender, 1 lateral slightly shorter, and 1 ventral, the shortest ( Fig. 16 ). Macrochaetae smooth, 1,1/3,3,3 in number, medial ones on Abd.V 1.8–2.1 times shorter than dens and 4.5–5.5 times longer than mucro. 7 foil chaetae at the tip of abdomen arranged as 4 anterior (fa1 and fa2) and 3 posterior (fp0 and fp2). Thorax without ventral chaetae.

Unguis of normal shape, without any teeth. Empodial appendage about half as long as unguis (0.45–0.55). Tibiotarsi with additional chaetae on Leg I and II (25–28 in all), and with many on Leg III (> 30 in all). Tibiotarsal tenent chaetae pointed. VT with 4+4(5) laterodistal and 5 posterior chaetae, anteriorly without chaetae. Tenaculum with 4+4 teeth and a chaeta. Anterior furcal subcoxae with 8–10, posterior one with 5 chaetae. Anterior side of manubrium with 5–6+5–6(4) paired chaetae and 1–2 unpaired in proximal part, arranged as: 3+3,1+1,1+1,1; 3+3,1+1,1+1,1+1,1; 3+3,1+1,1+1,2 ( Fig. 17 ). Posterior side of manubrium with at least 4+4 laterobasal, 2 apical chaetae (ap), 3+3 chaetae in distal transversal row (M1, ml1, L1), two pairs of lateral chaetae (l1, l2), and 6+ 6 in central part. Dens with 25–28 anterior chaetae ( Fig. 17 ). Posterior side of dens crenulated at the middle and with 6 normal chaetae (4 basal and 2 at the middle) and one rudimentary minute chaeta at the base of mucro ( Fig. 17 ). Mucro bidentate. Ratio of manubrium:dens:mucro = 4.9–5.9: 8.9–9.6: 1.

Discussion. F. maximovi sp. nov. and F. culter share many characters including the chaetotaxy of furca, shape of foil chaetae, sensillar chaetotaxy, and morphology of outer mouth parts. Two notable differences between the two species are ventral chaetae on Th.III (absent in F. maximovi sp. nov., present in F. culter ) and shape of accp3 and accp4 sensilla on Abd.V (accp3> accp 4 in F. maximovi sp. nov., accp3 = accp 4 in F. culter ).

Distribution and ecology. Known from three localities in the Zagansky Range (S Buryatia) ( Fig. 1 : loc. 3).

Etymology. In memory of Victor Maximov, a founder of General Ecology department of Moscow State University, who worked on theory of analysis of communities, among this the use of a similarity standard for comparing the springtail populations.

Figures

FIGURE 1. The sampling sites in Buryatia: 1 – 2 — Vitim Plateau (1 — Konda Basin, 2 — Eravna Basin), 3 – 5 — Selenga Low Plateau (3 — Zagansky Range, 4 — vicinities of Schuch'ye Lake, 5 — vicinities of Karasinoye Lake), 6 – 8 — Barguzinsky Range (6 — Ust' - Barguzin, 7 — vicinities of Barguzin, 8 — upper flow of Barguzin River), 9 — Khamar-Daban Range, 10 — Tunkinskiye Gol'tsy Range, 11 — vicinities of Ulan-Ude, 12 — estuary of Selenga River, 13 — vicinities of Khorinsk, 14 — vicinities of Unnokent'evka, 15 –– Turka.

FIGURES 16 – 19. F. maximovi sp. nov. (16, 17) and F. sensivillosa sp. nov. (18, 19): 16, sensilla and macrochaetae of Abd. IV – VI; 17, 18, furca, lateral view (on manubrium chaetae of only one side shown); 19, furca, anterior view.