Folsomia biparis, 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 : 320-321

Folsomia biparis sp. nov.

Fig. 24

Type material. Holotype: female. Russia (East Siberia), Buryat Republic, Valley of Uda River, near Khorinsk (ca 150 km N Ulan-Ude), dry pine wood with sparse vegetation covering, flotation of sand, 16.viii.2008 and 3.viii.2009, 3 paratypes from the same locality, leg. A. Gulgenova & M. Potapov. Holotype and 3 paratypes in MSPU.

Other material. Buryat Republic, Dzerginsky Nature Reserve, vicinities of station '81 km' (upper flow of Barguzin River), 1080 m alt., 55.34350°N, 111.50290°E, floodplain sandy meadow at river bank, 10.ix.2012. leg. A. Gulgenova & M. Potapov. Buryat Republic, Vitim Highland, Eravna Basin, steppe with Kobresia and Leontopodium , near Sosnovo-Ozyorskoye (ca 200 km NE Ulan-Ude), ca. 950 m alt., 21.viii.2009 and 27.ix.2009. Irkutsk Area, west shore of Baikal Lake, nearby Bol'shoye Goloustnoye, taiga forest, viii.1990, leg. M.Kalinin.

Description. Body size about 0.4 mm, shape, granulation, outer mouth part, and antennae as in F. uniparis sp. nov. Ocelli lacking. PAO narrowly elliptical, not constricted, 0.9–1.0 as long as width of Ant I and 1.5–1.8 as long as inner unguis length.

Sensillary formula as 4,3/2,2,2,3,5 (s), 1,0/1,0,0 (ms). Sensillar chaetotaxy, macrochaetae, and foil chaetae as in F. uniparis sp. nov. (as in Fig. 31 ). Macrochaetae on Abd.V 1.6–1.7 times shorter than dens and 1.9–2.2 times longer than mucro ( Fig. 24 ). Axial chaetotaxy as 7–8,4–5/3,3,4. Thorax without ventral chaetae.

Unguis of normal shape, without lateral and inner teeth. Empodial appendage about half as long as unguis (0.5–0.6). Tibiotarsi without additional chaetae on Leg I and II (21 chaetae), and with few ones on Leg III (25–27). Tibiotarsal tenent chaetae pointed. VT and tenaculum as in F. uniparis sp. nov. Anterior furcal subcoxae with 3–5 chaetae, posterior one with 3. Anterior side of manubrium with 2+2 chaetae. Posterior side of manubrium with 4+4 laterobasal, 2 apical chaetae (ap), 2+2 chaetae in distal transversal row (M1, L1), and 2+ 2 in central part ( Fig. 24 ). One pair of lateral chaetae presnt or absent. Dens with 9 anterior chaetae arranged as 1,2,1,2,3 ( Fig. 24 ). Posterior side of dens crenulated at the middle and with 4 normal chaetae (2 at base and 2 at the middle) and usually one rudimentary subapical chaeta. Mucro bidentate. Ratio of manubrium:dens:mucro =3.8–4.2:3.1–3.5:1.

Discussion. The species belongs to ' heterocellata ' group and resembles F. uniparis sp. nov. The only difference between F. uniparis sp. nov. and F. biparis sp. nov. is chaetotaxy of furca: one ( uniparis ) vs. two ( biparis ) pairs of chaetae on anterior side of manubrium, a pair of chaetae at the middle of posterior side of dens absent ( uniparis ) vs. present ( biparis ), one ( uniparis ) vs. two ( biparis ) chaetae in the second position on anterior side of dens, 3+3 ( uniparis ) vs. 2+2 ( biparis ) chaetae in central area of posterior side of manubrium.

Distribution and ecology. The ecological preferences seems generally to be as in F. uniparis sp. nov., but the two species are usually not collected together. Occurs in sandy or dry sites ( Fig 1 : loc. 1, 2, 8, 13).

Etymology. Springtails with two pairs of chaetae on anterior side of manubrium.

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 24 – 30. F. biparis sp. nov. (24) and F. pseudovtorovi sp. nov. (25 – 30): 24, posterior part of abdomen; 25, dens; 26, manubrium, posterior view; 27, VT; 28, anterior part of the head; 29, Abd. IV – VI; 30, sensilla of Abd. V.

FIGURES 31 – 32. Habitus and chaetotaxy of F. uniparis sp. nov. (31) and F. uniramia sp. nov., adult male (32).