Folsomia mofettophila Schulz & Potapov, 2010, sp. nov.

Folsomia mofettophila sp. nov.

Figs 1–8, Tab. 1–2

Type locality. NW-Czechia, Bohemia, 12o, 27´, 46´´ E, 50o, 07´, 59´´N, Plesna valley, Hartousov meadow (vegetation mainly Bistortia officinalis, Deschampsia cespitosa and Festuca ovina), 423 m a.s.l., soil core sample (reduktosol, 0–5cm), 30.ix.2008, leg. H.-J. Schulz.

Type material. Holotype: female on slide (deposited at the Senckenberg Museum of Natural History Görlitz; 4 paratypes on slides, 30.ix.2008, deposited in Görlitz (Senckenberg Museum of Natural History), 3 paratypes on slides, 14.v.2008, deposited in Moscow (Moscow State Pedagogical University, Department of Zoology and Ecology), 3 paratypes on slides, 25.iii.2009, deposited in Görlitz, all paratypes from the same location, leg. H.-J. Schulz.

Etymology. Named after the specific type of habitat, “mofette”, in which the new species was collected.

Description. Body size from 0.7 mm (male) up to 0.9 mm (largest female). Length of holotype 0.75 mm. Colour white, no pigmentation and ocelli.

PAO without constrictions, 1.1–1.4 times as long as width of Ant. I and more than two times longer than inner edge of claw III. Maxillary palp bifurcate, outer maxillary lobe with 4 sublobal hairs (Fig. 1). Labral formula 4(3)/554. Ventral side of head with 4+4 chaetae along the linea ventralis, labium with 4+4 basomedian chaetae and a full set of guard chaetae (16 - including e7).

Ant. I with 2 small basal microsensilla (dorsal and ventral, bms), and 2 ventral sensilla (s), Ant. II with 3 bms and 1 latero-distal s (Fig. 1), Ant. III with 1 bms and usually 6 distal s including mostly 2 (more rarely 1) lateral ones (Fig. 2). Ant. IV with weakly differentiated sensilla, subapical organite small as is common for the genus.

Sensillar formula for Th. II to Abd. V: 4,3/2,2,2,3,5 (s), 1,0/1,0,0 (ms) (Fig. 3). Medial sensilla on all tergites situated within the p-row, on Abd. I–III between macrochaetae 1 and 2. Macrochaetae smooth and relatively short (medial ones on Abd. V 2.4–3.0 times shorter than the length of the dens and 1.7–2.9 times longer than the mucro), pattern from Th. II–Abd. III: 1,1/3,3,3 (Fig. 3). Axial chaetom of Th. II–Abd. III: 9– 10, 7–8, 4, 4–5, 4–5. Thorax without ventral chaetae.

Unguis without lateral and inner teeth. Tibiotarsi of leg I and II at most with 1–2 additional chaetae (total number 22–23), tibiotarsi III with many additional chaetae (up to 28). Ventral tube with 4–6 + 4–6 laterodistal and 5–7 posterior chaetae. Tenaculum 4+4 teeth and 1 chaeta. Anterior furcal subcoxae 9–11, posterior ones 6 (5) chaetae. Anterior side of manubrium with 2+2 chaetae (specimens with 1+2 and 2+3 observed). Posterior side of manubrium with 5+5 baso-lateral, 2 apical (ap), and ml1 chaetae (Fig. 5), totally with 34 chaetae (including basal and lateral). Dens with 14–18 anterior chaetae, posteriorly constantly with 5 (3+2) (Fig. 4). Mucro bidentate. Ratio of manubrium:dens:mucro = 5:5:1 (mean of 10 individuals). Males present.

paratype 1 144 159 66 69 12 16 9 25 9 3

paratype 2 128 144 59 62 12 12 9 22 9 3

paratype 3 150 162 69 69 12 12 9 25 9 3

paratype 4 150 166 69 69 16 16 9 28 9 3

paratype 5 150 153 56 59 12 12 9 25 9 3

paratype 6 131 119 53 50 9 9 6 19 9 3

Discussion. Folsomia mofettophila sp. nov. belongs to the F. fimetaria- group because of abdominal sensilla positioned in the p-row, ventral chaetae on Th. III usually missing and only one pair of macrochaetae present on thoracic segments (Potapov 2001). Two pairs of chaetae on anterior side of manubrium allow to separate Folsomia bisetosa -complex with five species, but the new species is close to F. b i s e t o s a Gisin, 1953 and F. kuznetsovae Potapov & Taskaeva, 2009 in number of chaetae on anterior side of manubrium and number microsensilla on Abd.I. Full chaetotaxy of manubrium was studied in one individual only. The number of common chaetae situated medially to lateral sensilla of Abd. II sternum is more than 20 (21–24), i.e. similarly as in F. bisetosa. The new species differs from them in having much larger PAO (see table 2). Besides, adult individuals of the new species have normally 2 lateral sensilla on Ant. III (1 lateral sensilla in F. bisetosa and F. kuznetsovae). Foil chaetae weakly developed as in F. bisetosa (as in Potapov & Taskaeva 2009; Fig. 12). F. mofettophila is a sexual species whereas males have not been found in the other two mentioned species (Fjellberg 2005; Potapov & Taskaeva 2009).

Mofette fields. The new species was found in the Hartousov mofette field (Eastern part of the Cheb basin, Northwest Bohemia). Mofettes are continental vent systems exhaling geogenic CO2 and often occur in regions of tectonic, magmatic or volcanic unrest. These areas constantly emit geogenic CO2. Emission rates vary temporally. The location of CO2 emission drifts very slowly. Soil and ground-level CO2 concentrations can reach 100%. F. mofettophila was only found in the high-CO2-samples and even there was very rare.

Characters F. bisetosa F. kuznetsove F. mofettophila Lateral sensilla on Th. III supplied with chaeta + +

Chaeta ml1 on posterior side of manubrium – + +

Number of common chaetae on Abd. II sternum> 20 <20> 20 Foil-chaetae on Abd. IV sternum + – +

PAO <Ant I width <Ant I width> Ant I width