Folsomia orientalis Martynova, 1977

Potapov, Mikhail B., Fjellberg, Arne & Bokova, Anna, 2017, Folsomia najtae n. sp. (Collembola: Isotomidae) - a new species with ‘ mobile’ forms from the Far East of Russia, Zoosystema 39 (1), pp. 95-102 : 100-101

Folsomia orientalis Martynova, 1977

( Figs 3G ; 4B )

Folsomia orientalis Martynova, 1977: 121 .

MATERIAL. — Several adult and subadult ♂ and ♀: Russia, Far East, Kamchatka, Elizovsky District , Malki , 53°19.316’ N, 157°33.013’ E c. 260 m alt., coniferous ( Pinus pumila (Pall.) Regel ) and birch ( Betula ermanii Cham. ) forests, litter and rotten wood, 26.VI.2012, coll. N. Kuznetsova and M. Potapov. Holotype and one paratype: Far East, Magadan Region, Snezhnaya Valley , coll. D. Berman.

ECOLOGY AND DISTRIBUTION. — F. orientalis is recorded from Magadan region and Kamchatka (NE Asia).

REDESCRIPTION

Colouration bluish grey, irregular.Body of normal shape. 6+6 corneas of ocelli well visible, arranged in two groups (4 anterior and 2 posterior). PAO narrow, constricted, longer (1.5- 1.6) than width of Ant.I and 1.6-1.9 as long as inner unguis length, without chitinized wrinkles. Outer mouth parts as in F. najtae n. sp. while guard e7 present. Ventral side of head with 4-5+4-5 postlabial chaetae. Ant.1 with 2 ventral s and 3 small bms, with 13 common chaetae. Ant.2 with 3 bms and a latero-distal s. Ant.3 with bms and with 6 distal s (including two lateral), without additional s. Ant.4 with big and roundish organite. S- and ms-formula as in F. najtae n. sp. Abd.V with 3 dorsal s (as, accp1, accp2) of middle size, one dorso-lateral accp3 longer and slightly thicker that other s, and one short ventro-lateral accp4 ( Fig. 4B ), s-chaetae on other segments of body short. Common chaetae short. Macrochaetae short and smooth, 2,2/3,3,3 in number, medial pair on Th.II short while well visible. Medial macrochaetae on Abd.V shorter than dens (0.5-0.6) and 1.9-2.1 times longer than mucro. No foil chaetae. Axial chaetotaxy abundant. Unguis with lateral teeth. Empodial appendage about half as long as inner edge of unguis. Tibiotarsi with several additional chaetae. VT with 6-8+6-8 laterodistal and more than 10 posterior chaetae. In some specimens posterior side with an additional group of few chaetae at base of VT. Tenaculum with 4+ 4 teeth and normally 2-3 chaetae (4 in holotype). Anterior furcal subcoxae with 9-12, posterior one with 5-6 chaetae. Anterior side of manubrium with two pairs of chaetae. Posterior side of manubrium with 5-6+5-6 laterobasal, 1+ 1 apical (a1), 3+ 3 distal chaetae (M1, L1, ml1), and 7+ 7 central chaetae. Lateral chaetae (l2) present. Dens with 9 (more rarely 8 or 10) anterior and 5 posterior chaetae ( Fig. 3G ). Ratio of manubrium: dens: mucro = 3.9-4.3: 3.4-3.7: 1.

REMARK

It is the largest and the most polychaetotic species among the three forms under consideration. For more detail comparison see the Remarks part to F. najtae n. sp.

Figures

FIG. 3. — A-D, Folsomia najtae n. sp.: variability of PAO (A); s-chaetae and macrochaetae on tergites of Abd.II-VI (B) and Th.II,III and Abd.I (C), apical part of leg 3 (D); E, F, F. setula Christiansen & Tucker, 1977, dens, lateral view (E), PAO (F); G, F. orientalis Martynova,1977 furca, lateral view. Abbreviations: see Material and methods. Scale bars: A, D-F, 0.03 mm; B, C, 0.02 mm; G, 0.05 mm.

FIG. 4. — s-chaetae and macrochaetae on Abd. IV-VI of F. setula Christiansen & Tucker, 1977 (A) and F. orientalis Martynova, 1977 (B). Abbreviation: see Material and methods. Scale bar: 0.1 mm.