Folsomia calcarea Potapov

Potapov, Mikhail, Hasegawa, Motohiro, Kuznetsova, Natalia, Babenko, Anatoly & Kuprin, Alexander, 2018, Isotomidae of Japan and the Asiatic part of Russia. I. Folsomia ' inoculata' group, ZooKeys 750, pp. 1-40 : 23-24

Folsomia calcarea Potapov sp. n. Figs 69, 71-75

Type material.

Holotype, female, Russia, European part, Samarskaya District, Samarskaya Luka National Park, calcareous stone-pit, soil, 02.v.2010, coll. Y. Shveenkova. Six paratypes from the same location and maple forest nearby. Deposited in MSPU.

Diagnosis.

Blind. Body slender. Dorsal macrosetae (Md) present on both Th.II and Th.III. Sensillary formula incomplete (43/22235; 10/000). Medial s-setae on body tergites in anterior position. Th.III with 1+1 ventral setae. Anterior side of manubrium with 1+1 setae, dens with 6-7 anterior setae. Mucro bidentate.

Description.

Body size near 1.1 mm (for the largest subadult female). Body slender, tubular (Fig. 69). Cuticle with fine hexagonal primary granulation ( “smooth”). Ocelli absent. PAO slender, constricted, 1.8-2.5 as long as width of Ant.I and 2.3-2.7 as long as inner unguis length. Labium with five usual papillae ( A–E), guard setae e7 absent, three proximal and four basomedian setae. Ventral side of head with 3+3 postlabial setae. Ant.I with 11-12 common setae, two ventral s-setae (s) and three basal micro s-setae (bms), two dorsal (middle-sized and short) and one ventral (short), Ant.II with three bms and one latero-distal s, Ant.III with one bms and with four distal s (lateral s absent), without additional s-setae. Organite short and small.

Common setae short. Sensillary formula as 43/22235 (s), 10/000 (ms) (Fig. 71). Tergal s-setae thin and hardly differ from common seta, longer on dorsal side of Abd.V. Medial s-setae on Th. II–Abd.III situated in mid-tergal position, on Abd. I–III between Md and Mdl. Abd.V with five s-setae arranged as four ones (as, accp1, accp2, accp3), long and slender, and one latero-ventral, short ( ‘4+1’ pattern) (Fig. 72), accp3 s-setae almost as long as accp2 (0.9-1.2). Macrosetae smooth, 2,2/3,3,3 in number, medial ones on Abd.V as long as 0.8-1.3 of dens and 2.6-3.3 times longer than mucro. Metathorax with 1+1 ventral setae.

Unguis of normal shape, without lateral and inner teeth. Empodial appendage as long as 0.4-0.5 of unguis. Tibiotarsi with few setae: 21-22 on legs I–II and 24-27 on leg III. Upper and lower subcoxae of legs I–III with 0,1/3,5 –7/4–5,6– 6 setae, respectively. Coxae of leg I with two front setae. Ventral tube with 4+4 latero-distal and 4-5 posterior setae (four in distal transversal row), anteriorly without setae. Tenaculum with 4+4 teeth and a seta. Anterior furcal subcoxae with 3-4, posterior one with three setae. Anterior side of manubrium with 1+1 setae (Fig. 75). Posterior side of manubrium with 3+3 latero-basal, 4+4 on main part, and 1+1 setae on lateral side (Fig. 73). Dens with seven (rarely six) anterior setae (Figs 74 and 75). Posterior side of dens slightly crenulated and with three setae (two basal and one at the base of mucro. Mucro bidentate. Ratio of manubrium: dens: mucro = 2.8-3.9: 2.6-3.4: 1.

Remarks.

Two key characters, short furca and anterior position of medial s-setae on body tergites, are shared with only F. torpeda . F. calcarea sp. n. differs by ms-setae on Abd.I missing (vs present in F. torpeda ) and fewer number of setae on posterior side of manubrium. The absence of lateral s on Ant.III is shared only with F. breviseta sp. n. but value of this characteristic requires further study.

Distribution and ecology.

Known only from the type locality. The species possibly belongs to calciphilous fauna.

Derivatio nominis.

The species was recorded in calcareous soil.