Folsomia macrochaetosa Martynova in Martynova, Berman & Chelnokov, 1977

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 : 15

Folsomia macrochaetosa Martynova in Martynova, Berman & Chelnokov, 1977 Figs 47-49, 90

Type Material.

Three paratypes labelled as "Magadanskaya Region, vicinities of Magadan, Snow Valley, dwarf-wood belt. 18.ix.1974. coll. Berman." Kept in Zoological Institute (S.-Petersburg).

Other material.

Far East of Russia, Khabarovsky Krai, Vicinities of Nikolaevsk-na-Amure, lower flow of Amgun’ River, larch and birch forests, 1.vii.1990, coll. N. Ryabinin; Primorsky Krai, Ussuriysky Reserve, Komarovskoye Forest District, mixed forest, 22.vii.2016, coll. M. Potapov and N. Kuznetsova; Terneysky District, Sikhote-Alinski Reserve, Kabany station, hardwood with Rhododendron , litter, 08.viii.2017, coll. N. Kuznetsova, A. Geras’kina, A. Kuprin; South Kuril Islands, Kunashir Isl., Krugly Cape and 5 km E Yu-Kuril’sk, viii–ix.1997, coll. Y. Marusik.

South Korea, Gangwon-do, Palsan Mt., mixed forest in foothills, litter, 09.ix.2017, coll. A. Kuprin.

Description.

Body size from 0.9 to 1.5 mm. Body without pigmentation, cuticle with fine primary granulation. Ocelli absent. PAO slender, constricted, 1.4-1.6 as long as width of Ant.I and 1.4-2.2 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 a head with 4+4 postlabial setae. Ant.I with 15-16 common setae, s-setae of antennae as in F. imparis sp. n. Organite stick-like, small.

Common setae long. Sensillary formula as 43/22235 (s), 10/100 (ms). Tergal s-setae long, medial ones on Th. II–Abd.III situated in posterior position. 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), accp3 s-setae somewhat shorter than accp2 (accp2: accp3 = 1.1-1.5). p1-setae on Abd.V long (Fig. 47, see also the Discussion and Table 2). Macrosetae smooth and long, 2,2/3,3,3 in number, medial ones on Abd.V 1.3-1.7 times shorter than dens and 4.6-6.4 times longer than mucro. Metathorax with 3+3 ventral setae, one long.

Unguis of normal shape. Empodial appendage as long as 0.50-0.55 of unguis. Chaetotaxy of tibiotarsi and subcoxae similar to F. amurica sp. n. and F. imparis sp. n. Number of front setae on coxae of leg I varies (2-3), variant with two setae common for specimens from Magadan and Kunashir. Ventral tube with 4+4 latero-distal and 6-8 posterior setae, anteriorly without setae. Tenaculum with 4+4 teeth and a seta. Anterior furcal subcoxae with 11-12, posterior one with five setae. Anterior side of manubrium with 2 –3+2– 3 pairs of setae (2+2 usually in males), without axial unpaired setae (Figs 48-49). Dens with 21-30 anterior setae. Posterior side of dens crenulated and with six normal setae and one rudimentary at the base of mucro. Mucro bidentate. Ratio of manubrium: dens: mucro = 4.3-5.7: 6.4-10.0: 1. Males present.

Remarks.

F. amurica sp. n., F. imparis sp. n., F. macrochaetosa , and F. setifrontalis combine a group of species with long macrosetae and furca, sparse setae covering, and posterior position of median s-setae on all tergites. The differences between the species of this subgroup are shown in Table 2.

Distribution.

Scattered records all over the coastal areas from Magadan (Russian Far East) to South Korea (Fig. 90).