Folsomia mongolica Huang & Potapov, 2020

Potapov, Mikhail, Huang, Cheng-Wang, Gulgenova, Ayuna & Luan, Yun-Xia, 2020, New and little known Isotomidae (Collembola) from the shore of Lake Baikal and saline lakes of continental Asia, ZooKeys 935, pp. 1-24 : 1

Folsomia mongolica Huang & Potapov sp. nov. Figures 32-39 , 40-42

Type material.

Holotype: female. NE China, E Inner Mongolia Autonomous Region, Hulun Buir, New Barag Zuoqi, Xinbaoligexi Sumu, Bayin Chagan Nuori Lake, at shore of the saline lake, 48.38°N, 118.71°E, 669 m alt., 09.VIII.2014, coll. C.W. Huang and M. Potapov. 20 paratypes from the same place. Holotype and 10 paratypes deposited in SEM, 5 - in MSPU, 5 - in SMNG.

Other material.

NW China, E Inner Mongolia Autonomous Region, Hulun Buir, New Barag Zuoqi, Xinbaoligexi Sumu, Hujiri Nuo Ergacha Lake, at shore of the saline lake, 48.30°N, 118.56°E, 649 m alt., 09.VIII.2014, coll. C.W. Huang and M. Potapov. China, W Inner Mongolia Autonomous Region, Helan Mts., near Halawu, mixed sample from broadleaved bush and coniferous trees, 2325 m alt., 08.VIII.2010, coll. C.W. Huang and Y. Bu.

Description.

Size 1.0-1.3 mm. Body of normal shape (Fig. 32 ). Usually without pigmentation apart from two contrasting black ommatidia on each side of head (Figs 32 , 33 ). Darker specimens with diffuse black grains also on head and trunk. Specimens with weak eye pigmentation sometimes occur among normal ones, while cornea of ocelli are still distinct. Juveniles almost unpigmented. Cuticle with weak hexagonal primary granulation ( “smooth”), thin belts of courser granulations at posterior edge of head, between Abd.IV and V and on medial line of thorax. Two widely separated large subequal ocelli on each side of head, like in F. quadrioculata (Tullberg, 1871) (Fig. 38 ). PAO narrow, well constricted, 1.1-1.4 as long as width of Ant.1 and 1.6-1.9 as long as inner unguis length. Maxillary outer lobe with four sublobal hairs, maxillary palp simple. Labral formula as 4/554. Labium with five papillae ( А-Е) and full set of guard setae (e7 present), with three proximal and four basomedian setae. Ventral side of a head with 4-5+4-5 postlabial setae. Ant.1 with three ventral s-setae and three short basal ms-setae (bms), two dorsal and one ventral (Fig. 38 ), Ant.2 with three bms and one latero-distal s, Ant.3 with one bms and with five distal s (including one lateral), without additional s-setae. S-setae on Ant.4 weakly differentiated. Organite small.

Macrosetae smooth and short, 1,1/3,3,3 in number (Fig. 40 ), medial ones on Abd.V 0.4-0.5 as long as dens and 2.0-3.1 as long as mucro. No foil setae at the tip of abdomen. Axial chaetotaxy as 8-10,7-8 /5,5,4-6 for Th.II-Abd.III. Thorax without ventral setae. S-formula as 4,3/2,2,2,3,5 (s), 1,0/1,0,0 (ms) (Fig. 40 ). Tergal s-setae as long and wide as common setae and hard to observe. Medial s-setae on Th.II-Abd.III situated in mid-tergal position, on Abd.I between Mac1 and Mac2, on Abd.II and III behind Mac2 (Fig. 40 ). Abd.V with five s-setae arranged as three dorsal ones (al, accp1, accp2), middle-sized and slender and one lateral (accp3) 2/3 as long as dorsal, and one ventral (the shortest, Fig. 41 ).

Unguis of normal shape, without lateral and inner teeth. Empodial appendage about half as long as unguis. Tibiotarsi with few additional setae on Legs 1 and 2 (23-25 setae), Leg 3 more polychaetotic. Tibiotarsal tenent setae pointed. VT with 4+4 (3+3 in small juveniles) laterodistal and six posterior setae, no anterior setae (Fig. 42 ). Tenaculum with 4+4 teeth and one seta. Anterior furcal subcoxae with 12-20 setae, posterior one with 4-6. Anterior side of manubrium with 2+2 setae (Figs 34 , 37 ). Posterior side of manubrium with 4+4 laterobasal, two apical setae (ap), 3+3 setae in distal transversal row (M1, m1, L1), and 6-7+6-7 in central part (Fig. 39 ). Two pairs of lateral setae present. Dens with 12-14 (rarely 11 or 15) anterior setae (Figs 34 , 37 ). Posterior side of dens crenulated, with seven setae: four setae at base one of which larger, two at middle part, and one rudimentary subapical seta which is often absent or hardly seen (Figs 35 , 36 ). Mucro bidentate. Manubrium a little shorter than dens. Ratio of manubrium: dens: mucro = 3,9-5,4: 4,7-6,2: 1. Males present.

Affinity.

The species belongs to " heterocellata " group due to simple maxillary palp. F. mongolica sp. nov. is very similar to two other species inhabiting arid landscapes of continental Asia: F. pseudodecemoculata Stebaeva, 1971 and F. heterocellata Stebaeva & Potapov, 1997. All three forms have no body pigmentation and share several important characters: structure of furca, body chaetotaxy, number of s-setae on antennae. The only sharp difference is number of ocelli on each side of the head: two in F. mongolica sp. nov., four in F. heterocellata , and five in F. pseudodecemoculata . The last species has shorter PAO than in the new species. F. montana Martynova, 1971 (1971b) (high mountains plateaus of Kirghisia) also belongs to " heterocellata " group and has 2+2 ocelli, but differs by three basal setae on posterior side of dens (vs. four in F. mongolica sp. nov.), 3+3 (vs. 4+4) laterobasal setae on posterior side of manubrium, and shorter PAO.

Distribution and ecology.

The species is probably distributed in Inner Mongolia (China). This halophilic species is abundant on saline lands but also inhabits dry forest slopes.

Name derivation.

It is named after the location of type place (Inner Mongolia Autonomous Region).

Figures

Figures 32 - 39. Folsomia mongolica sp. nov. 32 appearance 33 pigmention of eye areas (two different specimens) 34 dens and distal part of manubrium, anterior view 35, 37 dens, posterior (35) and lateral (37) views 36 distal part of dens and mucro, another specimen, posterior view 38 ommatidia, PAO, and Ant. 1 39 manubrium, posterior view. Abbreviations: s-s-seta.

Figures 40 - 42. Folsomia mongolica sp. nov. 40 s-, ms-setae, and macrosetae on body tergites 41 s-setae and macrosetae of Abd. IV-VI (common setae shown as sockets, only p-row of setae presented on Abd. IV) 42 ventral tube, lateral view. Abbreviations: s-s-seta, ms-micro s-seta.