Allonychiurus subvolinensis, Babenko, Anatoly B., Chimitova, Ayuna B. & Stebaeva, Sophya K., 2011

Babenko, Anatoly B., Chimitova, Ayuna B. & Stebaeva, Sophya K., 2011, New Palaearctic species of the tribe Thalassaphorurini Pomorski, 1998 (Collembola, Onychiuridae), ZooKeys 126, pp. 1-38 : 21-22

Allonychiurus subvolinensis sp. n. Figs 45-49

Material.

Holotype ♂, Russia, Tuva Republic, northern macroslope of Eastern Tannu-Ola Mt Range, 5 km S of Lake Chagytai [51°00'N, 94°43'E], larch forest belt, 1,300 m alt., under larch ( Larix sibirica ), 16.vi.2003, leg. S.K. Stebaeva (MSPU).

Paratypes ♂, same region and locality, ca 1,400 m, 17.vi.2003; ♀, same region, meadow steppe, ca 1,200 m alt., under Dracocephalum ruyschiana , 17.vi.2003; 6♀ and 3♂, Russia, Tuva Republic, southern macroslope of Eastern Tannu-Ola Mt Range, 20 km N of Khol’ -Oozhu [50°44'N, 94°23'E], 1,600 m alt., meadow steppe, under Spiraea sp., 16.vii.1993; 7 specimens, Russia, Tuva Republic, foothills of southern macroslope of Eastern Tannu-Ola Mt Range, basin of Aryskannyg-Khem River, 15 km E of Khol’ -Oozhu [50°41'N, 94°35'E], ca 1,100-1,250 m alt., dry steppe, under Nanophyton grubovii , 17.vii.1993; 12♀ and 10♂, Russia, Tuva Republic, Sangelen Plateau, 25-30 km NE of Erzin [50°15'N, 95°09'E], ca 1,000 m alt., upper terrace of Erzin River, steppe with Caragana spinosa , 03viii.1995, all leg. S.K. Stebaeva (MSPU).

Description.

Colour white. Size 0.55-0.62 mm. Body slender and elongated, slightly wider in region of Abd.4. Antennae about as long as head, antennal area not clearly demarcated. Ant.4 rather short and wide, 2 usual sensilla not especially thickened but distinct, a subapical organite and a basal microsensillum present. Ant.3 organ consisting of 4 low papillae, 2 sensory rods, 2 smooth sensory clubs without clear ribs, 5 guard setae, and a lateral microsensillum. Ant.1 and 2 with 8 and (12)13 setae, respectively. PAO wide (length/width ratio ca 1.5), with about 7-10 composed vesicles set close together. Labrum as a rule with 7 setae and 4 prelabral ones, but holotype with an abnormal number of setae set asymmetrically. Apical part of labium with thick terminal setae on papillae A, B and C (ABC - type), seta A clearly thicker, 6 long (e2 absent) and four spiniform (a1, b1-2 and d2), guard setae, a1shorter than others. Proximal field of labium with 5 setae, basal fields (mentum and submentum) with 4 and 5 setae. Maxillary palp simple, with 2 sublobal setae.

Pseudocellar formula (pso) as follows, dorsal: 32/233/33343 (Fig. 45), ventral: 11/000/1112. Each upper subcoxa with two pso. Granulation fine and uniform, without areas of enlarged granules. Dorsal chaetotaxy more or less symmetrical, setae smooth and rather thick, clearly differentiated only on abdominal tip, sensilla: 1/011/222111 (dorsal) and 2/000/00010 (ventral), but distinguishable mainly because of their stable positions, only lateral ones on Th.2-Abd.1 and posterior one on Abd.5 always distinct (Fig. 45), as well as a sensillum on coxae of Lg.3. Th.1 with 5+5(6) setae. Terga of Th.2-Abd.1 with 3, Abd.2-3 with 3(4), Abd.4 with 2-3 and Abd. 5 with 1, pairs of axial microsetae, additionally each tergum with 1+1 posterior axial mesosetae set slightly out of line with microsetae. Some unpaired dorsal setae also present: d0 on head, microseta m0 on Abd.4, microseta a0 on Abd.5, and two macrosetae a0 and m0 on Abd.6, supplemented by 2+2 prespinal microsetae (Fig. 45, 49). Lateral microsensilla present on both Th.2-3.

Each sternum of Th. 1-3 with 1+1 setae along linea ventralis. Secondary division of Abd.3 sternum unclear because of bad preservation. Furca reduced to a small area of fine granulation situated at some distance from border between Abd.3-4 sterna with 2+2 small posterior setae arranged in 2 rows (Fig. 46), manubrial area with 4+4 setae arrange in 2 rows but only one of them set posteriorly to dental setae (Fig. 46). Ventral tube usually with 1+1 frontal, 6+6(5-7) distal and 2 proximal setae at corpus base. Upper subcoxae usually with 4-4-4, tibiotarsi with 18-18-18. setae: distal row on each leg with 9 setae (7 A and 2 T-setae), 7 setae in row B, setae M and Y present (Figs 47-48). Unguis simple, with neither inner nor lateral tooth, unguiculus narrow, almost as long as unguis (ca 0.9 U3).Anal spines thick and slightly curved, set without clear papillae. Reproductive males with MVO identical to that in Allonychiurus volinensis with 4+4 modified club-like setae in mid-ventral section of Abd.4 behind furcal remnant (Fig. 46), in not reproductive males these setae spiniform.

Affinities.

Allonychiurus subvolinensis sp. n. is very similar to the European Allonychiurus volinensis (Szeptycki, 1964), comb. n. in many features. Both have a somewhat isolated position within the volinensis-group of Allonychiurus due to the wide PAO, the presence of MVO on Abd.4 and the different positions of pso at the antennal base, with b-pseudocelli set closer to the mid-line than a-pseudocelli. They can easily be distinguished from each other due to the different number of tibiotarsal setae (9 setae in distal whorl in Allonychiurus subvolinensis sp. n. versus 7 setae in Allonychiurus volinensis ) and by the presence of ventral setae on all thoracic sterna in Allonychiurus subvolinensis sp. n. ( Allonychiurus volinensis lacks setae on Th.1). The third very similar species of the same group, Allonychiurus unisetosus sp. n., is described below. For differences with Allonychiurus volinensis and Allonychiurus subvolinensis sp. n. see the description of Allonychiurus unisetosus sp. n.

Etymology.

The name reflects the general similarity to Allonychiurus volinensis .

Distribution.

The new species was previously listed for Tuva as Onychiurus s.str. by Stebaeva (2003). It appears to be rather common in the region in various plant communities, from mountain forests to arid steppes.