Oligaphorura montivaga, Shveenkova & Babenko, 2022

Shveenkova, Yulia B. & Babenko, Anatoly B., 2022, Three new Oligaphorura species (Collembola: Onychiuridae) of the marcuzzii-group from the Caucasus, Zootaxa 5116 (4), pp. 579-590 : 581-583

Oligaphorura montivaga sp. nov.

Figs 3 , 9 – 14 ; Table 1

Type material. Russia: holotype, male, Northern Caucasus, North Ossetia-Alania, Alagir District, North Ossetia State Nature Reserve , vicinity of Nar [42.6792°N, 44.0303°E], 1780 m alt., pine forest, soil and litter, 20.06.2016, N. Kuznetsova & A. Geraskina leg. Paratype: female, same data as holotype. The types are kept in the MSPU collection .

Diagnosis. Body cylindrical. Dorsal sensilla on body well-marked. Anal spines absent. Pseudocellar formulae 43/144/44354 (dorsal), 11/000/1112 (ventral), 222 (subcoxal). Ventral psx hardly visible. AIIIO with 5 papillae. PAO slightly larger than nearest pso, with 3–4 lobes. Labium of ABD-type (papilla E entirely absent). Th. III without lateral ms. Abd. IV with unpaired seta p0. Tibiotarsal chaetotaxy complete: distal whorls (A+T) of each Ti with 11 setae. Furcal remnant of schoetti - type, with a small cuticular fold.

Description. Size 0.61–0.65 mm, holotype 0.61 mm. Colour white in alcohol. Body cylindrical. Granulation regular, slightly coarser around dorsal pso (11–13 granules) ( Fig. 9 ).

Number of pso: 43/144/44354 (dorsal) and 11/000/1112 (ventral) ( Figs 9–11 ). Ventral psx virtually invisible, only in few cases their asymmetric presence on Abd. II still being detected ( Fig. 10 ). Each upper Sc of legs I–III with 2 pso.

Antennae slightly shorter than head. Ant. IV with 3 poorly thickened S-setae, subapical organite present, microsensillum located in proximal row of setae ( Fig. 13 ). AIIIO on Ant. III consisting of 5 papillae, 5 guard setae, 2 sensory rods, 2 granulated clubs (external one larger) and lateral ms. Ant. I–II with 9 and 14 setae, respectively. Antennal area not marked. PAO located laterally in a cuticular furrow, with 4(3) lobes, slightly larger than nearest pso. Maxilla unmodified. Maxillary palp simple with 1 basal seta and 2 sublobals. Labrum with 4/342 setae. Labium with 6 proximal, 4 basomedian and 5 basolateral setae, terminal sensilla of papillae A, B and D thickened, papilla C and its terminal sensillum clearly shorter, papilla E entirely absent (labium of ABD type) ( Fig. 12 ). Ten guard setae present on labial palp, four of them spiniform as usual, six others also rather short. Their exact assignment problematic: four guards located on site of reduced papilla E, and other two—next to papillae B and D.

Dorsal setae poorly differentiated into macro—and microsetae, symmetrical in general ( Fig. 9 ). S-setae well marked and distributed as follows: 11/022/22211 (dorsally), 11/000/000101 (ventrally) and 0, 0, 1 on lower Sc of legs I–III. Head with an axial unpaired seta a0, but without a0’, d0 being absent as usual for the genus. Setae p1 on head at level with p2. Th. I with 5+5 dorsal setae. Lateral ms present only on Th. II and absent on Th. III. Terga of Th. II–Abd. III with 3–4 pairs of axial setae. Abd. IV with an unpaired seta p0. Setae a0 and a2 on Abd. VI almost equal in length, setae a1 half as long as a0. Thoracic sterna with 0-1-1 setae each side of ventral line. Ventral chaetotaxy as in Figs 10–11 .

Upper subcoxae of legs I–III with 4(3), 5(3), 5(3) setae, respectively. Tibiotarsal chaetotaxy complete with 20–21–19 setae, respectively: distal whorls (T+A) with 11 setae, 7 B-setae (B7 absent only on Ti III), one seta (or two on the second leg) of C-whorl and an unpaired seta M. Unguis with neither inner nor lateral teeth, unguiculus with a narrow basal lamella, about half as long as inner edge of unguis ( Fig. 14 ). VT with 6+6 proximal and (1)2+2 setae at base. Furcal remnant of schoetti - type, cuticular fold small, sometimes indistinct ( Figs 3 , 10 ). Each lateral anal valve with a0 and 2a1 setae, unpaired valve with a0, 2b1, 2b2 and 7 setae in c-row (b0 and a1 absent). Anal spines absent.

Etymology. The species is named after its habitat preferences, derived from montivagus (Lat.) [mons + vagor] meaning a mountain wanderer.

Affinities. The main diagnostic features of all known representatives of the marcuzzii -group are shown in Table 1 . According to these data, O. montivaga sp. nov. is most similar to O. kremenitsai and O. humicola , in which the labial palps are also of the ABD-type with short guards. Trio clearly differ in pso-formulae (43/144/ 44354 in O. montivaga sp. nov., vs 42/144/ 33354 in O. kremenitsai and 42/133/ 33354 in O. humicola ), the types of the furcal area (the “schoetti”- type in O. montivaga sp. nov. compared to the humicola - type in both O. kremenitsai and O. humicola ) and the number of tibiotarsal setae (11 distal setae in O. montivaga sp. nov., vs only 6 such setae in both O. kremenitsai and O. humicola ).

Differences of O. montivaga sp. nov. from O. tatianae sp. nov. and O. igori sp. nov. are to be found in the Affinities sections of the respective species descriptions, as well as in Table 1 .

It is noteworthy that O. montivaga sp. nov. is not the only species of the group inhabiting the area under study. A few specimens of another, still undescribed form characterized by the same type of the labium but a different pseudocellar formula and a different number of distal setae on the tibiotarsi, have been found in an adjacent territory (North Ossetia – Alania, North Ossetia Nature Reserve, Tsey River gorge, pine forest, litter [42.7972°N, 43.9243°E], ~ 1670 m alt., 20.06.2016, leg. N. Kuznetsova & A. Geraskina). Unfortunately, all of them are juveniles that cannot be described at the moment.

Figures

FIGURES 1–8. Types of furcal area in Oligaphorura species. 1–5, S or schoetti-type: 1–2, two different interpretations, Oligaphorura tatianae sp. nov.; 3, Oligaphorura montivaga sp. nov.; 4, Oligaphorura igori sp. nov.; 5, O. psammophila Shveenkova & Babenko, 2021; 6, A or absoloni-type, O. jiguliensis Shveenkova & Babenko, 2021; 7, H or humicola-type, O. kremenitsai; 8, D or differens-type, O. imosolica Shveenkova & Babenko, 2021.

FIGURES 9–12. Oligaphorura montivaga sp. nov.: 9, dorsal chaetotaxy; 10, ventral chaetotaxy of abdomen; 11, ventral chaetotaxy of head; 12, labial palp with basomedian and basolateral parts of labium (spiniform guards not shown). Scales. Figs 9–11: 0.05 mm; 12: 0.025 mm.

FIGURES 13–18. Oligaphorura montivaga sp. nov. (13–14), Oligaphorura tatianae sp. nov. (15–16), Oligaphorura igori sp. nov. (17–18): 13, antenna, different views; 14, tip of leg II; 15, tip of leg I; 16, antenna, different views; 17, antenna, different views; 18, tip of leg I. Scales. Figs 13, 16, 17: 0.05 mm; 14, 15, 18: 0.025 mm.