Vertagopus nunataki, Lafooraki & Hajizadeh & Antipova & Kremenitsa & Shayanmehr & Potapov & Hosseini, 2020

Lafooraki, Elham Yoosefi, Hajizadeh, Jalil, Antipova, Maria, Kremenitsa, Alexander, Shayanmehr, Masoumeh, Potapov, Mikhail & Hosseini, Reza, 2020, Vertagopus (Collembola, Isotomidae) of Iran and Caucasus, Zootaxa 4786 (4), pp. 574-582 : 578-580

Vertagopus nunataki sp. nov. Potapov & Kremenitsa

Figs 16–26

Type material. Holotype: subadult female (kept in MSPU). Russia, N Caucasus, Kabardino-Balkaria, Elbrus massive, rocky range above house „Odinadtsati“ 4300 m alt., N 43.3166, E 42.4623, moss and soil in cracks, 19.08.2002, leg. A. Babenko. Paratypes: 4 specimens on slides (kept in MSPU), the same data as holotype .

Description. Body size up to 1.5 mm. Body as common for the genus, not especially wider in posterior part ( Fig. 21 ). Deeply black, appendages paler (their exact pigmentation was difficult to ascertain since all type specimens have been cleared. 6+6 ommatidia, G and H not seen ( Fig. 19 ). PAO elliptical, ca. two times longer than nearest ommatidium and twise shorter (0.5–0.6) than Ant.I width. Maxillary outer lobe with 4 sublobal hairs and bifurcate palp. Labral edge with four sharp ridges. Frontoclypeal area with ca.10 setae. Labrum as 4/554. Labial palp with all papillae and 16 guards (e 7 present), 4 proximal, 4 basomedian and 5 basolateral setae. Ventral side of head with about 5+5 postlabial setae. Maxillary head with unmodified lamellae. Ant.I with 2 ventral bms and 4–5 ventral s of which 2 short ones in distal row. Ant.III with several short additional s-setae, inner sens of antennal organ small ( Fig. 20 ). Ant.IV with bifurcate subapical pin-seta and peg-like organite, apex with two papillae.

Macrosetae smooth, on Abd.V 0.6–0.7 as long as this segment length and 1.8–2.1 as long as inner edge of claw ( Figs 16–18 ). S-setae very shot, their number variable (see the Discussion): 4,4/3(2),3(1,2),3(2),4(2,3),5–6 ( Figs 16–18 ). On all segments accp -sens in p -row. Microsens 1,0/0,0,1 in number, on Abd.III ms as large as lateral s, associated with p -row or slightly in front of it. Th.III without ventral setae, Abd.II without ventromedial group of setae.

Legs with slender erect claws with two lateral and without inner teeth. Empodium with small inner tooth. Tibiotarsi with 11 setae in distal whorl, all T -setae present ( Figs 24–25 ). Clavate tenent hairs present, 3,3, 3 in number: A 1, A 2 and A 7. A 1 clavate tenent hair slightly longer (ca. 1.1) than inner edge of claw. Retinaculum with 4+4 teeth and 4 setae. Ventral tube with 4+4 laterodistal, 1–2+1–2 anterior and with about 8 posterior setae (number in distal transversal row uncertain). Furca ca 1.1 times longer than length of antennae. Manubrium with numerous setae on anterior side ( Fig. 22 ), with “double” row of setae on lateral sides ( Fig. 23 ). Manubrial thickening simple. Dens continuously narrowed, crenulated, with 10–13 setae on posterior side and numerous (ca. 60) on anterior. Mucro of variable shape ( Figs 26–27 ) with four teeth, often seems tridentate, apical tooth small, two proximal teeth at nearly the same level.

Discussion. The new species obviously resembles group of European alpine species (V. helveticus ( Haybach, 1980) and V. alpinus ( Haybach, 1972)) by deeply black body, erect claws and presence of e7 on labial palp. V. nunataki sp. nov. differs from the two species by presence of 3 (vs. 2) clavate hairs on tibiotarsus I and longer macrosetae which are 0.6‒0.7 as long as Abd.V segment (vs. 0.3–0.4). The length of clavate tenent hairs in the new species as common for the genus (vs. small in helveticus and alpinus). Vertagopus montanus Stach, 1947 probably belongs to this group (the description is insufficient) and differs from V. nunataki sp. nov. by normal (vs. slender) claw and 2 (vs. 3) clavate hairs on tibiotarsus I. The variability of number of s-setae on body is remarkable: basic set 4,4/3,3,3,4,6 indicate ‘westerlundi’ group but one or two s-setae can be lost on any abdominal segment, incl. Abd.V. V. nunataki sp. nov. also shares absence of ventral setae on Th. III with high arctic V. brevicaudus ( Carpenter, 1900) which differs in shorter furca, more setae on ventral tube and other characters.

Etymology. The species was named after habitat. Nunatak (from Inuit language) is a rocky element of ridge free of ice or snow within an ice field or glacier.

Distribution and ecology. Known only from the type locality. It is obviously an element of nival fauna in high mountains of the Caucasus.

Figures

FIGURES 16–21. Vertagopus nunataki sp. nov.: 16, Sensillar chaetotaxy of holotype (2); 17, Lateral s and micro s of Abd.III; 18, Chaetotaxy of Abd.V and posterior edge of Abd.IV; 19, Ocelli and PAO; 20, Setae s of Ant.III, dorso-lateral view; 21, Appearance, macrosetae are shown; s—s-seta, ms—micro s-seta.

FIGURES 22–27. Vertagopus nunataki sp. nov.: 22, 23, Anterior (22) and lateral (23) sides of manubrium; 24, 25 Distal part of tibiotarsi II (24) and I (25); 26, 27, Distal part of furca, variation.