Ephemerotoma skarzynskii, Potapov, Mikhail, Kahrarian, Morteza, Deharveng, Louis & Shayanmehr, Masoumeh, 2015

Potapov, Mikhail, Kahrarian, Morteza, Deharveng, Louis & Shayanmehr, Masoumeh, 2015, Taxonomy of the Proisotoma complex. V. Sexually dimorphic Ephemerotoma gen. nov. (Collembola: Isotomidae), Zootaxa 4052 (3), pp. 345-358 : 347-351

Ephemerotoma skarzynskii sp. nov.

Figs 1–16 , 41

Material. Holotype subadult male: Iran, SE Kermanshah Province, Osmanvand rural district, Cheshmeh Sorkh village, 33°58.319' 047°18.018', 1913 m elev., oak forest, in leaf litter, 31. i. 2014, leg. M. Kahrarian. Paratypes (adult and subadult females): 20 specimens, same locality as for holotype. Type specimens deposited in IAU, MSPU, and MNHN.

Description. Size of fully developed adult unknown, from 1.5 to 1.7 mm in subadult individuals. Colour brown. Cuticle finely reticulated, size of largest polygons much smaller than bases of chaetae. Abd.V and VI with rugosity ( Figs 13 , 39 ), profile of Abd.V concave (slightly varies, less in juvenile specimens). Ocelli 8+8, G and H smaller. PAO narrow, elliptical, not constricted, as long as 1.4–2.1 ocellus diameter and 0.4–0.7 as long as U3. Maxillary outer lobe with simple maxillary palp and 4 sublobal hairs 2 of which larger ( Fig. 2 ). Maxillary head with unmodified lamellae. Labral formula as 2/554. Labium with all papillae (A–E), papillae A–D with normal number of guards (1,4,0,4), E with 4 guards ( Fig. 4 ), with 3 proximal and 4 basomedian chaetae. Ventral side of head with 5+5 postlabial chaetae (more rarely with 6 or 4 on one side). Ant.1 with about 30 chaetae, 2 small basal microsens (bms), one each dorsally and ventrally, the dorsal microsens often as a pair, 3–4 ventral sens (s) in females ( Fig. 5 ) and 5–8 in males ( Figs 6–7 ); increased number of sens in males due to additional pair in more lateral position. Ant.2 with 3 (rarely 4) bms and 1 laterodistal s, Ant.3 without bms and with 5 distal s (including one lateral spine-like), guard sens of AO 1.5 times the length of inner ones ( Fig. 3 ). Sens on Ant.4 weakly differentiated, subapical organite small.

Body with numerous and rather long chaetae. Dorsal axial chaetom of Th.II–Abd.IV variable: 9–11,8–9/7– 8,7–8,8–9,10–11. Common chaetae long and often curved, smooth ( Fig. 14 ). Th.III with 1–2 ventral axial chaetae on each side of ventral line, Th.I and II without ventral chaetae. Macrochaetae differentiated, medial chaetae on Abd.V as long as 0.30–0.45 of tergal midline, often curved apically. Sens on tergites clearly differentiated, short. S-formula as 3,3/2,2,2,2,4 (s) and 1,1/1,1,1 (ms). Sens on Abd.I–III in front of p-row of

chaetae. Microsens on Abd. I–III in front of lateral sens ( Fig. 1 ). On Abd.V sens arranged as one long pair in anterior position and one short pair in posterior position ( Figs 1 , 13, 14 ). Unguis simple, without inner or lateral teeth ( Fig. 10 ). Tibiotarsi with many chaetae: 28–31 chaetae on Ti.1 and 2, and>32 on Ti.3. B-row of chaetae on Ti.1–2 complete (B4 and B5 present). Tibiotarsal tenent chaetae (1,2,2), blunt, sometimes very slightly clavate, 1.1–1.4 as long as U3. Femur 1 with 10–12 a -chaetae, 1 ae -chaeta, 4–5 e -chaetae, and 15–17 chaetae of pe-p-pi-i - group (after the notation of Huang & Potapov 2012). Ventral tube with 6–9 chaetae on each side, 8 – 10 posterior chaetae. Tenaculum with 3+3 teeth and one chaeta. Anterior furcal subcoxae with 20–29 chaetae, posterior subcoxae with 10–15 chaetae. Furca well developed. Anterior side of manubrium with a pair of distal chaetae ( Figs 8 , 12 ), posterior side with about 30+30 chaetae on main part and 6+6 chaetae on laterobasal lobes ( Fig. 11 ). Dens stout, normally with 5 anterior chaetae arranged as 1,1,1,2, one of them always proximal, the others distal. Variants with arrangements as 1,1,1,1,2 and 1,1,1,3 also found ( Figs 8, 9 , 12 ). Posterior side of dens with clear humps and 7 (6–8) chaetae, arranged as 5–6 chaetae in proximal half, one at the middle and one distally. Mucro with 2 teeth, slightly lamellate. Ratio of manubrium: dens: mucro = 6.0–9.0: 4.0–6.0: 1.0.

Epitokous males. Reproductive males are absent in our collection so only preliminary description of their sexual dimorphism is possible so far. Subadult males show slightly broader antennae ( Fig. 16 ) and slightly thicker macrochaetae on lateral parts of the body tergites and head than in females ( Fig. 15 ). Males also have more sens on Ant.1.

Affinity. Among congeners the new species most closely resembles E. porcella (Mediterranean: Crete) by having a rugose swelling at the posterior margin of Abd.V ("rosette" of Ellis 1976), presence of ventral chaetae on metathorax, and similar sexual dimorphism. In the first description of porcella ( Ellis 1976) a ventral chaetotaxy of 0+0, 1+1, 0+0 was given for the three thoracic segments. We believe this was an error since such a combination has never been reported in Collembola . The new species differs by the presence of a distant proximal chaeta on anterior side of dens (encircled in Figs 8 and 9 ), and an increased number of sens on Ant.1; both characters are unique for the new species. In both E. skarzynskii sp. nov. and E. porcella the sexual dimorphism affects the head and body spines, which are grouped together on lateral parts of body tergites in males. The shape of basal segments of the antennae is also affected (swollen in males). Strict comparison of the dimorphism between the two species is impossible since E. skarzynskii sp. nov. is described based on females and non reproductive males while E. porcella was collected in a reproducing population.

Distribution and ecology. Known only from the type locality. The species was observed in mass aggregations in oak leaf litter and on the ground. It was recorded only in January and February and was absent in June and September.

Name derivation. It is our pleasure to dedicate this species to our colleague, Dr. Dariusz Skarżyński, the leading expert on collembolans of the family Hypogastruridae .

Figures

FIGURES 1 – 10. Ephemerotoma skarzynskii sp. nov.: 1, chaetotaxy; 2, outer maxillary lobe; 3, antennal organ of Ant. 3; 4, labium; 5 – 7, sens of Ant. 1 in females (5) and two males (6,7); 8, furca, lateral view; 9, dens, anterior view; 10, distal part of leg 3. ls—lateral sens, is—inner sens, gs—guard sens.

FIGURES 11 – 14. Ephemerotoma skarzynskii sp. nov.: 11, 12, Furca, posterior (11) and anterior (12) view; 13, profile of Abd. V and VI; 14, chaetotaxy of Abd. V and VI.

FIGURES 15 – 16. Habitus of female (15) and immature male (16) of Ephemerotoma skarzynskii sp. nov.

FIGURES 34 – 41. Posterior part of abdomen in genera Ephemerotoma and Proctostephanus: 34, E. porcella, Abd. V; 35, P. cidi, Abd. V, dorsal view, only sens shown; 36, posterior part of abdomen of P. sanctiaugustini, lateral view; 37 – 41, modification of posterior part of abdomen in Proctostephanus (37 – 39) and Ephemerotoma (40 – 41): P. c i di (37), P. stuckeni (38), P. anopolitanus (39), E. multituberculata (40), E. skarzynskii sp. nov. (41).