Lepidocyrtus isabelleae sp. nov.

Figs 1–22, Tab 1

Type material. Holotype: female on slide (slide code: HNHM-collpr-795), Rum, Rumi Forest, com. Győr-Moson- Sopron (Hungary), 175 m above sea level, N 47°05'40" ; E 16°49'41", from forest litter, hand collecting, 0 9.08.2016, leg. Á. Erdő & D. Winkler. Paratypes: 2 females and 1 male on slide (slide codes: HNHM-collpr-796 to HNHM-collpr-798); same data as holotype. The holotype and paratypes are deposited in the Hungarian Natural History Museum, Budapest .

Other material. 29 specimens (same data as holotype) preserved in 96% alcohol (vial code: LEP-ISA-v001) in the author’s collection at the University of West Hungary, Faculty of Forestry, Sopron.

Diagnosis. Medium sized (1.6 mm of maximum length of body), variable coloured Lepidocyrtus species. Mesothorax not projecting over the head. Antennal segments and legs without scales. All labial chaetae (M1M2R*EL1L2) in “p row” well developed and ciliated, R* shortened. Apical bulb on Ant. IV absent. Dorsal cephalic and body macrochaetae formula as R0R1s R1R2STS o/00/0101+2. Abd. III with five dorsolateral macrochaetae.

Etymology. The species is named after author’s niece Isabelle De Bonis.

Description. Holotype body length 1.5 mm (without head nor furca), paratypes 1.3–1.6 mm. Mesothorax not projecting over the head (Fig. 1). Body color from greyish-blue to dark bluish-black, with Abd. IV always paler than other parts of trunk (Fig. 1). Ant. blue, with increasing intensity from base to apex of segments. Head anteriorly darker, posteriorly paler, marbled. Legs (except coxae) and furcula pale. On darker specimens blue shade also on legs, manubrium and ventral tube.

Scales densely cover the whole body, ventral surface of manubrium and dens. Ant., legs (beyond coxae) and dorsal surface of manubrium without scales.

Antennae long, antennal length to head diagonal length ratio is 2.0–2.3 (head diagonal measured from the cervical edge to the apex of the mouth part). Relation of the antennal joints I–IV as 1: 1.9: 2.3: 3.3. Antennal base with two pseudopores on the inner side and ventrolaterally with an antennobasal lenticular organ (sensu Hüther 1986) guarded by a sennsilla. Ant. III sensillary organ composed by two bent sensory rods partially behind a cuticular fold (Fig. 2). Ant. IV without apical bulb.

Arrangement of chaetae on the labrum 4/554, prelabral chaetae ciliated, first, second and apical row of labral chaetae smooth (Fig. 3). Labrum intrusion inverted V-shaped, labral edge with four distinguishably separated, equal-sized rounded labral papillae with no conical spine expansion (Fig. 3). Outer maxillary palp with two smooth chaetae and three smooth sublobal chaetae (Fig. 3). Lateral process (sensu Fjellberg 1999) on papilla E straight (Fig. 4), not reaching the top of papilla.

Labium chaetotaxy formed by 5 smooth "a" chaetae and in the basal row by ciliated chaetae M1M2R*EL1L2 (Fig. 5) with R* somewhat smaller than other chaetae (ratio of R*/M ~0.7). Ventral cephalic grove with 4+4 ciliated chaetae (Fig. 5).

Dorsal cephalic macrochaetae chaetotaxy R0R1R2STS o (Fig. 6), but also with pair of smaller supplementary macrochaetae R1s between R0 and R1 (Fig. 7). Maximum number of macrochaetae " A " on head 13+13 (Fig. 7).

Eye patches dark blue, eyes well visible. Diameters of ocelli A–F about the same, ocelli G and H slightly smaller (A:G; A:H = 1.2). Interocular chaetotaxy (Fig. 8) with s, t, p chaetae and 2–3 intraocular scales.

Body macrochaetae 00/0101+2 (Fig. 6). Dorsal chaetotaxy of Th. II–III and Abd. I as in Figs 9–11. Mesothorax with 2 anterolateral s-chaetae (al and ms) and without macrochaetae in posterolateral position (p3 =mesochaeta). Th. III with a sensillum (al) guarded by ciliated chaetae. Abd. I with lateral S-microchaeta (ms) external to a6. Chaetotaxy of Abd. II–III as in Figs 12–13. Abd. II chaetotaxy between two dorso-medial trichobothria characterized by mesochaetae a2, a2p, a3, p4, sensilla as and macrochaeta m3. Chaetae ml and m3e Features L. serbicus L. tomosvaryi L. isabelleae sp. nov. Sources on Abd. II absent. On Abd. III, apart from macrocheatae p6 and pm6 additional macrochaeta a7 with smaller socket present (Fig 14). Abd. III chaeta d3 present. Chaetae associated with trichobotria on Abd. II–III fan-shaped, except for chaeta a2 on Abd. II and Abd. III. Chaetotaxy and trichobothrial complex on Abd. IV as in Figs 15–16. Macrochaetae B5, B6, C1, D3, E2, E3, E4, F1, F2 and F3 broader with broad socket, while D2, De3, E1, E4p, E4p2, F3p, Fe4, Fe5, T6 and T7 thinner with smaller socket. Macrochaeta F2 above macrochaeta E3. Ratio of distances between macrochaetae C1–B5 / B5–B6 on Abd. IV 0.8–1.1. Accessory chaeta s associated with trichobotrium T2 absent. Abd. IV chaetae associated with two trichobotria fan-shaped (a, m, pe, pi), except for longer, ciliated mesochaeta D1. On anterior dorsomedial part of Abd. IV, 13 elongate sensilla (S-chaetae) also present. Smooth posterior mesochaetae (5) on Abd. IV present.

Legs without scales (except for coxae). Trochanteral organ with up to 20 smooth spiny chaetae forming a +/- V shape pattern (Fig. 17). Unguis and unguiculus as in Fig 18. Unguis with sub-equal paired basal teeth distinct (at 55%) from inner edge, and with unpaired teeth at 75% from inner edge. On six out of 24 specimens examined, very small subapical tooth at 88% from inner edge also present. Apart from two small lateral teeth an outer tooth also present. Unguiculus lanceolate, outer lamella smooth or finely serrated. Tibiotarsal tenent hair spatulate, as long as claw. Ratio of supraempodial chaeta (smooth chaeta on tibiotarsus III opposite to tenent hair) / unguiculus is around 0.7.

Ventral tube without scales, with 17+17 ciliated and 1+1 smooth chaetae on anterior side and 8+8 ciliated chaetae on posterior side (Fig. 19). Lateral flap (Fig. 20) with maximum of 17 laterodistal chaetae (10 ciliated and 7 smooth).

Manubrium and dens with scales on ventral surface. Dental tubercle absent. Mucro as in Fig. 21. Ratio manubrium/dens/mucro as 16:15:1. Manubrial plate with 2 inner chaetae and 4–7 chaetae outer 2 psp (Fig. 22).

Ecology and distribution. The specimens of L. isabelleae sp. nov. were found in the upper layer and litter of a lowland riverine oak-elm-ash woodland. This new Lepidocyrtus is a silvicolous, phytodetriticolous and hygrophil species.

Discussion. By dorsal macrochaetae chaetotaxy L. isabelleae sp. nov. is close to L. pseudosinelloides Gisin, 1967, L. serbicus and L. tomosvaryi Winkler & Traser, 2012 (Tab. 1). From L. pseudosinelloides the new species differs by the presence of Abd. II chaeta a2p and the absence of Abd. II chaeta m3e. L. isabelleae sp. nov. can be differentiated from the species L. serbicus also by the interocular chaetotaxy, the relative size of ocelli G and H, the morphology of labral papillae, the position of lateral process in relation to the top of the papilla E, the morphology of Abd. III chaeta a7, the presence of Abd. III chaeta d3 and the morphology of tenent hair on claw III. Another differential character of L. serbicus is the apical bulb on Ant. IV (Gruia & Popa 2005), which can, however, eventually also be absent (Ionut Popa pers. com.). From L. tomosvaryi also differs by the color pattern, the morphology of labral papillae and Abd. III chaeta a7, and the absence of dental tubercle.

The new species L. isabelleae sp. nov. bears some unique characters. The additional lateral macrochaeta (a7) on Abd. III has not been observed on any European Lepidocyrtus species so far. The pattern of tergal S-chaetotaxy also bears high taxonomic importance (Deharveng 2004; Zhang & Deharveng 2014, Mateos & Greenslade 2015). Notwithstanding, information on S-chaetae (sensilla) on the dorsomedial part of Abd. IV in European Lepidocyrtus is scarce. Apart from L. isabelleae sp. nov., a variable number of Abd. IV S-chaetae (other than as and ps) have also been noted on L. curvicollis (Bourlet, 1839), L. cyaneus Tullberg, 1871 and L. lanuginosus (Gmelin, 1788) (Deharveng 1979, Zhang & Deharveng 2014).