Levantoniscus bicostulatus n. sp.

Figures 1–6

Material examined. Cyprus: 1 ♂ Holotype (MZUF 9609), Kampos Potamos, northern slopes of Troodos Mt., 35°04’44.80’’N 32°44’06.15’’E, 430 m, 29.XI.2012, leg. S. Sfenthourakis; 5 ♀ Paratypes (MZUF 9609), same data as Holotype; 6 ♂, 6 ♀ Paratypes (MZUF 9610), same locality, 25.III.2015, leg. S. Sfenthourakis; 1 ♀ Paratype (MZUF 9611), Chalefka, Pentadaktylos Mt., 35º17’09.03’’N 33º32’08.28’’E, 520 m, 5.XII.2012, leg. S. Sfenthourakis; 2 ♂, 3 ♀ Paratypes (MZUF 9612), Akanthou, northern slopes of Pentadaktylos Mt., 35º22’09.73’’N 33º45’18.10’’E, 120 m, 5.XII.2012, leg. S. Sfenthourakis.

Description. Maximum size: ♂: 4.0 x 2.7 mm, ♀: 4.2 x 2.0 mm. Colour in ethanol: head with brown lobes and pale vertex; pereonites brown in median part, two pale stripes between tubercles and epimera; pereon and pleon epimera brown; tergites of pleonite 4 and 5 pale; antennae, pereopods, pleopods, telson and uropods pale. Body with distinct dorsal ornamentation (Figs 1 A, B, 5A–C, E) disposed as follows: two quadrangular lamellar tubercles on posterior part of cephalon and an oblique line of four low rounded tubercles on each side next to eyes; two quadrangular lamellar tubercles on each pereonite, and two on pleonite 1; two, progressively more pointed tubercles on pleonites 2–4; no tubercles on pleonite 5 and telson. Dorsum with cuticular structure consisting of hexagonal or pentagonal cells and small wart-like protuberances (Fig. 5 D), whole surface covered with long piliform setae (Fig. 1 C), which are longer and denser on tubercles; noduli laterales (Fig 1 A, B) on pereonites 1–4 inserted on outer surface of tubercles near tubercle posterior corner, and on pereonites 5 to 7 on postero-lateral corner of pereonites, progressively closer to posterior margin. Cephalon (Figs 1 D, 5B) with quadrangular frontal lateral lobes, obliquely directed outwards, and rectangular median lobe more protruding than lateral lobes and directed upwards. Eyes small with five ommatidia. Epimera (Figs 1 A, B, 5A) of pereonite 1–3 quadrangular with posterior margins slightly concave; epimera of pereonites 4–7 progressively more acute and backwards directed. Telson (Fig. 5 C) almost twice as broad as long, distal part with rounded corners and very slightly concave distal margin. Antennula (Fig. 1 E) with second article shorter than first and third; distal articles with two apical and five subapical aesthetascs. Antenna (Fig. 1 F) short, reaching posterior margin of pereonite 1; flagellum slightly shorter than fifth segment of peduncle, first flagellar article 3 times shorter than second, second flagellar article with row of three aesthetascs. Right mandible (Fig. 2 A) with 1+1 and left mandible (Fig. 2 B) with 2+1 free penicils. Maxillula (Fig. 2 C) outer branch with 4+6 teeth; inner branch with distinct triangular posterior point and two subequal penicils. Maxilla (Fig. 2 D) with inner lobe 1.5 times larger than outer lobe, covered with thick apical setae; three large setae between two lobes. Maxilliped (Fig. 2 E) endite with broad and rounded distal margin bearing three triangular teeth and long seta; pulp short with proximal article bearing two thick setae. Pereopod 1 (Fig. 3 A) carpus with antennal brush consisting of large area of short setae obliquely directed. Pleopods with uncovered lungs largely exposed on exopodites 1 and 2 (Fig. 6 A, B), and in invaginations on exopodites 3–5 (Fig. 6 C, D). Uropod (Fig. 2 F) protopodite with concave outer margin, not grooved; exopodite ventrally grooved, slightly longer than endopodite and reaching distal margin of telson.

Male. Pereopod 1 (Fig. 3 A) merus and carpus with line of strong setae on sternal margin. Pereopod 7 (Fig. 3 B) with enlarged basis, ischium with straight sternal margin, merus and carpus with slightly concave sternal margins. Pleopod 1 (Fig. 3 C, D) exopodite small, subrectangular, about 2.5 times as wide as long; endopodite with thickset distal part and pointed apex. Pleopod 2 (Fig. 3 E, F) exopodite triangular distinctly shorter than endopodite. Pleopod 3 (Fig. 4 A, B) and 4 (Fig. 4 C, D) trapezoidal with distinctly concave distal margin; pleopod 5 (Fig. 4 E, F) trapezoidal with distal margin oblique and almost straight.

Etymology. Latin: bi = double + costulatus = with ribs. The name of the species refers to the double line of lamellar tubercles on the cephalon, pereon and pleon.

Remarks. The species has been found only at the close vicinity of running water, under leaves and stones hidden inside the wet litter layer of hygrophilic plants. Taking into account its dorsal ornamentation, the species should be considered rather as an endogean species, coming to the surface only in locations with very high humidity.