Rharodesmus tabarkensis n. sp.

Figs 1–17

Material examined. 13 3, 8 ƤƤ, 14 juveniles, TUNISIA, Jendouba Governorate, Tabarka, N36°57.8, E8°44.6, alt. <40 m, coastal slope below the Genoese fort, under stones, 9.iii.2009, N. Akkari & H. Enghoff leg. (ZMUC). Etymology. Named after the type locality, Tabarka (northwestern Tunisia).

Description (all measurements in mm). Whitish to light brownish, 20 body rings in both sexes; length: 7–7.9 (males) and 7–8.2 (females); width of prozona 0.40–0.47 (males) and 0.37–0.52 (females); width of metazona: 0.88–0.95 (males) and 0.80–0.95 (females).

Head transverse; dorsal surface microgranulate, epistome with short scattered setae, labral and supra-labral surface with longer ones (Fig. 1). Antennae claviform and stout (Fig. 1), length of antennomeres: 5=6>3>2=4>7>1. Collum (Fig. 2): anterior margin with 10 distinct lobes; dorsal surface domed with numerous small tubercles and 4 bigger ones on the posterior margin.

Body rings: Prozona with fine longitudinal stripes on the anterior margin, followed by a scaly cellular structure covering most of the surface (Figs 3, 4). Posterior limit of the latter area marked by a row of tooth- shaped (dorsal side) or rectangular (ventral side) cuticular ‘cells’ forming a distinct transverse ridge. Prozona behind ridge (ca. ¼ of the length of prozona) with a regular covering of subhemisphaerical knobs.

Metaterga (following the terminology of Hoffman 1976) with 4 longitudinal–two paramedian and two dorso-lateral—rows of big tubercles (Fig. 4) and additionally smaller ones irregularly scattered over the lateral surfaces. Paraterga surmounted of a pair of big caudolateral tubercles (Figs 4, 5, 7, t). The three first body rings following the collum with 2 (sometimes 3) transversal tergal rows (Fig. 4), subsequent body rings with 3 rows (Fig. 5). Tubercles of the posteriormost body rings generally much bigger and strongly protruding caudad. Limbus narrow with regularly denticulate margin (Fig. 6). Paraterga well expanded with 3 lateral lobes on body ring 2 (Fig. 2) then becoming bilobed (Figs 2, 4), except on the poriferous rings. In latter rings, the posterior lobe bifurcating into a big lobe forming the porostele and a smaller posterior one (Figs 5, 7, p). Ozopores opening on porosteles, present on body rings 5, 7, 9, 10, 12, 13, 15 and 16 (Figs 5, 7, o). Legs almost invisible from above, length of podomeres: tarsus>femur>prefemur>postfemur= tibia>claw. Telson (Fig. 8): epiproct short and subtruncate, ventrally with scattered marginal setae and 4 spinnerets (Fig. 8, s) (cf. Shear 2008); paraprocts each with 2 setae, both located well away from mesal margin; hypoproct subtriangular with 2 strong setae on caudal edge.

FIGURES 7–8. Rharodesmus tabarkensis n. sp., close-up of ozopore and Telson: Fig. 7 Ozopore on the 16th tergite, adult male; Fig. 8 Telson, adult female. Abbreviations: lb: posterior lobe; o: ozopore, s: spinneret-like setae; t: caudolateral tubercle.

Male sexual characters. Tarsus of 1st and 2nd pairs of legs with ca 17 stout, spatulate setae; tibia of these legpairs with a few similar setae (Fig. 9). Coxal gonapophyses on 2nd pair of legs flattened (Fig. 10). Prefemur modified on the 7th and 8th pairs of male legs (Fig. 11): apically protruding into a pointed knob surmounted by a stout and contorted seta emerging from a densely poriferous basal area (Fig. 12).

FIGURES 9–12. Rharodesmus tabarkensis n. sp., secondary sexual characters in male: Fig. 9 Spatulate setae on right second leg; Fig. 10 Flattened coxal gonapophyses on second leg pair; Fig. 11 Modified prefemora on the 7th and 8th pairs of legs; Fig. 12 close up of prefemoral process and seta on the 7th left leg.

Gonopods: in situ with crossing telopodites (Figs 11, 13); coxa voluminous, covering most of the lateral side of the telopodite (Figs 11, 13, c), hemispherical with a granulate surface and a rounded-triangular smooth distal process (Fig. 14, 15, sp) surmounting a small setose hump (Fig. 14, 15, h), median margin with scattered short setae. Basal part of telopodite consisting of a big subrectangular, transverse, strongly granulated and setose ‘prefemoral’ part (Fig. 14, p) linked to the coxa by a small cannula (Fig. 14, ca); median margin of ‘prefemoral’ part with stout setae, becoming longer anteriad (Fig. 14). ‘Post-prefemoral’ part of telopodite elongated and distally divided in a short membranous rounded cylindrical branch (Figs 14, 16, r) and 2 processes of the same length: process A subrectangular (Figs 14, 16, A), folded interolaterad and distally serrated, especially on the margin; process B abruptly expanded distad (Fig. 16, B) and bifurcating into an elongated smooth conical process (Figs 14, 16, cp) and a shorter truncated one (Fig. 16, so) forming the solenomere; seminal groove arising from the bases of processes (A) and (B) and running into a lateral furrow up to the tip of the solenomere.