Gabunillo aridicola sp. nov.

(Figs 1–7)

Material examined. Holotype: 3 (MNRJ 21800), 6.0 mm long, 2.8 mm wide, in glycerin gel slides, dissected and drawn, around Gruta do Sobradinho, Sítio Pé Queimado, Aiuaba, Ceará State, Brazil, 12.vii.2002, L.A. Souza leg.

Paratypes: 1 Ƥ (MNRJ 21801) 4.0 mm long, 1.6 mm wide, in 75% ethanol, around Gruta do Sobradinho, Sítio Pé Queimado, Aiuaba, Ceará State, 12.vii.2002, L.A. Souza leg.; 1 3 (MNRJ 21802) 4.5 mm long, 2.1 mm wide, coated with gold-palladium, Lajedo da Soledade, Apodi, Rio Grande do Norte State, 28.viii.2007, M.S. Silva leg.; 1 3 (MNRJ 21803) 6.0 mm long, 2.3 mm wide, in 75% ethanol, dissected and drawn, Lajedo da Soledade, Apodi, Rio Grande do Norte State, 28.viii.2007, M.S. Silva leg.; 1 Ƥ, 6.9 mm long, 2.4 mm wide and 1 juvenile, 3.3 mm long, 1.4 mm wide (MNRJ 21804), in 75% ethanol, Lajedo da Soledade, Apodi, Rio Grande do Norte State, 28.viii.2007, M.S. Silva leg.

Diagnosis. Species of Gabunillo distinguished by the eyes formed by 13 ommatidia, posterior margin of pereonite 1 smoothly arched, forming an attenuate semi-circle, outer lobe of schisma longer and wider than inner lobe, and uropod exopod dorsally attached.

Description. Holotype, male (figure references also of male paratype MNRJ 21802). Body length 5 mm. Color light-brown, posterior margins of cephalon, pereonites and pleonites dark-brown. Habitus (Figs 1 B–D, 4A–B) body convex; volvational ability partial. Tergites (Figs 1 A–D, 4A) smooth, without granulations, tubercles or ribs, covered with scale-setae. Cephalon (Figs 1 B–D, 4A–B) frontal shield folded continuous with vertex, boundary between frontal shield and vertex marked by faint line starting at the eyes and interrupted in the middle. Lateral lobes weakly developed, median lobe absent. Eyes (Figs 1 A–D; 4A–B) with 13 well-pigmented ommatidia. Pereon (Figs 1 A, 4A, C–D) with schisma on pereonite I. Pereonites II and III (Figs 4 C–D) with transverse ridge on ventral surface (more developed in II). Epimera of pereonites II–IV very narrow. Male pereonite VII sternite with bilobed lamellar process, which is a synapomorphy for the family Armadillidae . Pleon (Figs 1 A, 4A) without ventral grooves or locking devices. Pleotelson (Figs 2 C, 4A, E) Tshaped, instead of hourglass-shaped, distal part much narrower than proximal, apex in situ reaching posterior margin of uropodal protopods.

Antennule (Fig. 4 B) with 3 articles, intermediate much shorter, distal article with a groups of at least 5 distal aesthetascs on inner (medial) latero-distal margin.

Antenna (Figs 1 A–E, 4A) short, reaching posterior margin of pereonite I. Last article of peduncle with conspicuous sensorial spine. Flagellum with 2 articles, distal one with row of few aesthetascs on proximal region. Distal cone short, about 1/5 as long as last article of flagellum, with free bristles, without sheath.

Mandibles (Fig. 5 A–B). Left mandible with 2 penicils on pilous lobe and 1 penicil between pilous lobe and molar process, this represented by a tuft of pilous bristles inserted on a socket. Right mandible with an intermediary penicil between pilous lobe and molar process.

Maxillule (Fig. 5 C) inner endite with 2 long hairy subequal penicils; latero-distal border ending in acuminate point. Outer endite with 4 teeth in outer group and 4 in inner group, of which at least 2 with small supplementary points.

Maxilla (Fig. 5 D) bilobed, both lobes densely setose on outer latero-distal margin, at least the seta closest to inner margin as a scale-seta; inner margin with thin setae on distal portion.

Maxilliped (Fig. 5 E) endite with outer latero-distal margin widely rounded. Endite with 3 small spines: 1 at inner distal angle, 2 below distal margin and 1 bristle.

Pereopods (Figs 1 F, 6A–B) of males and females similar, scarcely spined, most spines simple-pointed; dactylus with inner claw slightly smaller than outer claw; dactylar and ungual setae simple.

Genital papilla (Figs 2 A–B, 6C) with ventral shield surpassed by a lobe.

Male pleopods (Figs 3, 7). Pleopods 1 and 2 similar to those of G. c o e c u s. Endopod of pleopod 1 with grooved distal half, row of short, thick setae along medial side of dorsal groove. Pleopod 2 exopod with distal portion shorter and more acuminate than in G. c o e c u s; endopod thin, narrow, tapering. Male pleopod 5 with subtriangular exopod with at least 5 spines on outer latero-distal margin, at least the first one (scale-seta) closer to inner margin; inner margin finely setose on distal portion. No perceptible respiratory fields are present.

Uropods (Figs 2 C–E, 4A, F) with semi-rectangular protopods; endopods roughly cylindrical, ventral surface flattened, visible only in ventral view, reaching distal third of protopod; exopods conical, with conspicuous apical bristles, inserted dorsally on distal third of protopod.

Etymology. The species name is a noun in apposition (“dweller in the arid”) and refers to the semi-arid environment where this species is found.

Remarks. In the same way as happens with our sample, Schmalfuss & Ferrara (1983) have not reported females with marsupium, but considering that our animals are ca. 4–7 mm long and theirs only 3 mm, there is a good chance of ours being adults as well.

Gabunillo aridicola differs from G. c o e c u s by: 1. Well developed eyes with 13 dark pigmented ommatidia (as opposed to anophthalmy); 2. Body pigmentation light brown with dark-brown areas (as opposed to unpigmented); 3. Uropodal exopods inserted dorsally on protopods (as opposed to inserted distally); 4. Pereonite I with incomplete tiny groove along its margin (as opposed to complete); 5. Uropodal endopods in situ covered by telson in dorsal view (as opposed to extremities visible); 6. Dorsal tegument covered by scalesetae (or tricorns) that have a vertical stem arising from a cuticular depression and a Y-shaped scale overlying the stem (as opposed to scale-setae [“scale-spine” in Schmalfuss and Ferrara, 1983] with a serrate margin). Character states 1–3 are possibly plesiomorphic and 4–6 possibly apomorphic for the new species. It is not possible to compare the maxillula because it has not been described for G. c o e c u s.

Variation. The population of Apodi, RN is much lighter in color, almost unpigmented.

Geographic distribution. Brazil: Gruta do Sobradinho, municipality of Aiuaba, 6º34’S, 40º07’W, Ceará State (type locality), and Lajedo da Soledade, municipality of Apodi, 5º35’S, 37º48’W, Rio Grande do Norte State (Figs 8–9). Epigean, in the semi-arid, near entrances of caves.