Caraiboscia jabutiensis Campos-Filho, Taiti & Bichuette, n. sp.

(Figs 6; 7; 8B)

urn:lsid:zoobank.org:act: 6624633A-A478-4C60-B44A-422EE464D4AF

TYPE MATERIAL. — Holotype. Brazil • ♂; Caverna do Jabuti, Curvelândia, state of Mato Grosso; 15°33’56.1”S, 57°59’20.04”W; 324 m a.s.l.; 29.IX.2017; J. E. Gallão, A. Chagas-Jr & R. Machado leg.; LES 27985.

Paratypes. Brazil • 1 ♂ (parts in micropreparations), 2 ♀ (one with parts in micropreparations); same data as holotype; LES 27986 .

ETYMOLOGY. — The new species name refers to the locality where specimens were collected: Caverna do Jabuti.

DESCRIPTION

Maximum body length: ♂ 3 mm, ♀ 4 mm. Body pigments and eyes absent; cephalon with yellowish spots of muscle insertions. Body (Fig. 6A) with lateral sides almost parallel. Dorsal surface of cephalon and pereonites 1-3 slightly granulate, 4-7 only on posterior portion. Dorsal scale-setae triangular (Fig. 6B). Noduli laterales d/c and b/c coordinates as in Figure 6C and D, respectively. Cephalon (Fig. 6E, F) with lateral lobes triangular, slightly developed, suprantennal line faintly visible and bent down in middle. Pereonite 1 epimera with anterior corners slightly directed frontwards; pereonites 1-4 with posterior margins straight, 5-7 gradually arched (Fig. 6A). Pleon (Fig. 6A, G) slightly narrower than pereon, epimera of pleonites 3-5 short and directed backwards; telson about twice as wide as long, lateral margins slightly concave, and rounded apex. Antennula (Fig. 6H) with proximal and distal articles similar in length, distal article bearing one row of four stout aesthetascs medially plus 5-6 apically. Antenna (Fig. 6I) reaching pereonite 2 when extended backwards; flagellum first and second articles subequal in length, third article longest, second and third articles bearing two aesthetascs, apical bearing two short free sensilla. Mandibles (Fig. 6J, K) with dense cushion of setae on incisor process, molar penicil of five branches. Maxillula (Fig. 6L) inner endite with two apical penicils plus outer tip; outer endite with 4 + 4 teeth, inner set with two teeth apically cleft. Maxilla (Fig. 6M) inner lobe rounded, covered with thick setae; outer lobe rounded, three times as wide as inner lobe, covered with thin setae. Maxilliped (Fig. 6N) palp with two setae on proximal article; endite subrectangular, medial seta not surpassing distal margin, distal margin rounded. Pereopod 1-7 merus to propodus bearing sparse setae on sternal margin, pereopod 1 carpus with short transverse antennal grooming brush and distal seta hand-like; dactylus of two claws, inner claw shorter, dactylar and ungual setae simple, not surpassing outer claw. Uropod (Fig. 7A) protopod subquadrangular; exopod twice as long as endopod.

Male

Pereopods 1 and 7 without sexual dimorphism (Fig. 7B, C). Genital papilla (Fig. 7D) bearing triangular ventral shield, papilla with two subapical orifices. Pleopod 1 (Fig. 7E) exopod subquadrangular; endopod with distal portion straight and bearing small setae on medial margin. Pleopod 2 (Fig. 7F) exopod triangular, outer margin slightly concave bearing one seta; endopod flagelliform, stout, longer than exopod. Pleopod 3 and 4 exopods as in Figure 7G and H, respectively.

REMARKS

Caraiboscia jabutiensis Campos-Filho,Taiti & Bichuette, n. sp. is readily distinguished from its congeners by the absence of eyes and the shape of the male pleopods 1 and 2. Moreover, it differs in having the dorsal scale-setae triangular (vs fan-shaped in all other species), telson with lateral sides slightly concave (vs straight in all other species), antennal flagellum with apical organ slightly shorter than distal article (vs longer in all other species), outer endite of the maxillula with two teeth apically cleft (vs all simple in C. christiani; one cleft in C. microphthalma), dactylar seta apically simple (vs plumose in all other species), and uropod exopod twice as long as endopod (vs slightly longer in C. christiani) (see Vandel 1968; Leistikow 2001a).

The new species is tentatively placed into the genus since it shows most of its diagnostic characters. The absence of eyes and the shape of the male pleopod 1 exopod are considered autapomorphic conditions of the species, probably related to habitat selection and reproductive patterns. Future molecular analyses are needed to confirm the validity of both the genus and all its representatives.

The new species is considered to be a troglobite, and represents the first terrestrial isopod described in hypogenic caves from Brazil. It is the first troglobitic species for the region of Curvelândia and represents the first record of the genus from Brazil, expanding considerably our knowledge of its distribution.