Xangoniscus antiquus Lopez-Orozco, Carpio-Díaz & Campos-Filho 2024, sp. nov.

Xangoniscus antiquus López-Orozco, Carpio-Díaz & Campos-Filho sp. nov. Figs 1, 11, 12,, 14 Type material. Holotype • 1 male (MZUSP 29513), Bahia, Canápolis, Gruta da Represa cave, - 13.08105, - 44.145703, February 1986, leg. A. Auler. Paratypes • 1 male (parts in slides) (MZUSP 29513), same data as holotype. Description. Maximum body length: male 7.8 mm. Body outline as in Figs 11 A, B, 12 A. Colourless (Fig. 11). Dorsal surface smooth, with scattered fringed scale setae (Figs 11, 12 B). Cephalon (Figs 11 C, 12 C) with large quadrangular antennary lobes; vertex with slightly lateral depression to fit antennae when extended backwards, profrons with V-shaped suprantennal line, not surpassing antennule insertion; eyes absent. Pereonite 1 epimera with distal corners developed frontwards, posterior corners right-angled; pereonites 2–7 epimera gradually directed backwards, posterior corners progressively more acute; pleon narrower than pereon; pleonites 3–5 epimera posterior point developed (Figs 11 A, B, 12 A). Telson with concave sides and an almost straight apex (Fig. 12 D). Antennula (Fig. 12 E) composed of three articles, proximal and distal articles subequal in length, second article short, distal article with eight very long aesthetascs. Antenna (Fig. 12 F) short, not surpassing pereonite 2 when extended backwards; flagellum shorter than of fifth article of peduncle, composed of three articles subequal in length. Left mandible (Fig. 12 G) with two penicils; right mandible (Fig. 12 H) with lacinia mobilis and one penicil. Maxillula (Fig. 12 I) inner endite with three penicils; outer endite with 5 + 5 teeth, apically simple, and two plumose stalks. Maxilla (Fig. 12 J) with setose and bilobate apex, outer lobe smaller. Maxilliped (Fig. 12 K) basis enlarged on distal portion bearing fringe of fine setae; first article of palp with two tiny setae, distal articles with three tufts of setae; endite rectangular, outer and medial margins setose, apically with two triangular teeth and large rounded penicil. Uropod (Fig. 12 D) branches short and inserted at same level, exopod slightly longer than endopod. Pereopods 1–7 (Fig. 13 A – G) gradually elongated, with merus, carpus, and propodus bearing sparse setae; dactylus of one claw bearing many setae on outer margin. Male. Pereopods 1–6 (Fig. 5 A – F) merus with proximal portion bearing fringed scales and thin setae on sternal margin. Pereopod 1 (Fig. 13 A) carpus with large antennal grooming brush. Pereopod 5 (Fig. 13 E) carpus with small lobe on proximal sternal margin. Pereopod 6 (Fig. 13 F) ischium enlarged with flattened sternal part; carpus enlarged, rostral portion bearing dense field of tiny lobules; propodus with central part enlarged, with longitudinal furrow in ventral view, and field of short setae on dorsal part. Pereopod 7 (Fig. 13 G) without distinct modifications. Genital papilla (Fig. 14 A) lanceolate. Pleopod 1 (Fig. 14 A) exopod subtriangular, longer than wide, inner and outer margins bearing fringe of fine setae; endopod longer than exopod, with narrow basal article and flagelliform distal article; basipod distal margin elongate and semicircular apex, slightly longer than exopod, with fine and long setae. Pleopod 2 (Fig. 14 B) exopod trapezoidal, distal margin almost straight; endopod of two articles, distal article about three times as long as proximal, with distal margin subquadrangular and apex rounded, with transversal process in V-like on apex in ventral view. Pleopod 3 (Fig. 14 C) exopod triangular, longer than wide, covering pleopods 1 and 2, fringed with short setae. Pleopod 4 and 5 (Fig. 14 D, E) exopods trapezoidal, wider than long, with margins bearing several short setae. Etymology. Latin, antiquus = old. The new species name refers to the long period of time that the samples remained preserved until their description. Perhaps this material represents the first specimens of Xangoniscus collected in Brazil. Distribution. Presently known only from Gruta da Represa cave, in the state of Bahia, northeastern Brazil (Fig. 1). Remarks. Xangoniscus antiquus sp. nov. resembles X. chaimowiczi sp. nov. in the modifications on male pereopods and number of articles on flagellum of antenna; however, it differs in the number of aesthetascs on antennula (eight vs. twelve in X. chaimowiczi sp. nov.), telson apex (almost straight vs. rounded apex in X. chaimowiczi sp. nov.), and basipod distal margin (semicircular apex, slightly longer than exopod vs. acute apex, longer than exopod in X. chaimowiczi sp. nov.).