Diploexochus troglobius López-Orozco, Borja-Arrieta & Campos-Filho sp. nov.

Figs 1, 9, 10, 11, 12, 13 C

Type material.

Colombia • 1 ♂, holotype, Roca madre Cave, Campo Aventura Roca Madre, La Piche, Toluviejo, Sucre, 9°30'50.2"N, 75°23'36.6"W, 12. VII. 2018, leg. CM López-Orozco, R Borja-Arrieta, CBUDC-CRU 393 • 1 ♂, paratypes, same data as holotype, CBUDC-CRU 394 • 1 ♂, 1 ♀ (parts in micro-preparations), paratypes, same data as holotype, CBUDC-CRU 396 .

Description.

Maximum body length: male 2.7 mm, female 4.2 mm. Body outline as in Fig. 9 A. Color faintly brown; body pigments not discernible in vivo (Fig. 12 D). Endoantennal conglobation (Figs 9 A, 12 D, 13 C). Dorsum covered with large triangular tubercles, arranged as follows (Fig. 9 A, B): vertex of cephalon with 10 tubercles in two rows; pereonite 1 with 19 tubercles; pereonites 2–6 with 13 tubercles; pereonite 7 with 11 tubercles; pleonites 3, 4, and telson with two median tubercles. Pereonites 1–7 epimera with one line of noduli laterales per side inserted on outer surface of second tubercle of posterior row (Fig. 9 A). Dorsal surface densely covered with elongated semi-circular scale-setae, conferring pilous aspect (Fig. 9 C). Cephalon (Fig. 9 D – F) with prominent frontal shield, distinctly protruding above vertex; eyes with four ommatidia. Pereonites 1–7 epimera flattened and slightly directed outwards; pereonite 1 grooved on posterior lateral margin, inner lobe of schisma rounded and extending beyond posterior margin of outer lobe. Pereonite 2 with triangular ventral lobe rounded at apex, extending beyond posterior margin of epimera; pereonites 3 and 5–7 with well-marked ventral ridge (Fig. 9 A, F, G). Pleonites 3–5 epimera (Fig. 9 H, I) well developed, sub-rectangular, and directed outwards, distal margins rounded. Telson (Fig. 9 H) with proximal part broader than distal part, dorsum slightly depressed, distal margin sinuous. Antennula (Fig. 9 J) of three articles, proximal and distal subequal in length, distal article with five stout aesthetascs inserted sub-apically. Antenna (Fig. 9 K) short, not surpassing posterior margin of pereonite 1 when extended backward; flagellum of two articles, the distal about three times as long as first, bearing one row of two lateral aesthetascs. Mandibles with molar penicil semi-dichotomized; left mandible (Fig. 10 A) with 2 + 1 penicils, right mandible (Fig. 10 B) with 1 + 1 penicils. Maxillula (Fig. 10 C) inner endite with two stout penicils, distal margin bearing thin setae; outer endite with 4 + 6 teeth simple. Maxilla (Fig. 10 D) inner lobe rounded covered with thick setae; outer lobe rounded three times as wide as inner lobe covered with thin setae. Maxilliped basis (Fig. 10 E) rectangular, bearing sparse setae; palp with two distinct setae on basal article; endite subrectangular, medial seta surpassing distal margin, distal margin bearing one seta. Pereopods 1–7 merus and carpus with sparse setae on sternal margin; carpus 1 with distal seta cleft at apex; ungual seta and dactylar organ simple not surpassing outer claw. Uropod (Fig. 10 F) protopod flattened, enlarged on basal part, distal part elongated and sub-rectangular, distal margin rounded, medial margin concave with L-shaped appearance; exopod as long as endopod inserted dorsally near medial margin bellow distinct lobe, lobe not extending beyond medial margin; endopod short bearing many short setae. Pleopods 1–5 exopods with monospiracular respiratory structures.

Male. Pereopods 1–7 (Fig. 11 A, B) without particular modifications. Genital papilla as in Fig. 11 C. Pleopod 1 (Fig. 11 D) exopod hour-glass shaped, twice as wide as long, inner portion rounded, outer portion triangular, distal and proximal margins narrow on middle; endopod about three times as long as exopod. Pleopod 2 (Fig. 11 E) exopod triangular, outer margin strongly concave; endopod slightly longer than exopod. Pleopod 3–5 exopods as in Fig. 11 F – H.

Etymology.

Latin: troglo + bio = cave-dwelling. The new name of the species is an adjective that refers to the troglobitic category of the species.

Remarks.

Diploexochus troglobius sp. nov. is easily distinguishable from the congeners in the arrangement of the dorsal tubercles of the pleon, dorsal surface with pilose aspect, eyes of four ommatidia, and the shape of the male pleopod 1 exopod.

Natural history.

Specimens of D. troglobius sp. nov. were collected in the aphotic zone of the Roca Madre Cave, beneath limestone rocks (Fig. 12 D). This species is considered troglobitic due to the reduction of body pigments and reduction in the number of ommatidia. In addition, several surveys were conducted outside the cave and other subterranean ecosystems to confirm its restricted distribution. This species is considered endemic to the study area.

Distribution.

This species is known only from the type locality at Roca Madre Cave, Sucre, inserted on TDF area (Fig. 1).