Diploexochus brevispinis (Pearse, 1915) comb. nov.

Figs 1, 2, 3, 4, 8 A, 13 A

Cubaris brevispinis Pearse, 1915: 543, fig. 5.

Cubaris brevispinis: Van Name 1936: 382, fig. 232.

Venezillo (Vandelillo) brevispinis: Arcangeli 1957: 121.

Venezillo brevispinis: Leistikow and Wägele 1999: 47; Schmalfuss 2003: 286.

Material examined.

Colombia • 1 ♂, 1 ♀ (parts in micropreparations), Hacienda Cafetera Cincinati, Sierra Nevada de Santa Marta, Santa Marta, Magdalena, 11°6'34.14"N, 74°5'30.84"W, leg. CM López-Orozco, YM Carpio-Díaz, 13. VIII. 2018, CBUDC-CRU 344 • 3 ♂, 4 ♀, same locality and collectors as for preceding, CBUDC-CRU 343 .

Redescription.

Maximum body length: male 7 mm, female 7.5 mm. Color dark brown, cephalon, pereon, pleon, and telson strongly pigmented, pleonites 3–5 epimera less pigmented (Fig. 8 A); upper portion of tubercles, pereonite 1 epimera anterior and posterior corners, pereonites 2, 3, and 6 epimera weakly pigmented, sometimes depigmented. Color pattern preserved in ethanol (Figs 2 A, 13 A). Body in lateral view as in Fig. 2 A. Endoantennal conglobation (Figs 2 A, 13 A). Dorsum covered with large triangular tubercles, arranged as follows (Fig. 2 A, B): vertex of cephalon with 10 tubercles in three rows; pereonite 1 with 25–29 tubercles; pereonites 2–6 with 17 tubercles; pereonite 7 with 15 tubercles; pleonites 3–5 with one tubercle on median portion, and telson with two paramedian tubercles. Pereonites 1–7 epimera with one line of noduli laterales per side inserted on outer surface of second tubercle of posterior row (Fig. 2 A). Dorsal surface with short semi-circular scale-setae (Fig. 2 C). Cephalon (Fig. 2 D – F) with frontal shield prominent, distinctly protruding above vertex; eyes of 16 ommatidia. Pereonites 1–7 epimera flattened and directed outwards; pereonite 1 strongly grooved on lateral margin, inner lobe of schisma rounded, not extending beyond posterior margin of outer lobe (Fig. 2 G – H), pereonite 2 with triangular ventral lobe obliquely directed backwards; pereonites 3–7 with oblique ventral ridge (Fig. 2 A – G). Pleonites 3–5 (Fig. 2 I, J) with epimera well developed, rectangular, and directed outwards. Telson (Fig. 2 I) with proximal part slightly broader than distal part, dorsum slightly depressed, distal margin straight. Antennula (Fig. 2 K) of three articles, proximal article longest, distal article with five aesthetascs inserted apically. Antenna (Fig. 2 L) short, not surpassing posterior margin of pereonite 1 when extended backwards; flagellum of two articles, distal article about three times as long as first bearing one row of two lateral aesthetascs. Mandibles with molar penicil dichotomized; left mandible (Fig. 3 A) with 2 + 1 penicils, right mandible (Fig. 3 B) with 1 + 1 penicils. Maxillula (Fig. 3 C) inner endite with two stout penicils; outer endite with 4 + 6 simple teeth. Maxilla (Fig. 3 D) inner lobe rounded and covered with thick setae; outer lobe rounded, twice as wide as inner lobe, covered with thin setae. Maxilliped (Fig. 3 E) basis rectangular bearing sparse setae; palp with two distinct setae on basal article; endite subrectangular, medial seta overpassing distal margin, distal margin with one short seta. Pereopods 1–7 merus and carpus with sparse setae on sternal margin; carpus 1 with distal setae cleft at apex; ungual seta and dactylar organ simple. Uropod (Fig. 3 F) protopod flattened, enlarged on basal part, distal part subrectangular, medial margin slightly concave; exopod short, inserted dorsally near medial margin below distinct lobe, lobe not extending beyond medial margin. Pleopod exopods 1–5 with monospiracular respiratory structures.

Male. Pereopods 1–7 (Fig. 4 A, B) without particular modifications. Genital papilla as in Fig. 5 C. Pleopod 1 (Fig. 4 D) exopod triangular, wider than long, outer and inner margin bearing many small setae, distal part triangular, proximal outer part quadrangular; endopod about twice as long as exopod, distal portion slightly directed outwards. Pleopod 2 (Fig. 4 E) exopod triangular, outer margin strongly concave bearing many setae; endopod longer than exopod. Pleopod 3–5 exopods as in Fig. 4 F – H.

Remarks.

Pearse (1915) described Cubaris brevispinis from Minca, Sierra Nevada de Santa Marta, Colombia. Vandel (1952) proposed new morphological characters for the genus Venezillo, such as the shape of the epimera and ventral lobes of pereonites 1 and 2. Arcangeli (1957), based on the previous characters, transferred C. brevispinis to the genus Venezillo, at that time within the subgenus Vandelillo .

Among the characteristics mentioned by Pearse (1915), the number and arrangement of the dorsal tubercles of the cephalon, pereonites 2–7, pleon, and telson, the shape and direction of the pereonites 1–7 epimera, and the number of ommatidia were confirmed here. The only distinct characteristic contrasting with the original description was the number of tubercles on pereonite 1. Pearse reported 29 tubercles, while 25 were observed in the present study. Probably, this difference is related with the size of the specimens. Additionally, in the drawings of Pearse, the lateral schisma of the pereonite 1 epimera reached about half of its length, which was also confirmed here [see Fig. 2 F – H for comparison with Pearse (1915)]. Thus, based on the generic diagnostic characters mentioned previously, V. brevispinis is placed into the genus Diploexochus .

Diploexochus brevispinis comb. nov. easily differs from D. carrapicho, D. echinatus, D. exu, D. obscurus, and D. spinatus in the number and arrangement of the dorsal tubercles of the cephalon, pereon, and pleon. Moreover, it differs in having the antennula with five distal aesthetascs (vs six in D. exu and D. carrapicho, 10 in D. echinatus, seven in D. obscurus, and nine in D. spinatus), mandibles with dichotomized molar penicil (vs simple in all species), and uropod protopod with median lobe not protruding beyond the medial margin (vs protruding in all species) (see Campos-Filho et al. 2017 a, 2023 a; Cardoso et al. 2023).

Natural history.

Specimens of Diploexochus brevispinis comb. nov. were collected under fallen logs in a sub-Andean forest close to the road at the Cincinnati farm in the Sierra Nevada de Santa Marta, Magdalena, Colombia (Fig. 8 A).

Distribution.

This species is known only from its type locality in Tropical Dry Forest (TDF) and Andean forest of Sierra Nevada de Santa Marta (Fig. 1).