Lepteces ornatus Rathbun, 1893

Alves-Júnior, Flavio De Almeida, Lucatelli, Débora, Santana, William & Souza-Filho, Jesser Fidelis De, 2019, First record of two rare spider crabs (Crustacea: Decapoda: Brachyura: Majoidea) from Brazil, Zootaxa 4688 (1), pp. 111-118 : 112-115

Lepteces ornatus Rathbun, 1893

( Figs. 1‒3 )

Lepteces ornatus Rathbun, 1893: 84 , pl. 6 fig. 1; 1925: 292, fig. 98, pl. 244 fig. 2— Melo & Crivelaro 2002: 777, fig. 1— Ng et al. 2008: 103 (list).

Material examined. 1 male, cl: 7.8 mm, cw: 12 mm ( MOUFPE 15648 ), R/ V Seaward Johnson, Potiguar Basin, Rio Grande do Norte, station #MT–52, 04°44’S, 036°25’W, 23 May 2011, otter trawl, 180 m, gravel bottom, temperature 28.8°C, salinity 36.6 .

Geographic distribution. Western Atlantic: Gulf of Mexico (Yucatan channel – type locality) ( Rathbun 1893); Uruguay (off Cabo Polonio) ( Melo & Crivelaro 2002); Brazil (Rio Grande do Norte) (present study).

Commonly found between 180 and 250 m depth ( Rathbun 1893; 1925; Melo & Crivelaro 2002).

Remarks. Lepteces ornatus fits well with the original description provided by Rathbun (1893; 1925). Based on that we include some new characters to the original description:

Carapace subpyriform, slightly convex, densely tuberculated, with hooked setae, interspaced with simple long setae. Tubercles in gastric, branchial, cardiac regions forming circular row in form of flat-topped mushrooms, while in intestinal region tubercles form semicircle row ( Fig. 1 A–E). Rostrum long, bifurcate, covered with curled robust setae ( Fig. 1B, C ). Preorbital spine present, long, acute, strongly curved upwards ( Fig. 1B ). Eyestalk long, pedunculated, fitting in orbital cavity ( Fig. 1B ). Postorbital spine present forming two hiatuses ( Fig. 1B ). Basal article of antenna with outer margin convex, with strong spine directed forward forming antero-lateral angle ( Fig. 1C ). Antennular flagellum surpassing rostrum ( Fig. 1B ). Antennular fossae vertical, conical; inter-antennular septum like inverted triangle with small spines ( Fig. 1C ); epistome sharply recessed at middle. Ischium of third maxilliped longer than merus with internal margin crenulated ( Fig. 2B ). Chelipeds slender, shorter than pereopod 2 ( Fig. 2C ); fingers much shorter than palm; without setae. Pereopods 2–5 (ambulatory legs 1–4) strongly armed with longitudinal rows of robust spines, on inner, outer, dorsal margins ( Fig. 2 D–G); surface densely tuberculate except off distal portion of dactylus; robust spines decreasing in size from P2 to P5, with scattered plumose setae along the surface; merus of P2, P3 with few distal setae. Pleonal somites free, densely granulated, telson smooth ( Fig. 1D ). Gonopod 1 (G1) well developed, slightly convergent at midline of thoracic sternum, wide base, slightly curved at the middle, curved at tip ( Fig. 3A ). Gonopod 2 (G2) straight, smooth, short, almost one-fifth length of G1, stout ( Fig. 3B ).

The first record of L. ornatus from the southwestern Atlantic was made by Melo & Crivelaro (2002) based on a female from Uruguayan waters (34°45’S, 52°05’W, 180 m, station GEDIP#1881 – MZUSP: 6126), mistakenly referred to as “ Rio Grande do Sul ( Brazil)”. Lepteces ornatus can be found beneath coral reefs and on sandy bottoms along the continental shelf and slope between 180 and 250 m depth ( Rathbun 1893; 1925; Melo & Crivelaro 2002). The Brazilian specimen was found at 180 m, in gravel and muddy bottoms, corroborating with the observations provided by Rathbun (1893; 1925) and Melo & Crivelaro (2002).

Figures

FIGURE 1. Lepteces ornatus Rathbun, 1893, male, cl: 7.8 mm, cw: 12 mm (MOUFPE 15648). A, dorsal habitus; B, rostrum, dorsal view; C, rostrum, ventral view; D, pleon with somites 1–6 and telson; E, carapace, dorsal view. Scale bars = 5 mm.

FIGURE 2. Lepteces ornatus Rathbun, 1893, male, cl: 7.8 mm, cw: 12 mm (MOUFPE 15648). A, carapace, sagittal view; B, third maxillipeds, ventral view; C, left cheliped (P1), dorsal view; D. left P2; E, left P3; F, left P4; G, left P5. Scale bars = 5 mm.

FIGURE 3. Lepteces ornatus (MOUFPE 15648). A, right G1; B, right G2. Scale bar = 0.5 mm.