Pachycheles chubutensis Boschi, 1963

Ferreira, Luciane Augusto De Azevedo & Melo, Gustavo Augusto Schmidt De, 2016, Porcelain crabs from Brazil (Crustacea: Decapoda: Anomura: Porcellanidae), Zootaxa 4092 (2), pp. 175-194 : 180-181

Pachycheles chubutensis Boschi, 1963

( Fig. 1 F)

Pachycheles chubutensis Boschi, 1963: 35 , figs. 2, 3a, e, f (type-locality: Gulf of San Matías, Chubut, Argentina).

Material examined. Brazil: Rio de Janeiro—Arquipélago das Cagarras, Ilha das Palmas, 1 male, 2 ovigerous females (MNRJ-18394); Angra dos Reis, 1 male, 2 ovigerous females (MNRJ-3777). Rio Grande do Sul—Proj. GEDIP, st. 394, 33 °56’S, 52°40’W, 35 m, 2 males, 1 female, 5 ovigerous females (MZUSP-7193); 3 males, 3 ovigerous females (MZUSP-7194).

Recognition characters. Carapace subquadrate, as broad as long in males, slightly broader than long in females; rugose, mainly on branchial region; lateral margin slightly upturned. Front narrow, with a tuft of short and dense setae. Outer orbital angle produced into acute tooth. Basis-ischium of antenna with distal serrate lobe on mesial margin. Chelipeds robust, subequal, grained and covered with dense short setae; scattered long setae on extensor margin; merus with subtriangular and serrate tubercle on flexor margin; carpus with 2 to 4 serrate lobes on flexor margin. Walking legs pubescent; propodus with 4 spines on flexor margin, dactylus with 4 spines on flexor margin. Gonopods present in males. Telson composed of 7 plates; posterior plates partially subdivided in some specimens.

Habitat. Preference for sandy bottoms (Veloso & Melo 1993), down to depths of 28 m (Bremec & Cazzaniga 1984); found associated with sponges.

Geographic distribution. Western Atlantic—Brazil (Rio de Janeiro and from Santa Catarina to Rio Grande do Sul) and Argentina, Chubut.

Variation. In the original description of Pachycheles chubutensis by Boschi (1963), the telson is composed of 7 plates in males and usually 5 plates in females, and in some female specimens, two small posterior plates partially subdivided. Bremec & Cazzaniga (1984) mentioned that almost all the females examined possess the telson of 7 plates. In the present material, we observed the occurrence of 7 plates in both males and females, and in few specimens had one of the posterior plates partially subdivided. On the other hand, Harvey & De Santo (1996) mentioned that, although the dorsal surface of carpus and palm of the cheliped is usually covered with dense setae, this character considerably varies in our specimens and some of them lack setae.

Figures

FIGURE 1. Preseved specimens, dorsal view. A, Megalobrachium mortenseni Haig, 1962, ovigerous female (MZUSP- 24529); B, Megalobrachium roseum (Rathbun, 1900), female (MZUSP- 19905); C, Megalobrachium soriatum (Say, 1818), male (MZUSP- 19903); D, Minyocerus angustus (Dana, 1852), ovigerous female (MZUSP- 17473); E, Pachycheles ackleianus A. Milne-Edwards, 1880, male (MZUSP- 19548); F, Pachycheles chubutensis Boschi, 1963, male (MZUSP- 7194); G, Pachycheles greeleyi (Rathbun, 1900), male (MZUSP- 21232); H, Pachycheles laevidactylus Ortmann, 1892, male (MZUSP- 18723). Scales: A – E (1 mm); F – H (5 mm).