Pachygrapsus corrugatus

Pachygrapsus corrugatus (von Martens, 1872)

(Fig. 50A–F)

Grapsus (Leptograpsus) corrugatus von Martens, 1872: 107 [Type locality: Cuba].

Trindade specimens. 3 ovigerous females (MZUSP 40346), Trindade Island, Praia da Calheta, J.B. Mendonça coll., 5.viii.2015, rocky coast, low tide. 1 male (MZUSP 40237), 1 male (MZUSP 40243), ibidem, 20°30’29.5’’S, 29°18’37.0”W, J.B. Mendonça coll., 13.xii.2017, rock crevices, low tide. 1 male (MZUSP 40323), 1 male (MZUSP 40334), 1 ovigerous female (MZUSP 40328), ibidem, J.B. Mendonça coll., 20.xi.2017, low tide. 1 male (MZUSP 40263), 3 males (2 juveniles) (MZUSP 40261), ibidem, J.B. Mendonça coll., 2.xii.2017, rocky tide pool. 1 female (MZUSP 39617), 1 juvenile female (MZUSP 39618), ibidem, J.B. Mendonça coll., 20.vii.2018, rocky coast, low tide. 2 males (1 juvenile) (MZUSP 33823), ibidem, 20°30’28.89’’S, 29°18’37.76”W, J.B. Mendonça coll., 27.iv.2014, rocky coast. 1 juvenile female (MZUSP 41262), ibidem, 20°30’29.5’’S, 29°18’37.0”W, J.B. Mendonça coll., 21.vi.2016, 12.5 m. 1 soft-shelled female (MZUSP 33835), ibidem, Praia dos Andradas / Tartarugas, 20°31’03.8’’S, 29°18’08.4’’W, J.B. Mendonça coll., 20.iv.2014, rocky coast, low tide. 1 male (MZUSP 33825), 1 male (MZUSP 40349), ibidem, 20°29’53.9’’S, 29°19’24.1’’W, J.B. Mendonça coll., 12.iv.2014, rocky coast, low tide. 1 ovigerous female, 1 juvenile female (MZUSP 40351), ibidem, Ponta Norte, Crista do Galo, 20°29’22.1’’S, 29°20’03.1”W, J.B. Mendonça coll., 19.iv.2014, among rocks, low tide. 3 males (2 juveniles), 1 ovigerous female (MZUSP 40262), ibidem, J.B. Mendonça coll., 16.vi.2016, rocky tide pool, 1.5 m. 1 male (MZUSP 40324), ibidem, Praia das Tartarugas, 20°31’11.6’’S, 29°18’0.6’’W, J.B. Mendonça coll., 15.xi.2017, rocky tide pool, 1.5 m.

Size of largest male: cl 17.5 mm, cw 19 mm; largest female: cl 13 mm, cw 14.9 mm.

Comparative material examined. Pachygrapsus corrugatus: Caribbean Sea: 1 ovigerous female (USNM 72340), Virgin Islands, Saint Croix, Judith Fancy Bay, H.A. Beatty coll., 1935–1936, on coastal rocks, M.J. Rath-

coll., 17.ix.1979, L.B. Holthuis det. Ascension Island: 1 male (USNM 252325), South of Collyer Point, adjacent to Cable and Wireless Beach, R.B. Manning coll., 25.v.1971, intertidal rocky flat around blow-hole, R.B. Manning det.

Distribution. Bahamas, Cuba, Puerto Rico, Virgin Islands, Brazil (São Pedro and São Paulo Archipelago and Trindade) (Rathbun 1918; Manning 1963; Chace & Hobbs 1969; Holthuis 1980; Poupin et al. 2005). This is the first record of P. corrugatus from Trindade. Central Atlantic: Ascension Island (Manning & Chace 1990).

Ecological notes. Rare, P. corrugatus inhabits rocky coasts where it is found on pink algal encrustations, rock pools and rocky tide pools (São Pedro and São Paulo). In Trindade it occurred in the intertidal zone among rocks, on rock crevices, and rocky tide pools.

Remarks. Poupin et al. (2005) commented on the resemblance between Pachygrapsus corrugatus and the west and central Pacific P. fakaravensis Rathbun, 1907, and clarified that both species can be separated by the more pronounced striation of the pleonal somites in P. fakaravensis, which also has striae on the thoracic sternites, absent in P. corrugatus. Pachygrapsus corrugatus differs from the southwestern Atlantic P. gracilis and P. transversus in several aspects, including by having the carapace distinctly subquadrate and longitudinal striae on the lateral face of the P1 propodus (already present in the juveniles, such as MZUSP 40261) (Fig. 50A–F). Contrary, P. gracilis and P. transversus have the lateral margins of the carapace convergent posteriorly and lack the striae on the P1 propodus.