Pagurus leptonyx Forest & Saint Laurent, 1968

(Figs. 1E, 2E, 3E, 4E)

Pagurus leptonyx Forest & Saint Laurent, 1968: 128, figs 81, 85, 86, 89, 90, 100.— Coelho & Ramos, 1972: 164.— Scelzo & Boschi, 1973: 214.— McLaughlin, 1974: 41; 1975: 372.— Lemaitre et al., 1982: 678, figs 1c, d.— Coelho & Ramos-Porto, 1986: 41.— Rieger, 1998: 414.— Melo, 1999: 130, fig. 74.

Pagurus leptonix .— Fausto-Filho, 1970a: 58; 1970b: 71.

Diagnosis. Shield as broad as long. Rostrum obtuse, triangular, smaller than lateral projections. Ocular peduncles elongate and slender, corneae slightly dilated. Ocular acicles each with 3 or 4 submarginal spines and sometimes 1 accessory marginal spinule. Antennular and antennal peduncles overreaching corneae; flagellum of antennal peduncle with long setae inserted in pairs. Right cheliped flattened on mesial face, palm longer than carpus, length of fingers half that of palm; dorsomesial margin of carpus with single or double row of spines or spinulose tubercles. Left cheliped much smaller than right; carpus elongate, with row of strong teeth on dorsomesial region. Second and third pereopods with dactyls curved along entire length; ventral margins each with row of corneous spinules; propodi unarmed; carpi each with dorsodistal spine. Telson with posterior margins strongly oblique, armed with large and small spines; lateral margins with corneous spinules.

Distribution. Western Atlantic — Brazil (from Ceará to Santa Catarina).

Habitat. On sandy and muddy substrates, from shallow waters to 20 metres.

Material examined. Brazil: Alagoas — Maceió, st. 31, 2 females: 1.5, 1.2 mm, 1 male: 1.3 mm (MZUSP –6472); ES-1, 2 females: 1.9, 1.0 mm (MZUSP –6829); S-3, 1 male: 2.2 mm (MZUSP –6831); 1 female: 1.6 mm (MZUSP –6827); EO-21, 1 male: 1.9 mm (MZUSP –6835). Sergipe – Aracaju, 2 males: 2.1, 2.3 mm (MZUSP –9603). São Paulo – Proj. Monitoramento, st. 14, 5 males: 1.6, 2.2, 1.7, 1.3, 1.6 mm, 2 females: 1.3, 1.2 mm (MZUSP –13347).

Remarks. Pagurus leptonyx is very close to P. criniticornis and P. trichocerus . One can quickly distinguish P. leptonyx from P. criniticornis by means of the ocular acicles, which in P. criniticornis have only one spine. Pagurus trichocerus, which occurs in Uruguay, can be distinguished from P. l e p t o n y x basically by the shape and ornamentation of the right cheliped and by the armature of the dactyls of the ambulatory legs.