Pagurus leptonyx Forest & Saint Laurent, 1968

Nucci, Paulo Ricardo & Melo, Gustavo Augusto Schmidt De, 2007, Hermit crabs from Brazil. Family Paguridae (Crustacea: Decapoda: Paguroidea): Genus Pagurus, Zootaxa 1406, pp. 47-59 : 54-55

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.