Petrolisthes lamarckii ( Leach, 1820 )

Osawa, Masayuki, 2007, Porcellanidae (Crustacea: Decapoda: Anomura) from New Caledonia and the Loyalty Islands, Zootaxa 1548, pp. 1-49 : 25-26

Petrolisthes lamarckii ( Leach, 1820)

Pisidia lamarckii Leach, 1820: 54 (type locality: not specified).

Porcellana dentata H. Milne Edwards, 1837: 251 (type locality: Java).

Porcellana pulchripes White, 1847: 129 (nomen nudum).

Porcellana speciosa Dana, 1852: 417 (type localities: Drummond Island, Kingsmills Group; Wake Island; Mangsi Islands, Philippines; Raraka, Tuamotu Archipelago); 1855: pl. 26, fig. 8.

Petrolisthes lamarckii .— Stimpson, 1858: 227.— Borradaile, 1898: 464.— Miyake, 1942: 342, text-figs. 7, 8.— Kropp, 1984: 100.— Haig, 1992: 315, fig. 11.

Porcellana bellis Heller, 1865: 76 (type locality: Nikobar).

Material examined. New Caledonia. Amédée, lagon, low tide, 17 Sep.1978, coll. C. Vadon, 2 males CL 4.2, 5.4 mm, 1 female CL 5.3 mm, 2 ovig. females CL 5.7, 7.1 mm. Poingam, lagoon, low tide, 10 May 1997, coll. B. Richer de Forges, 1 female CL 3.7 mm. Platier de Thio, St Gabriel, lagoon, low tide, 0.8 m, 19 May 1996, coll. B. Richer de Forges, 2 females CL 4.5, 4.9 mm, 3 ovig. females CL 4.8–5.0 mm. Nouméa, Ricaudy, 20 Jun. 2001, coll. Berthault, 1 male CL 6.2 mm.

Remarks. Kropp (1984) discussed in depth the Petrolisthes lamarckii species complex of Borradaile (1898) and attempted to clarify the confused taxonomy. He retained Pisidia lamarckii Leach, 1820 , Porcellana dentata H. Milne Edwards, 1837 , Porcellana pulchripes White, 1847 , Porcellana speciosa Dana, 1852 , Porcellana bellis Heller, 1865 , and Petrolisthes obtsusifrons Miyake, 1937 b, in the synonymy of Petrolisthes lamarckii . All the species are characterized by the possession of an epibranchial spine and usually of three teeth on the dorsoflexor margin of the carpus of the cheliped. However, Kropp (1984) did not examine the types of all the species included in the synonymy of P. l a m a rc k i i. Thus, it is not entirely clear what the true identities of the species considered by Kropp (1984) as synonyms of P. lamarckii really are. Kropp (1984) also mentions that a photograph of the type of Porcellana dentata shows four fairly well-developed teeth which the late Janet Haig told him is suggestive of Petrolisthes haswelli . Examination of the holotype of P. obtsusifrons (Shika, Ishigaki-jima, Ryukyu, coral reef, coll. S. Miyake, 6 July 1933: ovig. female CL 5.9 mm, ZLUK 4272) has revealed that it is conspecific with P. varicolor Osawa, 1998 c on the basis of the subparallel median branchial margins of the carapace and chelae with several short setae on the proximal extensor margin. Petrolisthes obtsusifron is excluded from the synonymy of P. l a m a rc k i i, but regarded as the senior synonym of P. varicolor .

Examination of the specimens keyed out to P. l a m a rc k i i from scattered Indo-West Pacific localities has revealed that they have variations in the shapes of the rostrum and merus of the third maxilliped, development of the dorsoflexor teeth of the carpus of the cheliped, and armature on the distoflexor margin of the merus of the first ambulatory legs, in addition to coloration in life. The material examined from New Caledonia is tentatively referred to P. lamarckii until more detailed examination is made on the P. l a m a rc k i i species complex.

Distribution. Throughout the tropical Indo-West Pacific, westward to African coast, eastward to Line and Tuamotu Islands; intertidal, under rocks ( Haig 1979).