Key to Indo-West Pacific genera of the Porcellanidae 1. Antennal peduncle with movable (second to fourth) articles freely accessible to orbit.............................. 2 - Antennal peduncle with movable articles excluded from orbit by projection of immovable (first) article meeting anterior margin of carapace........................................................................................................... 6 2. Chelipeds flattened. Pterygostomian flap entire.......................................................................................... 3 - Chelipeds robust. Posterior part of pterygostomian flap composed of 1 or more pieces separated by mem- branous interspaces from anterior part ............................................................ Pachycheles Stimpson, 1858 3. Rostrum narrow, triangular, with row of spines on each lateral margin. Telson composed of 5 plates........ ................................................................................................................................ Petrocheles Miers, 1876 - Rostrum broad, unarmed except for sometimes with supraocular spine on each lateral margin. Telson composed of 7 plates................................................................................................................................... 4 4. Carapace with gastric region strongly elevated. Ambulatory legs subcylindrical......................................... ..................................................................................................................... Neopetrolisthes Miyake, 1937a - Carapace flattish or somewhat convex on dorsal surface. Ambulatory legs flattish................................... 5 5. Carapace uneven on dorsal surface. Median lobe of rostrum with pair of lateral elevations........................ ........................................................................................................................... Novorostrum Osawa, 1998a - Carapace genarally even on dorsal surface. Median lobe of rostrum without lateral elevations.................. .......................................................................................................................... Petrolisthes Stimpson, 1858 6. Carapace broader than long......................................................................................................................... 7 - Carapace as long as or longer than broad.................................................................................................. 11 7. Ambulatory legs with dactyli each terminating in simple claw (no corneous spines present on flexor mar- gin) .................................................................................................................... Raphidopus Stimpson, 1858 - Ambulatory legs with dactyli each with biunguiculate claw....................................................................... 8 8. Branchial margins of carapace armed with spines, outer orbital angle terminating in small spine............... ................................................................................................... Aliaporcellana Nakasone & Miyake, 1969 - Branchial margins of carapace without spines, outer orbital angle unarmed.............................................. 9 9. Carapace with pair of transverse ridges along cervical regions. Telson composed of 5 plates..................... ........................................................................................................................ Heteropolyonyx Osawa, 2001 - Carapace with weak or distinct, cervical grooves. Telson composed of 7 plates...................................... 10 10. Carapace with dorsal regions well defined by grooves; cervical and gastric grooves formed by thinning and gradual decalcification of cuticle ........................................................Eulenaios Ng & Nakasone, 1993 - Carapace with dorsal regions not distinctly defined by grooves .......................... Polyonyx Stimpson, 1858 11. Carapace distinctly elongate. Dactyli of ambulatory legs triunguiculate or quadriunguiculate................ 12 - Carapace not elongate. Dactyli of ambulatory legs each terminating in a single claw............................. 13 12. Carpi of chelipeds longer than broad. Dactyli of ambulatory legs quadriunguiculate.................................. ............................................................................................................................. Porcellanella White, 1852 - Carpi of chelipeds broader than long. Dactyli of ambulatory legs triunguiculate......................................... .................................................................................................... Pseudoporcellanella Sankarankutty, 1961 13. Carapace strongly areolate on dorsal surface............................................................................................ 14 - Carapace nearly smooth or striate on dorsal surface................................................................................. 15 14. Branchial margins of carapace with spines. Chelae flattened........................... Enosteoides Johnson, 1970 - Branchial margins of carapace without spines. Chelae inflated ..................... Capilliporcellana Haig, 1978 15. Chelipeds subequal, dactyulus of smaller cheliped not twisted .......................... Porcellana Lamarck, 1801 - Chelipeds unequal, dactylus of smaller cheliped usually twisted.............................................................. 16 16. Carapace with dorsal regions clearly defined. Rostrum broadly triangular or rounded in dorsal view, median lobe strongly deflexed ............................................................................... Ancylocheles Haig, 1978 - Carapace with dorsal regions weakly defined. Rostrum horizontal, tridentate or trilobate in dorsal view [except for Pisidia dispar (Stimpson, 1858) with rostrum strongly bent ventrally, broadly rounded in dor- sal view]..................................................................................................................................................... 17 17. Chelae rather flattish, showing pronounced sexual dimorphism in spinulation as well as in degree of dis- tortion of fingers ............................................................................................................ Pisidia Leach, 1820 - Chelae subcylindrical, generally similar in both sexes ...................................... Lissoporcellana Haig, 1978

Published as part of Osawa, Masayuki, 2007, Porcellanidae (Crustacea: Decapoda: Anomura) from New Caledonia and the Loyalty Islands, pp. 1-49 in Zootaxa 1548 on pages 4-5, DOI: 10.5281/zenodo.178040