Key to five species of Petrolisthes
1. Epibranchial spine present....................................................................... P. armatus
– Epibranchial spine absent.............................................................................. 2
2. Carapace granulate or tuberculate........................................................................ 3
– Carapace smooth, at most with fine striae.................................................................. 4
3. Carapace finely granulate. P1 carpus with distinct lobe on anterior margin................................ P. cinctipes
– Carapace covered with tubercles, 2 short spines on anterior margin of P1 carpus............................ P. ornatus
4. P1 carpus anterior margin with proximal spine. Antennule article 3 with 1 spinule. P2 merus ventrolateral margin with large tooth distally............................................................................... P. kranjiensis
– P1 carpus anterior margin unarmed. Antennule article 3 without spinule. P2 merus ventrolateral margin unarmed or with a vestigial tooth distally.................................................................... P. tanmayi sp. nov.