Thalassina, Latreille, 1806

Key to the extant species of Thalassina View in CoL

1. Rostrum with blunt tip; posterodorsal median process of carapace long or short; sternites of pleomeres 2–5 each with median or lateral tubercles........................................................................2

– Rostrum with acute or subacute tip; posterodorsal median process of carapace short; sternites of pleomeres 2–5 only with lateral tubercles on either side of midline ..............................5

2. Lateral margin of rostrum and dorsolateral carina of pereopod 1 palm with conspicuous tubercles.........................................3

– Lateral margin of rostrum and dorsolateral carina of pereopod 1 palm without conspicuous tubercles or at most with obsolescent tubercles [posterodorsal median process of carapace long; tergites of pleomeres 2–5 each with median tubercles]........... .................................................................................. T. krempfi View in CoL

3. Posterodorsal median process of carapace long; dorsolateral carina of pereopod 1 palm extending over entire length.......4

– Posterodorsal median process of carapace small; dorsolateral carina of pereopod 1 palm extending to half or proximal threefourths length...........................................................................6

4. Cervical groove of carapace unarmed or bordered with a few tubercles; merus of pereopod 3 with minute spines on dorsal margin in limited extent......................................... T. anomala View in CoL

– Cervical groove of carapace bordered with spines at least laterally; merus of pereopod 3 with row of conspicuous spines on dorsal margin over entire length .......................................5

5. Postcervical carapace covered with numerous spines; cervical groove bordered by row of spines entirely ............. T. spinosa View in CoL

– Postcervical carapace only armed with a few spines adjacent to linea thalassinica; cervical groove bordered by spines only laterally................................................. T. pratas View in CoL , new species

6. Postrostral median groove extending beyond posterior ends of rostral lateral carinae; male gonopod 1 generally slender with 3 or 4 conspicuous teeth on lateral margin proximally........... ................................................................................ T. kelanang View in CoL

– Postrostral median groove not reaching posterior ends of rostral lateral carinae; male gonopod 1 generally broad, unarmed on lateral margin..................................................... T. squiamifera

7. Lateral margins of rostrum with tubercles only.....................8

– Lateral margins of rostrum and anterolateral margins of carapace with tubercles and spines [pereopod 1 merus with large spines on ventral margin proximally, palm with dorsolateral carina extending almost over entire length, lateral ventral carina with spiniform tubercles and spines; sternites of pleomeres 2–5 with lateral tubercles only in males, no lateral tubercles in females] .......................................................... T. spinirostris View in CoL

8. Pereopod 1 merus with large spines on ventral margin proximally, palm with dorsolateral carina extending nearly over entire length; sternites of pleomeres 2–5 with faint lateral tubercles in males, no lateral tubercles in females .................. .................................................................................. T. gracilis View in CoL

– Pereopod 1 merus without large spines on ventral margin proximally, palm with dorsolateral carina extending to about midlength; sternites of pleomeres 2–5 with lateral tubercles and often numerous anterior tubercles ...................................9

9. Pereopod 1 palm with covering of granules on space between dorsolateral and dorsomesial carinae, latter carina with 14–16 spiniform tubercles.............................................. T. saetichelis View in CoL

– Pereopod 1 palm without covering of granules on space between dorsolateral and dorsomesial carinae, latter carina with 18–23 blunt tubercles.................................................. T. australiensis View in CoL