Palaemonella

Komai, Tomoyuki & Yamada, Yusuke, 2015, A new species of the palaemonid shrimp genus Palaemonella Dana, 1852 (Crustacea: Decapoda: Caridea) from Okinawa Island, Ryukyu Islands, Japan, Zootaxa 3964 (3), pp. 352-362 : 360

Key to the Indo-West Pacific species of Palaemonella

1. Supraorbital tooth present............................................................................... 2

- Supraorbital tooth absent................................................................................ 6

2. Ischia of second pereopods each with distoventral tooth.................................... P. crosnieri Bruce, 1978

- Ischia of second pereopods without distoventral tooth......................................................... 3

3. Postorbital ridge on carapace distinct...................................................................... 4

- Postorbital ridge on carapace obscure or absent.............................................................. 5

4. Dactyli of third to fifth pereopods long, slender, about 9–11 times as long as basal width..... P. longidactylus Hayashi, 2009

- Dactyli of third to fifth pereopods relatively short and moderately slender, 4.6–6.0 times as long as basal width............................................................................................ P. spinulata Yokoya, 1936

5. Rostrum as long as or longer than carapace.............................................. P. dijonesae Bruce, 2010

- Rostrum shorter than carapace.......................................................... P. maziwi Bruce, 2002

6. Dactyli of third to fifth pereopods slender, more than 8.0 times longer than basal width.............................. 7

- Ambulatory dactyli moderately slender, less than 8.0 times longer than basal width................................ 12

7. Hepatic tooth in branchiostegal position.................................................................... 8

- Hepatic tooth not in branchiostegal position................................................................ 10

8. Carapace with distinct postorbital carina, posteriormost tooth of dorsal rostral series located at about 0.3 of carapace length...................................................................................................... 9

- Carapace without postorbital carina, posteriormost tooth of dorsal rostral series located at 0.25 of carapace length........................................................................................... P. meteorae Bruce, 2008

9. Carapace with large antennal tooth.................................................. P. k o m a ii Li & Bruce, 2006

- Carapace with small antennal tooth............................. Palaemonella sp. sensu Li, Mitsuhashi & Chan, 2008

10. Propodi of third to fifth pereopods subdivided, each with ventral spinules................. P. dolichodactylus Bruce, 1991

- Propodi of third to fifth pereopods not subdivided, without ventral spinules....................................... 11

11. Chela of second pereopod with fingers shorter than palm; dactylus of third pereopod 0.4 times as long as propodus................................................................................ Palaemonella sp. sensu Bruce, 2003

- Chela of second pereopod with fingers longer than palm; dactylus of third pereopod 0.2 times as long as propodus.......................................................................................... P. h a c h ij o Okuno, 1999

12. Merus of second pereopod without conspicuous tooth at ventrolateral distal angle.................................. 13

- Merus of second pereopod with conspicuous tooth at ventrolateral distal angle.................................... 17

13. Carapace with distinct postorbital ridge........................................................ P. okunoi n. sp.

- Carapace without postorbital ridge....................................................................... 14

14. Carapace with 3 postrostral teeth, of which 2 located posterior to level of hepatic tooth.............. P. aliska Marin, 2008

- Carapace with 1 or 2 postrostral teeth, of which only 1 or none located posterior to level of hepatic tooth............... 15

15. Carpus of second pereopod with 2 conspicuous distomesial teeth................................. P. lata Kemp, 1922

- Carpus of second pereopod unarmed on distomesial margin................................................... 16

16. Rostrum not reaching distal end of antennular peduncle, with 6 dorsal (including 1 postrostral) and 1 ventral teeth; eye with cornea not wider than eyestalk, eyestalk not narrowing proximally.............................. P. pusilla Bruce, 1975

- Rostrum overreaching distal end of antennular peduncle, with 8 dorsal (including 2 postrostral) and 2 ventral teeth; eye with cornea wider than eyestalk, eyestalk distinctly narrowing proximally.......................... P. burnsi Holthuis, 1973

17. Distoventral tooth on carpus of second pereopod distinctly subterminal......................... P. tenuipes Dana, 1852

- Distoventral tooth on carpus of second pereopod terminal..................................................... 18

18. Postorbital ridge on carapace distinct; dorsal rostral teeth moderately stout, not markedly curved..................... 19

- Postorbital ridge on carapace absent; dorsal rostral teeth slender, curved........................... P. foresti Bruce, 2002

19. Dactyli of third to fifth pereopods each with flexor margin ventrally concave; flexor distal spines on propodi long, about 0.5 of dactylus length................................................................ P. ro t u m a n a (Borradaile, 1898)

- Dactyli of third to fifth pereopods each with flexor margin sinuous or biconcave; flexor distal spines on propodi short, about 0.25 of dactylus.................................................................. P. pottsi (Borradaile, 1915)