Palaemonetes ID?

[eraserbones]

I have a group of (presumed) Palaemonetes shrimp collected in a coastal area in Florida (Doctor's inlet, Jacksonville.) I've just spent a couple of hours trying to figure out what species they are. Given that I have the original species descriptions in front of me (http://decapoda.nhm.org/pdfs/25755/25755.pdf) and close-up photos of rostrum and legs, I would've thought that I could ID this myself. But, to my untrained eye, the distinguishing differences between species are laughably subtle.





My best guess is P. pugio. Can someone with a more experienced eye back me up or set me straight?

Thanks!

[Mustafa]

I have not had any personal experience with Palaemonetes pugio or P. vulgaris, but it's gotta be one of those if you fished them out of saline waters. The freshwater species that occur in your area (P. paludosus and P. kadiakensis) don't usually venture into the ocean or even high salinity waters, although they can, rarely, occur in low salinity waters. P. vulgaris *usually* occurs in higher salinity waters than P. pugio, so that hint might help you narrow down things a bit. It's hard to see much detail on the rostrum from the pictures, so you may have to use a microscope to see more detail in the end. If I had had personal experience with the two brackish/saltwater species, I could have told you pretty much right away which species you have, as there are *always* other (besides purely morphological visible under a microscope) distinguishing characteristics on live animals. After all, these shrimp don't look at each others rostrums etc. to tell if they belong to the same species.