Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
amphipod? - Idotea balthica

amphipod? - Idotea balthica
Bass Beach, Rye, Rockingham County, New Hampshire, USA
July 7, 2013
Size: 1/2 in.
I have been finding these for years at the beach, never knowing what they were. They cling to seaweed, sometimes in the hundreds, and so I'd take a clump and put it in a bucket and watch them all disperse into the water. They seem to come in a variety of colors and sizes, most too small for me to photograph (though I have photos of a few others, red ones). This is the largest one I've found. I'm really interested to know what these are, they're a part of my childhood!

Images of this individual: tag all
amphipod? - Idotea balthica amphipod? - Idotea balthica

Moved from Valvifera.

Nice picture
Surprisingly, there aren't very many valviferan isopod species locally; the coloration is just extremely variable in some species. I'll get back to you tonight on which species (or at least genus) this is. I suspect Idotea but need the keys in front of me to make a determination. Your picture shows the features key to an ID very clearly. It seems I'm the only one here familiar with New England saltwater isopods...

Idotea balthica (Pallas, 1772)
Keys to I. balthica in this source. The main key to this ID is the pointed telson.

thank you!
I appreciate the help! It's great to finally know what these amazing little creatures are. There's no page in the guide for it though, should one be made?

Moved from ID Request.

Close...Isopods, Valvifera
These are fun little animals...
I'm guessing your's are similar to the usual (Pent)Idotea on the West coast.