THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource
fdsf
  Identify taxaJointed legsCrustaceaAmphipodaFirst antennae longer than the second
 

Gammarus (family Gammaridae)
In mature specimens, eyes are usually present; the extra filament that sticks out near the base of the first antennae usually has more than 2 segments; the plate on the hind end is M shaped with the split in the middle going all the way to the bottom; the tiny spines on top of the last 3 segments are in clusters of 2 or 3 with one cluster on top and one to each side of the top (characters may not be as clear in immatures)

 
       
  Crangonyx (family Crangonyctidae)
Eyes usually present; if present, the extra filament that sticks out near the base of the first antennae is never more than 2 segments; the plate on the hind end is M shaped with a split in the middle; split never goes all the way to the bottom		  
       
 
fdsf

© 2007 Xerces Society
Contact info@xerces.org