HABITAT ADAPTATIONS OF NORTH AMERICAN CAPRELLID AMPHIPODA (CRUSTACEA)

¹ Department of Zoology, Mississippi State University, Mississippi State, Mississippi 39762

1. Caprellid amphipods occur epibiotically or free on the bottom. There are four general types of substrata and caprellids have distinctive morphological adaptations to each substratum type.

2. Those caprellids without specific substratum preferences have primative propod structure including proximal grasping spines and distinct palm development.

3. Starfish epibionts have cylindrical propods and both setae and spines are reduced. Bryozoan and gorgonian epibionts have morphological adaptations similar to starfish epibionts, but the selective forces for the parallelism differ between the two groups.

4. Caprellids existing free on the bottom have reduced pereopods 5, which result in a modified upright stance. The modified upright stance allows a greater prey search area without an increase in body size.

5. Various substratum types support different arrays of available food for the caprellids. Gorgonians and starfish generally support scraping/filter-feeding species while those species regularly occurring free on the bottom are predators. No feeding type is favored on most filamentous substrata.