Biology of the brachyuran crab Pinnixa chaetopterana Stimpson (Decapoda: Pinnotheridae) symbiotic with tubicolous polychaetes along the Atlantic coast of the United States, with additional notes on other polychaete associations

Abstract

ABSTRACT The pinnotherid crab Pinnixa chaetopterana inhabits marine polychaete tubes (e.g., Amphitrite ornata and Chaetopterus variopedatus) along the Atlantic and Gulf of Mexico coasts of the United States. This crab occurred in 58.5% of Amphitrite tubes in New Jersey. The polychaete Lepidametria commensalis was found in 64.6% of Amphitrite tubes, often (41.7%) with the crab. In North Carolina, the occurrences of P. chaetopterana and the porcellanid crab Polyonyx gibbesi in Chaetopterus tubes were 69.1% and 30.9%, respectively. In addition, juveniles of the pinnotherid Tumidotheres maculatus occurred with 13.6% of these worms, nearly all (95.1%) of which were in tubes with P. chaetopterana. In Florida, 82.6% of Chaetopterus tubes harbored crabs, but P. gibbesi was dominant with a prevalence of 79.7% versus 2.9% for P. chaetopterana. The tubes of other species of polychaetes and bivalve burrows, however, were used as habitats by the pinnixid. The pinnixid crabs living with Amphitrite were significantly sm...