Giant Actinotroch, a Larva of Phoronida from the South China Sea: The Giant Larva Phenomenon

摘要

Phoronida is a group of marine invertebrates occurring worldwide [5]. Adult Phoronida are benthic animals living in tubes on sandy ground or in holes that they drill in stones and mollusk shells. All Phoronida except one species, Phoronis ovalis, havepelagic larvae that feeds and can live in plankton for one to three months [5]. Phoronida larvae (actinotrochs) have characteristic structure and are easily identifiable in collected plankton. Most actinotrochs are 0.7-0.9 mm in size. We found an unusually large actinotroch (3.5 mm). This larva is described below.