Meeting Abstract
Amphinomidae represent a diverse group of polychaetes that include some large and highly colorful coral reef-dwelling taxa. When irritated, amphinomids are generally well-known among divers and snorkelers for their ability to impart painful stings (due to a trimethylamine) whenever contact is made with the worm’s sharp, detachable notochaetae. Anatomically, amphinomids are unique among annelids in possessing a suite of traits that includes: calcareous chaetae, a well-developed prostomial caruncle, two pairs of ventral nerve chords, and an unarmed muscular ventral pharynx. Besides the five prostomial appendages generally present in every known species of this family, no other antennae or tentaculate appendages have ever been described. We describe the presence a novel structure in the Amphinomidae that is newly described here for the very first time: a pair of retractile grooved oral tentacles that arise from within the anterior digestive tract that protract through the mouth. The structure of these canaliculate tentacles is described along with their surmised function, and compared with similar structures present in other families of polychaetes.
