Overview

Alpheus naos is a snapping shrimp associated with innkeeper worms (echiurans) occurring in the eastern Pacific (Anker et al. 2007). Described from the Pacific coast of Panama, A. naos is morphologically and genetically most similar to two eastern Pacific species of alpheid, Alpheus christofferseni and A. aequus, that are also commensal with echiurans (Anker et al. 2007). Estimates of divergence based on genetic sequence variation (mitochondrial cytochrome oxidase I) suggest that A. naos was isolated from its closest western Atlantic (transisthmian) relative (A. christofferseni) ~11-12 million years ago, far earlier than the closure of the Isthmus of Panama approximately three million years ago.