A new genus and species of bristle worm from Beibu Gulf, South China Sea (Annelida, Polychaeta, Amphinomidae).

Alleurythoe , a new genus with type species Alleurythoe tenuichaeta sp. n. , is described and illustrated based on material from Beibu Gulf, northwestern South China Sea. The new genus is distinguished from all genera within Amphinomidae by a combination of characters: caruncle trilobed, conspicuous, attached to and confluent with the posterior prostomial lobe, which is free from the body wall and has 6-7 folds on each of the lateral lobes; both noto- and neuropodial aciculae are spinose, extending beyond the chaetal lobe. Alleurythoe tenuichaeta sp. n. is characterized by having branchiae present from chaetiger 4 and a bifurcate neurochaetae capillary. A key distinguishing the genera of Amphinominae is provided.