geph·y·ro·cer·cal \|jefə(ˌ)rō|sərkəl\adjective Etymology: Greek gephyro- (from gephyra) + English -cercal 1.: having the dorsal and anal fins confluent at the aborted end of the vertebral column of a fish's tail 2.: having or relating to a gephyrocercal tail • geph·y·ro·cer·cy\ˈ ̷ ̷ ̷ ̷ ̷ ̷ˌsərsē\noun-es