Evolution of the connection patterns of the cephalic lateral line canal system and its use to diagnose opsariichthyin cyprinid fishes (Teleostei, Cyprinidae)

Abstract

The cephalic lateral line canal systems were compared among 12 species of the cyprinid tribe Opsariichthyini. All species were characterized by the separation of the supraorbital canal from both the infraorbital and the temporal canals, and the left side of the supratemporal canal from the right side of the canal. In species of Candidia, Opsariichthys, Parazacco, and Zacco, and Nipponocypris sieboldii the temporal canal was separated from the preoperculomandibular canal. In Nipponocypris temminckii and N. koreanus, the temporal canal was connected to the preoperculomandibular canal. Separation of the left and right sides of the supratemporal canal is a possible synapomorphy of the opsariichthyin cyprinids. Opsariichthys uncirostris and O. bidens are unique among the opsariichthyins in that the connection between the infraorbital and temporal canals is retarded. The variation in arrangement of the cephalic lateral line canal system can be used as diagnostic characters for the opsariichthyin species.