Homologies of cephalic lateral line canals in Pseudorhombus pentophthalmus and Engyprosopon grandisquama (Pleuronectiformes): Innervation and upper eye floor formation

Cephalic lateral line canals in two pleuronectiforms, Pseudorhombus pentophthalmus (Paralichthyidae) and Engyprosopon grandisquama (Bothidae), were studied and their homologies between the ocular and blind sides assessed on the basis of position and innervation patterns. A blind side canal, comprising small ossicles in a line lateral to the upper eye floor, was confirmed as the infraorbital line because the canal was not innervated by a ramus associated with the upper nasal (i.e., the superficial ophthalmic ramus innervating the supraorbital line). Consequently, the ramus innervating the canal was identified as the buccal ramus (associated with the infraorbital line). The blind side frontal forming the posterior half of the upper eye floor was identified as that part bearing the anteriormost otic canal in the ocular side, hypertrophy of the blind side component being evident. The supraorbital line of the blind side was represented by the upper nasal only in E. grandisquama.