Characters of the lateral-line system and their use in taxonomy of Paralichthys, Hippoglossina and Lioglossina (Paralichthyidae, Pleuronectiformes)

Abstract

A morphological study of eight species of Paralichthys, two species of Hippoglossina, and Lioglossina tetrophthalma, has revealed head lateral-line canal topography differences of taxonomic value. In species of Paralichthys, segment of the supraorbital canal in nasale of the blind side is connected with other canals and canaliculi are ramified, whereas in species of Hippoglossina this segment is not connected and canaliculi are not ramified. These different character states corroborate the generic distinction between Paralichthys and Hippoglossina. The connection of the supraorbital canal in nasale of the blind side with other canals and ramified canaliculi found in L. tetrophthalma and P. oblongus are against regarding them as Hippoglossina species. It appears necessary to restore the monotypic genus Lioglossina and to place P. oblongus in the genus Paralichthys until new morphological or molecular data are obtained. Paralichthys species vary in the degree of ramification of canaliculi, presence or absence of infraorbital canal segment in the lacrimale of the ocular side and posterior line of CST. Differences in lateral-line canal topography of H. macrops and H. bollmani were not found.