Larvae and Juveniles of the Argentinid, Glossanodon Lineatus, with Comments on Ontogenetic Pattern in the Genus

Early developmental stages of the argentinid, Glossanodon lineatus, are described on the basis of 14 specimens (4.7 mm NL–41.0 mm SL) collected from the western North Pacific. They are distinguished from the confamilials G. semifasciatus and Argentina kagoshimae by a combination of pigmentation pattern and meristic counts (9 vs. 11–13 lateral blotches, 4 vs. 5 branchiostegals, 13–15 vs. 10–13 anal rays and 53–55 vs. 48–53 vertebrae). Comparison of two species of the genus Glossanodon revealed clear differences in their ontogenetic patterns. G. lineatus settles at 41–51 mm SL and transformes gradually with few morphological and meristic changes. In contrast, G. semlfasciatus settles at 21–23 mm SL with drastic morphological changes. These contrasting patterns suggest that the Argentinidae may be divided into two groups: one that retains larval characters at settlement; and one that transforms abruptly. The phylogenetic implications of these findings are unclear, since larval and juveniles are undescribed for most members of both genera.