Development of the axial, paired and unpaired fin skeleton in three species of Patagonian zoarcids

Zoarcids are abundant in the intertidal zone of the Argentine Patagonian coast. However, their osteological development has not yet been described. Thus, the aim of this work is to describe the ontogeny of the axial skeleton and that of the paired and unpaired fins of the zoarcids Iluocoetes elongatus , Phucocoetes latitans and Dadyanos insignis . The three species studied showed a high degree of development at hatching and meristic counts coincide with those of the adults. At hatching, most of the structures showed that the appearance of bones was in progress. In the three species studied, this process occurred in a cephalo-caudal direction and, in most of the structures, the appearance of bones is observed from the middle to the rim.