Meeting Abstract
Catfishes (Siluriformes) are characterized by a number of skeletal autapomorphies including the modification of several elements of the pectoral-girdle. In particular, the pectoral-fin radials of catfishes differ markedly from the condition found in other otophysan fishes by possessing fewer proximal radials (2-3 vs. 4), of which one is an enlarged element that is commonly referred to as the “complex” pectoral distal radial. Despite numerous anatomical studies on the skeleton of catfishes, the homology of this element remains unresolved. Additionally, most previous studies have only focused on describing the adult condition, while comprehensive information on ontogeny remains scarce. In order to further our understanding of the identity of the supporting skeletal elements of the pectoral fin in catfishes, we document and describe the earliest stages of pectoral-fin radial formation in cleared and double stained representative siluroid (Noturus gyrinus and Ictalurus punctatus) and loricarioid (Megalechis personata, Corydoras panda and Ancistrus sp.) catfishes. We also compare the formation of the pectoral-fin radials in these five species to each other and to Danio rerio in order to determine homology of these elements.
