DETECTION AND GENERATION OF ELECTRIC SIGNALS | Development of Electroreceptors and Electric Organs

Primitive ampullary electroreceptor organs are found in cartilaginous and nonteleost bony fishes. Derived ampullary and tuberous electroreceptor organs are found in some teleosts. The primitive ampullary organ develops from placodes giving rise to neuromasts and ampullary organs. In teleosts, development placodes occur in catfishes, whereas electroreceptors develop directly from general ectoderm in mormyrids and gymnotiforms. In mormyrids, there are three distinct types of larval electroreceptors. Electric organs (EOs) have evolved several times independently. All organs develop from muscle tissue, even in fishes of the apteronotid family that possess neurogenic organs as adults. In mormyrids and some gymnotiforms, separate larval EOs develop early during ontogeny.