Osteoglossoidei

The Osteoglossoidei are a suborder of primitive bony fishes, considered the most ancient group of bony fishes. They are unique for using their tongue as the opposing surface for biting food. This group includes diverse freshwater species found primarily in tropical regions of Africa, Asia, South America, and Australia.1

Key characteristics include a rudimentary caudal skeleton and the absence of intermuscular bones in certain body regions. While generally of little importance to humans, some species are commercially fished. Notable members include the arapaima (pirarucu) and arowana.12