Osteoglossomorpha

Osteoglossomorpha is a superorder of ray-finned fishes within the clade Teleostei that comprises two living orders: Osteoglossiformes (the bony-tongues) and Hiodontiformes (the mooneyes). The name derives from Greek roots meaning bone tongue, a reference to the toothed oral bones and palate elements characteristic of many members. Osteoglossomorpha is among the earliest diverging lineages of living teleosts, with a fossil record that extends back to the Jurassic and is important for understanding early teleost evolution.

Today, members of Osteoglossiformes inhabit freshwater systems across Africa, South America, Asia, and Australia, occupying a variety of niches from surface-feeding predators to mid-water omnivores. A few species tolerate brackish water. Hiodontiformes are restricted to North America, represented by the family Hiodontidae, including species such as the goldeye and mooneye.

Osteoglossomorph fishes are generally medium to large in size and often have elongated bodies. A hallmark of the group is the presence of specialized, tooth-bearing bones in the mouth and tongue region, which underpins the name “bone tongue.” Ecologically, many Osteoglossiformes are important mid- to top-level predators in freshwater ecosystems, contributing to their ecological roles in rivers and lakes. Conservation concerns affect several species due to habitat loss, overfishing, and damming of rivers, with some populations declining or listed as threatened.

---