Osteichthyes
Embed This Widget
Add the script tag and a data attribute to embed this widget.
<script src="https://cdn.jsdelivr.net/npm/fishfyi-embed@1/dist/embed.min.js" defer></script>
<div data-fishfyi="glossary" data-slug="osteichthyes"></div>Embed via iframe for maximum compatibility.
<iframe src="https://fishfyi.com/iframe/glossary/osteichthyes/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://fishfyi.com/glossary/osteichthyes/Add a dynamic SVG badge to your README or docs.
[](https://fishfyi.com/glossary/osteichthyes/)Use the native HTML custom element.
<script src="https://cdn.jsdelivr.net/npm/fishfyi-embed@1/dist/embed.min.js" defer></script>
<fishfyi-glossary slug="osteichthyes"></fishfyi-glossary>Definition
The taxonomic class of bony fish, encompassing over 28,000 species with skeletons made primarily of bone. Includes ray-finned fishes and lobe-finned fishes.
Detailed Explanation
Osteichthyes is divided into Actinopterygii (ray-finned fish, ~99% of species) and Sarcopterygii (lobe-finned fish: lungfish, coelacanths, and the tetrapod lineage). The mineralized endoskeleton of bony fish — replacing the cartilaginous skeleton of their ancestors — enabled the evolution of more complex jaw mechanics and the diversification of tooth types. The bony skeleton preserves well as fossils, providing a rich record extending to the Silurian (~430 million years ago). Bony fish are distinguished from chondrichthyes by the presence of true bone, an operculum covering the gills, and a gas bladder derived from a primitive lung.