Britannica
Sources used in this answer
Which fins of catfish may have spines formed from fused soft rays?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
ostariophysan
Knifefish, or featherback (Xenomystus nigri)
In most catfishes, spines formed from fused soft rays are commonly found in the dorsal and pectoral fins. While ostariophysans typically possess flexible, segmented, and branched soft rays, these elements can fuse during development in certain species to create a rigid spinous ray, or spine.1