pterygiophore

from The Century Dictionary.

• noun In fishes, one of the nodules of bone or cartilage between the dorsal and anal rays and their respective interspinous bones.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun marine biology The bones in a fish that support the dorsal fin. There are two to three of them: proximal, middle, and distal; In spinous fins the distal is often fused to the middle or not present at all.