Assertion: porpoise's fin | /r/HasProperty | keel-shaped
Facets:
Source sentences:
text: The flukes are broad and triangular, and the dorsal fin, which is keel-shaped, is short in height but very long, extending from the middle of the body to the caudal region.
text: The porpoise has a triangular fin, chisel-shaped teeth, small flippers and lacks a beak.