1. having an asymmetrical tail fin with the backbone extending into the upper lobe
Usage: biology; ichthyology

Examples

• Sharks have heterocercal tail fins that help them maintain buoyancy.
• The heterocercal tail structure is characteristic of cartilaginous fish.
• Most bony fish have homocercal tails, unlike sharks with their heterocercal design.
• The heterocercal fin provides lift as the shark swims forward.
• Paleontologists can identify ancient fish species by their heterocercal tail fossils.
• The asymmetrical heterocercal tail distinguishes sharks from most other fish.