Definition of "heterocercal" [het•er•o•cer•cal]

• Relating to, having, or being a tail fin in which the upper lobe is larger than the lower and the vertebral column extends into the upper lobe, as in sharks. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "This so called heterocercal tail is only known to exist, as a permanent adult feature, in the sturgeons of to-day."
• "Paddlefish are not closely related to sharks, but they do share some common characteristics including a skeleton primarily composed of cartilage, and a deeply forked, abbreviate heterocercal tail fin (the top fin lobe is slightly larger than the lower fin lobe)."
• "These are the even-lobed, or homocercal (Fig. 68), and the uneven-lobed, or heterocercal (Fig. 69)."