heterocercal

Thân thiện

A shark's heterocercal tail provides powerful propulsion through the water.

Definition

1. Adjective:
   • Possessing a tail with the upper lobe larger than the lower and with the vertebral column prolonged into the upper lobe: This term describes a specific anatomical structure of a fish's tail fin, where the spine extends into the longer, upper part of the tail.

Usage Examples

• Adjective:
  • Sharks and sturgeons have a heterocercal tail fin.
  • The fossil clearly shows the heterocercal structure of the ancient fish's tail.

Advanced Usage

• In Ichthyology: The term is used in scientific descriptions to classify and contrast fish based on tail morphology. It is the opposite of a homocercal tail, where the lobes appear equal.
  • The heterocercal condition is considered a primitive trait in fish evolution.

Variants and Related Words

• Heterocercality (n): The state or condition of having a heterocercal tail.
• Homocercal (adj): Possessing a tail fin with seemingly equal upper and lower lobes, as seen in most bony fish like tuna or salmon.

Synonyms

• Asymmetrical tail (descriptive synonym, less precise)
• Unequally lobed tail (descriptive synonym)

Antonyms

• Homocercal (adj): Having a tail fin with symmetrical upper and lower lobes.

Học thuật

Adjective

1. possessing a tail with the upper lobe larger than the lower and with the vertebral column prolonged into the upper lobe