agnathan

Thân thiện

An agnathan swims slowly through a deep ocean trench.

Definition

1. Noun:
   • A jawless fish: An agnathan is a primitive, eel-shaped vertebrate that lacks jaws and paired fins. This group includes living forms like lampreys and hagfish, as well as many extinct species.

Usage Examples

• Noun:
  • The lamprey is a well-known example of an extant agnathan.
  • Fossil records show that agnathans were among the earliest vertebrates.

Advanced Usage

• In scientific classification: The term "agnathan" is used in taxonomy and paleontology to describe members of the superclass Agnatha, which is characterized by the absence of jaws.
  • The study compared the skeletal structures of various agnathan fossils.

Variants and Related Words

• Agnatha (n): The taxonomic superclass that includes all jawless fish.
  • Agnatha is a paraphyletic group in modern cladistics.

Synonyms

• Jawless fish: A descriptive synonym.
• Cyclostome: A more specific term often used for the living, round-mouthed agnathans (hagfish and lampreys).

Different Meanings

• This is a specialized zoological term with a single, precise meaning related to vertebrate anatomy and evolution. It does not have common idiomatic or figurative uses.

Học thuật

Noun

1. eel-shaped vertebrate without jaws or paired appendages including the cyclostomes and some extinct forms

Từ đồng nghĩa

• jawless vertebrate
• jawless fish