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