Home Fish Science Is a Fish a Reptile or Amphibian? (Quick Read)

Is a Fish a Reptile or Amphibian? (Quick Read)

by gvald

Some vertebrates do not need feathers or hair on their bodies to keep warm. They are ectothermic, or “cold-blooded”. This means that their internal temperature is identical to that of their environment, which is the case for fish, amphibians and reptiles.


Indeed, if the tuna and the shark are similar, they are not less distant in the family tree. So to group them in the same group under the same name of fish does not make sense today for scientists. Conversely, crocodiles and birds share characters inherited from a common ancestor. As close relatives, they are classified in a new group: the group of Archosaurians.


Is a fish a reptile ?

It is a vertebrate animal, cold-blooded and with skin covered with scales. The female lays eggs. Ex: snake, iguana, alligator, varan


Most fish do not fit into this classification, since they breathe through the bronchi. Fish are not reptiles.


Is a fish an amphibian ?

Fish are aquatic vertebrate animals with gills, fins and a body that is usually covered with scales.


However, amphibians do not have scales, so it is also impossible to classify them in this category!


Is a fish a reptile or amphibian?

Neither! Indeed, most of the time, fishes form an independent class, similar to that of reptiles and amphibians. There is however a scientific term: Actinopterygians


The actinopterygians form the very large group of fishes with a bony skeleton. With 27,000 known species, they currently represent half of the vertebrate species. Their fins are supported by rays.


What are the Actinopterygians?

Actinopterygians are gnathostome vertebrates (they have a jaw) and whose skeleton is bony (unlike chondrychtians).

They belong to the polyphyletic group commonly called “fish”.


The actinopterygians group almost half of the vertebrates. The species of this taxon occupy all aquatic environments – freshwater and sea – to extreme depths and very high altitudes.


Among the characteristics that are specific to them, we note a well-developed swim bladder or the disappearance of the anterior dorsal fin.

The vast majority of actinopterygians belong to the infraclass of teleosts.

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