Sarcopterygii

fish taxon

Also known as: fleshy-finned fish, lobe-finned fish

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 13, 2026

Quick Summary

Sarcopterygii, also known as fleshy-finned fishes, represent an ancient group of bony fishes that first appeared in the Lower Devonian period. These fish are characterized by their paired, lobed fins that resemble limbs.12

There are differing views on whether Sarcopterygii gave rise to amphibians. Some scientists believe that amphibians evolved from rhipidistians, a group within Sarcopterygii, while others suggest a different lineage. Rhipidistians are now extinct, but other groups like coelacanths and lungfish have survived to the present day, though in small numbers.1

Early coelacanths were freshwater fish, later becoming marine. While they were thought to be extinct after the Cretaceous period, live specimens have been discovered in recent times. Lungfish, also part of this group, have changed little from their ancient forms and are adapted to survive in environments that experience seasonal drying.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

vertebrate
The chondrichthyes
…subclasses Actinopterygii (ray-finned fishes) and Sarcopterygii (lobe-finned fishes). The latter group includes the lungfishes, which live in marshes, ponds, or streams, and are frequent air breathers. They lay fairly large eggs, with a limited amount of yolk, that are enclosed in jelly coats like those of an amphibian. The eggs…
Read More
…subclasses Actinopterygii (ray-finned fishes) and Sarcopterygii (lobe-finned fishes). The latter group includes the lungfishes, which live in marshes, ponds, or streams, and are frequent air breathers. They lay fairly large eggs, with a limited amount of yolk, that are enclosed in jelly coats like those of an amphibian. The eggs…
Read More

fish
Sarcopterygii: fleshy-finned fishes
Fishes of the class Sarcopterygii are extremely ancient in origin, their first remains appearing in Lower Devonian strata of Germany. Some authorities contend that the rhipidistians, one of the three groups of sarcopterygians, gave rise to the amphibians by the end of…
Read More
Fishes of the class Sarcopterygii are extremely ancient in origin, their first remains appearing in Lower Devonian strata of Germany. Some authorities contend that the rhipidistians, one of the three groups of sarcopterygians, gave rise to the amphibians by the end of…
Read More

tetrapod
…fleshy-finned or lobed-finned fishes (Sarcopterygii), although total agreement does not exist on which sarcopterygian group is ancestral to them. The difficulty in deciding tetrapod ancestry stems from the inability to determine conclusively which traits are ancestral and which traits arose after one group diverged from another. Furthermore, the diversity…
Read More
…fleshy-finned or lobed-finned fishes (Sarcopterygii), although total agreement does not exist on which sarcopterygian group is ancestral to them. The difficulty in deciding tetrapod ancestry stems from the inability to determine conclusively which traits are ancestral and which traits arose after one group diverged from another. Furthermore, the diversity…
Read More