Batrachia

The Batrachia are a group of amphibians that includes frogs and salamanders. They do not include caecilians or the extinct allocaudates. This group was first named by the French zoologist Pierre André Latreille in the year 1800.

Scientists use the term Batrachia in a special way called a phylogenetic sense. This means they look at the last common ancestor of frogs and salamanders and all animals that came from that ancestor.

We know that frogs and salamanders are more closely related to each other than to caecilians. This is supported by looking at their body structures and studying their genes. For example, both frogs and salamanders can raise and lower their eyes, which other vertebrates cannot do. However, some scientists think that salamanders and caecilians might be more closely related to each other, with frogs being their closest relative. This idea is part of a group called the Procera.

Origins

The earliest batrachians were stem-frogs like Triadobatrachus and Czatkobatrachus, living about 250 million years ago in the Early Triassic. Some scientific estimates suggest that frogs and salamanders may have diverged even earlier, possibly in the Permian or as far back as the Late Devonian. However, fossils from that time do not show clear evidence of modern amphibians. The groups thought to be ancestors of today's amphibians appeared around 300 million years ago in the Late Carboniferous.