Batrachia

The Batrachia /bəˈtreɪkiə/ are a clade of amphibians that includes frogs and salamanders, but not caecilians nor the extinct allocaudates. This group is important because it helps scientists understand how these interesting animals are related to each other. The name Batrachia was first used by French zoologist Pierre André Latreille in 1800 when he was talking about frogs. Since then, scientists have learned more about how frogs and salamanders share a common ancestor.

Today, Batrachia is used in a special way called a phylogenetic sense. This means it includes the last common ancestor of frogs and salamanders and all of that ancestor's descendants. One strong piece of evidence that frogs and salamanders are closely related is that they are the only vertebrates able to raise and lower their eyes. However, some scientists have a different idea. They think salamanders and caecilians might be each other's closest relatives in a group called the Procera, with frogs being the sister taxon to this group.

Origins

The earliest batrachians, which are early forms of frogs, appeared around 250 million years ago during the Early Triassic period. These early frogs include Triadobatrachus and Czatkobatrachus. Some scientific estimates suggest that the split between the lineages leading to frogs and salamanders may have happened even earlier, possibly as far back as 367 million years ago in the Late Devonian period. However, fossils from that time do not show clear evidence of modern amphibians. The groups thought to be ancestors of today's amphibians first appeared around 300 million years ago in the Late Carboniferous period.