A selection of reptilomorph amphibians, known as embolomeres, to scale.

Flooded/wet forests are incredibly interesting environments, where animals live in a complex three dimensional world, sliding between tree branches and floating amongst aquatic plants. Modern examples of these forests that come to mind are the Florida Everglades and the seasonal flooding along tributaries of the Amazon. Go much further back in time to the Carboniferous period and vast swaths of Europe and North America were covered in lush humid swampy forests. Towering trees, clubmosses and horsetails all contributed to the organic debris that would later be compressed and converted into the global coal deposits. Atmospheric oxygen reached it's maximum at 35% (it sits at 21% today), allowing amphibians and insects to grow to gigantic sizes (oxygen saturation levels are a limiting factor on size). In the Carboniferous, embolomeres became the first of the super-sized carnivorous tetrapods. Anthracosaurs is an older name which the group is often known by; directly translated it means coal lizards.

With long cylindrical bodies and flattened tails, these amphibians were easily able to navigate submerged obstacles in the wet forests. Eyesight was not an important sense in the murky waters. Instead it is possible that they employed a lateral line system along the side of their bodies for detecting movement, similar to unrelated eel-like amphibians, the amphiumas and sirens.

One of the earliest species from the mid Carboniferous was Proterogyrinus, a mid-sized embolomere capable of hunting on land as well as in the water. It's high positioned eyes are indicative of a surface swimmer. Later species such as Pholiderpeton and Anthracosaurus were much bigger. Behaving much like giant eels with small limbs, Pholiderpeton (previously known as Eogyrinus) was a massive 4 metre long and the apex aquatic predator of it's time. Anthracosaurus was slightly smaller, but had an particularly long vertebral column. The mouth was full of long sharp teeth, beneficial for trapping slippery prey. One of the last surviving embolomeres was the modest sized Archeria, a common species from the Early Permian known from complete skeletons.