Fish with four legs and able to walk

The anatomical transition that allowed the progressive adaptation of aquatic animals to life on land is one of the most fascinating metamorphoses of evolution, but much is unknown about it.

Fortunately, some living animals have anatomical features that can give us clues about what those transitional animals looked like and how they moved.

This, together with analyzes of extinct animals when the state of conservation of their remains allows it, helps to get an idea of ​​which anatomical innovations were the most important to enable the beginning of animal life on land. The image shows a high resolution tomographic reconstruction of a rare extant fish.

The reconstruction was done within the framework of a study carried out by a team made up of, among others, Callie Crawford, from the New Jersey Institute of Technology (NJIT), and Zachary S. Randall, from the Florida Museum of Natural History, both institutions in USA.

This fish, Cryptotora thamicola, has four legs. We can call them that because they are used to move on land in a similar way to how amphibians and numerous reptiles do.

(Image: Zach Randall, Florida Museum of Natural History)

As far as is known, Cryptotora thamicola is the only non-extinct species of fish that possesses this ability. (Font: NCYT by Amazings)