These Amphibians Grow Lungs At First, Until They Mysteriously Vanish

The lungs are large. Animals that wear their skeletons on the inside can't live without them. These delicate organs are no longer cared for by some extraordinary salamanders.

Some lungless animals start to grow their breathing organs at first, and then their development process changes as they get older.

The salamanders have been breathing through their mouth and skin for 25 million years. The only way they can absorb oxygen through their skin is if their skin is moist.

Most of the salamanders are found in the Americas but there are a few in Europe and South Korea.

Little is known about how the cold-blooded water lovers misplace their lungs.

In their paper, the researchers confirm that an incipient lung forms in embryos. The axolotl and Ambystoma mexicanum are lunged salamanders.

The lungs develop and branch out for three weeks in P. cinereus. A form of cell death occurs before the salamanders hatch.

The researchers think lung development stops because the cells don't get the signals they need to grow. They decided to take a look at this hypothesis.

Lewis said that they put mesenchyme from a salamander with lungs into a lungless salamander embryo. It resulted in the creation of structures that look like lungs, offering some evidence that lungless salamanders are still capable of developing lungs.

salamanders have many of the genes and processes that salamanders need to grow, even though they have no lungs as adults.

Some of the signals needed to complete the process seem to be missing.

Many of the tools and ingredients for lung making have been preserved in animals that have not used lungs before.

The researchers theorize that the lung rudiment may play an important role in the development of the heart. Sonic hedgehog is used for both lung and limb development

These connections show how organ remnants can help us understand the twisting and turning mechanisms behind developmental and evolutionary processes and provide insight into the workings of our organs.

Sparse fossil records of salamanders make it hard for researchers to narrow down when these animals lost their breathing organs, depending on whether it happened in one ancestral species or multiple times within this salamander family.

According to Lewis, lungless salamanders do fine without lungs, since they make up about two-thirds of all salamander species. This remarkable evolutionary success may have been enabled by the loss of lungs.

The research was published in a peer-reviewed journal.