Okay I'll start us off
BiologySome salamanders - those of the family plethodontidae -can breathe through their skin and don't have lungs (well they develop them as embryos but yeah).
The fact that lungless salamanders can live in a very diverse range of thermal conditions puzzles scientists because theoretically lungs' enormous surface area is important in thermoregulation.
Plethodontidae are relatively small, are "thread" shaped, and have a low rate of metabolism - all of which serve to compensate for the lack of the favourable SA over which gas exchange can occur : volume ratio which is usually provided by the lungs of an organism.
It has been found that during embryonic development, lungs in plethodontidae do start to form, but never fully mature and are only of minor importance in the family's gas exchange methods.
Most of their gas exchange occurs due to high levels of vascularisation (vessel formation) in the skin, mouth, pharynx and larynx.
All of this is effectively caused by the activation and expression of a gene which codes for a protein that makes cell membranes more permeable for gases (which obviously helps with the gas exchange)