In fantasy and science fiction cool monsters and creature desgins constantly appear, this feature specifically (a mouth that exists in and occupies a good portion of the ribcage area) doesn't seem to stick to what is biologically or physically possible, but sometimes their body shapes could work or at the least look similar in the real life. So in this case I have the doubt about if its possible that some creture could have an open rib cage as it's mouth or something that could look similiar, this also can be interpreted as a second belly or chest mouth.
These are some examples I found to illustrate better what I mean:
Lastely I saw questions about the possibility of the existance of fantasy like creatures and for me this chest mouth is a very interesting concept i'd like to use, but I dont know about the great changes to the anatomy and organs to make it possible.
Summing up: Is it possible for a vertebrate animal, given our understanding of biology, to have a mouth located in it's chest in a ribcage-like fashon? If so, what changes to it's overall anatomy would be needed in order for this trait to exist?
(I tried to think how this could affect it and I'm almost sure that a thing like this is not currently possible for the earth animals as we know them, maybe alterating the evolutionary story changing the developing of the notocord, so probably bilaterial current creatures are discarded, but maybe some arthropod with retarded mandibules and a lobuled head, but this is very different from the initial idea. So my best current guess is a radial organism like an equinoderm with a centered body mouth but are not vertebrate like creatures).