Anything worth improving or this is good?

I brought up possible issues with its size and habitat here. Of course, in this case, it would be irrelevant if it were simply shrunk to 30 cm or smaller, like an olm.

I don't think there would be such an abundance of detritus as to make it fatter than its ancestor as a direct consequence, unless one should presume Sagan 4's ecology here is substantially different from Earth's.

Thermoregulation should be Ectothermic, also the description could be longer

Describe how it moves, slowly skimming across the floor shuffling through the debris with it's whiskers, like a cave dwelling catfish

Yeah the description feels a bit short, do you think you could add to it?

added thermoregulation and lengthened description

So its ancestor got renamed into Nothogyrinus, unless your species is a new genus I recommend editing the scientific name of your species as well.