Microstomus is a genus of righteye flounders native to the northern Pacific and north-eastern Atlantic oceans.
The word Microstomus is derived from the Greek üùúÃÂὸà(mikros), meaning "small", and ÃÂÃÂÃÂüñ (stoma), meaning "mouth".
There are currently five recognized species in this genus:
A single fossil species is known in â Microstomus tochigiensis <small>Sakamoto & Uyeno, 1993</small> from the Middle Miocene of Japan.