 "Megachasma" is known from a single living species, "Megachasma pelagios".In addition to the living "M. pelagios", however, two extinct megamouth species – the Priabonian "M. alisonae" and the Oligocene–Miocene "M. applegatei" – have also recently been proposed on the basis of fossilized tooth remains.An early ancestor of the recent species "Megachasma pelagios" was reported from the early Miocene (Burdigalian) of Belgium.