[2] Until recently, only a single specimen from this family was known.

This individual had been caught off Saint Helena in 1868.

In the 1990s and 2000s, deep-sea submersibles identified several more individuals, including four further species.

[3] The first known species, M. compressus, was bright red in colour, but not all other species share this trait.

The currently recognized species in this genus are:[4][5] This Anguilliformes article is a stub.