Discovered in 2021, what type of animals are the kitefin, blackbelly and southern lantern?

Researchers have discovered that three deep-sea shark species — the kitefin shark (Dalatias licha), the blackbelly lanternshark (Etmopterus lucifer), and the southern lanternshark (Etmopterus granulosus) — all have bioluminescent properties.
The kitefin shark, which glows blue, is the largest known vertebrate to emit bioluminescence.
Further research is needed to fully understand how and why these sharks emit light.