''Chromidina'' is a genus of

apostome The Apostomatida are an order of ciliates from the class Oligohymenophorea. Individual organisms from this the order are called apostomes. They are symbiotic with Crustacea. For majority of their life cycle they are dormant and encysted on the ...

ciliates of the family Opalinopsidae. Species of ''Chromidina'' are parasitic in the renal and pancreatic appendages of

cephalopods A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, an ...

. In 2016, a molecular study found that the closest relatives of ''Chromidina'' spp. were species of the apostome ''

Pseudocollinia ''Pseudocollinia'' is a genus of parasitoid ciliate of the Colliniidae Colliniidae is a family of ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in stru ...

''.

References

Oligohymenophorea Ciliate genera Taxa described in 1905 {{ciliate-stub