Desmoplakiidae

Desmoplakiidae is a family of parasitic flatworms in the phylum Platyhelminthes, class Monogenea. The group comprises a small number of described species that are marine ectoparasites of fish, typically infecting the gills of teleosts. As with other monogeneans, Desmoplakiidae species have a direct life cycle and do not require intermediate hosts.

Morphology within Desmoplakiidae is centered on the opisthaptor, the posterior organ used for attachment to the host. The opisthaptor often bears clamps or hooks, and its structure is a key feature in diagnosing the family and distinguishing it from related groups. The tegument is syncytial, a common trait among monogeneans, and reproductive organs are arranged in ways that support their classification within Monogenea. Because only a subset of species has been described, the full range of morphological variation in the family remains incompletely known.

Taxonomic status and phylogeny of Desmoplakiidae have been subject to revision. The family is generally placed within Monogenea, but its exact relationships to other families are uncertain due to limited molecular data and the relatively small number of described species. Ongoing revisions in monogenean systematics may lead to changes in circumscription or the inclusion of additional genera.

Ecology and distribution of Desmoplakiidae are tied to marine fish communities. Records are sporadic and often rely on targeted sampling of host fishes, so geographic and host ranges are not well defined. The ecological impact of desmoplakiids is typically localized to the health of individual hosts and may be of interest in aquaculture where parasite loads can affect fish welfare. See also Monogenea and parasitic flatworms.