Fecampiida is an order of
flatworms
The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegment ...
in the class
Rhabditophora
Rhabditophora (from ''rhabdito''-, rhabdite + Greek -φορος ''phoros'' bearer, i.e., "rhabdite bearers") is a class of flatworms. It includes all parasitic flatworms (clade Neodermata) and most free-living species that were previously gr ...
. It is a considerably recent clade, erected after molecular studies.
Description
The order Fecampiida, as currently defined, was erected based on molecular studies.
They all are parasitic organisms and are united by a similar development of the
basal bodies
A basal body (synonymous with basal granule, kinetosome, and in older cytological literature with blepharoplast) is a protein structure found at the base of a eukaryotic undulipodium ( cilium or flagellum). The basal body was named by Theodo ...
during
spermiogenesis
Spermiogenesis is the final stage of spermatogenesis, during which the spermatids develop into mature spermatozoon, spermatozoa. At the beginning of the stage, the spermatid is a more or less circular cell containing a cell nucleus, nucleus, Golg ...
.
Classification
Three families of Fecampiida were initially classified in different flatworm orders:
Urastomatidae and
Genostomatidae were considered
prolecithophora
The ''Prolecithophora'' are an order consisting of an estimated 300 species of small (typically 0.2 – 12 mm, one species up to 50 mm), active, aquatic flatworms. The order lacks a common English name. Most species are shaped like an e ...
ns, while
Fecampiidae was considered a
rhabdocoel. When the genus ''
Notentera'' was discovered, its relationship with Fecampiidae was clear based on morphology, and both groups were united under Fecampiida.
Further
ultrastructural studies suggested that Urastomatidae and Genostomatidae were closely related to Fecampiidae and
Notenteridae, which was confirmed by molecular studies.
Due to similarities in the
protonephridial flame bulb, sperm and spermiogenesis, as well as the parasitic lifestyle, fecampiids were thought to be closely related to
neodermatans,
but molecular studies revealed them to be more closely related to
triclads and
prolecithophora
The ''Prolecithophora'' are an order consisting of an estimated 300 species of small (typically 0.2 – 12 mm, one species up to 50 mm), active, aquatic flatworms. The order lacks a common English name. Most species are shaped like an e ...
ns.
References
{{Taxonbar, from=Q10494503
Rhabditophora