Bucephalidae is a family of trematodes that parasitize fish. They lack suckers, having instead a muscular organ called a "rhynchus" at the front end which they use to attach to their hosts. The characteristics of the rhynchus are used to help define the genera of the family. It is one of the largest digenean families, with 25 genera containing hundreds of described species. Bucephalids are cosmopolitan, having been recorded all over the world. They are parasites of fish from freshwater, marine, and brackish water habitat types.

The name Bucephalus, meaning "ox head", was originally applied to the genus Bucephalus because of the horn-like appearance of the forked tail (furcae) of its cercaria larva. By what Manter calls a "curious circumstance", horns are also suggested by the long tentacles of adult worms.

These flatworms typically occur in teleost fishes as sexually reproducing adults. In their intermediate hosts, which include mollusks and at least one amphibian, they occur as asexually reproducing stages.

The characteristic feature is an anterior rhyncus or holdfast that is separate from the digestive system. They also differ from other digeneans in the configuration of the digestive systems and genitalia. The intestine is simple and saccular; they have no acetabulum.

The spermatozoa of adult bucephalids has been studied by transmission electron microscopy in several species belonging to the Bucephalinae and Prosorhynchinae, but, in the absence of data on the three other subfamilies, these studies could not provide information on the phylogenetic relationships within the family.

A schematic reconstruction of the mature spermatozoon of a bucephalid

Genera

The genera are organised by their subfamilies.

  • Bucephalinae Poche, 1907 Alcicornis MacCallum, 1917 Bucephalus von Baer, 1827 Glandulorhynchus Thatcher, 1999 Parabucephalopsis Tang & Tang, 1976 Prosorhynchoides Dollfus, 1929 Pseudobucephalopsis Long & Lee, 1964 Pseudorhipidocotyle Wang & Pan in Long & Lee, 1964 Rhipidocotyle Diesing, 1858 Rhipidocotyloides Long & Lee, 1964 Roparhynchus Gupta & Kumari, 1978
  • Dolichoenterinae Yamaguti, 1958 Dolichoenterum Ozaki, 1924 Grammatorcynicola Bott & Cribb, 2005 Pseudodolichoenterum Yamaguti, 1971
  • Heterobucephalopsinae Nolan, Curran, Miller, Cutmore, Cantacessi & Cribb, 2015 Heterobucephalopsis Gu & Shen, 1983
  • Paurorhynchinae Dickerman, 1954 Bellumcorpus Kohn, 1962 Paurorhynchus Dickerman, 1954 Rhoporhynchus Wang, 1995
  • Prosorhynchinae Nicoll, 1914 Dollfustrema Eckmann, 1934 Muraenicola Nolan & Cribb, 2010 Myorhynchus Durio & Manter, 1968 Neidhartia Nagaty, 1937 Neoprosorhynchus Dayal, 1948 Prosorhynchus Odhner, 1905 Pseudoprosorhynchus Yamaguti, 1938 Telorhynchus Crowcroft, 1947