MORPHOLOGY: Relatively large, leaf-like body; scolex lacking, but small sucker-like organ may be present at anterior of body. Ten minute hooks, retained from larval form, may be present at posterior extremity of adult body. Monozoic (i.e., unsegmented), possessing only a single set of male and a single set of female reproductive organs per individual. Testes numerous, in 2 lateral bands. Cirrus-sac absent. Male and female genital pores usually separate, occasionally combined, opening in posterior extremity of body. Ovary posterior; seminal receptacle posterior, minute to extensive. Vitellarium follicular, in lateral bands external to testes. Uterus tubular, N-shaped, opening via uterine pore at anterior extremity of body. Eggs with ten-hooked larva (decacanth).

DIVERSITY: Eight species are known. Generic and familial classification is controversial. Rhode (1999) recognizes 3 genera and 1 family, but up to 8 genera and 4 families have been proposed by other authors.

PHYLOGENETIC RELATIONSHIPS: Generally considered, along with the gyrocotylideans, to represent the most basal cestode taxa, although the exact relationships between gyrocotylideans, amphilinideans and the remaining cestodes (i.e., the eucestodes) remain to be determined.

DEFINITIVE HOSTS: Chondrosteans, basal freshwater teleosts, some marine teleosts, and a few freshwater turtles.

SITE IN DEFINITIVE HOST: Body cavity.

GEOGRAPHIC DISTRIBUTION: Cosmopolitan (Holarctic, South America, Africa, Indian subcontinent, East Indies, Australia).

LIFE-CYCLES: Life-cycles are poorly known, but appear to involve two hosts. Decacanth larvae hatch from unoperculated eggs. Some species are known to develop as a juvenile stage in crustaceans such as amphipods, crayfish and freshwater prawns.

Selected References:

Poche, F. 1922. Zur Kenntnis der Amphilinidea. Zoologischer Anzeiger 54: 276-287. PDF

Dubinina, M. N. 1982. [Parasitic worms of the class Amphilinida (Platyhelminthes).] Trudy Zoologicheskogo Instituta, Leningrad 100: 1-142. [In Russian.] PDF

Bandoni, S. M. and D. R. Brooks. 1987. Revision and phylogenetic analysis of the Amphilinidea Poche, 1922 (Platyhelminthes: Cercomeria: Cercomeromorphae). Canadian Journal of Zoology 65: 1110-1128. PDF

Gibson, D. I. 1994. Order Amphilinidea Poche, 1922. pp. 3-10. In Keys to the cestode parasites of vertebrates, L. F. Khalil, A. Jones, and R. A. Bray (eds). CAB International, Wallingford, U.K. PDF

Rohde, K. 1994. The minor groups of parasitic Platyhelminthes. Advances in Parasitology 33: 145-234. PDF

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