MORPHOLOGY: Body normally not longer than 100 mm to very small (less than 1 mm). Scolex with 4 suckers (usually unarmed) and sac-like rostellar apparatus. Rostellar hooks absent or present, in 2 rows, rarely in 1 row or in zigzag line. Strobila consisting of 3-4 to several hundred craspedote proglottids. Genital pores unilateral or alternating, situated on lateral proglottid margin. Proglottids hermaphroditic, with a single set of male and female genital organs. Testes ranging between 3 and 300 in number, usually numerous (several dozen). Seminal vesicles lacking, functionally replaced by coiled vas deferens. Ovary usually two-winged or fan-shaped, lobate, and median. Vitellarium compact or lobate, posterior to ovary. Uterus variable in structure: sac-like, labyrinthine, reticulate, or divided into parenchymatous capsules.

DIVERSITY: Over 100 genera and over 750 species. Traditionally, a group of genera parasitic in fish-eating birds are considered as members of Dilepididae; these are known to have a three-host life cycle and distinct morphology of larval stages. On this basis, they are currently recognised as a distinct family, the Gryporhynchidae.

PHYLOGENETIC RELATIONSHIPS: Together with hymenolepidids and anoplocephalids, dilepidids form the most derived clade within the Cyclophyllidea.

DEFINITIVE HOSTS: Birds, with a much lower number of genera in mammals.

SITE IN DEFINITIVE HOST: Small intestine.

GEOGRAPHIC DISTRIBUTION: Cosmopolitan.

LIFE-CYCLES: Dilepidids have a two-host life cycle: invertebrate (arthropod, mollusk, or annelid) intermediate host and vertebrate (bird or mammal) definitive host. Various forms of cysticercoids develop in the intermediate hosts.

Selected References:

Matevosyan, E. M. 1963. Dilepidoidea - tapeworms of domestic and wild animals. in Skrjabin, K.I. (Ed) Osnovy Tsestodologii, Volume 3, Moscow, Izdatel'stvo Akademii Nauk SSSR, 687 pp. [In Russian.] PDF

Spasskaya, L. P. and A. A. Spasskii. 1977. [Cestodes of the birds in the USSR. Dilepididae of terrestrial birds]. Izdatel'stvo "Nauka", Moscow, 299 pp. [In Russian.] PDF

Spaskaya, L. P. and A. A. Spasskii. 1978. Cestodes of the birds in the USSR. Dilepididae of limnophilous birds. Izdatel'stvo "Nauka", Moscow, 314 pp. [In Russian.]

Schmidt, G. D. 1986. Handbook of Tapeworm Identification. Boca Raton, Florida : CRC Press 675 pp. PDF

Bona, F. 1994. Family Dilepididae Railliet & Henry, 1909. pp. 443-554. In Khalil, L .F., Jones, A., Bray, R. A. (Eds.) Keys to the cestode parasites of vertebrates. CAB International, Wallingford, U.K. PDF