Hooks of Neoskrjabinolepis singularis; SEM of Ditestolepis sp.; larvae of Coronacanthus vassilevi. (Photos courtesy of V. Tkach)
Small to relatively large cestodes, body from less than 1 mm to over 1 m long. Proglottids usually craspedote, hermaphroditic (but there are monoecious forms), sometimes apolytic. Scolex with 4 suckers and usually bearing an armed rostellum having 8 to several hundred hooks, however, rostellar armature sometimes reduced or lost, in the latter case a rudimentary rostellum may be present or absent. Different parts of the scolex such as the rhynchus or suckers, may be armed with spines. Strobila usually with numerous proglottids, although there are miniature forms with only few proglottids. Majority of species have 1-3 testes per proglottid, rarely more. Internal and external seminal vesicles present. Additional structures (stylet, accessory sac) may present in male copulatory system. Vitellarium compact, posterior to ovary. Genital pores typically unilateral, rarely alternating or paired. Uterus in gravid proglottids usually sac-like, rarely reticulate or labyrinthine; sometimes egg-protective structures such as syncapsules or cocoons are formed.
This is arguably the most speciose cestode family, containing more than 900 valid species; number of valid genera is about 90.
Together with the Anoplocephalidae and the Dilepididae, the Hymenolepididae forms the crown of cyclophyllidean and cestode phylogenetic trees. Recent molecular data (Tkach et al., unpublished data) demonstrate a sister-group relationship between the Hymenolepididae and the Anoplocephalidae.
Most species (about 700) are found in birds with a smaller number (about 250) in mammals.
Intestine; exceptions are Cloacotaenia (parasitic in cloaca of anseriform birds) and Gastrotaenia (parasitic under the gizzard lining of anseriform birds).
Cosmopolitan.
Life-cycles aquatic or terrestrial. Intermediate hosts are arthropods such as crustaceans or insects, sometimes mites or millipedes. A few representatives (e.g., Staphylepis cantaniana, Urocystis prolifer) are capable of asexual reproduction in the intermediate host. Numerous types of cysticercoids have been observed; shape and fate of the cercomer vary substantially.
Selected References:
Czaplinski, B. and C. Vaucher. 1994. Family Hymenolepididae Ariola, 1899. pp. 595-663. In Khalil, L. F., Jones, A., Bray, R. A. (Eds.) Keys to the cestode parasites of vertebrates. CAB International, Wallingford, U.K. PDF
Spasskii, A. A. 1963. Principles of Cestodology. Vol. II. Hymenolepididae - Parasites of Wild and Domestic Birds. Part I. Moscow: Izdatel'stvo "Nauka", 418 pp. [In Russian.]
Spasskaya, L. P. 1966 [Cestodes of birds in the USSR. Hymenolepididae.] Moscow, Nauka, 698 pp. [In Russian.]
Skryabin, K. I. and E. M. Matevosyan. 1945. [Tapeworms - Hymenolepidids of Domestic and Game Birds.] Selkhozgiz, Moscow, 488 pp. [In Russian]
Taxon Coordinator:
Dr. Vasyl Tkach
Department of Biology
University of North Dakota,
10 Cornell Street,
Grand Forks, ND 58202-9019
U.S.A.
PHONE: (701) 777-4675
E-MAIL: vasyl.tkach@und.nodak.edu
