Last Updated: June 10, 2026
Scolex of Diplophallus polymorpha; mature proglottids of D. polymorpha; example hosts of acoleids: Black-winged stilt (Himatopus himatopus), American avocet (Recurvirostra americana). (Photos of Diplophallus courtesy of B. Georgiev; Himatopus, www.oiseaux.net; Recurvirostra, www.ownmyphotography.com)
MORPHOLOGY: Large cestodes (up to 25 cm) with strongly developed musculature. Scolex with 4 suckers and armed or unarmed rostellum. One or 2 sets of male genitalia in each proglottid; in the former case, male genital pores opening on alternate sides of the proglottid. Proglottids each always possessing a single set of female gonads. Testes numerous. Vagina lacking. Compact vitellarium posterior to ovary. Uterus sac-like in gravid proglottids.
DIVERSITY: Two genera, fewer than 10 species.
PHYLOGENETIC RELATIONSHIPS: Closely related to the Progynotaeniidae and Dioecocestidae.
DEFINITIVE HOSTS: Charadriiform (stilts, avocettes, etc.) and ralliform birds.
SITE IN DEFINITIVE HOST: Intestine.
GEOGRAPHIC DISTRIBUTION: Cosmopolitan, mostly in tropical and temperate latitudes.
LIFE-CYCLES: No complete life-cycle is known.
Selected References:
Ryzhikov, K. M. and L. M. Tolkacheva. 1981. [Acoleata-tapeworms of birds]. Osnovy Tsestodologii 10: 215 pp. [in Russian.] PDF
Khalil, L. F. 1994. Family Acoleidae Fuhrmann, 1899. In Keys to the Cestode Parasites of Vertebrates, L. F. Khalil, A. Jones, and R. A. Bray (eds). CAB International, Wallingford, U.K., pp. 387-389. PDF
Taxon Coordinator:
Dr. Boyko B. Georgiev
Institute of Biodiversity and Ecosystem Research
Bulgarian Academy of Sciences
