LIFE-CYCLE, DELIMITATION AND REDESCRIPTION OF ECHINOSTOMA-REVOLUTUM (FROELICH, 1802) (TREMATODA, ECHINOSTOMATIDAE)

The life-cycle of Echinostoma revolutum (Froelich, 1802) Dietz, 1909 h as been completed experimentally beginning with infected snails collec ted at the type-locality, near Erlangen, Germany. Based on the specime ns obtained, each stage of the life-cycle has been redescribed. Import ant taxonomic features are discussed and hitherto unknown characterist ics are described. Synonyms for E. revolutum are: Fasciola revoluta Fr oelich, 1802; Echinostoma paraulum Dietz, 1909; E. audyi Lie and Umath evy, 1965; and E. ivaniosi Mohandas, 1973. Adults and larvae described as E. revolutum in other works are found to be identical with Echinos toma echinatum (Zeder, 1803), E. trivolvis (Cort, 1914), E. jurini (Sk vortsov, 1924), E. caproni Richard, 1964, Moliniella anceps (Molin, 18 59), Echinochasmus beleocephalus (Linstow, 1873) and other echinostome species. For nearly a century, incorrect morphological, biological, l ife-cycle and host information has been attributed to E. revolutum, an d at times these data have contributed to the diagnoses of the species . Occasionally, authors actually working with E. revolutum have ascrib ed their results to other species. Based on extensive experimental lif e-cycle studies beginning with infected snails from type-localities, i t is shown that (1) the first intermediate host is a lymnaeid snail; ( 2) the second intermediate hosts are various pulmonate and prosobranch snails, mussels, frogs and freshwater turtles; (3) the final hosts ar e birds; (4) E. revolutum cercariae and adults have 37 collar spines; (5) the species occurs only in Europe and Asia; (6) Cercaria echinata Siebold, 1937, Echinostoma echinatum (Zeder, 1803) and E. jurini (Skvo rtsov, 1924) are the closely related 37-spined allies in Europe; and ( 7) species specific characteristics are expressed only in the larvae a nd the host-parasite relationships. The adults of E. revolutum cannot be identified using morphological criteria and it is proposed that wor ms with 37 collar spines belonging to the genus Echinostoma and occurr ing in naturally infected birds in Europe and Asia be referred to an ' 'E. revolutum group.''