No Tail No Fail: Life Cycles of the Zoogonidae (Digenea)

The Zoogonidae is the only digenean family where known cercariae lack tail but actively search for second intermediate host. However, data on zoogonid life cycles are scarce. In present study, we elucidated and verified of from White Sea. Using rDNA data, showed that Pseudozoogonoides subaequiporus utilizes gastropods Buccinidae as first host protobranch bivalves one. This cycle can be facultatively truncated: some P. encyst within daughter sporocysts. Molecular also confirmed previous hypotheses Zoogonoides viviapus with buccinid acting hosts, annelids hosts. We demonstrated presence short primordium in developing both species. Based reviewed our own hypothesize emergence tailless evolution linked to switch non-arthropod it possibly happened subfamily Zoogoninae. Basally branching zoogonids have retained ancestral might tail.