Larval stages of Neoplagioporus elongatus (Goto and Ozaki, 1930) (Opecoelidae: Plagioporinae), with notes on potential second intermediate hosts

- Cercaria of Neoplagioporus elongatus were identified using a molecular technique.
- The cercaria was cotylomicrocercous-type developing in Semisulcospira nakasekoae.
- Experimental 2nd-intermediate hosts are oligochaetes, leeches and some dragonflies.

The morphology of sporocysts and cercariae of Neoplagioporus elongatus (Goto and Ozaki, 1930) is described for the first time. A cotylomicrocercous cercaria obtained from the sorbeoconch snail Semisulcospira nakasekoae was confirmed to be the cercaria of N. elongatus, based on the degree of sequence identity of the COI gene to that of adult worms. Freshwater annelids (oligochaetes and leeches) and some aquatic insects (odonates) were demonstrated experimentally to be potential second intermediate hosts.

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