Morphological and Molecular Characterization of Pande and Shukla 1976 (Digenea: Heterophyidae) from Chiang Mai Province.

Cyprinoid fish in Chiang Mai province has been reported the presence of a large number of metacercariae, particularly the metacercariae of and those not identified to species. This study aims to investigate morphological and molecular characteristic of the minute intestinal fluke metacercariae in two cyprinoid fish species from Chom Thong district, Chiang Mai province, Thailand: the Tinfoil barb () and the White eye barb (). A total of 180 fish (90 from and 90 from . ) were collected over three seasons: cool, hot and the rainy season (December 2015 to August 2016). Fish were examined for metacercariae infection, including areas such as muscle and the inner side of body scales, by using a light microscope. The prevalence of metacercariae in and was 73.33 % and 100 % respectively. metacercariae were identified as based on the morphological characteristics; the position of the acetabulum and the number and arrangement of the acetabular spines. Phylogenetic analysis based on Cytochrome c Oxidase subunit I (COI) gene showed that metacercariae from and were the same species as the adult stage of from and . Both morphological and molecular characteristic could indicate that metacercariae originated from this study were . Furthermore, it is a new record of the minute intestinal fluke in Chiang Mai Province.