Abstract
Adult notocotylid flukes (Digenea: Notocotylidae) were recovered from the ceca of Pitalah ducks (Anas sp.) in Aceh Province, Indonesia. These flukes were morphologically characterized by a median ventral ridge with 2 lateral rows of ventral papillae and the absence of both a ventral sucker and pharynx, consistent with the characteristics of the genus Catatropis. They exhibited a genital pore located just posterior to the oral sucker, 10-11 pairs of ventral papillae, a deep and multi-lobed ovary and testes, a metraterm equal in length to the cirrus sac, and ceca bearing numerous diverticula; accordingly, they were identified as Catatropis indicus Srivastava, 1935. Adult specimens measured 3.01-3.77 mm (average 3.47 mm) in length and 0.98-1.21 mm (average 1.11 mm) in width (n=8). Uterine eggs measured 0.016-0.023 mm (average 0.019 mm) in length and 0.008-0.014 mm (average 0.012 mm) in width (n=20), each bearing 2 long polar filaments. These specimens resembled Catatropis vietnamensis Izrailskaia et al., 2019, and Catatropis pakistanensis Schuster and Wibbelt, 2012, sharing features such as a genital pore immediately posterior to the oral sucker and other morphological traits. However, they differed from C. vietnamensis by having a larger body, ceca with numerous diverticula, and a broader anterior distribution of vitelline follicles. They also differed from C. pakistanensis in possessing a longer esophagus and ceca with multiple diverticula. In 28S rDNA sequence analysis, our specimens showed 99.1% identity with both C. indicus and C. vietnamensis. In contrast, internal transcribed spacer 2 (ITS2) sequence comparisons revealed only 96.0%-96.1% identity with C. vietnamensis (no GenBank data available for C. indicus), suggesting that our specimens are phylogenetically distant from C. vietnamensis. This represents the first report of C. indicus from ducks in Indonesia. A brief review of Catatropis species is provided.