Molecular analysis supports the morphological identification of the amphistome Pseudodiscus collinsi (Paramphistomoidea: Platyhelminthes) in wild elephants of Sri Lanka.

Post-mortem examinations of elephants in Sri Lanka's Yala National Park morphologically identified amphistome flukes as Pseudodiscus collinsi, a species previously found in Indian elephants. These Sri Lankan worms had 100% ITS-2 sequence identity with that of the Indian P. collinsi Wayanad specimen (GenBank: PQ046280). This species is currently placed in the paramphistomoid family Gastrodiscidae. We compared three markers, ITS-2, partial 28S rDNA (D1-D3 domain), and partial mitochondrial cox1 sequences to previously published data and constructed three maximum likelihood (ML) phylogenies. Across the three phylogenies, the Sri Lankan sequences grouped with other members of the Gastrodiscidae only in the tree inferred from cox1 sequences, albeit with low bootstrap support. The three ML phylogenies revealed inconsistent generic and familial interrelationships. They also suggested that the placement of P. collinsi in the Gastrodiscidae, may need to be reconsidered We report the first record of the amphistome Pseudodiscus collinsi Cobbold, 1875 Sonsino, 1895 (Paramphistomoidea: Platyhelminthes), using morphological and molecular identification, in wild elephants in Sri Lanka.