title: Phylogenetic analysis reveals cryptic species diversity within minute intestinal fluke, Stellantchasmus falcatus Onji and Nishio, 1916 (Trematoda, Heterophyidae).
abstract: OBJECTIVE
  To examine the taxonomic boundaries in the Stellantchasmus populations in different hosts and reveal the cryptic speciation of the Stellantchasmus in Thailand based on both morphological and molecular approaches.
  
  
  METHODS
  Stellantchasmus falcatus (S. falcatus) s.l. was collected from different hosts throughout Thailand. The worms were examined and measured. The nuclear ITS2 gene and the mitochondrial COI gene were used to investigate the S. falcatus s.l. from Dermogenus pusillus and Liza subviridis.
  
  
  RESULTS
  Stellantchasmus was one of food-borne trematode that widely distribute throughout Thailand. The comparison of S. falcatus s.l. from Dermogenus pusillus and Liza subviridis indicated a genetic divergence of nuDNA with 3.6% and mtDNA with 19.3%, respectively. Morphological characteristics were fairly different in the ratio of body size, length of prepharynx, and ratio of organ size.
  
  
  CONCLUSIONS
  Our results provide initial evidence that S. falcatus s.l. from different hosts tend to be a different species based on both molecular and morphological characters. Cryptic species complexes are generally found among parasites that tend to have large populations and/or rapid evolution. The degree of genetic diversity existing would suggest the practice of targeted regimes to design and minimize these lections of anthelmintic resistance in the future.
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand; Applied Technology for Biodiversity, Institute for Science and Technology, Chiang Mai University, Chiang Mai 50202, Thailand. Electronic address: wchalobol@gmail.com.
authors.forename: Chalobol
authors.initials: C
authors.lastname: Wongsawad
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand.
authors.forename: Nattawadee
authors.initials: N
authors.lastname: Nantarat
authors.affiliation: Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand; Economic Plant Genome Service Centre, Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand.
authors.forename: Pheravut
authors.initials: P
authors.lastname: Wongsawad
keywords: Cryptic species; Host-parasite relationship; Speciation; Stellantchasmus; Trematode