Phylogenetic position of the monogeneans Sundanonchus, Thaparocleidus, and Cichlidogyrus inferred from 28S rDNA sequences.

A molecular phylogeny was inferred from newly obtained partial 28S rRNA gene sequences of Sundanonchus micropeltis (Sundanonchidae), Thaparocleidus siamensis and Cichlidogyrus sp. (Ancyrocephalidae), and other already available sequences. Although sequences are lacking for several families, the following phylogenetic relationships could be inferred. The Diplectanidae were the sister-group to a clade including Sundanonchus and the Ancyrocephalidae; Sundanonchus was the sister-group to the Ancyrocephalidae, therefore suggesting validity of the Sundanonchidae, which include this single genus; within the Ancyrocephalidae, Thaparocleidus (Ancylodiscoidinae) was the sister-group to the four other taxa, though with relatively low support, suggesting that the Ancylodiscoidinae are the sister-group to the Ancyrocephalinae.