Phylogenetic position of the monogeneans Sundanonchus, Thaparocleidus, andCichlidogyrus inferred from 28S rDNA sequences

A molecular phylogeny was inferred from newly obtained partial 28S rRNA gen e sequences of Sundanonchus micropeltis (Sundanonchidae), Thaparocleidus si amensis and Cichlidogyrus sp. (Ancyrocephalidae), and other already availab le sequences. Although sequences are lacking for several families, the foll owing 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 sugg esting validity of the Sundanonchidae, which include this single genus; wit hin the Ancyrocephalidae, Thaparocleidus (Ancylodiscoidinae) was the sister -group to the four other taxa, though with relatively low support. suggesti ng that the Ancylodiscoidinae are the sister-group to the Ancyrocephalinae. (C) 2000 Published by Elsevier Science Ltd on behalf of the Australian Soc iety for Parasitology Inc. All rights reserved.