Differentiation of Mexican species of Haematoloechus Looss, 1899 (Digenea : Plagiorchiformes): Molecular and morphological evidence

Molecular evidence is interpreted in the light of morphology to examine the validity of several species of Haematoloechus described as Mexican endemic s. Internal transcribed spacers 1 and 2 and 28S ribosomal genes were sequen ced for 11 isolates. Phylogenetic analysis of separate partitions and combi ned databases was conducted. Results were analyzed, in the light of morphol ogical evidence. Haemarolaechus macrorchis is proposed as a junior synonym of Haematoloechus longiplexus. Haematoloechus pulcher is a sibling species with Haematoloechus complexus in Lerma wetlands. In Mexico, Haematoloechus medioplexus is distributed along the east coast coinciding with the distrib ution of Rana berlandieri. The sister species of H. medioplexus is Haematol oechus caloradensis, sharing the distribution of the uterus as a synapomorp hic character. Haematoloechus illimis is more closely related to H. mediopl exus and H. coloradensis than to H. complexus. Tt can be distinguished by t he distribution of the uterus, lobed ovary, and testes.