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The evolutionary history of the 'Oxycanus' lineages of hepialid moths in New Zealand

Brown, Barbara
Fields of Research
This thesis attempted to reconstruct the evolutionary history of part of New Zealand's hepialid fauna. Phylogenetic analysis was used to test the monophyly of the informal 'Oxycanus' Cladoxycanus and 'Oxycanus' s. str. lineages. Data were morphological characters and molecular characters from the mtDNA COI & II and nrDNA ITS2 regions. Morphological and COI & II phylogenies indicated that the 'Oxycanus' Cladoxycanus and 'Oxycanus' s. str. lineages were monophyletic clades. Addition of Australian hepialid exemplars to the morphological data set indicated that Oxycanus and Jeana taxa were sister group to the monophyletic New Zealand 'Oxycanus' lineage s. str., while addition to the COI & II data set indicated that 'Oxycanus' Cladoxycanus was sister group to the 'Oxycanus' lineage s. str. The morphology and COI & II phylogenies were mostly congruent, with both recovering clades that corresponded to the informal Aenetus, Aoraia, 'Oxycanus' Cladoxycanus and 'Oxycanus' s. str. lineages. The morphological and COI & II phylogenies were not congruent with respect to the placement of the Dumbletonius taxa. The morphological data set recovered Dumbletonius characterifer in a clade with D. unimaculatus, while the COI & II data set recovered D. characterifer as the basal taxon in the 'Oxycanus' lineage s. str. and D. unimaculatus in a clade with Wiseana taxa. Tracing the evolution of morphological characters that supported the monophyly of the genus Dumbletonius on to the independently derived COI & II phylogeny indicated that all characters were plesiomorphic. Spectral analysis gave higher support to the (D. unimaculatus, Wiseana) clade compared with the (D. characterifer, D. unimaculatus) clade. Morphological characters were mapped on to the COI & II phylogeny. Aenetus and Aoraia taxa were hypothesised to exhibit ancestral character states, male genitalic characters were less homoplasious compared with other data partitions and the morphological synapomorphies supporting the 'Oxycanus' lineages and the 'Oxycanus' s. str. lineage alone, were homologous. The combined morphology, COI & II and ITS2 data set did not support the monophyly of the 'Oxycanus' lineages. Dumbletonius unimaculatus, D. characterifer, Cladoxycanus, Heloxycanus and Dioxycanus taxa were recovered in a clade together. This topology was not recovered from any other data sets. Saturation of nucleotide sites in more divergent taxa and inconsistency in the parsimony method may have contributed to this result. The combined morphology and COI & II data set recovered a phylogeny congruent with that from the morphology alone. A combined morphology, COI & II, ITS2 and allozyme data set with Dumbletonius unimaculatus as outgroup, recovered the most resolved phylogeny for the genus Wiseana. The two clades recovered were: (((Wiseana cervinata 'southern', Wiseana cervinata 'northern'), W. jocosa), (W. copularis 'southern', W. copularis 'northern'), (W. fuliginea, W. mimic)) and CCW. signata 'southern', W. signata 'northern'), W. umbraculata). A diagnostic test was developed for Wiseana taxa based on the cleavage of the mtDNA COI & II gene regions with restriction enzymes. All Wiseana taxa, apart from W: fuliginea and W. mimica, were identified by unique restriction fragment length polymorphism patterns.