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Phylogenetic Analysis of Diprotodontian Marsupials
Based on Complete Mitochondrial Genomes

Maruo Munemasa, Masato Nikaido, Stephen Donnellan, Christopher C. Austin,
Norihiro Okada and Masami Hasegawa

Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Kanagawa 226-8501, Japan
Evolutionary Biology Unit, South Australian Museum, North Terrace, SA 5000, Australia
Museum of Natural Science, Louisiana State University, LA 70803, USA
Department of Evolutionary Biology and Biodiversity, National Institute for Basic Biology, Okazaki 444-8585, Japan
Institute of Statistical Mathematics, Tokyo 106-8569, Japan
Department of Biosystems Science, Graduate University for Advanced Studies, Kanagawa 240-0193, Japan

 

ABSTRACT. Australidelphia is the cohort, originally named by Szalay, of all Australian mar­supials and the South American Dromiciops. A lot of mitochondria and nuclear genome studies support the hypothesis of a monophyly of Australidelphia, but some familial relationships in Australidelphia are still unclear. In particular, the famil­ial relationships among the order Diprotodontia (koala, wombat, kangaroos and possums) are ambiguous. These Diprotodontian families are largely grouped into two suborders, Vombatiformes, which contains Phascolarctidae (koala) and Vom­batidae (wombat), and Phalangerida, which contains Macropodidae, Potoroidae, Phalangeridae, Petauridae, Pseudocheiridae, Acrobatidae, Tarsipedidae and Bur­ramyidae. Morphological evidence and some molecular analyses strongly support monophyly of the two families in Vombatiformes. The monophyly of Phalangerida as well as the phylogenetic relationships of families in Phalangerida remains uncer­tain, however, despite searches for morphological synapomorphy and mitochondrial DNA sequence analyses. Moreover, phylogenetic relationships among possum families (Phalangeridae, Petauridae, Pseudocheiridae, Acrobatidae, Tarsipedidae and Burramyidae) as well as a sister group of Macropodoidea (Macropodidae and Potoroidae) remain unclear. To evaluate familial relationships among Dromiciops and Australian marsupials as well as the familial relationships in Diprotodontia, we determined the complete mitochondrial sequence of six Diprotodontian species. We used Maximum Likelihood analyses with concatenated amino acid and codon sequences of 12 mitochondrial protein genomes. Our analysis of mitochondria amino acid sequence supports monophyly of Australian marsupials + Dromiciops and monophyly of Phalangerida. The close relatedness between Macropodidae and Phalangeridae is also weakly supported by our analysis