Data from: The Phylogenetic Position of the Musky Rat-Kangaroo and the Evolution of Bipedal Hopping in Kangaroos (Macropodidae: Diprotodontia)

Kangaroos and their relatives (family Macropodidae) are divided into the
subfamilies Macropodinae (kangaroos, wallabies, pademelons) and Potoroinae
(rat-kangaroos, potoroos, bettongs). The musky rat-kangaroo,
Hypsiprymnodon moschatus, is traditionally allied with other potoroines
based primarily on osteological characters and aspects of the female
reproductive system. Unlike other macropodids, however, which are capable
of bipedal hopping, Hypsiprymnodon is a quadrupedal bounder and lacks
several derived features of the pes and tarsus that are presumably
adaptations for bipedal hopping. Other derived features, such as a complex
stomach, loss of P2 with the eruption of P3, and reduction of litter size
to one, are also lacking in Hypsiprymnodon but occur in all other
macropodids. Thus, available evidence suggests that Hypsiprymnodon either
is part of a monophyletic Potoroinae or is a sister taxon to other living
macropodids. To test these hypotheses, we sequenced 1,170 base pairs of
the mitochondrial genome for 16 macropodids. Maximum parsimony, minimum
evolution, maximum likelihood, and quartet puzzling all support the
hypothesis that macropodines and potoroines are united to the exclusion of
Hypsiprymnodon. This hypothesis implies that characters such as bipedal
hopping evolved only once in macropodid evolution. Aside from
Hypsiprymnodon, the remaining macropodids separate into the traditional
Macropodinae and Potoroinae. Macropodines further separate into two
clades: one containing the New Guinean forest wallabies Dorcopsis and
Dorcopsulus, and one consisting of the genera Macropus, Setonix,
Thylogale, Onychogalea, Wallabia, Dendrolagus, Peradorcas, and
Lagorchestes. Among potoroines, there is moderate support for the
association of Bettongia and Aepyprymnus to the exclusion of Potorous.
Divergence times were estimated using 12S ribosomal RNA transversions. At
the base of the macropodid radiation, Hypsiprymnodon diverged from other
macropodids approximately 45 million years ago. This estimate is
comparable to divergence estimates among families of Australasian possums
based on single-copy DNA hybridization and 12S rRNA transversions.
Macropodines and potoroines, in turn, diverged approximately 30 million
years ago. Among macropodines Dorcopsis and Dorcopsulus separated from
other taxa approximately 10 million years ago.