Macropodiformes

Abstract: The Australasian marsupial order Diprotodontia includes ten extant families that are grouped into the suborders Vombatiformes (koalas and wombats), Macropodiformes (kangaroos and allies), and Phalangeriformes (possums and gliders). We investigated interfamilial relationships using mitochondrial 12S rRNA, valine tRNA, and 16S rRNA gene sequences. Our results support the monophyly of both Vombatiformes and Macropodiformes, but not Phalangeriformes. Among possums and gliders, there was strong support for a petauroid clade that includes Pseudocheiridae (ringtail possums), Petauridae (sugar glider, striped possums), Acrobatidae (feathertail possums), and the monotypic family Tarsipedidae, which is represented by the highly specialized and autapomorphic honey possum (Tarsipes rostratus). Other prior hypotheses for the phylogenetic placement of the honey possum were rejected by statistical tests. The inclusion of the honey possum within Petauroidea suggests that derived ultrastructural features of Tarsipes' spermatozoa evolved independently in Tarsipes versus polyprotodont Australasian marsupials.

Abstract: The exceptionally diverse macropodiform’s (kangaroos, rat-kangaroos and their fossil allies) currently have a fossil record that spans from the late Oligocene to the Holocene with an Australasian w

Abstract: Kangaroos and kin (Macropodiformes) are the most conspicuous elements of the Australasian marsupial fauna. The approximately 70 living species can be divided into three families: (1) Hypsiprymnodontidae (the musky rat kangaroo); (2) Potoroidae (potoroos and bettongs); and (3) Macropodidae (larger kangaroos, wallabies, banded hare wallaby and pademelons). Here we examine macropodiform relationships using protein-coding portions of the ApoB, BRCA1, IRBP, Rag1 and vWF genes via maximum parsimony, maximum likelihood and Bayesian methods. We estimate times of divergence using two different relaxed molecular clock methods to present a timescale for macropodiform evolution and reconstruct ancestral states for grades of dental organisation. We find robust support for a basal split between Hypsiprymnodontidae and the other macropodiforms, potoroid monophyly and macropodid monophyly, with Lagostrophus as the sister-taxon to all other macropodids. Our divergence estimates suggest that kangaroos diverged from Phalangeroidea in the early Eocene, that crown-group Macropodiformes originated in the late Eocene or early Oligocene and that the potoroid–macropodid split occurred in the late Oligocene or early Miocene followed by rapid cladogenesis within these families 5 to 15 million years ago. These divergence estimates coincide with major geological and ecological changes in Australia. Ancestral state reconstructions for grades of dental organisation suggest that the grazer grade evolved independently on two different occasions within Macropodidae.