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The generic and specific status of fossil kangaroo specimens attributed to Nambaroo and Ganawamaya from the Riversleigh World Heritage Area, Australia, are revised and new material is described. Results indicate that the previously proposed 12 species (eight of Nambaroo and four of Ganawamaya) represent four species from a single genus (Ganawamaya). Previous studies distinguished species of Ganawamaya from Nambaroo in lacking a protostylid on the lower first molar. However, our analyses indicate that the apparent presence/absence of the protostylid is related to the degree of dental wear, being totally worn in older individuals. Unworn specimens from Riversleigh were previously typically attributed to Nambaroo, while worn specimens were most commonly attributed to Ganawamaya. With support from phylogenetic analyses, we refer Riversleigh's N. couperi and N. gillespieae to Ganawamaya. The diagnoses of both genera are revised. We also assign undescribed specimens from the Ngapakaldi Quarry and Leaf Locality, South Australia, to Gan. couperi comb. nov. and Gan. acris, respectively, and describe new material of Gan. acris and Gan. aediculis.

Fibromuscular dysplasia is rarely reported in the infra-inguinal arteries. We report a case of an 86-year-old woman who presented with a ruptured profunda femoris artery aneurysm who was found to have angiographic findings of fibromuscular dysplasia in the bilateral deep femoral arteries and bilateral renal arteries. The rupture was treated successfully with a balloon-expandable covered stent. Keywords: Fibromuscular dysplasia, Aneurysm, Profunda femoris, Rupture, Endovascular

The Riversleigh World Heritage Area, northwestern Queensland, Australia, contains numerous Oligo-Miocene and Pleistocene fossil bearing deposits. Species of the suborder Macropodiformes (kangaroos and allies) described from Oligo-Miocene sediments at Riversleigh include representatives of all three macropodiform families: Macropodidae, Hypsiprymnodontidae and Balbaridae, a family of extinct fanged kangaroos. Despite extensive taxonomic study, few studies have focused on the ecology of balbarids that are present in Late Oligocene to Late Miocene faunal assemblages. Recently, several macropodiform species from Riversleigh have been described or revised that significantly alter previous interpretations of species richness and abundance at Riversleigh. In this study, Riversleigh macropodiform species richness and relative abundance is explored against a framework of recently revised taxonomic interpretations and biostratigraphy. With the exception of the Early Miocene, our results suggest that balbarids were less abundant than macropodids at Riversleigh. Balbarid species richness declined by the Early Miocene while macropodid species diversity declined from the Early Miocene to Middle Miocene and again in the Late Miocene. We also estimate body mass for macropodiform taxa throughout the Oligo-Miocene. A statistically significant increase in body mass is evident for most taxa through time. A number of ancestral macropodid genera suffer extinction in the Middle Miocene and are replaced by larger sthenurine macropodids around the time of the Miocene Climatic Optimum. Trends in faunal turnover (extinction and replacement of several macropodiform species) in the Middle Miocene are consistent with trends for other mammalian groups both from Riversleigh and globally.

The functional form of the friction law employed in dynamic earthquake simulations is directly related to the energy partitioning of rupture and slip (e.g., Kanamori and Rivera, 2006). Earthquake ruptures can propagate along geometrically complex faults by bending and jumping along fault segments (Wesnousky, 1988), however, this is dependent on how much energy is available to further rupture propagation and how much energy is needed. For planar fault stepovers with homogeneous stress, rupture can jump segments or it can arrest at the edge of a segment. Since friction laws, along with stress regimes, implicitly specify the energy budget, different laws can lead to different rupture dynamics. Using realistic, laboratory-derived friction laws to simulate rupture is a constant ambition in seismology. The rate-state friction formulation includes intuitive variables such as time, slip speed history, and normal stress history as well as exhibits reasonable properties such as stick-slip sliding, creep, and healing (Dieterich, 1978b, 1979; Linker and Dieterich, 1992). Particularly, including the change in friction coefficient with normal stress history is imperative for earthquakes that produce large dynamic fluctuations in normal stress, including both stepovers and dip-slip faults that penetrate the free surface.In this study we use FaultMod to run dynamic earthquake simulations on fault stepovers using the various friction formulas listed above. Firstly, we investigate effects of the functional form of the friction laws on jumping rupture at stepovers. The functional forms are associated with unique energy budgets that can determine how far rupture can jump within a given amount of time. We find that making the energy budgets similar between the friction parameterizations makes the rupture processes more similar at the stepover region (e.g., similar maximum jump distances). We also find that for larger jumps the rupture speeds increase to supershear speeds, even though the initial stress conditions would preclude such a result on a planar strike-slip fault (Andrews, 1976b). Secondly, we add to the stepover simulations by introducing the Linker-Dieterich formulation, in which friction coefficient depends on normal stress. It is well known that stepovers exhibit perturbations in normal stress along the offset region during rupture, with the sign being opposite for compressional and dilational stepovers. Adding the normal-stress-dependent state variable to the friction formulation decreases the maximum rupture jump for both types of stepover, however. Additionally, we apply the Linker-Dieterich formulation to normal and reverse dip-slip faults, both of which are known to exhibit dynamic fluctuations in normal stress due to the free surface (Brune, 1996; Nielsen, 1998; Oglesby et al., 1998). Differences in shear stress direction between normal and reverse faults produce asymmetric normal stress perturbations along the fault during rupture, causing the motion from a reverse fault to be larger than that of an otherwise equivalent normal fault. Adding a normal-stress-dependent state variable serves to mitigate this effect. We also find that decreasing the initial shear stress inhibits rupture more on normal faults than on reverse faults, given that the faults intersect the free surface.