Revision of Oligo-Miocene kangaroos, Ganawamaya and Nambaroo (Marsupialia: Macropodiformes, Balbaridae)

Incorporating uncertainty is essential to macroecological inferences: Grass, grit, and the evolution of kangaroos

“…These node priors cause a dramatic increase in the height of the macropodoid tree, including pulling the 290 Lagostrophinae-Macropodinae split from 12 to 19 MYA. Concerningly, the phylogenetic position of Ganguroo has also varied among studies (Prideaux & Warburton 2010;Butler et al 2016Butler et al , 2018, suggesting its affinities are equivocal, and as such, the hard minimum node prior should be considered carefully.…”

“…Ngamaroo is generally used to provide a late Oligocene (24.7 Mya) or early Miocene (16 Mya (Phillips et al 2013;Cascini et al 2018;Celik et al 2019). Morphological phylogenetic analyses however, 360 tend to place this taxon within the clade comprising Potoroidae and Macropodidae (Prideaux & Warburton 2010;Butler et al 2016Butler et al , 2018. This suggests a disconnect between the phylogenetic position of the taxon and the implementation of a fossil age prior.…”

“…Fossil ages for two extinct taxa Ganguroo bilamina and Ngamaroo archeri are often used as node priors to calibrate marsupial trees. Ngamaroo is generally used to provide a late Oligocene (24.7 Mya) or early Miocene (16 Mya (Prideaux and Warburton 2010;Butler et al 2016Butler et al , 2018. This suggests a disconnect between the phylogenetic position of the taxon and the implementation of a fossil age prior.…”

Climbing adaptations, locomotory disparity and ecological convergence in ancient stem ‘kangaroos’

“…Although QM F59022–QM F59025 share multiple synapomorphies with Balbaridae, we have deferred a formal classification herein because these remains cannot yet be distinguished from those of the closely related Propleopinae (extinct ‘giant rat-kangaroos’) [1,19,26–30], whose postcranial osteology is virtually unknown [17]. Representatives of both these clades occur coevally at ‘Upper Site’ [37], as well as other late Oligocene–Miocene deposits throughout the RWHA [49] and have similar estimated body masses [49].…”

“…The oldest recorded specimens comprise a few isolated tarsal and pedal elements, together with a handful of incomplete skeletons from upper Oligocene [18,19] and Miocene strata [20–27]. The most morphologically peculiar of these have been referred to the basally branching clade Balbaridae [21,26–29] and are epitomized by a single articulated skeleton—the holotype (Queensland Museum, Brisbane, Australia [QM] F34532) of Nambaroo gillespieae [26]—which was recently assigned to another closely related genus Ganawamaya [30]. This fossil is distinguished by numerous osteological adaptations that indicate habitual quadrupedal locomotion, coupled with either bounding or hopping, and limited climbing ability [26].…”