Bettongia moyesi

The relationship between Bettongia moyesi and other macropods has long been the subject of debate. Flannery and Archer initially described Bettongia moyesi as a close relative of Bettongia lesueur and a member of the newly-named clade Bettongini. At that time, the group only contained species of Bettongia, Aepyprymnus and Caloprymnus.^[1] However, subsequent studies have since referred the fossil taxa Borungaboodie, Gumardee, Milliyowi and Wakiewakie to the clade.^[2][3] The first phylogenetic analysis to include Bettongia moyesi was that of Kear and colleagues in 2007, which reaffirmed its taxonomic placement within the family Potoroidae.^[4] Following the 2015 redescription of the early macropodid Wabularoo, Bettongia moyesi was recovered in an unresolved polytomy with other traditionally recovered potoroines.^[5] A study published a year later by the same authors recovered it as sister taxon to Wakiewakie, rather than other Bettongia, in a monophyletic Potoroinae within the family Macropodidae. The authors hence suggested that the generic attribution of B. moyesi is in need of revision.^[6]

While most studies generally recover Bettongia moyesi as a member of Potoroinae, some select few propose that it was instead a stem macropodid. Cooke (1997a) and Cooke & Kear (1999) both suggested that Bettongia moyesi was a basal bulungamayine macropodid.^[7] In 2016, Kaylene Butler and colleagues performed several phylogenetic analyses, both of which found it to be in an outgroup to all other macropodids.^[8] Similar results have since then also been recovered by Travouillon and colleagues in 2022.^[9]

Bettongia moyesi is known from remains found at the Two Trees and Henk’s Hollow sites of the Riversleigh World Heritage Area, which are thought to be Middle Miocene in age.^[1] At this point in time, the Riversleigh area had a tropical climate and was covered in rainforest habitat.^[10] Bettongia moyesi shared its paleoenvironment with other macropods, such as the propleopine Ekaltadeta ima, the balbarid Balbaroo nalima, the basal macropod Ganguroo robustiter, and the sthenurine Wanburoo hilarus.^[11][12][13] It also lived alongside the palorchestid Propalorchestes novaculacephalus; the diprotodontids Neohelos stirtoni and Nimbadon lavarackorum; and the thylacinids Muribacinus gadiyuli and Nimbacinus dicksoni.^[14]

Like modern potoroids, Bettongia moyesi probably used its relatively large, sectorial premolars to crack open hard-shelled nuts and seeds.^[15]