ABSTRACT

The genus Wakaleo represents a close outgroup to the charismatic marsupial hypercarnivore Thylacoleo carnifex. While early species of Wakaleo were likely arboreal, or at least scansorial, the ecology of later species of Wakaleo is not well understood. Here we present descriptions of new postcranial material of W. vanderleueri and W. alcootaensis from mid- and late-Miocene fossil deposits from the Australian Northern Territory. New calculations suggest that these taxa were smaller than previously thought, around 30 kg and 50 kg respectively. The postcrania reveal increasing adaptation towards terrestrial locomotion and felid-like grappling predation within this lineage, in contrast to the more canid-like adaptations occurring at around the same time in the other major group of terrestrial marsupial carnivores, the thylacinids. This hypothesis seems to reflect similar patterns of divergent morphological adaptation towards large carnivorous forms among placental mammals, and highlights a greater diversity in the evolutionary history of medium to large sized marsupial carnivores during the Miocene in Australia than previously recognized.

摘要

Wakaleo属代表着有魅力的有袋动物食肉动物Thylacoleo carnifex。虽然Wakaleo的早期物种很可能是树栖植物，或至少是scan壳的，但对Wakaleo的后期物种的生态学却知之甚少。在这里，我们介绍W. vanderleueri和W. alcootaensis的新颅后材料的描述来自澳大利亚北领地的中新世中期和晚期化石矿床。新的计算结果表明，这些分类单元比以前想象的要小，分别约为30公斤和50公斤。与其他主要的陆地有袋类食肉动物，即甲状腺素类在大约同一时间发生的更多犬科动物类适应相反，后颅骨揭示了在该谱系中对陆上运动和类似猫科动物的捕食的适应性增加。该假说似乎反映了胎盘哺乳动物对大型食肉动物形态学适应的相似模式，并突显了中新世时期澳大利亚中新世代至大型食肉动物食肉动物进化史上更大的多样性。