Behaviour of the Pleistocene marsupial lion deduced from claw marks in a southwestern Australian cave.

Samuel D. Arman,Gavin J. Prideaux

doi:10.1038/srep21372

Abstract

The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates. With a highly-specialised dentition, powerful forelimbs and a robust build, its overall morphology is not approached by any other mammal. However, despite >150 years of attention, fundamental aspects of its biology remain unresolved. Here we analyse an assemblage of claw marks preserved on surfaces in a cave and deduce that they were generated by marsupial lions. The distribution and skewed size range of claw marks within the cave elucidate two key aspects of marsupial lion biology: they were excellent climbers and reared young in caves. Scrutiny of >10,000 co-located Pleistocene bones reveals few if any marsupial lion tooth marks, which dovetails with the morphology-based interpretation of the species as a flesh specialist.

Highlights

The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates
The doubts over how to interpret its bizarre combination of features are not due to a lack of fossil bones: T. carnifex is better represented in Pleistocene localities that any other large carnivore[11,12], and more complete or partial skeletons are known from caves than for any other extinct Pleistocene species[8,12,13,14]
In the event that these marks could be confidently attributed to T. carnifex, we addressed the degree to which this lateral digital movement might have been facilitated by the enlarged semi-opposable digit I alone by focusing on scratch sets composed of > 1 pair of marks, and subsequently eliminating the largest IDS

Summary

Introduction

The marsupial lion, Thylacoleo carnifex, was the largest-ever marsupial carnivore, and is one of the most iconic extinct Australian vertebrates. When humans first set foot in Australia around 50,000 years ago they entered a unique landscape occupied by large reptiles, birds and mammals seen nowhere else The current consensus is that T. carnifex was a carnivore, other lines of evidence are required to generate further insights into its behaviour and ecology Trace fossils, such as trackways or burrows, can provide insights into locomotory abilities and behaviours unobtainable via functional analyses of the skeleton alone. It is seldom possible to associate skeletal and trace fossils[15] This underscores the significance of a claw-mark assemblage in the main chamber of Tight Entrance Cave (TEC), southwestern Australia (Fig. 1), where a now-blocked entrance in the ceiling provided access to the surface for species capable of navigating the steep, convoluted cave terrain. For tooth marks on bones, which we hypothesised may be evident if carnivores played a role in accumulating the bones

Methods

Results

Conclusion