How to build a mammalian super-predator.

Area of Science:

• Paleobiology
• Paleontology
• Functional Morphology

Background:

• Large fossil predators, particularly sabertooth cats, present unique biological questions due to their distinct morphology compared to extant carnivores.
• The behavior and ecology of extinct carnivores like sabertooth cats and the marsupial lion (Thylacoleo carnifex) remain subjects of scientific debate.

Purpose of the Study:

• To investigate the palaeobiology of machairodont sabertooths and Thylacoleo carnifex by comparing their cranio-dental and postcranial indices with extant mammalian carnivores.
• To explore potential relationships between body proportions, behavior, and ecological roles in extinct and extant predatory mammals.

Main Methods:

• Compilation of a comprehensive dataset including cranio-dental and postcranial indices from various extinct sabertooth species (Smilodon, Homotherium, Machairodus), Thylacoleo carnifex, and a wide array of extant mammalian carnivores.
• Application of multivariate analyses to examine relationships between morphological indices and ecological characteristics within the dataset.

Main Results:

• Multivariate analyses revealed significant correlations between body proportions and behavior in extant mammalian carnivores.
• Postcranial morphologies of Smilodon species differed significantly from extant felids, clustering instead with bears.
• Scimitar-tooth species (Homotherium, Machairodus) and the marsupial lion exhibited postcranial morphologies that grouped with modern pantherine cats and Smilodon, respectively.

Conclusions:

• The study suggests distinct ecological roles and predatory adaptations among different sabertooth cat lineages and the marsupial lion, based on postcranial morphology.
• Smilodon's 'bear-like' postcrania, combined with felid-like cheektooth adaptations, may indicate a specialized ecomorph for tackling large prey.
• Homotherium, Machairodus, and Thylacoleo carnifex may represent a different ecomorph, potentially adapted for large prey, identifiable by specific postcranial and dental features.