The acquisition of elongated, sabre-like canines in multiple vertebrate clades during the last 265 Myr represents a remarkable example for convergent evolution. Due to striking superficial similarities in the cranial skeleton, the same or similar skull and jaw functions have been inferred for sabre-toothed species and interpreted as an adaptation to subdue large-bodied prey. However, although some sabre-tooth lineages have been classified into different ecomorphs (dirk-tooths and scimitar-tooths) the functional diversity within and between groups and the evolutionary paths leading to these specializations are unknown. Here, we use a suite of biomechanical simulations to analyse key functional parameters (mandibular gape angle, bending strength, bite force) to compare the functional performance of different groups and to quantify evolutionary rates across sabre-tooth vertebrates. Our results demonstrate a remarkably high functional diversity between sabre-tooth lineages and that different cranial function and prey killing strategies evolved within clades. Moreover, different biomechanical adaptations in coexisting sabre-tooth species further suggest that this functional diversity was at least partially driven by niche partitioning.

中文翻译：

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形态趋同掩盖了剑齿食肉动物的功能多样性


在过去的 265 迈里，多个脊椎动物分支中获得了细长的、剑状的犬齿，这是趋同进化的一个显着例子。由于颅骨表面具有惊人的相似性，剑齿虎物种具有相同或相似的颅骨和下颌功能，并将其解释为对制服大型猎物的适应。然而，尽管一些剑齿类谱系已被分为不同的生态形态（短剑齿和弯刀齿），但群体内部和群体之间的功能多样性以及导致这些专业化的进化路径尚不清楚。在这里，我们使用一套生物力学模拟来分析关键功能参数（下颌张开角度、弯曲强度、咬合力），以比较不同群体的功能表现并量化剑齿类脊椎动物的进化速率。我们的结果表明剑齿虎谱系之间具有非常高的功能多样性，并且不同的颅骨功能和猎物捕杀策略在进化枝内进化。此外，共存剑齿虎物种的不同生物力学适应性进一步表明，这种功能多样性至少部分是由生态位划分驱动的。