Why the long teeth? Morphometric analysis suggests different selective pressures on functional occlusal traits in Plio-Pleistocene African suids

Neogene and Pleistocene African suids displayed convergent evolutionary trends in the third molar (M3) morphology, with increasingly elongated and higher crowns through time. While these features can prevent premature loss of masticatory functionality and potentially increase long-term reproductive success, changes in dental occlusal traits such as enamel complexity and thickness can also improve chewing efficiency and increase short-term energetic return. While both long-term and short-term benefits can contribute to the thriving of a lineage, the selective pressures associated with each category can be different. To examine how crown elongation correlates with these functional occlusal traits, we selected M3s of Kolpochoerus, Notochoerus, and Metridiochoerus from Kenya and South Africa, dated between 3.0 Ma and 0.4 Ma. To account for dental wear, we used micro-CT imaging of unworn/slightly worn M3s to simulate wear progression within each tooth. We compared morphometric representative...新近纪（Neogene）与更新世（Pleistocene）时期的非洲猪科动物，其第三臼齿（M3）形态演化呈现趋同趋势：随地质时间推移，牙冠愈发修长高耸。此类特征可避免咀嚼功能过早丧失，或能提升类群的长期繁殖成功率；而牙咬合相关性状（如釉质复杂度与釉质厚度）的演化改变，同样可提升咀嚼效率、增加短期能量回报。尽管长期与短期收益均可助力演化支系的繁盛，但二者所对应的选择压力存在差异。为探究牙冠修长与这些功能性咬合性状之间的关联，我们选取了产自肯尼亚与南非、年代介于3.0 Ma与0.4 Ma之间的科尔波猪属（Kolpochoerus）、诺托猪属（Notochoerus）以及梅特里多猪属（Metridiochoerus）的M3标本。为校正牙齿磨损带来的影响，我们对未磨损/轻微磨损的M3进行微计算机断层扫描（micro-CT）成像，以模拟单颗牙齿的磨损进程。我们对形态计量学代表性样本进行了比较……