Data from: Convergence on dental simplification in the evolution of whales

The fossil record of mammal dentition provides crucial insight into key ecological and functional transitions throughout their evolutionary history. For cetaceans, both extant clades differ markedly from their stem ancestors; neither retains the differentiated dentition, nor the tribosphenic molars characteristic of Mammalia. We used quantitative measures of dental complexity across fossil and living cetaceans to identify a trend towards dental simplicity through the Neogene. Both extant cetacean clades depart from the ancestral mammalian condition and concurrently converge upon a reduced and simplified dentition; modern mysticetes all have become entirely edentulous (at birth) and living odontocetes possess teeth as single rooted, conical pegs. These two parallel trends accompany major shifts in feeding strategy (i.e., filter-feeding in mysticetes, and echolocation in odontocetes), suggesting that these evolutionary innovations for prey acquisition are enabling factors for the loss of prey processing and subsequent convergence on dental simplification.哺乳动物牙齿的化石记录，为其演化历程中关键的生态与功能转型提供了至关重要的认知视角。对于鲸类而言，两个现生支系均与其干群祖先存在显著差异：二者既未保留异型齿特征，也不具备哺乳纲（Mammalia）标志性的三角座臼齿（tribosphenic molars）。本研究通过对化石及现生鲸类的牙齿复杂度开展量化分析，揭示了新近纪以来齿列趋于简化的演化趋势。两个现生鲸类支系均脱离了哺乳纲祖先的原始齿列状态，并同步趋同演化出缩减且简化的齿列：现代须鲸类（mysticetes）在出生时即完全无齿，而现生齿鲸类（odontocetes）仅拥有单根圆锥状齿突。这两套平行演化趋势，与摄食策略的重大转变相伴随——即须鲸类的滤食习性与齿鲸类的回声定位能力——这表明这些用于猎物获取的演化革新，正是齿列猎物加工功能丧失、进而趋同形成齿列简化的驱动因素。