Data from: Chewing on the trees: constraints and adaptation in the evolution of the primate mandible

Chewing on different food types is a demanding biological function. The classic assumption in studying the shape of feeding apparatuses is that animals are what they eat, meaning that adaptation to different food items accounts for most of their interspecific variation. Yet, a growing body of evidence points against this concept. We use the primate mandible as a model structure to investigate the complex interplay between shape, size, diet and phylogeny. We find a weak but significant impact of diet on mandible shape variation in primates as a whole but not in anthropoids and catarrhines as tested in isolation. These clades mainly exhibit allometric shape changes which are unrelated to diet. Diet is an important factor in the diversification of strepsirrhines and platyrrhines and a phylogenetic signal is detected in all primate clades. Peaks in morphological disparity occur during the Oligocene (between 37 and 25 Ma) supporting the notion that an adaptive radiation characterized the evolution of South American monkeys. In all primate clades, the evolution of mandible size is faster than its shape pointing to a strong effect of allometry on ecomorphological diversification in this group.咀嚼不同类型食物是一项具有严苛生理要求的生物学功能。在研究取食器官（feeding apparatuses）形态时，学界经典假设认为"动物如其所食"，即对不同食物的适应性演化是其种间形态差异的主要成因。然而，越来越多的实证研究对这一观点提出了质疑。 本研究以灵长类下颌骨（primate mandible）为研究模型，探究形态、大小、食性与系统发育（phylogeny）之间的复杂相互作用。整体来看，食性对灵长类下颌骨形态变异存在微弱但显著的影响，但单独检验类人猿亚目（anthropoids）与狭鼻小目（catarrhines）类群时，该效应并不显著。这两类演化支（clades）主要呈现与食性无关的异速生长形态变化。 食性是原猴亚目（strepsirrhines）与阔鼻小目（platyrrhines）类群分化的重要驱动因素，且所有灵长类演化支中均检测到系统发育信号（phylogenetic signal）。形态差异度（morphological disparity）的峰值出现在渐新世（Oligocene，3700万至2500万年前），该结果支持"南美猴类的演化以适应辐射（adaptive radiation）为核心特征"的论断。 在所有灵长类演化支中，下颌骨大小的演化速率均快于形态，这表明异速生长对该类群的生态形态多样性格局（ecomorphological diversification）存在强烈调控作用。