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.取食不同食物类型的咀嚼行为是一项高要求的生物学功能。在研究取食器官形态的经典假说中，学界曾提出"动物如其所食"的观点，即对不同食物的适应性演化是物种间形态差异的主要驱动因素。然而，越来越多的研究证据对这一概念提出了挑战。本研究以灵长类下颌骨（primate mandible）为模式结构，探究形态、大小、食性与系统发育之间的复杂相互作用。研究结果显示，整体而言食性对灵长类下颌骨的形状变异存在微弱但显著的影响，但单独检验类人猿亚目与狭鼻小目时，该效应并不显著。上述两类演化支主要呈现与食性无关的异速生长形状变化。食性是原猴亚目与阔鼻猴类类群多样化的重要影响因素，且所有灵长类演化支中均检测到系统发育信号。形态差异度的峰值出现在渐新世（3700万至2500万年前），这一结果支持"南美猴类的演化以适应辐射为特征"的观点。在所有灵长类演化支中，下颌骨大小的演化速率均快于形状演化，这表明异速生长对该类群的生态形态多样化具有强烈影响。