Data from: Patterns of cranial shape diversification during the phylogenetic branching process of New World monkeys (Primates: Platyrrhini)

One of the central topics in evolutionary biology is understanding the processes responsible for phenotypic diversification related to ecological factors. New World monkeys are an excellent reference system to investigate processes of diversification at macroevolutionary scales. Here, we investigate the cranial shape diversification related to body size and ecology during the phylogenetic branching process of platyrrhines. To investigate this diversification, we used geometric morphometric techniques, a molecular phylogenetic tree, ecological data and phylogenetic comparative methods. Our statistical analyses demonstrated that the phylogenetic branching process is the most important dimension to understand cranial shape variation among extant platyrrhines and suggested that the main shape divergence among the four principal platyrrhine clades probably occurred during the initial branching process. The phylogenetic conservatism, which is the retention of ancestral traits over time within the four principal platyrrhine clades, could be the most important characteristic of platyrrhine cranial shape diversification. Different factors might have driven early shape divergence and posterior relative conservatism, including genetic drift, stabilizing selection, genetic constraints due to pleiotropy, developmental or functional constraint, lack of genetic variation, among others. Understanding the processes driving the diversification among platyrrhines will probably require further palaeontological, phylogenetic and comparative studies.

进化生物学的核心议题之一，是解析驱动与生态因子相关的表型分化的演化过程。新大陆猴是开展宏观进化尺度下类群分化过程研究的优质参考体系。本研究聚焦阔鼻猴类（platyrrhines）的系统发育分支过程中，与体型大小及生态特征相关的颅骨形状分化。为探究此类分化，我们采用了几何形态测量技术、分子系统发育树、生态数据及系统发育比较方法。统计分析结果显示，系统发育分支过程是解释现生阔鼻猴类颅骨形状变异的最核心维度；研究同时表明，四大主要阔鼻猴演化支间的主要形状分化，大概率发生于初始分支阶段。系统发育保守性——即四大主要阔鼻猴演化支内祖先性状随时间的保留——或许是阔鼻猴类颅骨形状分化最关键的特征。驱动早期形状分化与后续相对保守性的因素或存在差异，涵盖遗传漂变、稳定选择、多效性引发的遗传约束、发育或功能约束、遗传变异缺失等诸多情形。若要解析驱动阔鼻猴类类群分化的演化过程，或需开展进一步的古生物学、系统发育学及比较研究。