Acevedo Aldemar A, Palma R Eduardo, Olalla-Tárraga Miguel Ángel
Laboratory of Evolutionary Biology, Department of Ecology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.
Laboratory of Genetics and Evolution, Department of Ecological Sciences, Faculty of Sciences, Universidad de Chile, Santiago, Chile.
Sci Rep. 2022 Oct 27;12(1):18106. doi: 10.1038/s41598-022-22181-5.
Body size is a key organismal trait. However, the environmental and evolutionary factors that drive body size patterns at the interspecific level remain unclear. Here, we explored these relationships between phenotype-environment using neotropical frogs of Pristimantis, the world's most diverse vertebrate genus. We analyzed: (a) whether this group follows the Rensch's rule, a trend of sexual size dimorphism (SSD) to increase with size when males are the larger sex; (b) whether environmental constraints have influenced body size variation; and (c) how the rates of body size evolution have varied over time. Analyses were based on two information sources, the first one including body sizes of ~ 85% (495 species) of known species in the genus, and a second one incorporating molecular phylogenetic information for 257 species. Our results showed that all Pristimantis species exhibited marked SSD but did not follow Rensch's rule. We found that the models that best explained body size in males, females, and SSD contained environmental variations in temperature, precipitation, and elevation as predictors. In turn, body size has evolved toward an optimum, with a decelerating rate of evolution differentiated between the large Pristimantis clades.
体型是一个关键的生物体特征。然而，在种间水平上驱动体型模式的环境和进化因素仍不明确。在这里，我们利用世界上最多样化的脊椎动物属——原蛙属的新热带蛙类，探索了表型与环境之间的这些关系。我们分析了：（a）该类群是否遵循伦施法则，即当雄性体型较大时，性大小二态性（SSD）随体型增大的趋势；（b）环境限制是否影响了体型变化；以及（c）体型进化速率如何随时间变化。分析基于两个信息来源，第一个包括该属约85%（495种）已知物种的体型，第二个纳入了257个物种的分子系统发育信息。我们的结果表明，所有原蛙属物种都表现出明显的SSD，但不遵循伦施法则。我们发现，最能解释雄性、雌性和SSD体型的模型包含温度、降水和海拔的环境变化作为预测因子。反过来，体型已经朝着一个最佳状态进化，大型原蛙类分支之间的进化速率有所减缓。
