Gartner S M, Larouche O, Evans K M, Westneat M W
Organismal Biology and Anatomy Department, University of Chicago, Chicago, IL 60637, USA.
Department of Biology and Biochemistry, University of Houston, Houston, TX 77204, USA.
Integr Org Biol. 2023 Sep 26;5(1):obad035. doi: 10.1093/iob/obad035. eCollection 2023.
The concept of modularity is fundamental to understanding the evolvability of morphological structures and is considered a central framework for the exploration of functionally and developmentally related subsets of anatomical traits. In this study, we explored evolutionary patterns of modularity and integration in the 4-bar linkage biomechanical system of the skull in the fish family Labridae (wrasses and parrotfish). We measured evolutionary modularity and rates of shape diversification of the skull partitions of three biomechanical 4-bar linkage systems using 205 species of wrasses (family: Labridae) and a three-dimensional geometric morphometrics data set of 200 coordinates. We found support for a two-module hypothesis on the family level that identifies the bones associated with the three linkages as being a module independent from a module formed by the remainder of the skull (neurocranium, nasals, premaxilla, and pharyngeal jaws). We tested the patterns of skull modularity for four tribes in wrasses: hypsigenyines, julidines, cheilines, and scarines. The hypsigenyine and julidine groups showed the same two-module hypothesis for Labridae, whereas cheilines supported a four-module hypothesis with the three linkages as independent modules relative to the remainder of the skull. Scarines showed increased modularization of skull elements, where each bone is its own module. Diversification rates of modules show that linkage modules have evolved at a faster net rate of shape change than the remainder of the skull, with cheilines and scarines exhibiting the highest rate of evolutionary shape change. We developed a metric of linkage planarity and found the oral jaw linkage system to exhibit high planarity, while the rest position of the hyoid linkage system exhibited increased three dimensionality. This study shows a strong link between phenotypic evolution and biomechanical systems, with modularity influencing rates of shape change in the evolution of the wrasse skull.
模块性的概念是理解形态结构可进化性的基础，并且被认为是探索解剖特征中功能和发育相关子集的核心框架。在本研究中，我们探究了隆头鱼科（隆头鱼和鹦嘴鱼）头骨的四杆联动生物力学系统中模块性和整合的进化模式。我们使用205种隆头鱼（隆头鱼科）以及一个包含200个坐标的三维几何形态测量数据集，测量了三个生物力学四杆联动系统的头骨分区的进化模块性和形状多样化速率。我们在科级水平上发现了对双模块假说的支持，该假说将与三个联动相关的骨骼识别为一个独立于由头骨其余部分（脑颅、鼻骨、前颌骨和咽颌）形成的模块的模块。我们测试了隆头鱼四个族的头骨模块性模式：高鳍隆头鱼族、朱红隆头鱼族、唇鱼族和锦鱼族。高鳍隆头鱼族和朱红隆头鱼族显示出与隆头鱼科相同的双模块假说，而唇鱼族支持四模块假说，其中三个联动相对于头骨其余部分为独立模块。锦鱼族显示出头骨元素模块化增加，其中每块骨头都是其自身的模块。模块的多样化速率表明，联动模块的形状变化净速率比头骨其余部分更快，唇鱼族和锦鱼族表现出最高的进化形状变化速率。我们开发了一种联动平面度度量方法，发现口腔颌联动系统具有高平面度，而舌骨联动系统的静止位置显示出三维性增加。这项研究表明表型进化与生物力学系统之间存在紧密联系，模块性影响隆头鱼头骨进化中的形状变化速率。
