Phylogenetic convergence and multiple shell shape optima for gliding scallops (Bivalvia: Pectinidae)
Phylogenetic convergence and multiple shell shape optima for gliding scallops (Bivalvia: Pectinidae)
复制标题
滑翔扇贝（双壳纲：扇贝科）的系统发育趋同和多种贝壳形状最佳值
DOI：
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发表时间：
2017
影响因子：
2.1
通讯作者：
D. Adams
中科院分区：
文献类型：
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作者：
J. Serb;E. Sherratt;E. Sherratt;Alvin Alejandrino;Alvin Alejandrino;D. Adams
进化生物学中的一个重要问题是，相似的生态环境会在多大程度上引发远亲关系的类群向相同的表型进化？在某些情况下，特定表型的重复进化可能是意料之中的，例如，当物种暴露在由强烈的功能需求产生的共同选择性力量中时。在双壳扇贝(Pectinidae)中，一些物种表现出独特的游泳行为(滑行)，这需要特定的生物力学属性来在机车事件中产生升力和减少阻力。此外，系统发育分析显示，滑翔行为至少独立进化了四次，这提出了一个问题，即这些独立的谱系是否也汇聚在一个相似的表型上。在这里，我们使用几何形态计量学和评价多变量性状进化模式的系统发育比较方法相结合的方法来检验滑动扇贝显示贝壳形状收敛的假设。我们的发现表明，在布朗运动的中性进化表型变化模型下，滑行物种在形态空间上表现出较小的形态差异和显著的进化收敛。有趣的是，形态空间模式表明，滑行谱系遵循相似的进化轨迹，不是一个而是两个形态空间区域，随后的分析发现它们的生物力学参数存在显著差异，这表明这两组扇贝以不同的方式完成滑翔。因此，虽然在整个系统发育过程中有一个清晰的滑行表型，但明显存在功能上不同的形态亚型，这表明在Pectinidae中可能存在两个最适的滑行表型。
An important question in evolutionary biology is how often, and to what extent, do similar ecologies elicit distantly related taxa to evolve towards the same phenotype? In some scenarios, the repeated evolution of particular phenotypes may be expected, for instance when species are exposed to common selective forces that result from strong functional demands. In bivalved scallops (Pectinidae), some species exhibit a distinct swimming behaviour (gliding), which requires specific biomechanical attributes to generate lift and reduce drag during locomotive events. Further, a phylogenetic analysis revealed that gliding behaviour has independently evolved at least four times, which raises the question as to whether these independent lineages have also converged on a similar phenotype. Here, we test the hypothesis that gliding scallops display shell shape convergence using a combination of geometric morphometrics and phylogenetic comparative methods that evaluate patterns of multivariate trait evolution. Our findings reveal that the gliding species display less morphological disparity and significant evolutionary convergence in morphospace, relative to expectations under a neutral model of Brownian motion for evolutionary phenotypic change. Intriguingly, the phylomorphospace patterns indicate that gliding lineages follow similar evolutionary trajectories to not one, but two regions of morphological space, and subsequent analyses identified significant differences in their biomechanical parameters, suggesting that these two groups of scallops accomplish gliding in different ways. Thus, whereas there is a clear gliding morphotype that has evolved convergently across the phylogeny, functionally distinct morphological subforms are apparent, suggesting that there may be two optima for the gliding phenotype in the Pectinidae.