A Practical Guide to Sliding and Surface Semilandmarks in Morphometric Analyses
A Practical Guide to Sliding and Surface Semilandmarks in Morphometric Analyses
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DOI：
10.1093/iob/obz016
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发表时间：
2019-01-01
影响因子：
1.5
通讯作者：
Goswami, A.
中科院分区：
文献类型：
--
作者：
Bardua, C.;Felice, R. N.;Goswami, A.
近年来，计算机断层扫描 (CT) 和表面扫描等成像技术的进步促进了高分辨率三维 (3D) 标本重建大型数据集的快速生成。这些数据集中提供的大量表型信息有可能帮助我们理解形态变异和进化。然而，编译 3D 数据集的难度不断增加，迫切需要复杂的方法来捕获反映生物形式复杂性的高密度形状数据。地标通常无法充分利用高分辨率 3D 标本重建中提供的丰富形状信息，因为它们通常仅限于可以跨标本可靠识别的缝合线或过程，并排除大部分表面形态。滑动和表面半地标技术的发展极大地增强了形状的量化，但它们在不同数据集上的应用可能具有挑战性，特别是在处理结构内某些区域的变量缺失时。使用涵盖鸟类、有鳞动物和蚓螈整个进化枝的颅骨综合 3D 数据集，我们演示了捕获极其多样化形状的形态的方法。我们详细介绍了将半地标应用于高度不同结构的可比区域相关的许多困难，并为其中一些挑战提供了解决方案，同时考虑了人们在应用这些方法时做出的决策的后果。最后，我们分析了高密度滑动半地标方法相对于仅地标研究在捕获不同生物体形状方面的优势，并讨论了这些方法在生物体形态研究中的前景。
Advances in imaging technologies, such as computed tomography (CT) and surface scanning, have facilitated the rapid generation of large datasets of high-resolution three-dimensional (3D) specimen reconstructions in recent years. The wealth of phenotypic information available from these datasets has the potential to inform our understanding of morphological variation and evolution. However, the ever-increasing ease of compiling 3D datasets has created an urgent need for sophisticated methods of capturing high-density shape data that reflect the biological complexity in form. Landmarks often do not take full advantage of the rich shape information available from high-resolution 3D specimen reconstructions, as they are typically restricted to sutures or processes that can be reliably identified across specimens and exclude most of the surface morphology. The development of sliding and surface semilandmark techniques has greatly enhanced the quantification of shape, but their application to diverse datasets can be challenging, especially when dealing with the variable absence of some regions within a structure. Using comprehensive 3D datasets of crania that span the entire clades of birds, squamates and caecilians, we demonstrate methods for capturing morphology across incredibly diverse shapes. We detail many of the difficulties associated with applying semilandmarks to comparable regions across highly disparate structures, and provide solutions to some of these challenges, while considering the consequences of decisions one makes in applying these approaches. Finally, we analyze the benefits of high-density sliding semilandmark approaches over landmark-only studies for capturing shape across diverse organisms and discuss the promise of these approaches for the study of organismal form.