In dolphins, centrum shape is one of the features that allows determination of stable and flexible regions in the vertebral column. The Commerson's (Cephalorhynchus commersonii; n = 37), Peale's (Lagenorhynchus australis; n = 24), dusky (Lagenorhynchus obscurus; n = 29), and hourglass dolphins (Lagenorhynchus cruciger; n = 10) are closely related species inhabiting the Southern Hemisphere that have diverse prey and habitat preferences. We applied 3D geometric morphometrics to describe differences in centrum shape along the vertebral columns of these species, and hypothesize how these differences may affect swimming. On each column, we chose a maximum of eight vertebrae and digitized 18 landmarks on each centrum with a Microscribe G2X. We explored shape differences amongst regions employing principal components analyses and computing Mahalanobis distances. We describe differences in centrum shape in relation to functional regions and among species; and analyze shape changes in relation to particular biomechanical requirements. The species studied here may be partially sympatric in the Southern Hemisphere, but they have important differences in foraging ecology and habitat preferences that could be related to differences in centrum shape along the vertebral column.

中文翻译：

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南大西洋西南部海豚的椎体中心形态：3D形态学方法及其功能含义

在海豚中，中枢形状是可以确定椎骨柱中稳定和灵活区域的特征之一。Commerson氏（Cephalhyhynchus commersonii；n = 37），Peale氏（Lagenorhynchus australis；n = 24），昏暗的（Lagenorhynchus obscurus ； n = 29）和沙漏海豚（Lagenorhynchus cruciger；n）= 10）是居住于南半球的密切相关物种，具有不同的猎物和栖息地偏好。我们使用3D几何形态计量学来描述这些物种的脊柱沿椎体形状的差异，并假设这些差异如何影响游泳。在每一列上，我们使用Microscribe G2X选择最多八个椎骨，并在每个中心数字化18个界标。我们利用主成分分析和计算马氏距离研究了区域之间的形状差异。我们描述了相对于功能区域和物种之间中心形状的差异。并分析与特定生物力学要求有关的形状变化。在这里研究的物种可能在南半球部分同胞，