Intraspecific variation in cetacean vertebral anatomy as a result of ageing, growth, and sexual dimorphism is poorly understood. Using 3D geometric morphometrics, we investigated allometric patterns, sexual dimorphism, and ontogenetic trajectories in the vertebral column of false killer whale (Pseudorca crassidens). Our data set includes thoracic, lumbar, and caudal vertebrae of 30 specimens, including neonates, juveniles, and adults of both sexes. Vertebral shape was significantly correlated with size within each region. Neonatal vertebral shape differed significantly from juveniles and adults, displaying ontogenetic shape change. Allometric and growth patterns of the vertebral regions, particularly of the lumbar region with the thoracic and caudal regions, differed significantly, which may influence the function and mobility patterns of the vertebral regions during different life stages. Using quantitative methods, we could not conclude that the Pseudorca vertebrae are sexually dimorphic. This study describes for the first time intraspecific vertebral patterns in a cetacean species across ontogenetic stages. Pseudorca individuals live in large pods and swim together, sharing the same swimming mode. The neonates have a more flexible column and swim less efficiently following their mothers to nurse.

中文翻译：

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假虎鲸（Pseudorca crassidens）脊柱出生后发育过程中形状和生长速度的个体发生变化

由于衰老、生长和性别二态性而导致的鲸目动物椎骨解剖结构的种内变异尚不清楚。使用 3D 几何形态测量学，我们研究了伪虎鲸脊柱的异速生长模式、性别二态性和个体发育轨迹。克拉斯伪虎）。我们的数据集包括 30 个标本的胸椎、腰椎和尾椎，包括新生儿、青少年和成人。椎骨形状与每个区域的大小显着相关。新生儿椎骨形状与青少年和成人显着不同，表现出个体发育形状变化。椎骨区域的异速生长和生长模式，特别是腰椎区域与胸椎和尾椎区域的异速生长和生长模式存在显着差异，这可能会影响椎骨区域在不同生命阶段的功能和活动模式。使用定量方法，我们无法得出结论：伪虎属椎骨有性二态性。这项研究首次描述了鲸类物种在个体发育阶段的种内椎骨模式。伪虎属个体生活在一个大的群体中，一起游泳，共享相同的游泳模式。新生儿的脊柱更灵活，跟随母亲吃奶时游泳的效率较低。