Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, 25761 Büsum, Schleswig-Holstein, Germany.
Laboratoire de Morphologie Fonctionnelle et Evolutive, AFFISH Research Center, Université de Liège, B-4000 Liège, Belgium.
Sci Rep. 2017 Apr 25;7:46734. doi: 10.1038/srep46734.
Several mass strandings of sperm whales occurred in the North Sea during January and February 2016. Twelve animals were necropsied and sampled around 48 h after their discovery on German coasts of Schleswig Holstein. The present study aims to explore the morphological variation of the primary sensory organ of sperm whales, the left and right auditory system, using high-resolution computerised tomography imaging. We performed a quantitative analysis of size and shape of cochleae using landmark-based geometric morphometrics to reveal inter-individual anatomical variations. A hierarchical cluster analysis based on thirty-one external morphometric characters classified these 12 individuals in two stranding clusters. A relative amount of shape variation could be attributable to geographical differences among stranding locations and clusters. Our geometric data allowed the discrimination of distinct bachelor schools among sperm whales that stranded on German coasts. We argue that the cochleae are individually shaped, varying greatly in dimensions and that the intra-specific variation observed in the morphology of the cochleae may partially reflect their affiliation to their bachelor school. There are increasing concerns about the impact of noise on cetaceans and describing the auditory periphery of odontocetes is a key conservation issue to further assess the effect of noise pollution.
2016 年 1 月至 2 月期间，北海发生了几起抹香鲸大规模搁浅事件。12 头抹香鲸在德国石勒苏益格-荷尔斯泰因州海岸被发现后约 48 小时进行了解剖和采样。本研究旨在使用高分辨率计算机断层扫描成像技术，探索抹香鲸主要感觉器官（左、右听觉系统）的形态变异。我们使用基于地标几何形态测量学对耳蜗大小和形状进行了定量分析，以揭示个体间的解剖变异。基于 31 个外部形态特征的层次聚类分析将这 12 个个体分为两个搁浅聚类。形状变异的相对量可归因于搁浅地点和聚类之间的地理差异。我们的几何数据允许区分在德国海岸搁浅的抹香鲸之间的不同单身汉群体。我们认为，耳蜗具有个体形状，在尺寸上变化很大，并且在耳蜗形态上观察到的种内变异可能部分反映了它们与其单身汉群体的隶属关系。人们越来越关注噪音对鲸目动物的影响，描述齿鲸的听觉外围是评估噪声污染影响的一个关键保护问题。
