Evangelista Carla, Mills Morena, Siebeck Ulrike E, Collin Shaun P
Sensory Neurobiology Group, The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
J Morphol. 2010 Apr;271(4):483-95. doi: 10.1002/jmor.10812.
Studies on the elasmobranch inner ear have focused predominantly on a small group of sharks, particularly, carcharhinids. As a result, subsequent studies in other species have subdivided species into two main groups: those typical and those atypical of carcharhinid sharks. This study proposes a different set of inner-ear morphology groupings to those previously suggested. The inner ears from 17 species of elasmobranchs (representing both sharks and rays) are examined in this study and based on morphometric data some groups include both rays and sharks. Four groups are now proposed based predominantly on the shape and dimensions of the membranous otoconial organs, and characteristics of the semicircular canals. Evident morphological differences between the ear types belonging to the new groups include the membranes of the semicircular canals being bound to the otoconial organs in some species, while only being connected via the canal ducts in others, as well as clear variation present in saccular organ size. Previous studies examining variation in the inner ear have attributed differences to either phylogeny or functional significance. Results from this study suggest that neither phylogeny nor feeding strategy solely accounts for the morphological diversity present in the external morphology of the elasmobranch inner ear.
关于板鳃亚纲动物内耳的研究主要集中在一小部分鲨鱼，特别是真鲨科鲨鱼。因此，后续对其他物种的研究将物种细分为两个主要类别：具有典型真鲨科鲨鱼内耳特征的物种和不具有典型特征的物种。本研究提出了一套与先前建议不同的内耳形态分组。本研究检查了17种板鳃亚纲动物（包括鲨鱼和鳐鱼）的内耳，并基于形态测量数据，有些组同时包含鳐鱼和鲨鱼。现在主要根据膜质耳石器官的形状和尺寸以及半规管的特征提出了四个组。属于新组的耳型之间明显的形态差异包括，在一些物种中半规管膜与耳石器官相连，而在其他物种中仅通过管道相连，以及球囊器官大小存在明显差异。先前关于内耳变异的研究将差异归因于系统发育或功能意义。本研究结果表明，系统发育和摄食策略都不能单独解释板鳃亚纲动物内耳外部形态的形态多样性。
