Sagittal otoliths are structures integrating the sensory system of teleost fish, assisting in balance and hearing and are normally formed by calcium carbonate as aragonite. Sagittal otoliths have intraspecific shape, the aim of this study was to check the frequency of anomalous otoliths and to characterize the crystallization of sagittal otoliths in Atherinella brasiliensis. For that, 45 specimens of A. brasiliensis were collected in the Paranaguá Estuarine Complex (25°32'59” S–48°23'20” W), from which the otoliths were removed from the palate region. Raman spectrometry was performed on 30 otoliths; aragonite deposition was observed in otoliths without morphological changes (n = 26) and aragonite (n = 2) and vaterite (n = 2) deposition in those with morphological changes. Therefore, the frequency of otoliths with morphological changes was 8.8%. The fact that this is the first report of otoliths with morphological changes and deposition of vaterite for A. brasiliensis, demonstrates the need for studies that correlate environmental changes with physiological stress in estuarine fish.

中文翻译：

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Atherinella brasiliensis 异常耳石的首次记录

矢状耳石是整合硬骨鱼感觉系统的结构，有助于平衡和听力，通常由碳酸钙作为文石形成。矢状耳石具有种内形状，本研究的目的是检查异常耳石的频率并表征Atherinella brasiliensis矢状耳石的结晶。为此，在巴拉那瓜河口复合体（25°32'59” S–48°23'20” W）中收集了 45 个A. brasiliensis标本，从中去除了上颚区域的耳石。对 30 个耳石进行拉曼光谱分析；在没有形态变化的耳石（n  = 26）和文石（n  = 2）和球霰石（n = 2) 有形态变化的沉积物。因此，耳石出现形态变化的频率为8.8%。这是第一份关于A. brasiliensis耳石形态变化和球霰石沉积的报告，这表明需要进行研究，将环境变化与河口鱼类的生理应激联系起来。