The morphology and morphometry of otoliths have emerged as powerful indicators of ecological characteristics of fishes. However, shape descriptors that can accurately predict well-documented functions played by species in tropical ecosystems are either restricted to a few groups or poorly known. Therefore, we evaluated the power of two otolith shape descriptors (ecomorphological indexes and Fourier harmonics) in discriminating trophic and depth strata preference groups of tropical fish species. Differences in otolith shape of ecological groups were visualized by linear discriminant analysis (LDA), and tested by a jack-knife cross-validation method and permutational multivariate analysis of variance (PERMANOVA) for both methods. Visually and statistically, both descriptors were good predictors of trophic groups and depth preference categories (PERMANOVA, p < 0.05). Overall jack-knifed classification success between both descriptors were very similar, with harmonics correctly classifying 90.38% of assigned trophic groups and 75.96% of given depth preference categories, against 82% and 56.25% of ecological indexes, respectively. Our results suggest that Fourier descriptors and ecomorphological indexes of otoliths should be used as functional traits in future studies, as otolith shape provides a wider range of ecological information regarding feeding habitat, mobility, substrate association and water column use.

中文翻译：

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热带鱼耳石的生态形态模式：通过形状评估营养组和深度层偏好

耳石的形态学和形态测量学已成为鱼类生态特征的有力指标。然而，能够准确预测热带生态系统中物种所发挥的有据可查的功能的形状描述符要么仅限于少数群体，要么鲜为人知。因此，我们评估了两个耳石形状描述符（生态形态指数和傅立叶谐波）在区分热带鱼物种的营养和深度层偏好组方面的能力。生态群体耳石形状的差异通过线性判别分析 (LDA) 进行可视化，并通过两种方法的千斤顶交叉验证方法和置换多元方差分析 (PERMANOVA) 进行测试。在视觉和统计上，两个描述符都是营养组和深度偏好类别的良好预测因子（PERMANOVA，p < 0.05）。两个描述符之间的整体 jack-knifed 分类成功非常相似，谐波正确分类了 90.38% 的指定营养组和 75.96% 的给定深度偏好类别，而生态指数分别为 82% 和 56.25%。我们的研究结果表明，耳石的傅立叶描述符和生态形态指标应作为未来研究的功能特征，因为耳石形状提供了更广泛的关于觅食栖息地、流动性、基质关联和水柱使用的生态信息。96% 的给定深度偏好类别，分别为 82% 和 56.25% 的生态指数。我们的研究结果表明，耳石的傅立叶描述符和生态形态指标应作为未来研究的功能特征，因为耳石形状提供了更广泛的关于觅食栖息地、流动性、基质关联和水柱使用的生态信息。96% 的深度偏好类别，分别为 82% 和 56.25% 的生态指数。我们的研究结果表明，耳石的傅立叶描述符和生态形态指标应作为未来研究的功能特征，因为耳石形状提供了更广泛的关于觅食栖息地、流动性、基质关联和水柱使用的生态信息。