Cichlidae have a magnificent ecological versatility that provides the species to explore many trophic niches, and behavioural biology. This versatility was achieved by modifications in the cranial and pharyngeal apparatus of cichlids. Accordingly, we aim to examine the relationships between pharyngeal morphology and diet of three species of the genus Crenicichla. We analysed the stomach contents and the morphology (through the geometric morphometric and teeth types) of their lower pharyngeal jaws (LPJ). We tested the hypothesis that LPJ morphology predicts the diet of Crenicichla species in streams. Our results indicated that the diet and the patterns of pharyngeal jaws were different among the species of Crenicichla, mainly the posterior process of the LPJ, the region of muscle insertion of LPJs with the neurocranium and the curvature of LPJ. Variation among the lower pharyngeal jaw shapes was shown to be directly associated with the use of food resources. Crenicichla species had a carnivorous diet based on fish and invertebrates (Aegla and aquatic insects). Higher fish consumption was observed in species with elongated lateral process in the LPJ and larger numbers of teeth, mainly recurved and conical unicuspid and bicuspid teeth (C. scottii and C. lepidota). On the other hand, higher consumption of Aegla was associated with a robust LPJ and molariform teeth (C. punctata). The total number of teeth was positively correlated with higher fish consumption. In addition, our results point to the need for investigations about spatial-temporal variations in Crenicichla diets to understand this group’s success in several freshwater environments.

中文翻译：

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巴西南部乌拉圭和 Jacuí 盆地河流中 Crenicichla 物种（慈鲷科：慈鲷科）的饮食与咽颌形态的关系

慈鲷科具有壮丽的生态多样性，使该物种能够探索许多营养生态位和行为生物学。这种多功能性是通过修改慈鲷的颅和咽器官来实现的。因此，我们的目标是检查三种 Crenicichla 属的咽部形态与饮食之间的关系。我们分析了他们的下咽颌 (LPJ) 的胃内容物和形态 (通过几何形态测量和牙齿类型)。我们测试了 LPJ 形态预测溪流中 Crenicichla 物种饮食的假设。我们的研究结果表明，Crenicichla 物种之间的饮食和咽颌模式不同，主要是 LPJ 的后突、LPJ 与神经颅骨的肌肉插入区域和 LPJ 的曲率。下咽颌形状的变化被证明与食物资源的使用直接相关。Crenicichla 物种以鱼类和无脊椎动物（Aegla 和水生昆虫）为食肉。在 LPJ 侧突较长且牙齿数量较多的物种中观察到较高的鱼类消费，主要是后弯和圆锥形单尖牙和二尖牙（C. scottii 和 C. lepidota）。另一方面，较高的 Aegla 消费量与坚固的 LPJ 和臼齿（C. punctata）有关。牙齿总数与较高的鱼类消费量呈正相关。此外，我们的结果表明需要对 Crenicichla 饮食的时空变化进行调查，以了解该群体在几种淡水环境中的成功。