Dental convergence is a hallmark of cichlid fish adaptive radiations. This type of repeated evolution characterizes both the oral jaws of these fishes as well as their pharyngeal jaws that are modified gill arches used to functionally process prey like hard-shelled mollusks. To test several hypotheses regarding the evolution of cichlid crushing pharyngeal dentitions, we used x-ray computed tomography (CT) scans to comparatively examine dental evolution in the pharyngeal jaw of a diversity of New World Heroine cichlid lineages. The substantial variation in erupted tooth sizes and numbers as well as replacement teeth found in these fishes showed several general patterns. Larger toothed species tended to have fewer teeth suggesting a potential role of spatial constraints in cichlid dental divergence. Species with larger numbers of erupted pharyngeal teeth also had larger numbers of replacement teeth. Replacement tooth size is almost exactly predicted (r = 0.99) from the size of erupted teeth across all of the species. Mollusk crushing was therefore highly associated with not only larger pharyngeal teeth, but also larger replacement teeth. Whether dental divergence arises as a result of environmental induced plasticity or originates via trophic polymorphism as found in the species Herichthys minckleyi, there appear to be general rules that structure interspecific divergence in cichlid pharyngeal erupted and replacement dentitions.

中文翻译：

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挤压软体动物的慈鲷鱼咽颌牙列的趋同进化：牙齿大小、数量和替换的比较 X 射线计算机断层扫描

牙齿收敛是慈鲷鱼适应性辐射的标志。这种类型的重复进化表征了这些鱼的口腔颌骨以及它们的咽颌，它们是经过改良的鳃弓，用于功能性地处理像硬壳软体动物一样的猎物。为了检验关于慈鲷咬碎咽齿列进化的几个假设，我们使用 X 射线计算机断层扫描 (CT) 扫描来比较检查新世界女主角慈鲷谱系多样性的咽颌中的牙齿进化。在这些鱼中发现的牙齿大小和数量以及替换牙齿的显着变化显示出几种一般模式。较大的有齿物种往往有较少的牙齿，这表明空间限制在慈鲷牙齿发散中的潜在作用。具有大量萌出的咽部牙齿的物种也具有更多数量的替代牙齿。根据所有物种的萌出牙齿的大小，几乎可以准确预测替换牙齿的大小（r = 0.99）。因此，软体动物压碎不仅与较大的咽部牙齿高度相关，而且与较大的替代牙齿高度相关。无论牙齿分化是由于环境诱导的可塑性引起的，还是通过在 Herichthys minckleyi 物种中发现的营养多态性引起的，似乎都存在一般规则来构建慈鲷咽部萌出和替代牙列中的种间分化。因此，软体动物压碎不仅与较大的咽部牙齿高度相关，而且与较大的替换牙齿高度相关。无论牙齿分化是由于环境诱导的可塑性引起的，还是通过在 Herichthys minckleyi 物种中发现的营养多态性引起的，似乎都存在一般规则来构建丽鱼科鱼类咽部萌出和替代牙列的种间分化。因此，软体动物压碎不仅与较大的咽部牙齿高度相关，而且与较大的替代牙齿高度相关。无论牙齿分化是由于环境诱导的可塑性引起的，还是通过在 Herichthys minckleyi 物种中发现的营养多态性引起的，似乎都存在一般规则来构建慈鲷咽部萌出和替代牙列中的种间分化。