In the present study we evaluate the putative cases of sympatric speciation in the genus Herichthys by studying the variation of the head shape using principal component analysis, phylomorphospace and reconstructions of the ancestral states of feeding preferences. Herichthys includes both allopatric as well as sympatric sister-species, as well as sympatric unrelated species and offers thus great potential for evolutionary studies of putatively sympatric speciation. Herichthys is the northernmost group of cichlids in America and one of the most ecologically disparate genera within Middle American cichlids. Fifteen anatomical points were recorded on the heads of 293 specimens of the 11 species recognized within the genus. The results showed that in spite of having wide variation in consumed diets, most species of Herichthys are close in morphospace. However, morphological variation was great among the two pairs of sympatric sister species in agreement with the suggested sympatric model of speciation. This article is protected by copyright. All rights reserved.

中文翻译：

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头部形状和营养变异在Herichthys 属在同向和异向分化中的作用

在本研究中，我们通过使用主成分分析、系统形态空间和进食偏好祖先状态的重建来研究头部形状的变化，从而评估 Herichthys 属中同域物种形成的假定案例。Herichthys 包括异域和同域姐妹物种，以及同域无关物种，因此为假定同域物种形成的进化研究提供了巨大的潜力。Herichthys 是美洲最北端的慈鲷类群，也是中美洲慈鲷中生态差异最大的属之一。在该属内已识别的 11 个物种的 293 个标本的头部上记录了 15 个解剖点。结果表明，尽管食用的饮食差异很大，但大多数 Herichthys 物种在形态空间上都很接近。然而，两对同域姐妹物种之间的形态变异很大，与建议的同域物种形成模型一致。本文受版权保护。版权所有。