Data from: The evolution of pharyngognathy: a phylogenetic and functional appraisal of the pharyngeal jaw key innovation in labroid fishes and beyond

The perciform group Labroidei includes approximately 2,500 species and comprises some of the most diverse and successful lineages of teleost fishes. Composed of four major clades, Cichlidae, Labridae (wrasses, parrotfishes and weed whitings), Pomacentridae (damselfishes), and Embiotocidae (surfperches), labroids have been an icon for studies of biodiversity, adaptive radiation, and sexual selection. The success and diversification of labroids have been largely attributed to the presence of a major innovation in the pharyngeal jaw apparatus, pharyngognathy, which is hypothesized to increase feeding capacity and versatility. We present results of large-scale phylogenetic analyses and a survey of pharyngeal jaw functional morphology, that allow us to examine the evolution of pharyngognathy in a historical context. Phylogenetic analyses were based on a sample of 188 acanthomorph species, primarily percomorphs, and DNA sequence data collected from ten nuclear loci that have been previously used to resolve higher-level ray-finned fish relationships. Phylogenies inferred from this dataset using maximum likelihood and Bayesian analyses indicate polyphyly of the traditional Labroidei and clearly separate Labridae from the remainder of the traditional labroid lineages (Cichlidae, Embiotocidae, and Pomacentridae). These three “chromide” families all grouped together within a newly discovered clade of 40 families and more than 5,300+ species (>30% of percomorphs and >17% of all ray-finned fishes), which we name Ovalentaria for its characteristic demersal, adhesive eggs with chorionic filaments. This fantastically diverse clade includes some of the most species-rich lineages of marine and freshwater fishes, including all representatives of the Cichlidae, Embiotocidae, Pomacentridae, Ambassidae, Gobiesocidae, Grammatidae, Mugilidae, Opistognathidae, Pholidichthyidae, Plesiopidae (including Notograptus), Polycentridae, Pseudochromidae, Atherinomorpha, and Blennioidei. Beyond the discovery of Ovalentaria, this study provides a surprising, but well-supported, hypothesis for a convict-blenny (Pholidichthys) sister group to the charismatic cichlids and new insights into the evolution of pharyngognathy. Bayesian stochastic mapping ancestral state reconstructions indicate pharyngognathy has evolved at least six times in percomorphs, including four separate origins in members of the former Labroidei, one origin in the Centrogenyidae, and one origin within Beloniformes. Our analyses indicate that all pharyngognathous fishes have a mechanically efficient biting mechanism enabled by the muscular sling and a single lower jaw element. However, a major distinction exists between Labridae, which lacks the widespread, generalized percomorph pharyngeal biting mechanism, and all other pharyngognathous clades, which possess this generalized biting mechanism in addition to pharyngognathy. This suggests that labrids have a functionally more restricted pharyngeal system than all other pharyngognathous clades.

鲈形目（Perciformes）下的隆头鱼亚目（Labroidei）包含约2500个物种，是硬骨鱼（Teleostei）中多样性最高、演化最成功的类群之一。该亚目由四大演化支（clades）构成：丽鱼科（Cichlidae）、隆头鱼科（Labridae，涵盖濑鱼、鹦嘴鱼及白喉鱼）、雀鲷科（Pomacentridae，雀鲷）以及海鲫科（Embiotocidae，海鲫），长期以来都是生物多样性、适应性辐射与性选择研究的标志性类群。
隆头鱼亚目的演化成功与类群分化，很大程度上被归因于其咽颌装置（pharyngeal jaw apparatus）的一项关键创新——咽颌型（pharyngognathy），该特征被认为可提升取食能力与功能灵活性。本研究展示了大规模系统发育分析（phylogenetic analysis）与咽颌功能形态学调查的结果，借此我们得以在演化历史框架下探讨咽颌型的演化历程。
本次系统发育分析以188种棘鳍类鱼（acanthomorph）为样本，其中以真鲈形类（percomorph）为主，并采用了10个核基因座（nuclear locus）的DNA序列数据——这些序列此前曾被用于解析辐鳍鱼（ray-finned fish）的高阶类群演化关系。
基于本数据集，通过最大似然法（maximum likelihood）与贝叶斯分析（Bayesian analysis）推导得到的系统发育树显示，传统定义的隆头鱼亚目为并系群（polyphyly），且隆头鱼科与其余传统隆头鱼亚目类群（丽鱼科、海鲫科及雀鲷科）被清晰分隔开来。
这三个被称为“慈鲷类”的科共同汇聚到一个新发现的演化支中：该演化支包含40个科、超过5300个物种（占真鲈形类的30%以上，占所有辐鳍鱼的17%以上），我们因其具有底栖黏性卵且卵壳带有丝状物的特征，将其命名为卵丝鱼群（Ovalentaria）。
该演化支物种多样性极高，囊括了海洋与淡水鱼类中物种丰富度最高的诸多类群，涵盖丽鱼科、海鲫科、雀鲷科、双边鱼科（Ambassidae）、喉盘鱼科（Gobiesocidae）、鮨鲈科（Grammatidae）、鲻科（Mugilidae）、后颌鰧科（Opistognathidae）、鳞鳚科（Pholidichthyidae）、拟雀鲷科（Plesiopidae，包含裸盖鱼属Notograptus）、南鲈科（Polycentridae）、蓝纹鲈科（Pseudochromidae）、银汉鱼总群（Atherinomorpha）以及鳚亚目（Blennioidei）。
除发现卵丝鱼群之外，本研究还提出了一项令人意外但证据充分的假说：纹首鳚（Pholidichthys，鳞鳚属）与极具辨识度的丽鱼类群互为姊妹群，同时为咽颌型的演化提供了全新认知。
通过贝叶斯随机映射法（Bayesian stochastic mapping）进行的祖先状态重建（ancestral state reconstruction）结果显示，咽颌型在真鲈形类中至少独立演化了六次：其中原隆头鱼亚目类群中独立起源四次，厚头鱼科（Centrogenyidae）独立起源一次，颌针鱼目（Beloniformes）内部独立起源一次。
我们的分析表明，所有具有咽颌型的鱼类都拥有一套由肌肉吊带与单一下颌骨结构构成的、力学效率极高的咬合机制。
然而，隆头鱼科与其余所有具有咽颌型的演化支存在一项核心差异：隆头鱼科并不具备广泛存在的、典型的真鲈形类咽颌咬合机制，而其余演化支除咽颌型外，均拥有该典型咬合机制。
这表明，相较于其余所有具有咽颌型的演化支，隆头鱼科的咽颌系统功能更为受限。