The Holocephali is a major group of chondrichthyan fishes, the sister taxon to the sharks and rays (Elasmobranchii). However, the dentition of extant holocephalans is very different from that of the elasmobranchs, lacking individual tooth renewal, but comprising dental plates made entirely of self-renewing dentine. This renewal of all tissues occurs at the postero-lingual plate surface, as a function of their statodont condition. The fossil record of the holocephalans illuminates multiple different trends in the dentition, including shark-like teeth through to those with dentitions completely lacking individual teeth. Different taxa illustrate developmental retention of teeth but with fusion in their serial development. Dentine of different varieties comprises these teeth and composite dental plates, whose histology includes vascularized tubes within coronal dentine, merging with basal trabecular dentine. In this coronal vascularized dentine extensive hypermineralization forms a wear resistant tissue transformed into a variety of morphologies. Through evolution, hypermineralized dentine becomes enclosed within the trabecular dentine, and specialized by reduction into specific zones within a composite dental plate, with these increasing in morphological disparity, all reflecting loss of defined teeth but retention of dentine production from the inherited developmental package.

中文翻译：

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通过组织差异对大头鱼（软骨鱼）牙列的进化

Holocephali 是软骨鱼类的一个主要群体，是鲨鱼和鳐鱼 (Elasmobranchii) 的姐妹分类群。然而，现存的全头兽的牙列与弹性鳃的牙列有很大不同，它们没有单独的牙齿更新，而是由完全由自我更新的牙本质组成的牙板组成。所有组织的这种更新发生在后舌板表面，作为它们的statodont 条件的函数。全头兽的化石记录阐明了牙列的多种不同趋势，包括鲨鱼状牙齿到完全没有单个牙齿的牙列。不同的分类群说明牙齿的发育保留，但在它们的连续发育中融合。不同种类的牙本质包括这些牙齿和复合牙板，其组织学包括冠状牙本质内的血管化管，与基底小梁牙本质合并。在这个冠状血管化牙本质中，广泛的过度矿化形成了一种耐磨组织，转变为各种形态。通过进化，过度矿化的牙本质被封闭在小梁牙本质内，并通过减少到复合牙板内的特定区域而特化，随着这些形态差异的增加，所有这些都反映了特定牙齿的丧失，但保留了遗传发育包中的牙本质生成。