Cawley John Joseph, Marramà Giuseppe, Carnevale Giorgio, Kriwet Jürgen
University of Vienna, Department of Palaeontology, Vienna, Austria.
Dipartimento di Scienze della Terra, Università degli Studi di Torino, Turin, Italy.
PeerJ. 2018 May 18;6:e4809. doi: 10.7717/peerj.4809. eCollection 2018.
The pycnodontiform fish is one of the representatives of the highly diverse actinopterygian fish fauna from the early Eocene Bolca Lagerstätte, representing one of the youngest and thus last occurrences of this extinct neopterygian clade. This genus has historically been used as a wastebasket taxon in regards to poorly known pycnodontiform fossils. Authors have argued over the specific status of the Bolca Lagerstätte in terms of how many species are contained within the genus with some arguing for multiple species and others suggesting lumping all Bolca specimens together into one species.
Here, we use a quantitative approach performing biometric and geometric morphometric analyses on 52 specimens of in order to determine if the morphological variability within the sample might be related to inter- or intraspecific variation.
The analyses revealed that the variations of body shape, morphometric and meristic characters cannot be used to distinguish different morphotypes. On the contrary, our results show a remarkable link between shape and size, related to ontogeny.
Differences in body shape of small (juvenile) and large (adult) individuals is probably related to different microhabitats occupation on the Bolca reef with juveniles sheltering within crevices on the reef and adults being more powerful swimmers that swim above the coral. Taxonomically, we suggest that the Bolca should be referred to strictly as as this was the name given to the holotype. Additionally, an overview of species assigned to is given.
厚齿形鱼类是始新世早期博尔卡化石库中高度多样化的辐鳍鱼类群的代表之一，代表了这个已灭绝的新鳍类分支中最年轻且因此也是最后的出现记录之一。就鲜为人知的厚齿形化石而言，该属在历史上一直被用作一个混杂类群。关于博尔卡化石库的具体分类地位，作者们就是否该属包含多个物种存在争论，一些人主张有多个物种，而另一些人则建议将所有博尔卡标本归为一个物种。
在此，我们采用定量方法，对52个[此处原文缺失具体属名]标本进行生物测量和几何形态测量分析，以确定样本中的形态变异性是否可能与种间或种内变异相关。
分析表明，体型、形态测量和可数性状的变异不能用于区分不同的形态类型。相反，我们的结果显示了形状与大小之间与个体发育相关的显著联系。
小（幼年）个体和大（成年）个体的体型差异可能与它们在博尔卡礁上占据不同的微生境有关，幼年个体躲在礁体的缝隙中，而成年个体是更强壮的游泳者，在珊瑚上方游动。在分类学上，我们建议博尔卡[此处原文缺失具体属名]应严格称为[此处原文缺失具体种名]，因为这是模式标本所赋予的名称。此外，还给出了归入[此处原文缺失具体属名]的物种概述。
