Data from: Comparing phylogenetics and linear morphometrics to solve the generic assignment of Parabolinella? triarthroides Harrington (Trilobita, Olenidae)

The use of different methodological approaches together with an exhaustive qualitative study has helped to recognize important morphological traits to distinguish species in a systematic and phylogenetic framework. Parabolinella triarthroides Harrington, 1938 was described based on two cranidia from the Quebrada de Coquena, Purmamarca, Jujuy province. The generic assignment of P. triarthroides has been questioned by a phylogenetic analysis, which resolves this species as the sister group of Bienvillia Clark, 1924. To explore the generic assignment of this species, a revision of the type material, plus a morphometric analysis including specimens of Parabolinella Brøgger, 1882 and Bienvillia were performed. In addition, the original matrix used in the published phylogeny was reviewed and enlarged, including more species of Bienvillia. Continuous characters were coded in different ways in order to compare how they could affect the ordering of specimens and their phylogenetic relationships. Finally, both methodologies were compared, especially in regard to the behavior of the quantitative characters included in the analyses. From the combined analyses, it is shown that similarities between the cranidium of P. triarthroides and all other Parabolinella species are true homologies instead of a by-product of evolutionary convergence. Therefore, P. triarthroides should be considered a member of this genus. Finally, this study demonstrates that the best strategy for solving systematic problems in groups where the morphological variation is the only source of information (i.e., fossil taxa without living representatives) is the implementation of an integrative approach, combining different methodological techniques and a good description of specimens.结合多种方法学途径与详尽的定性研究，已助力识别出可在系统学与系统发育（phylogenetic）框架下区分物种的重要形态学特征。三突副波林三叶虫（Parabolinella triarthroides Harrington, 1938）的建立基于采自阿根廷胡胡伊省普尔马马卡地区科克纳河谷（Quebrada de Coquena, Purmamarca, Jujuy province）的两件头盖（cranidium，复数为cranidia）标本。此前有系统发育分析对该种的属级归属提出质疑，该分析将本种复原为比恩维尔三叶虫属（Bienvillia Clark, 1924）的姊妹群。为探究本种的属级归属，研究团队对其模式标本（type material）开展了修订，并完成了涵盖副波林三叶虫属（Parabolinella Brøgger, 1882）与比恩维尔三叶虫属类群标本的形态计量分析（morphometric analysis）。此外，研究人员对已发表系统发育分析中使用的原始矩阵进行了梳理与扩充，新增了更多比恩维尔三叶虫属物种。为比较不同编码方式对标本排序及其系统发育关系的影响，研究人员以多种方案对连续性状（continuous characters）进行编码。最后，研究团队对两种方法学途径展开了对比，尤其关注分析中纳入的数量性状的表现特征。综合分析结果表明，三突副波林三叶虫的头盖与其他副波林三叶虫属物种间的相似性实为同源性（homology），而非演化趋同（evolutionary convergence）的产物。因此，本种应归入副波林三叶虫属。本研究证实，针对仅以形态变异为唯一信息来源的类群（即无现生代表的化石类群），解决系统学问题的最优策略为采用整合研究路径（integrative approach），结合多种方法学技术与详尽的标本描述。