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.

将多样的方法学路径与详尽的定性研究（qualitative study）相结合，可助力在系统学与系统发育框架（phylogenetic framework）内，识别出用于区分物种的关键形态学性状（morphological traits）。三关节副波林三叶虫（Parabolinella triarthroides）Harrington, 1938是基于采自阿根廷胡胡伊省普尔马马尔卡地区科奎纳峡谷的2枚头盖（cranidia）所建立的物种。此前有系统发育分析（phylogenetic analysis）对该种的属级归类提出质疑，该研究将本种复原为边维利三叶虫属（Bienvillia）Clark, 1924的姊妹群。为明确本种的属级归类，研究团队对其模式标本（type material）开展了修订工作，并结合副波林三叶虫属（Parabolinella）Brøgger, 1882与边维利三叶虫属的标本完成了形态计量分析（morphometric analysis）。此外，研究人员对已发表系统发育研究中使用的原始系统发育矩阵（phylogenetic matrix）进行了修订与扩充，新增了更多边维利三叶虫属的物种。为探究连续形态性状（continuous characters）以不同方式编码后，对标本排序及其系统发育关系可能产生的影响，研究采用了多种编码方案对连续性状进行编码。最后，研究对两种方法学路径进行了对比，重点分析了纳入分析的定量性状的表现差异。综合分析结果表明，三关节副波林三叶虫的头盖与其他副波林三叶虫属物种之间的形态相似性属于真正的同源性（homologies），而非演化趋同（evolutionary convergence）的产物。因此，三关节副波林三叶虫应归入副波林三叶虫属。本研究最终证实，针对仅以形态变异作为唯一信息来源的类群（即无现生代表的化石类群（fossil taxa without living representatives）），解决其系统学问题的最优策略为采用整合研究方法（integrative approach），结合多样的方法学技术与规范的标本描述工作。