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

DANIELA S. MONTI; CONFALONIERI, V.A.

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Lugar: Lawrence; Año: 2017 vol. 91 p. 1 - 14

0022-3360

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. The combination of different methods has proved to be useful in the resolution of taxonomic and evolutionary hypotheses. Parabolinella triarthroides Harrington 1938 was described based on two cranidia from the Quebrada de Coquena, Purmamarca, Jujuy province. The generic assignation 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 assignation 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 presented 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. Based on the general morphology of the canidium together with the analysis of the qualitative characters and phylogenetic relationships, we propose to leave P. triarthroides within the genus Parabolinella. From the combined analysis could be established that the similarities in the morphology of the cranidium of P. triartrhoides compared to the rest species of Parabolinella can be considered true homologies, instead of a byproduct of evolutionary convergence. The implementation of an integrative approach, combining different methodological techniques and a good description of specimens, demonstrates to be the best way to proceed for solving systematic problems in groups which the morphological variation is the only source of information, like fossil taxa without living representatives