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.