Date Published: April 2, 2019
Publisher: Public Library of Science
Author(s): Seraina Klopfstein, Tamara Spasojevic, Tony Robillard.
The fossil record constitutes the primary source of information about the evolutionary history of extant and extinct groups, and many analyses of macroevolution rely on fossils that are accurately placed within phylogenies. To avoid misinterpretation of the fossil record, especially by non-palaeontologists, the proper assessment and communication of uncertainty in fossil placement is crucial. We here use Bayesian morphological phylogenetics to evaluate the classifications of fossil parasitoid wasps (Hymenoptera, Ichneumonidae) and introduce ‘RoguePlots’ to illustrate placement uncertainty on the phylogeny of extant taxa. Based on an extensive, newly constructed morphological matrix of 222 characters in 24 fossil and 103 extant taxa, we test three different aspects of models of morphological evolution. We find that a model that includes ordered characters, among-character rate variation, and a state-space restricted to observed states achieves the highest marginal likelihoods. The individual RoguePlots reveal large differences in confidence in the placement of the different fossils and allow some refinements to their classification: Polyhelictes bipolarus and Ichninsum appendicrassum are moved from an uncertain subfamily placement to Pimplinae, Plectiscidea lanhami is transferred to Allomacrus in Cylloceriinae (Allomacrus lanhami, comb. nov.), Lithotorus cressoni is moved from Diplazontinae to Orthocentrinae, and we note uncertainty in the generic placements of Rhyssella? vera and Xanthopimpla? messelensis. We discuss potential artefacts that might result in biased posterior probabilities in Bayesian morphological phylogenetic analyses, pertaining to character and taxon sampling, fossilization biases, and model misspecification. Finally, we suggest future directions both in ichneumonid palaeontology and in the way RoguePlots can improve both assessment and representation of placement uncertainty, both in fossils and other rogue taxa.
The fossil record provides crucial information about the evolutionary history of a group and allows us, by facilitating the inference of absolute ages, to put said history into a palaeogeographic and palaeoecological context. Many analyses that use the fossil record rely on a firm placement of fossils in the phylogenetic or at least taxonomic context of extant species. This is especially true for the dating of molecular trees through fossil calibrations , but also for the inference of ancient interactions between different groups of organism [2,3] and for the study of evolutionary trends in morphological characters over large timescales (e.g., [4,5]). Unfortunately, the correct taxonomic interpretation of fossils can be a formidable challenge due to incomplete preservation, difficulties in the taphonomic interpretation, and long gaps in the fossil record [6–8]. The proper communication of this uncertainty is crucial in order to avoid future misinterpretations and overconfidence in analyses that are relying on reliably placed fossils.