This article has been peer reviewed and accepted for publication. It is in production and has not been edited, so may differ from the final published form.
Where Fossils Dare and Males Matter: combined morphological and molecular analysis untangles the evolutionary history of the spider ant genus Leptomyrmex Mayr (Hymenoptera: Dolichoderinae)
The distinctive ant genus Leptomyrmex had been thought to be endemic to Australasia for over 150 years, but enigmatic Neotropical fossils have challenged this view for decades. This study responds to a recent and surprising discovery of extant Leptomyrmex species in Brazil with a thorough evaluation of the Dominican Republic fossil material, which dates to the Miocene. In the first case study of direct fossil inclusion within Formicidae, we incorporated both living and the extinct Leptomyrmex species. Through simultaneous analysis of molecular and morphological characters in both Bayesian and parsimony frameworks we recover the fossil taxon as sister to extant Leptomyrmex in Brazil, while considering the influence of taxonomic and character sampling on inferred hypotheses relating to tree topology, biogeography and morphological evolution. We also identified potential loss of signal in the binning of morphological characters and tested the impact of parameterization on divergence date estimation. Our results highlight the importance of securing sufficient taxon sampling for extant lineages when incorporating fossils and underscore the utility of diverse character sources in accurate placement of fossil terminals. Specifically, we find that fossil placement in this group is influenced by the inclusion of male-based characters and the newly discovered Neotropical “Lazarus taxon”.
IS16067 Accepted 09 April 2017
© CSIRO 2017