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Navigating the mt DNA road map out of the morphological maze: interpreting morphological variation in the diverse Monomorium rothsteini ( F orel) complex ( H ymenoptera: F ormicidae)

2013; Wiley; Volume: 39; Issue: 2 Linguagem: Inglês

10.1111/syen.12051

1365-3113

KATHRYN S. SPARKS, Alan N. Andersen, Stephen C. Donnellan, Andrew D. Austin,

Animal Behavior and Reproduction

Abstract Monomorium is a large and diverse ant genus with speciose radiations in both the A frotropical and A ustralian regions. According to the most recent taxonomic revision, many A ustralian species are characterised by very broad distributions and variable morphology, which suggests that some species may be unrecognised species complexes. With a continent‐wide distribution and diverse yet overlapping morphology, M. rothsteini ( F orel) is representative of the greater challenge that exists in A ustralian Monomorium systematics. Here we investigate species boundaries in M. rothsteini using a molecular phylogenetic framework to interpret the complex overlap of nine morphological characters (with 31 states) and examine biogeographic relationships among the lineages. Bayesian inference resolved 38 mt DNA lineages that were morphologically separable, at least from their sister lineage. Although the morphological characters were intermixed across the phylogeny, instances of inseparable morphology among sister clades was rare. Seventeen lineages exhibited complete morphological overlap with one or more other lineages and could not be separated by P rincipal C omponent A nalysis based on 12 morphometric variables. Two‐thirds of all lineages occurred sympatrically with one or more both genetically and morphologically divergent lineages. The two nuclear markers EF1αF2 and wingless were used to generate haplotype networks which were characterised by a star‐like pattern indicative of a rapid and recent radiation. Several haplotypes for both nuclear gene regions were shared among individuals occurring in separate mt DNA clades which we were also unable to distinguish morphologically or that were occurring in sympatry, indicating possible introgression in both the mt DNA and nuclear genomes. Clear biogeographic affinities among samples within a lineage were detected but there was no overall pattern in the biogeographic relationships among the lineages. We conclude that M. rothsteini is a large species complex that has undergone a complex evolutionary history following aridification of the A ustralian continent, and discuss the implications of this conclusion for the systematics of A ustralian Monomorium more generally.