Neotropical ant parasitoids (Hymenoptera: Eucharitidae): interpreting taxonomy, phylogeny and divergent morphologies. (16th December 2019) - Murray, Elizabeth A.
Abstract: The Neotropical 'Kapala Clade' is a group of 13 described genera of ant parasitoids that includes some of the most morphologically bizarre members in the family Eucharitidae (Chalcidoidea). Across the Kapala Clade, various conspicuous morphological modifications – notably the long mesoscutellar spines – have led to the description of numerous genera. Monophyly of the clade has been supported in morphological and molecular analyses; however, relationships among genera within the clade are not easily resolved. Within this clade, there is one especially problematic taxon: Kapala Cameron is a common, diverse and easily recognizable genus, with species distributed across the Neotropical region north into the southern Nearctic, and one disjunct species found in the Afrotropical region. However, Kapala is defined by pleisiomorphic features – lacking the derived characters of the other Kapala Clade genera – with previous molecular evidence showing this genus to be paraphyletic. To evaluate relationships among Kapala Clade genera, we use a comprehensive sampling of 195 taxa and a molecular dataset of five gene regions. A morphological matrix of 52 characters was analysed both separately and combined with molecular data, which allowed rare genera to be incorporated into the phylogeny. Molecular results were at odds with the historic generic relationships, and the genus Kapala was rendered polyphyletic by two distinct clades of other kapaline genera. We find that there were bursts of morphological change clustered in the phylogeny; however, these are not correlated with higher rates of diversification. We discuss the timing of divergence events, analyse diversification patterns, and evaluate life‐history information within a phylogenetic context. Abstract : The 14 genera of the Kapala Clade comprise a group whose evolutionary signal is obscured by bursts of phenotypic change, morphological convergence and retention of pleisiomorphic characters. The largest genus, Kapala, had been diagnosed from its invariable phenotype. Our phylogeny shows that Kapala is paraphyletic, but that its pleisiomorphic phenotype repeatedly gave rise to morphologically divergent genera. We used molecular and morphological data to estimate generic relationships and explore patterns of diversification, and we reviewed life‐history traits and behaviour in a phylogenetic context.