Molecular phylogeny places the enigmatic subfamily Masoninae within the Ichneumonidae, not the Braconidae

Abstract

AbstractThe Masoninae (type genus Masona van Achterberg) is a widespread but seldom collected group of morphologically aberrant tiny (body length 2 mm or less) wasps that have always been considered as a subfamily of Braconidae, albeit on little supporting evidence. Discovery of a fully winged female of Masona from remote Australia has enabled a reassessment of its relationships. This specimen yielded sequence data for the nuclear 28S and 18S rDNA genes, the barcoding fragment of mitochondrial cytochrome oxidase subunit 1 and the mitochondrial 16S rDNA gene. These were analysed separately and together, along with representatives of Braconidae and Ichneumonidae. Maximum likelihood analyses of all four genes separately and combined concur that Masona is nested within the Ichneumonidae and, therefore, is not a member of Braconidae. This is also supported by the position of the sternaulus low on mesopleuron, absence of fore wing vein (RS + M)a (though the great reduction in wing venation makes further interpretation problematic) and the articulated junction of metasomal tergites 2 and 3. On balance, molecular analyses place Masona basally among the ophioniformes lineage of Ichneumonidae. Formal description of the Australian species as Masona timpaynei Quicke sp. n. and a revised diagnosis of Masoninae are provided in S1 together with illustration of the holotype.