Phylogenetic position of the subfamily Symphrasinae (Insecta: Neuroptera), its intergeneric relationships and evolution of the raptorial condition within Mantispoidea

The superfamily Mantispoidea (Insecta: Neuroptera) includes the families Berothidae, Rhachiberothidae and Mantispidae. Among these taxa, the last two are collectively known as Raptorial Mantispoidea due to the presence of grasping forelegs for predatory habits. The Mantispidae classically included the subfamilies Symphrasinae, Drepanicinae, Calomantispinae and Mantispinae, yet recent research challenged this classification scheme as well as the monophyly of this family resulting in Symphrasinae being transferred to Rhachiberothidae. The phylogenetic position of the subfamily Symphrasinae within Mantispoidea is here inferred based on total evidence analysis combining three genes (COI, 16S and 18S) and 72 morphological characters scored from living representatives of all Mantispidae subfamilies (12 genera), the 3 genera of Symphrasinae, and Rhachiberothinae (1 genus). Representatives of Berothidae (four genera) and Hemerobiidae (one genus) were used as outgroup taxa. Results of the total evidence analysis were compared with parsimony and maximum likelihood analyses of the morphological and molecular datasets of the COI, 16S and 18S genes. The resultant phylogeny under total evidence recovered Rhachiberothidae as a monophyletic group with strong support in which Symphrasinae was found as sister to Rhachiberothinae. The three genera contained in Symphrasinae, i.e. Anchieta, Plega and Trichoscelia were each recovered as monophyletic in the parsimony analysis, with Anchieta as sister to Trichoscelia + Plega. The family Mantispidae was also recovered as monophyletic and sister to Rhachiberothidae, with Mantispinae as sister to Calomantispinae + Drepanicinae. Evolution of the raptorial condition in Mantispoidea is discussed based on the performed analyses. The morphology and the structure of the raptorial foreleg and the prothorax (i.e. the raptorial system) support the close relationship of Symphrasinae with Rhachiberothinae rather than to other Mantispidae subfamilies which possess a distinctive and well-differentiated raptorial apparatus. The Rhachiberothidae (including Symphrasinae) are distinguished by the presence of a foretarsal Stitz organ. Furthermore, a sit-and-wait predatory strategy is hypothesised for this taxon, whereas the Mantispidae are likely sophisticated active-ambushing predators.