Is †Skleroptera (†Stephanastus) an order in the stemgroup of Coleopterida (Insecta)?

Abstract

The Carboniferous insect taxon †Stephanastus polinae was assigned to a monotypic new order †Skleroptera, which was postulated as the sister group of the clade Strepsiptera + Coleoptera (= Coleopterida). The placement of †Stephanastus in Holometabola and the proposed relationship with Coleopterida are very likely unjustified. Suggested shared derived features of Skleroptera + Coleopterida are vague, insufficiently documented (characters of proximal leg segments) or likely based on misinterpretation (wing veins). Based on the wing venation we suggest a position in the extinct hemimetabolous order †Protelytroptera.