Bechala sommeri Ilger & Brauckmann, 2012 enlightens the Namurian griffenfly diversity (Insecta: Odonatoptera: Bechalidae)
Abstract
Bechala sommeri Tiger & Brauckmann, 2012, the type species of the type genus of the early Late Carboniferous (Namurian) family Bechalidae Ilger & Brauckmann, 2012, is redescribed. It does not belong to the order Megasecoptera as previously proposed.
The taxon is clearly attributable to Odonatoptera for the typical venation characters as CuA separating from MP obliquely, a true arculus with concave RP and convex MA emerging from a composite vein R+MA, short ScP, and presence of convex intercalaries IR2 and IR1 between the main branches of RP3/4, RP2 and RP1. We transfer this taxon with the mono-specific family Bechalidae to Odonatoptera.
A new diagnosis is given for Bechalidae and its type genus Bechala. Furthermore, the presence of an oblique subnodal crossvein very far from the ending of ScP and close to the base of RP2 confirms the hypothesis that the subnodus is a structure originally independent of the nodus with a different function in relation to wing tracheation.
The Bechalidae are included in a clade (Meganeuridae-Sinierasipteridae-Bechalidae-Lapeyridae-Nodialata), in contrast to a sister group relationships between the two clades Meganisoptera (=Namurotypidae-Paralogidae-Kargalotypidae-Kohlwaldiidae-Meganeuridae) and Odonatoclada (=Lapeyridae-Nodialata), while the potential relationships between the Campylopteridae and the Lapeyridae and Nodialata are rejected. Bechala represents a 'damselfly-like' ecological niche in the Namurian, showing the high diversity of the earliest known Odonatoptera, strongly suggesting an Early Carboniferous, if not Late Devonian age for this pterygote clade.