The “seeds” onPadgettia readiare insect galls: reassignment of the plant toOdontopteris, the gall toOvofoligallitesn. gen., and the evolutionary implications thereof

Abstract

The Early Permian (Asselian) Euramerican plantPadgettia readiMamay is reassigned toOdontopterisBrongniart, asO. readi(Mamay) Stull et al. n. comb. Distinctive elongate structures on neuropteroid pinnules of this plant, previously interpreted as fructifications, are herein reinterpreted as foliar histoid galls, structurally analogous to blister or vein galls, and probably induced by an early lineage of hemipterans or mites. These distinctive features are assigned to the new gall ichnogenusOvofoligallitesLabandeira, n. ichnogen. n. ichnosp, asO. padgettiLabandeira. The Early Permian association between anOdontopterishost andOvofoligallitesgallers probably originated during the Middle Pennsylvanian as a similar, antecedent association betweenMacroneuropteris scheuchzeri(Hoffmann) Cleal, Shute, and Zodrow and the maker of U-shaped surface features long known as a distinctive, unattributed damage type, but now recognizable as a likely gall. The persistence of this association between the galler and certain medullosan pteridosperms into the Permian adds to the morphological richness of the Permian galler insect fauna. The Permian ecological expansion of galling insects resulted in colonization of new host plants, primarily through a shift from the consumption of entire, mostly pteridophyte axial organs during the Pennsylvanian to the partitioning of seed plant tissues in leaves and small branches in the Permian. TheOvofoligallitesgaller was part of a diverse Permian galler guild involving a variety of plant taxa, organs and tissues that overwhelmingly targeted multiple lineages of seed plants.