Two new, subcomplete forewings belonging to the ‘triassolestid assemblage’, a group of Triassic stem-relatives of dragon- and damselflies (Odonata), are described. One, recovered from Australia (Aranbanga Volcanic Group), belongs to Mesophlebia antinodalis Tillyard, 1916, previously documented on the basis of two very incomplete wings. The other, recovered from South Africa (Molteno Formation), is assigned to a new species, Mesophlebia elegans sp. nov. The new data allow a reconsideration of the diagnosis of the genus Mesophlebia Tillyard, 1916 and a re-instatement of the family Mesophlebiidae Tillyard, 1916. Notably, the new specimens possess, near the wing base, a posterior lobe absent in most ‘triassolestid’ genera, but present in crown-Odonata and a number of their stem-relatives. Lobodonata tax. nov. is erected to accommodate odonates possessing this lobe. The nature of the ‘vein-like’ element anteriorly delimiting this lobe is discussed. We submit that it might have been initially composed of an invagination of the posterior wing-margin (‘fibula’), which was later captured by AA, imposing its course on CuP.

The file 'QMF58847 habitus' was processed using the software RTIbuilder. The original dataset included 54 photographs taken using a Canon EOS 5D Mark III equipped with Canon 100 mm macro lens. Original photographs were pre-processed using Adobe Photoshop CS6.

The file 'QMF58847 detail posterior lobe' was processed using the software RTIbuilder. The original dataset included 34 photographs taken using a Canon EOS 5D Mark III equipped with Canon MP-E 65 mm macro lens. Original photographs were pre-processed using Adobe Photoshop CS6.

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