Tardilly, Lambkin, 2019

Lambkin, Kevin J., 2019, Mesodiphthera Tillyard, 1919, from the Late Triassic of Queensland, the oldest cicada (Hemiptera: Cicadomorpha: Cicadoidea: Tettigarctidae), Zootaxa 4567 (2), pp. 358-366 : 362

Tardilly gen. nov.

Type species. Mesodiphthera prosboloides Tillyard, 1922

Diagnosis. Tegmen elongate (c. 3 times longer than wide), c. 15 mm long, apex (only preserved in type species) narrowly rounded; costal space, clavus and base of pre-nodal area coarsely punctate; costal space very broad, about three times as wide as CuA cell; nodal line well beyond ½ tegmen length; basal cell narrowed apically; primary R fork slightly proximal to that of M, about midway between apex of basal cell and nodal line; RP, M1+2 and M3+4 not noticeably angled at nodal line; RA1 very close to node; RA2 branching pattern not preserved; post-nodal cross-vein series closer to nodal line than tegmen apex (im and m-cu not preserved in type species), apical cells thus quite long; ir (preserved in type species only) upright; angle of primary M fork acute; both r-m and im backwardly inclined; im (preserved in dunstani only) between M2 and M3; M3+4 with three branches; CuA1 gently sinuous, directed towards apical margin, apparently about same length as M4; CuA1 cell very broad basally, strongly narrowed apically; CuA2 not sharply angled, diverging very gradually from nodal line, running to posterior margin, less than ½ as long as CuA1; clavus quite large, occupying a significant area of tegmen, extending beyond ½ tegmen length, claval veins well-developed.

Notes. The genus is similar to Mesodiphthera in the more or less aligned primary forks of R and M placed at about midway between the basal cell and the nodal line, and the fact that at least in M. dunstani , im is backwardly inclined and runs between M2 and M3. As noted above, these are two of the distinctive characters of Mesodiphthera . The genus is quite distinct, however, in its smaller size, broader costal space, three-branched M3+4, and differently shaped CuA and CuA2. The three-branched M3+4 is unusual for the family, M3+4 being always either simple or two branched, with the exception of the aberrant Elkinda , in which all post-nodal venation is polymerized ( Shcherbakov 1988, fig. 2i). The generic name is an anagram of the family name of its species author, Australian entomologist, Robin John Tillyard (1881–1937), and is masculine.