Mesojassus ipsviciensis Tillyard, 1916

Lambkin, Kevin J., 2020, Revision of Mesojassus Tillyard, 1916, from the Late Triassic of Queensland (Hemiptera: Cicadomorpha: Membracoidea: Archijassidae), Zootaxa 4718 (3), pp. 413-422 : 416

Mesojassus ipsviciensis Tillyard, 1916

( Figs 1–4 )

Mesojassus ipsviciensis Tillyard, 1916: 191 , plate 2, fig. 7; Tillyard, 1919: 886, text fig. 17; Evans, 1956: 211, fig. 13A; Becker- Migdisova, 1962: fig. 489; Evans, 1964: 180; Carpenter, 1992: 227, fig. 146.1; Jell, 2004: 44, 2 unnumbered figs.

Triassojassus proavitus Tillyard, 1919: 888 , text fig. 18; Evans, 1956: 209, fig. 12D; Carpenter, 1992: 259; Martins-Neto et al., 2003: 253; Jell, 2004: 40, 2 unnumbered figs.; syn. nov.

Triassocotis stricta Evans, 1961: 16 , fig. 1F; Jell, 2004: 39; Lambkin, 2019: 392; syn. nov.

(partim) Triassocotis australis: Evans, 1961: 16 , fig. 1E (specimen QMF3687).

Material. Holotype tegmen GSQ33, holotype tegmen of Triassojassus proavitus GSQ191a, both Denmark Hill; holotype tegmen of Triassocotis stricta QMF3688a/b, Mount Crosby. Twenty-five additional tegmina: GSQ: 56a/b, 90a/b, 111, 220a/b (clavus), 240 (clavus), 265, 282a, Denmark Hill; QMF: 60056, 60057, 60058a/b (+ crushed dorsal thorax), 60059a/b, 60060, 60061a/b, 60062a/b, 60063, 60064, Dinmore; 3687 (listed as Triassocotis australis by Evans 1961), 6977, 6984, 60065a/b, 60066, 60067, 60068, 60069a/b, Mount Crosby; ACC: I.100a/b, Mount Crosby.

Description. Tegmen 5.3–8.2 mm long (holotype 6.7, holotype of T. proavitus 6.5, holotype of T. stricta c. 8.2), 1.9–2.9 mm wide, length/width 2.7–3.2; no colour pattern detected ( Fig. 3 ), except in Dinmore specimens QMF60057 which has dark shading across the entire tegmen, and QMF60062a/b, 60063 and 60064 which are 2- toned, darkly shaded over the postero-basal ⅔, and pale in the antero-apical ⅓ ( Fig. 4 ).

Notes. The holotype tegmen of M. ipsviciensis has a narrowly rounded apex, whereas that of T. proavitus has the apex more broadly rounded. The two tegmina are otherwise similar in both size and venation. Contrary to Evans’s (1961) description, the estimated 8.2 mm long holotype tegmen of T. stricta has the typical Mesojassus venation, with a two-branched rather than a simple RA (R 1 of Evans), one r-m rather than two, and a three-branched rather than four-branched M. QMF3687, identified by Evans (1961) as T. australis , is a 6.7 mm long tegmen with the standard Mesojassus venation. It is of note that all Denmark Hill and Dinmore specimens are smaller, ranging from c. 5–7 mm in length, whereas the Mount Crosby specimens exhibit the full tegmen length range of the species.

Figures

FIGURES 1–2. Mesojassus ipsviciensis Tillyard, QMF60065a, Mount Crosby; a, arculus; bc, basal cell; CP, ‘additional lower carina in costal field’ (Shcherbakov 1984); dSc, distal portion of Sc; pc, precostal carina;

FIGURES 3–4. Mesojassus ipsviciensis Tillyard, Dinmore: 3, QMF60061a, broader specimen, apparently without coloration; 4, QMF60062b (mirrored), narrower specimen with 2-tone coloration.