Mesocixiodes termioneura Tillyard, 1922

Lambkin, Kevin J., 2020, Revision of the Hylicellidae of the Late Triassic of Queensland (Hemiptera Cicadomorpha: Hylicelloidea), Zootaxa 4790 (3), pp. 525-539 : 535

Mesocixiodes termioneura Tillyard, 1922

( Figs 13–17 )

Mesocixiodes termioneura Tillyard, 1922: 462 , text-fig. 82, plate liii, fig. 34; Tillyard, 1926: fig. 2; Handlirsch, 1939: 16; Evans, 1956: 209, fig. 12E; Carpenter, 1992: 257, fig. 162.6; Martins-Neto et al., 2003: 253 (as Mesocixiodes terminoneura Tillyard 1920 ); Jell, 2004, 41, 2 unnumbered figs.

Mesocixiodes brachyclada Tillyard, 1922: 463 , text-fig. 84; Handlirsch, 1939: 16; Evans, 1956: 243; Jell, 2004: 41, syn. nov.

Material. Holotype tegmen GSQ88 a, holotype and paratype tegmina of Mesocixiodes brachyclada GSQ325 a, GSQ4 , Denmark Hill. Two additional tegmina: RK1 , RK2 , Dinmore.

Description. Tegmen 13.5–15.0 mm long (holotype 13.5), 3.8–4.5 mm wide (holotype 3.8), length/width 3.3– 3.8; some diffuse dark shading in the costal space, darker at the base (detected only in RK1, the holotype tegmen is entirely pale brown iron oxide stained).

Notes. Tillyard’s holotype GSQ325a and paratype GSQ4 of M. brachyclada ( Figs 16, 17 ) are poorly preserved, but their size and what can be detected of their venation almost perfectly match the larger specimen (RK2) of M. termioneura ( Fig. 15 ). A fourth Denmark Hill specimen, GSQ337a, in a box labelled (by Tillyard, or possibly Dunstan?) ‘ Mesocixiodes brachyclada T[illyard]... Paratype’, but not mentioned in the original description, preserves only the apical ⅔ of the anterior area of the tegmen. Compared with the five other specimens of M. termioneura , however, it is significantly larger, and has RA 2 curved posteriorly after RA 1 and extensively pectinately forked. It thus does not meet the diagnosis for Mesocixiodes , and indeed the form of RA is very similar to Scytachile Shcherbakov , a mesojaboniid from the Triassic Madygen Formation of Kyrgyzstan ( Shcherbakov 2011). Tillyard described a third Denmark Hill species in the genus, Mesocixiodes orthoclada Tillyard, 1922 , but this has now been transferred to the Dysmorphoptilidae as Mesonirvana orthoclada ( Tillyard, 1922) ( Lambkin 2016, 2017).

Figures

FIGURES 13–14. Mesocixiodes termioneura Tillyard, RK1 (mirrored).

FIGURES 15–17. Mesocixiodes termioneura Tillyard: 15, RK2; 16, 17, holotype GSQ325a and paratype GSQ4 of Mesocixiodes brachyclada Tillyard (both mirrored).