Mesocixiodes 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 : 533-534

Mesocixiodes Tillyard, 1922

Mesocixiodes Tillyard, 1922: 462 .

Type species. Mesocixiodes termioneura Tillyard, 1922 , by original designation.

Emended diagnosis. Tegmen c. 3.5 times longer than wide, finely to somewhat coarsely punctate and tending to irregularly transversely rugose, extreme apical area possibly less so; costal margin broadly rounded, apex narrowly rounded; peripheral membrane of even width; costal space c. 3 times as wide as medial cell; R and M separating near apex of basal cell; basal cell quite broad proximally, slightly tapering and closed distally by a fusion for a short length of M and CuA; primary fork of R just before tegmen length, far basal to primary fork of M which is well beyond primary fork of RA and just proximal to very shallow CuA fork; RA 1 simple, obliquely angled towards anterior margin; RA 2 stem directed apically, more or less parallel with costal margin, with 4 or 5 long, sub-equal pectinate branches directed antero-apically; RA 1 + RA 2 field occupying entire antero-apical margin; RP deeply forked; one ir, running from RA 2 to RP 1; RP 2 fused with M 1+2 for a short length ( RK1 and RK2 ), or separate, with a single r-m, in line with ir (holotype); M with 4 or 5 branches; im between M 2 and M 3 or M 3+4;intra-medial cell quite broad but very small, c. 2 times longer than wide, occupying a very small portion of post-nodal area; CuA branches short, CuA 1 strongly angled at m-cua which joins M 3+4 around midpoint of intra-medial cell; crossvein field tending to alignment at level of claval apex, thus creating a fairly even series of long, sub-equal apical cells; clavus not preserved .

Notes. Mesocixiodes was placed by Tillyard (1922, 1926), Becker-Migdisova (1962a), and Jell (2004) in Cixiidae (Fulgoroidea) , by Handlirsch (1939) in Fulgoridae , by Evans (1956) in Chiliocyclidae , and was considered by Carpenter (1992) as ‘Family uncertain’. It was transferred to Hylicellidae by Hamilton (1992). It differs from all other hylicellids in the very late forking of M, well distal of that of RA, the very small intra-medial cell, and the tendency to alignment of the crossvein field at the claval apex to create a fairly even series of long, sub-equal apical cells.