PERMOCHORISTINAE Tillyard, 1917

Lara, María Belén, Bomfleur, Benjamin, Brauckmann, Carsten, Unverfärth, Jan, Mörs, Thomas & Möllmann, Magali, 2025, A first Triassic insect from Antarctica (Eisenhower Range, northern Victoria Land), Antarctic Science (Cambridge, England) 37 (2), pp. 100-103 : 101

Subfamily PERMOCHORISTINAE Tillyard, 1917

( Fig. 2 )

Referred material

GXIII-SETI02-025 imprint of fragmentary forewing, with basal part missing.

Locality

Lower part of the Section Peak Formation (Upper Triassic), northern Eisenhower Range , northern Victoria Land , East Antarctica (74 º 14’50"S, 162 º 28’47"E; Fig. 1 ).

Description

The forewing is very small (with a preserved length of only 8.2 mm), sub-oval in shape and completely flattened; the membrane appears rather soft and without distinct corrugation or sculpture ( Fig. 2 ). The basal and apical regions are not preserved, and the basal connections of the main veins are not preserved. The anterior margin is slightly convex, with a long concave course at the distal end of R 1. The venation is strongly reduced, with only few, vaguely visible cross-veins. The Sc is short, very slightly sigmoidal and ending in the anterior margin far proximally from the midwing. The pterostigma (pt) is partially visible, in coloured pigment, and is nearly lanceolate and elongate. R 1 is long and straight, ending in the proximal third of the concave course of the anterior margin. Rs and M bifurcate at the same level. Rs is basally bifurcate at the level of the distal end of ScP, with five terminal branches (Rs 1 (bifurcated), Rs 2, Rs 3 and Rs 4) running parallel to each other and reaching the apical margin, with an additional short fork on Rs 1. Rs 1+2 is forked apical of the Rs 3+4 fork. Stem M is long, straight and divided into two main branches (MP 1+2 and MP 3+4) at the same level as the forking of Rs. M is five-branched (with additional forks on M 4). M 1+2 is forked distal of the bifurcation of Rs 1+2. CuA remains visible. There is a distinctive stained colour pattern in the forewing.

Figures

Figure 1. Field images of the new fossil locality. a. View west onto the escarpment of the Polar Plateau along the Eisenhower Range between Eskimo Point in the south and Mount NewZealand inthe north,with anarrow indicatingthe fossil siteon the Antarctic continent and an star marking the position of the outcrop where the specimen was collected.b. Mass accumulations of plant debris on a freshly exposed bedding surface at the new fossil site.Photographs by Jan Unverfärth.

Figure 2. Specimen GXIII-SETI02-025 (Mecoptera:Permochoristidae) from the lower part of the Section Peak Formation (Upper Triassic),northern Eisenhower Range, northern Victoria Land,East Antarctica.a. Photograph of the forewing.b. Line drawing of the forewing.Scale bar = 1 mm.See text for abbreviations.