Stems arborescent, to 8 m tall, 5-10 cm diam. at narrowest point.
Leaves bright green, highly glossy or semiglossy, 115-160 cm long, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with 130-190 leaflets, tomentum shedding as leaf expands. Petiole 25-45 cm long (25-30% of total leaf), petiole glabrous, spinescent for 70-100% of length. Basal leaflets not gradually reducing to spines, 170 mm long.
Median leaflets simple, strongly discolorous, 200-300 mm long, 7.5-11 mm wide, inserted at 45° to rachis, decurrent for 6 mm, narrowed to 2.5 mm at base (to 30% of maximum width), 11.5 mm apart on rachis; median leaflets section flat; margins slightly recurved; apex aristate, spinescent; midrib flat above, raised below.
Cataphylls pilose, persistent.
Pollen cones ovoid, orange, 13-20 cm long, 5.5-8 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 20-30 mm long, 16-20 mm wide, fertile zone 18 mm long, sterile apex 5 mm long, level, apical spine prominent, sharply upturned, 10-11 mm long.
Megasporophylls 15-32 cm long, brown-tomentose; ovules 4-6, glabrous; lamina orbicular, 35-50 mm long, 35-50 mm wide, shallowly pectinate, with 8-20 soft lateral spines 15-17 mm long, 1 mm wide, apical spine distinct from lateral spines, 40 mm long.
Seeds ovoid, 39-40 mm long, 29-31 mm wide; sarcotesta yellow, 3 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.