The genus Gigaxytes is characterized by:
1. Paraterga subspiniform, long.
2. Metaterga with three regular rows of tubercles/cones/spines.
3. Metaterga 2–17 with a long caudolateral spine on each side.
4. Male femora 5, 6 or 5, 6, 7 with an apophysis (except. G. gigas comb. nov. without apophyses).
5. Postfemur of gonopod absent (mesal and lateral sulci poorly developed).
6. Lamina lateralis (ll) indistinctly demarcated from lamina medialis (lm).
7. Lamina lateralis (ll) larger and longer than lamina medialis (lm).