Hyalella cajasi sp. n., male. A left gnathopod 1, medial (armature on palm margin of propodus and on dactylus omitted) B inset of carpal lobe, medial C inset of palm margin and palm angle of propodus, medial D inset of dactylus, medial E right gnathopod 2, medial (armature on palm margin of propodus and on dactlylus omitted) F inset of carpal lobe, medial G detail of palm margin and palm angle of propodus, and of dactylus, medial (submarginal armature along lateral side of palm margin omitted). Scale bars: 0.2 mm (A, G); 0.1 mm (B–D, F); 0.5 mm (E).