The key provided by authors (see above) can be modified to accommodate Kiwaidae n. fam. as follows:
2. Abdomen folded up against thorax; body crab-like; chelipeds moderately elongate, stout or flattened................................................................................ Porcellanidae
— Abdomen folded up against itself (not against thorax); body shrimp-like; chelipeds greatly elongate, usually slender............................................................................ 3
3. Sternal plate on last thoracic somite, between last legs, well developed; telson without a transverse suture and not folded beneath the preceding abdominal somites with the tailfan; third maxilliped with epipod...................................... Galatheidae
— Sternal plate on last thoracic somite, between last legs, absent; telson with a transverse suture (sometimes difficult to see) and folded beneath the preceding abdominal somites with the tailfan; third maxilliped without epipod...................................... 4
4. Insertion of fifth pereopod clearly visible ventrally; sternite between third maxillipeds small, not produced anteriorly; eyes well developed; usually with antennal scale............................................................................................................ Chirostylidae
— Insertion of fifth pereopod not visible ventrally and situated beneath sternal plastron; sternite between third maxillipeds large, strongly produced anteriorly; eyes strongly reduced; antennal scale absent...................................................... Kiwaidae n. fam.