1 a. Spiracle present on first pedigerous segment.................................................................. .................................................................... macfaydeni Eason, 1993 [Falkland Islands]
1 b. Spiracle lacking on first pedigerous segment................................................................ 2
2 a. Leg 14 and 15 prefemur bearing a ventrodistal spur.................................................... 3
2 b. Leg 14 and 15 prefemur lacking a ventrodistal spur..................................................... 6
3 a. Leg 15 trochanter lacking ventrodistal spur........................................................................................................................................... productus Silvestri, 1899 [Chile: Temuco]
3 a. Leg 15 trochanter with ventrodistal spur....................................................................... 4
4 a. Coxal pores 2,2 on legs 14 and 15 of males.................................................................. 5
4 b. Coxal pores 1,1 on legs 14 and 15 of males................................................................... ....... patagonicus Silvestri, 1909 [Argentina: Santa Cruz; South Africa: Western Cape]
5 a. Dental margin of maxillipede with up to 8 + 8 teeth; maxillipede pleurite collar with weak median suture; leg 15 basitarsus 67 times longer than maximal width............... .......... neozelanicus Silvestri, 1909 [New Zealand, Auckland Islands, Chatham Island]
5 b. Dental margin of maxillipede usually with 5 + 5 teeth (maximum 6 + 6); maxillipede pleurite collar with subtrapezoidal median sclerite; leg 15 basitarsus 3.5 4 times longer than maximal width ....................... wrighti n. sp. [Australia: New South Wales]
6 a. Dental margin of maxillipede with 6 + 6 teeth and narrow, deep median notch; porodont between two outer teeth.............................. diversus Chamberlin, 1962 [Chile: Chiloé]
6 b. Dental margin of maxillipede with 5 + 5 teeth and broadly Vshaped median notch; porodont distal to outer tooth............................... actius Chamberlin, 1962 [Chile: Chiloé]