Key to the known species of Waematau Duncan, 1994 .

1. Uropod 1 distolateral robust seta enlarged (> 0.2 times length of outer ramus); pleopod 2 with rami present..............2

- Uropod 1 distolateral robust seta not enlarged (<0.2 times length of outer ramus); pleopod 2 vestigial, peduncle reduced, rami absent................................................................................ Waematau unuwhao

2. Pleopod 3 weakly to well-developed and biramous...........................................................3

- Pleopod 3 vestigial, peduncle reduced, rami absent...........................................................6

3. Uropod 3 peduncle compressed laterally into laminate faecal guide guarding sides of telson...........................4

- Uropod 3 peduncle not laminate..........................................................................5

4. Pleopod 3 rami minute (1–2 segments), difficult to observe.................................. Waematau muriwhenua

- Pleopod 3 rami small but distinctive......................................................... Waematau kaitaia

5. Propodus of gnathopod 1 subchelate; uropod 1 peduncle mesial and lateral margins with 3 or more robust setae each; uropod 3 peduncle with 2 robust setae........................................................... Waematau manawatahi

- Propodus of gnathopod 1 subsimple, palm very short and indistinct; uropod 1 peduncle mesial and lateral margins with no more than 2 robust setae each; uropod 3 peduncle with 1 robust seta................... Waematau ringanohinohi sp. nov.

6. Gill of pereopod 6 with subapical lobe; mesial margin of uropod 1 peduncle with 1 subapical robust seta; lateral margin of uro- pod 2 peduncle with 1 dorsal robust seta and 1 subapical robust seta; uropod 3 ramus approximately 0.7 times length of pedun- cle, with a lateral robust seta distally......................................................... Waematau reinga

- Gill of pereopod 6 without subapical lobe; mesial margin of uropod 1 peduncle with at least 1 dorsal robust seta and 1 subapi- cal robust seta; lateral margin of uropod 2 peduncle with 2 dorsal robust setae and 1 subapical robust seta; uropod 3 ramus 0.5– 0.6 times length of peduncle, without a lateral robust seta distally...............................................7

7. Propodus of gnathopod 1 subchelate, dactylus equal to (males) or slightly longer than (females) palm; mesial margin of uropod 1 peduncle with 1 dorsal robust seta and 1 subapical robust seta........................... Waematau kohuroa sp. nov.

- Propodus of gnathopod 1 subsimple, palm very short or indistinct; mesial margin of uropod 1 peduncle with 2 dorsal robust setae and 1 subapical robust seta....................................................... Waematau rereke sp. nov