Diastylis

Key to the New Zealand species of Diastylis

1. Carapace with few large spines anteriorly.................................................................. 2

- Carapace with small spines or none....................................................................... 3

2. Carapace with 4 large equal spines anteriorly; pereonite 5 and pleonite 1 with small or no ventral teeth D. homoacanthus n. sp.

- Carapace with 2 large spines with smaller spines between anteriorly; pereonite 5 and pleonite 1 each with large ventral tooth......................................................................................... D. curtain n. sp.

3. Carapace with multiple parallel ridges sweeping dorsally to anteroventrally........................... D. neozealanica

- Carapace without such ridges............................................................................ 4

4. Carapace with many spines.............................................................................. 5

- Carapace entirely without spines......................................................................... 10

5. Carapace with small spines only on anterior half.................................................. D. dasys n. sp.

- Carapace with spines throughout......................................................................... 6

6. Spines organized in lines............................................................. D. spinacellulosus n. sp.

- Spines scattered and unorganized......................................................................... 7

7. Telson less than 0.5 times length of uropod peduncles............................................... D. insularum

- Telson more than 0.5 times length of uropod peduncles........................................................ 8

8. Antennule article 3 longer than article 2................................................. D. acanthoelachys n. sp.

- Antennule article 3 shorter than article 2................................................................... 9

9. Anterior ventral margin of carapace strongly toothed; carapace, pereon and pleon with few setae..... D. adaioacanthus n. sp.

- Anterior ventral margin with few weak teeth; carapace, pereon and pleon with many setae.................. D. acuminata

10. Carapace smooth with few setae; telson with 10–11 pairs lateral setae................................ D. enodis n. sp.

- Carapace rugose, with single partial lateral ridge; telson with 4–5 pairs lateral setae................... D. implanus n. sp.