Caprellidae, Leach, 1814

Guerra-García, J. M., 2006, Caprellidae (Crustacea: Amphipoda) from the Great Barrier Reef and Adjacent Localities, Records of the Australian Museum 58, pp. 417-458 : 422-423

Key to the species of Caprellidae from the Great Barrier Reef and adjacent localities

This key can be used without dissection but should be used in conjunction with Figs 3–6

1 Gills present on pereonites 2, 3 and 4 ............................................................................................ 2

—— Gills present on pereonites 3 and 4, absent on pereonite 2 ......................................................... 10

2 Pereopods 3 and 4 six-articulate .................................................................................................... 3

—— Pereopods 3 and 4 absent or reduced to a tiny article ................................................................... 6

3 Pereopod 5 four-articulate ............................................................................................................. 4

—— Pereopod 5 five-articulate .............................................................................................................. 5

4 Antenna 1 clearly shorter than the body. Pereopods 3 and 4 shorter than pereonites 3 and 4 combined. Propodus of the male gnathopod 2 with a triangular projection ........................................... Quadrisegmentum triangulum ( Fig. 39)

—— Antenna 1 as long as body. Pereopods 3 and 4 longer than pereonites 3 and 4 combined. Propodus of the male gnathopod 2 without triangular projection ............................................ Quadrisegmentum lowryi ( Figs 34–38)

5 Abdomen with a pair of appendages .................................. Metaproto novaehollandiae ( Fig. 23)

—— Abdomen without appendages .......................................................... Pseudoproto fallax ( Figs 33)

6 Pereopod 5 absent or reduced to one tiny article .......................................................................... 7

—— Pereopod 5 present, three to six-articulate .................................................................................... 8

7 Body smooth, without acute dorsal projections ............................ Hircella berentsae ( Figs 7–11)

—— Body with acute dorsal projections ................................................... Hircella cornigera ( Fig. 12)

8 Pereopods 3 and 4 reduced to one tiny article. Flagellum of antenna 1 2-articulate. Body geniculate .................................................... Perotripus keablei ( Figs 24–27)

—— Pereopod 3 and 4 absent. Flagellum of antenna 1 more than 2- articulate. Body not geniculate ...................................................................................................... 9

9 Pereonite 3 with a pair of well-developed projections ...... Mayericaprella arimotoi ( Figs 18–22)

—— Pereonite 3 without projections ................................................. Jigurru vailhoggett ( Figs 13–17)

10 Pereopods 3 and 4 six-articulate ....................................................... Protogeton inflatus ( Fig. 28)

—— Pereopods 3 and 4 absent or reduced to one or two articles ....................................................... 11

11 Pereopods 3 and 4 absent ............................................................................................................. 12

—— Pereopods 3 and 4 reduced to one or two articles ....................................................................... 14

12 Pereopod 5 3-articulate .................................................. Pseudoprellicana johnsoni ( Figs 29–32)

—— Pereopod 5 six-articulate ............................................................................................................. 13

13 Head with a well-developed rostrum .................................................. Caprella penantis ( Fig. 42)

—— Head with a small rostrum ............................................................... Caprella danilevskii ( Fig. 41)

14 Pereonites 6 and 7 fused .......................................................... Metaprotella sandalensis ( Fig. 44)

—— Pereonites 6 and 7 not fused ........................................................................................................ 15

15 Head and/or body with dorsal projections ................................................................................... 16

—— Head and body completely smooth dorsally ............................................................................... 18

16 Pereonite 4 2-articulate .............................................................. Aciconula australiensis ( Fig. 40)

—— Pereonite 4 one-articulate ............................................................................................................ 17

17 Head with two acute projections. Body smooth ......................... Orthoprotella australis ( Fig. 45)

—— Head with a single acute projection. Body with numerous rounded projections ............................................................................ Pseudaginella biscaynensis ( Fig. 54)

18 Pereopods 3 and 4 2-articulate ..................................................................................................... 19

—— Pereopods 3 and 4 one-articulate ................................................................................................. 20

19 Pereopods 3 and 4 minute, shorter than half length of gills .................. Paracaprella sp. ( Fig. 52)

—— Pereopods 3 and 4 longer than half length of gills ........................ Orthoprotella mayeri ( Fig. 46)

20 Suture between head and pereonite 1 absent. Pereonite 2 with acute ventral projection between gnathopod 2 ................................ Hemiaegina minuta ( Fig. 43)

—— Suture between head and pereonite 1 present. Pereonite 2 without acute ventral projection ................................................................................................................ 21

21 Peduncle of antenna 1 distinctly longer than half body length ............... Protella similis ( Fig. 53)

—— Peduncle of antenna 1 about 1 ⁄ 3 body length ........................... Orthoprotella pearce ( Figs 47–51)