SUPERORDER : NATANTIA

Key to the infraorders

1. pleura of the second abdominal segment not overlapping those of first segment ........1

The pleura of the second abdominal segment overlap those of first and third segment ....... CARIDEA

2. Third pair of chelate legs normal ....... PENAEIDEA

One or both third pair of chelate legs are longer and much stouter than those of the first two pairs of leg

..........STENOPODIDEA

INFRAORDER : PENAEIDEA

Key to the Superfamilies

Last two pairs of walking legs well developed, gills many ............ PENAEOIDEA

Last one or two pairs of walking legs reduced or absent, gills few or wanting ......... SERGESTOIDEA

INFRAORDER : CARIDEA

Key to the Superfamilies

1. Fingers of the chela are spoon shaped and with brushes of long hairs ....... OPLOPHOROIDEA

Fingers of the chela noramal ........2

2. 1. Carpus of the second pair of legs not subdivided ........3

Carpus of the second pair of legs subdivided .............4

3. 2. First pereopods with normal chelae .............. PALAEMONOIDEA

First pereopods subchelate ............ CRANGONOIDEA

4. 2 Chelae of the first pair of pereopods small or absent ....... PANDALOIDEA

Chelae of the first pair of pereopods prominent ...... ALPHEOIDEA

KEY TO FAMILIES OF PRAWNS AND SHRIMPS

1. The third pereopods are chelate .

The pleurae of the second abdominal segment not overlapping those of first segment. Abdomen generally does not have sharp bend .........2

The third pereopods are not chelare. The pleurae of the second abdominal segment overlapping those of first and third segments. Abdomen generally has a sharp bend. ...........7

2. 1. Last two pairs of walking legs well developed, gills many .........3 Last one or two pairs of walking legs reduced or absent, gills few or wanting .... SERGESTIDAE

3. 2. Third pair of legs are normal and gills are dendrobranchiate ............4

One or both legs of the third pairs are longer and much stouter than those of the first two pairs, gills are trichobranchiate .......... STENOPODIDAE

4. 3. Post-orbital spine present ......... SOLENOCERIDAE

Post-orbital spine absent ..............5

5. 4. Carapace with a median dendate crest extending nearly or quite to the posterior margin ..... SICYONIIDAE

Carapace without a dendate crest except occasionally over the eyes .........6

6. 5. No distinct median tubercle or ocular peduncle; upper antennular flagellum subequal to lower one, attached to apex of third antennular segment ........ PENAEIDAE

7. 1. The finger of the chela are spoon-shaped and terminating in conspicuous brushes of long stiff hairs ..... ATYIDAE

The fingers of the chela are normal and no stiff hair on the terminal part of the chela .....8

8. 7. The carpus of the second pairs of legs are not subdivided or entire ........9

The carpus of the second pair of leg divided into two or more articles. ....10

9. 8. First pereopods subchelate and the rostrum is short .............. CRANGONIDAE

First pereopods with normal chela and the rostrum is long ....... PALAEMONIDAE

10. 8. Usually right first peropod chelate, left ending in simple claw like dactylus. In both chelate, rostrum with distal setose notch formed by subdistal dorsal tooth ........ PROCESSIDAE

Chelae of first pair of pereopods distinct on both sides, ends of fingers of this chela usually dark coloured, eyes free, never extremely elongate ......... HIPPOLYTIDAE

Chela of first pair of pereopods microscopically pereopods small and slender ....... PANDALIDAE