1. | Carapace and abdomen usually without large numbers of spines. |
2. | Posterolateral margins of carapace smooth, not produced posteriorly as spines and rarely overlapping more than abdominal somite 1. |
3. | Abdomen in mid- and late larvae with pleura of somite 2 overlapping those of somites 1 and 3. |
4. | Antennal exopod unsegmented (e.g. Fig. 2A) or in early larvae semented near distal end only (Fig. 3E). |
5. | Maxillipeds 1-3 present and with functional natatory exopod from hatching (except in some species with abbreviated development); endopod of maxilliped 1 shorter than that of maxilliped 2 which is shorter than that of maxilliped 3; basis of maxilliped 1 broad and flattened, with endopod at distal margin. |
6. | Telson dorsoventrally flattened; usually triangular in early larvae and parallel sided or tapering in mid- and late larvae; seta 2 not reduced to a small hair (Fig. 2E). |