As a follow-up to an earlier paper (Watling 1981) all eumalacostracan orders (except Decapoda and Amphionidacea) are examined with respect to their carapace, compound eyes, mandible, maxilliped, blood system, and developmental patterns. On the basis of these features, the eumalacostracan orders are grouped into the following Superorders: Syncarida, Brachycarida, Isopoda, Amphipoda and Eucarida. Syncarida and Eucarida represent one phylogenetic lineage, Isopoda and Brachycarida a second, and Amphipoda a third. No basis is found for maintaining the Peracarida as a Superorder; the Mysidacea is considered to be a separate line of the Eucarida, the Isopoda is elevated as a distinct Superorder, and the remaining orders are grouped as the Brachycarida. |
