Which other crab families are also placed here is a matter of some contention, and may be revised following molecular phylogenetic analyses.

[1] Their rather flat and smooth carapace is usually wider than long and of hexagonal, subhexagonal, rectangular, or transversely ovate shape.

The sutures of the sternum between segments 4 to 8 are usually incomplete, and in the Portunidae, the eighth sternite is usually visible if seen from below and has a penial groove.

[2] In males, the abdominal somites are either all free or the third to fifth are fused, often retaining the sutures though.

[citation needed] There are thirteen families in the superfamily Portunoidea, four of which are extinct:[1][3] It also contains the genus Garthopilumnus.