Red Swim Crab, Cronius ruber: The Red Swim Crab is characterized by having nine teeth-like extensions or spikes along the side of its hexagonally shaped shell that commence at the eyes and run to about halfway back on the shell or carapace.
The carapace of the Red Swim Crab is wider than it is long, reaching a maximum size of 3.75 x 2.25 inches. The spikes are anterolateral being of unequal size alternating between large and small. The Red Swim Crab's body is violet red in color with tan molting. The legs are striped. The tips of the spines on the claws are tipped in black.
The Red Swim Crabs are normally found up to 300 feet deep in the water column over a variety of bottom types including hard rock and coral structure. It is a global species found in abundance along the Atlantic coast of the United States and in all Mexican waters. It cannot be easily confused with another species.
The Red Swim Crab is a member of the Portunidae Family which are the swimming crabs known in Mexico as jaibas. The family has 16 individual species from five genera living in Mexican waters. Swim crabs are colorful and active crabs that are among the few crabs that are swift and agile swimmers. They swim sideways utilizing their paddle-like fifth pair (dactyl) of legs that rotate like propeller blades when they swim.
However, they are essentially bottom dwellers. They have a streamlined profile that allows for rapid swimming and long pincers armed with sharp spines to snag food. They are decapods with ten limbs. They consume clams, fish, snails, worms and other crustaceans. The commercially important Blue Crab, Callinectes sapidus, is the flagship member of this family.