Eriphioidea is a superfamily of crab

Crab

True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...

s, containing the six families Dairoididae, Eriphiidae, Hypothalassiidae, Menippidae

Menippidae

Menippidae is a family of crabs of the order Decapoda.-Genera:*Menippe De Haan, 1833*Myomenippe Hilgendorf, 1879*Pseudocarcinus H. Milne-Edwards, 1834*Ruppellioides A. Milne-Edwards, 1867*Sphaerozius Stimpson, 1858...

, Oziidae and Platyxanthidae. They are united by a number of characters, including a marked difference in size between the left and right claw

Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...

s, where the larger one has a crushing tooth, and the smaller one does not, and the relative breadth of the male abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

.