Identification Photos: Panamic Arrow Crab, Stenorhynchus debilus: The Panamic Arrow Crab is a common decapod (with ten legs) that is found in most tropical waters and is a member of the Inachidae Family.

It is found in rocky, intertidal (between the high and low tide) regions in and near reef crevices. The Panamic Arrow Crab is characterized by a triangular carapace (shell) and very long spider-like arms and legs. It is redish-brown in color.

The shell of the Panamic Arrow Crab reaches a maximum of 1 inch and it can reach a full 4 inches across when the legs are extended.

The Panamic Arrow Crab is an active nighttime predator preying predominately on algae and gastropods (mostly snails). It is found in all Mexican waters and during years with an El Niño it can be found in the coastal waters of southern California.

Panamic Arrow Crab, Stenorhynchus debilus: Collected from a tidal pool at El Tule, Km. 17, San Jose del Cabo, Baja California Sur, Mexico, in February 2007. Size approximately 0.75 inch. Description and photo courtesy of John Snow.