Deepwater Frog Crab, Raninoides benedicti 

Deepwater Frog Crab, Raninoides benedicti, Male. Crab provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, May 2013. Size: 5.5 cm (2.2 inches) x 2.6 cm 1.0 inch). Identification and related discussions courtesy of Dr. Christopher Boyko, American Museum of Natural History, New York City, New York.

General information:  The Deepwater Frog Crab, Raninoides benedicti, is a brachyuran crab and a member of the Raninidae Family, a family of unusual crabs, that are known as frog crabs due to their frog-like appearance and their habit of sitting on the bottom on the ocean like frogs. In Mexico they are known as cangrejo rana de aqua profundo. They are considered to be quite primitive and closely resemble the unrelated mole crabs due to parallel evolution or convergent evolution. Fossils of the family date to the Albian Period, 100 million years ago.

identification: The Deepwater Frog Crab has an elongated oval carapace (shell), with a smooth surfaced shell, that is slightly convex from side to side that are about twice as long as wide. The thorax is very wide and followed by a narrow shaped keel. The claws have been modified into digging tools and the body is rounded in shape that is easy to bury in sand. The eyes are small and on eyestalks. Unlike most other true crabs their abdomens are not curled under the cephalothorax. The Deepwater Frog Crab is a virtual unknown with only eleven different individuals documented within the literature to date.

Diet:  The Deepwater Frog Crabs are ambush predators burying themselves in the sand and waiting for unsuspecting prey. They are known to consume bivalves, other crabs, rays,  sardines, and squids.

Habitat and Range:  The Deepwater Frog Crab is found along the western coast and in the gulf of Mexico and their known range extends as far south as of Panama. They are found at depths between 1 m (3 feet) and 900 m (2,950 feet).

Conservation Status:  The Deepwater Frog Crab is exceedingly rare and has not been formally documented from a conservation perspective.