Pacific Lion’s Paw Shell, Nodipecten subnodosus

Pacific Lion’s Paw Shell, Nodipecten subnodosus, Juvenile, Right Valve. Shell collected off the beach at Punta Chivato, Baja California Sur, May 2025. Size: 3.9 cm (1.5 inches) x 3.8 cm (1.5 inches) x 0.9 cm (0.4 inches). Photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Pacific Lion’s Paw Shell, Nodipecten subnodosus, Juvenile, Left Valve. Shell collected off the beach at Punta Chivato, Baja California Sur, May 2025. Size: 5.0 cm (2.0 inches) x 4.5 cm (1.8 inches) x 1.1 cm (0.4 inches). Photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Pacific Lion’s Paw Shell, Nodipecten subnodosus. Shell collected off the beach at Punta Chivato, Baja California Sur, January 2023. Size: 12 cm (4.6 inches) x 12 cm (4.6 inches). Photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Pacific Lion’s Paw Shell, Nodipecten subnodosus. Shell collected off the beach of Punta Chivato, Baja California Sur, March 2025. Size: 9.4 cm (3.7 inches) x 9.5 cm (3.7 inches) x 1.8 cm (0.7 inches). Collection, photographs and identification courtesy of Colin Campbell, DVM, Punta Chivato.

Phylogeny: The Pacific Lion’s Paw Scallop, Nodipecten subnodosus (G.B. Showerby, I, 1835), is a bivalve mollusk that is a member of the Pectinidae Family of Scallops Shells. The genus Nodipecten is one of sixty-four genera in this family, and there are eleven species in this genus. They are also known as the Giant Lion’s Paw and the Lion’s Paw Scallop and in Mexico as Almeja Mano de Leon and Peine Catalina.

Description: Pacific Lion’s Paw Scallop shells are sturdy, with rounded or fan-shaped valves. They have pronounced auricles (ears) at the hinge. They have ten or eleven  broadly rounded radial ribs are often marked with nodules or knobs. The exterior of the shell is covered with many radiating fine lines. They vary significantly in color and can be gray, orange, pink, or reddish-brown in color. The Pacific Lion’s Paw is the largest of the free-swimming scallops found in the region. The Pacific Lion’s Paw Scallop Shell and can reach a maximum of 20.3 cm (8.0 inches) in length and 18.8 cm (7.4 inches) in height.

Habitat and Distribution: Pacific Lion’s Paw Scallops are found resting on sand or mud bottoms from the low intertidal zone to depths up to 110 m (360 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean with the exception that they are absent north of Isla Salvatierra, Baja California. Some sources extend the range within the Sea of Cortez as far north as Puerto Peñasco, Sonora.

Ecology and Behavior:  Pacific Lion’s Paw Scallops are suspension feeders that feed primarily on planktonic micro algae. They are hermaphrodites and reproduce sexually, through broadcast spawning, with external fertilization. They are known to host boring polychaetas of the genus Polydora, and various pycnogonids (sea spiders) as parasites. There is no mention of them engaging in any types of commensal or symbiotic relationships. They are edible and are fished and farmed. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms:  Lyropecten intermedius, Lyropecten subnodosis, Nodipecten subnodosus intermedius, Nodipecten subnodosus subnodosus, Pecten arthriticus, and Pecten subnodosis.