Fragment of a Pacific Lion's Paw or Pecten (probable Lyropecten subnodosus)
Phylum: Mollusca, Class: Bivalvia, Order: Pectinida, Family: Pectinidae, Genus: Lyropecten, Species: L. subnodosus · Pectinidae (Scallop family) · Bivalve (fragment); fan-shaped scallop. This appears to be a section of a valve near the ventral margin.
Species
Lyropecten subnodosus (Confidence: High for the genus based on Cabo origin, though the specimen is a fragment)
Shell Type
Bivalve (fragment); fan-shaped scallop. This appears to be a section of a valve near the ventral margin.
Family
Pectinidae (Scallop family)
Size
Approximately 1-1.5 inches in width. Based on the rib spacing, this is a fragment of a larger adult shell that would have been 4-8 inches in diameter.
Color & Pattern
The exterior is a weathered, sun-bleached off-white to pale lilac. In life, these are typically deep maroon, purple, or vivid orange. The interior (not fully visible but inferred) would be glossy and shaded with the shell's primary color.
Rarity
Common (as a fragment) to Uncommon (as a whole, perfect specimen). Fragments like this are very common on Cabo beaches after storms.
Habitat
Found in shallow to moderately deep water (subtidal to 150 feet) on sandy or rocky substrates, often near coral reefs or rocky outcrops.
Geographic Range
Eastern Pacific: From the Gulf of California (Cabo San Lucas/Baja California) southward to Peru.
Description
A thick, heavy fragment of a scallop valve showing distinct radial ribbing. The texture is coarse with prominent, raised ribs that show secondary striae (fine lines) running parallel to the main ridges. The edges are worn smooth by wave action, indicating it has tumbled in the surf for some time.
Key Features
Heavy calcification, broad and prominent radial ribs, and the distinctive sub-nodose structure where ribs meet the growth lines. The specific rib count and thickness are hallmarks of the Lion's Paw genus.
Collector Value
Minimal ($0-$1). While a whole, 6-inch 'Gem' grade Lyropecten subnodosus can sell for $50-$100, fragments serve primarily as sentimental beach mementos rather than investment pieces.
Condition Notes
Poor (Collector Grade). This is a beach-worn fragment rather than a complete specimen. It lacks the 'ears' (auricles) and the hinge. Significant weathering and sun-bleaching have removed the vibrant pigments and smoothed the rib texture.
Interesting Facts
The Lion's Paw is the largest scallop in the Eastern Pacific. They were historically used by indigenous peoples of the Baja peninsula for food and as bowls or scrapers due to their extreme thickness and durability.
Ecological Role
Active suspension feeders that filter plankton from the water. Their large, heavy shells provide a substrate for smaller encrusting organisms like barnacles and sponges.
Similar Species
Nodipecten nodosus (Western Atlantic Lion's Paw), which has more pronounced 'knobs.' This specimen's location in Cabo confirms it as the Pacific variant.
Beach Finding Tips
Look along the high tide line at Playa El Médano or the rocky coves near the Arch after a heavy swell. They are heavy and often settle in 'shell pockets' between rocks.
Notes
Cabo