Frog Shell / Fossilized Gastropod Shell (Bursa/Tutupha species)
cf. Bursa rubeta or Tutupha rubeta (Frog Shell) • Body fossil (invertebrate, molluscan gastropod)
Geological Period
Neogene to Quaternary (Miocene to Holocene / Recent)
Estimated Age
0 to 15 million years old (likely subfossil or recent modern shell)
Preservation Type
Unaltered original aragonite shell material or subfossilized calcium carbonate shell; retains original pigmentation, gloss, and surface micro-texture without sign of permineralization or replacement.
Condition Assessment
Very Good to Excellent condition; complete apex and main whorls with minimal beach wear, clear tuberculate sculpture, and vivid natural pigmentation.
Taxonomic Classification
Phylum Mollusca, Class Gastropoda, Subclass Caenogastropoda, Order Neogastropoda, Superfamily Tonnoidea, Family Bursidae
Morphological Description
Robust, thick-walled gastropod shell featuring coarse, prominent axial nodes and tuberculate ornamentation across the whorls. Shows a low spire with well-defined sutures, strong varices typical of the Bursidae family, and residual dark brown/reddish color patterns on a cream background.
Rock Matrix
None present (matrix-free specimen resting on a manufactured wood/laminate surface).
Formation & Location
Indo-Pacific marine realm; subfossil beds or coastal deposits in regions like the Philippines, Indonesia, or Queensland, Australia.
Size & Dimensions
Approximately 6 to 9 cm in total length, which is within the standard adult size range for medium-sized Bursidae gastropods.
Value & Rarity
Estimated Market Value
$5 - $20 USD
Auction Estimate
$10 - $25 USD
Rarity Assessment
Common (frequent in tropical marine environments and shell collections globally).
Scientific Significance
Low to Moderate; represents a well-preserved modern or subfossil marine gastropod showcasing typical Bursidae defensive morphology (thick shell and heavy nodular sculpture) used against predatory crabs and fish in tropical reef environments.
Preparation Recommendations
No invasive preparation needed. Dust gently with a soft brush; store out of direct sunlight to prevent UV degradation of residual shell pigments.
Notable Features
Remarkable preservation of original brown-and-white mottled color pattern and sharp nodular ornamentation along the varices.