Freshwater Mussel or Zebra Mussel (Dreissena)
Dreissena polymorpha (Zebra Mussel) • Modern sub-fossil or extant biological remains; invertebrate bivalve
Geological Period
Holocene (Modern)
Estimated Age
0 to 0.01 million years (Modern/Recent)
Preservation Type
Original biogenic calcium carbonate (aragonite/calcite); minimal permineralization
Condition Assessment
Good; single valve is intact with visible color patterns, though slightly weathered by wave action.
Taxonomic Classification
Phylum: Mollusca, Class: Bivalvia, Order: Myida, Family: Dreissenidae, Genus: Dreissena
Morphological Description
Small, D-shaped shell with a pointed umbo. Displays visible concentric growth lines and faint dark zigzag striping pattern characteristic of the species. The shell has a distinct ventral flattening.
Rock Matrix
None; loose beach find. Associated with Quaternary lacustrine sediments (sand/silt).
Formation & Location
Sterling State Park, Lake Erie shoreline, Michigan. Found in recent Great Lakes beach deposits.
Size & Dimensions
Approximately 1.5 - 2.5 cm in length, which is a mature size for this invasive species.
Value & Rarity
Estimated Market Value
$0 - $1 USD
Auction Estimate
Negligible/Non-commercial
Rarity Assessment
Common; extremely abundant in the Great Lakes region due to high reproductive rates and lack of natural predators.
Scientific Significance
Low paleontological value but high ecological significance as an invasive species in the Great Lakes; used for tracking modern ecosystem shifts and water quality changes.
Preparation Recommendations
No specialized preparation needed. Can be cleaned with mild soap and water and stored in a dry container.
Notable Features
Retention of the 'zebra' striping which often fades quickly after death; typical 'D' shape allows the shell to sit flat on surfaces.
Notes
Found at Sterling State Park in Michigan