Fossilized Manatee Rib Bone Fragment
Trichechus cf. antiquus or Trichechus sp. • Vertebrate body fossil (compact bone/osteosclerosis)
Geological Period
Neogene to Quaternary (Miocene to Pleistocene)
Estimated Age
5 to 2.5 million years old
Preservation Type
Permineralization and fossilization with dense mineral replacement, heavily tumbled and water-worn
Condition Assessment
Fair; heavily weathered, worn smooth by wave action with complete loss of articular ends, but structurally sound and solid
Taxonomic Classification
Phylum Chordata, Class Mammalia, Order Sirenia, Family Trichechidae, Genus Trichechus
Morphological Description
Elongated, cylindrical fragment exhibiting the characteristic dense, heavy, pachyosteosclerotic bone structure typical of sirenians. The surface is heavily water-worn and smoothed from wave action, showing no remaining periostal surface detail but retaining the solid, dense cortical bone interior common in marine mammal ribs.
Rock Matrix
None attached; recovered as a beach-worn pebble/cobble from marine or river deposits
Formation & Location
Found at Venice Beach, Florida, likely sourced from offshore Miocene-to-Pleistocene fossiliferous deposits such as the Peace River Formation or Tamiami Formation
Size & Dimensions
Approximately 10-15 cm in length and 3-4 cm in diameter, consistent with a mid-shaft rib fragment of an adult sirenian
Value & Rarity
Estimated Market Value
10 to 25 USD
Auction Estimate
5 to 15 USD
Rarity Assessment
Common; sirenian (manatee/dugong) bone fragments are frequently found by beachcombers and divers along the Gulf Coast of Florida
Scientific Significance
Provides evidence of past sirenian populations in the shallow marine and estuarine environments of ancient Florida during the Neogene/Quaternary periods
Preparation Recommendations
No preparation required as it is already fully exposed and weathered; clean gently with fresh water and mild soap if needed, and store in a dry environment
Notable Features
Exhibits extreme bone density (pachyostosis) which evolutionarily helps marine mammals maintain neutral buoyancy; displays a classic polished beach-worn patina
Notes
Vince beach Florida