Light and Electron Microscopy Study of Opportunistic Free-Living Nematodes Scavenging and Thriving within Buried Dinosaur Bones

Nematode worms are the most abundant multicellular organism on Earth. They thrive in every habitat known, and they are voracious feeders within the top 70 cm of soils. Their sturdy cuticle protects them from environmental factors and predators. Nematodes play a significant role in the decomposition of vertebrate remains in soil and serve as indicators of nutrients that enter soils during decomposition. Certain parasitic nematodes have been identified in fossil remains, but reports of fossil worms are rare. We demonstrate the abundant presence of opportunistic nematodes feeding within dinosaur bones from the Hell Creek formation, MT. The presence of visible worm ultrastructure indicates that they were alive when preserved within the dinosaur bones. Our findings are identical to worms characterized as “blood parasites” in a dinosaur bone from Brazil, demonstrating that there is sufficient soft tissue within dinosaur bone canals to sustain large populations of nematodes post-mortem.