Fossilized Plesiosaur Vomit Reveals Jurassic Feeding Habits
Ancient marine reptile's diet uncovered through fossilized regurgitation in North Sea cores.
1Unique fossil discovery
Geologist Dr. Dirk Knaust identified fossilized plesiosaur vomit (regurgitalites) in rock cores drilled beneath the North Sea. These rare specimens, preserved in Middle to Upper Jurassic layers, provide unprecedented insights into the feeding behaviors of these marine reptiles. The discovery was made near the Troll oil and gas field on the Horda Platform, where energy company Equinor operates.
2Composition reveals diet
The regurgitalites contain a tightly packed mix of broken and whole shells from bivalves, serpulid worm tubes, and crinoid fragments, along with fossilized wood bits. These components show clear signs of having passed through a predator's digestive system, including corroded shell surfaces and an unnatural mix of species that wouldn't occur together naturally in one location.
3Salinity mismatch puzzle
The fossilized vomit contains creatures that required full ocean salinity, yet was found in delta deposits where fresh water diluted seawater. This indicates the plesiosaur carried its food remains from farther offshore into shallower, brackish waters before regurgitating them. Such behavior parallels modern marine mammals like seals and dolphins.
4Cryptoclididae connection
Based on tooth shape, feeding style, and preserved stomach contents from related species, researchers attribute these regurgitalites to Cryptoclididae plesiosaurs. These long-necked, small-headed marine reptiles likely foraged along the seafloor for clams and worms offshore before swimming shoreward to regurgitate indigestible material.
5First systematic classification
Dr. Knaust formally named this new trace fossil type 'Vomitus' and identified three varieties based on dominant contents: bivalve-rich, serpulid worm tube-dominated, and crinoid fragment-heavy. While similar clumps have been found globally over the past century, these represent the first documented in continuous drill-core material.
6Research significance
Most prior fossilized vomit research focused on vertebrates eating other vertebrates. This marks the first identification of plesiosaur vomit and its shellfish contents. The findings provide crucial evidence about plesiosaur abilities and behavior, filling gaps in our understanding of Jurassic marine ecosystems.
7Historical misidentification
Similar fossil clumps discovered over the past century were often mistaken for storm deposits or fecal material. The Norwegian specimens represent a breakthrough as they were found in situ within drill cores, allowing for proper context and systematic classification that previous isolated finds lacked.
8Future research potential
These findings open new avenues for understanding prehistoric marine life through regurgitalite analysis. As Dr. Knaust notes, this is just the beginning - fossilized vomit can reveal much more about extinct animals' diets, behaviors, and ecosystems when studied systematically rather than as curiosities.