Prehistoric dinosaurs along ancient coastlines may have consumed seaweed and other marine resources washed onto beaches 100 million years ago, according to ScienceDaily.
“We show that coastal terrestrial organisms in the greenhouse climates of the Cretaceous relied on marine resources to supplement their diets in a similar way that modern organisms do,” said first author Dr. Clayton Forster, a geologist at the University of Arkansas, in a study published in Frontiers in Ecology and Evolution suggesting this relationship between land and sea existed during the age of dinosaurs.
Scientists call this process marine subsidization. It occurs when powerful storms deposit ocean material along shorelines to provide extra food for land animals.
The study examined remains from sites along the shores of the Western Interior Seaway and the ancient coastline of the Gulf of Mexico. Around 100 million years ago, that enormous inland sea divided North America into two separate landmasses, ScienceDaily reported.
The team analyzed dinosaur, fish, and crocodile fossils by measuring carbon isotope signatures, known as δ13C, in powdered tooth enamel. Coastal fossils consistently contained higher values than inland samples. These values remained similar across different locations regardless of latitude or geological age.
The chemical pattern appeared across a wide variety of animals. “This pattern is shared from fish to megaherbivores and indicates that the extra carbon source must have been low in the food-chain to affect both aquatic and terrestrial animals,” Forster explained, indicating the extra carbon source entered the food chain near its base.
ScienceDaily said marine macroalgae or macrophytes—seaweed—emerged as the most likely explanation. Few other organisms exist exclusively along coastlines while remaining available for millions of years.
Forster said, according to ScienceDaily, that large coastal herbivores today almost universally supplement their diets with seaweed. “Given the almost ubiquitous behavior of large coastal herbivores today to supplement their diet with seaweeds, it's likely that most of the sampled herbivorous dinosaurs were no different,” Forster said, noting it is probable that the majority of the herbivorous dinosaurs examined behaved in the same way.
Not every dinosaur took advantage of those coastal resources. One notable exception was Tenontosaurus tilletti, whose tooth enamel contained values comparable to modern animals feeding strictly on land plants, ScienceDaily reported. This finding contrasts with the 100 million-year-old record of coastal feeding habits.
Earlier coverage: Meet Infernogallus: The Rare 'Hell Chicken' Dinosaur That Ate Fruit
