But now a team of geologists directed by Joshua Smith, Ph.D., assistant professor of earth and planetary sciences at Washington University in St. Louis, have found a well-preserved fossil of a crab within inches of a tail vertebra from a massive plant-eating dinosaur.
Necrocarcinidae (crab) meet titanosaurian sauropod (dinosaur).
The find, in Egypt's Bahariya Oasis, is the first instance of a crab fossil found with a dinosaur fossil. It reveals much about both species and the kind of ecosystem where the fossils were found, thought to be a predator-rich mangrove setting dominated by tree ferns and other coastal plants, similar to Florida's swampy Everglades. The rocks containing these fossils are about 94 million years old, which means they date back to the Cretaceous Period, which lasted from 130-65 million years.
"The two normally don't hang with each other, or they are at least not commonly discovered together," said Smith, of crabs and dinosaurs. Smith made international news in 2001 when he and collaborators published results of their discovery of the second most massive dinosaur ever unearthed, Paralititan stromeri, in the same part of the Bahariya Oasis. "There have been anecdotal mentions of crabs with dinosaurs, but those remains turned out to be lobsters or ghost shrimp. Even if the time gap between the two is thousands of years, we have visual proof of these two coexisting together. This is a nice surprise. It fills in more about this kind of ecosystem."
The results are in a paper that will be published later this year in the Journal of Paleontology.
Smith and collaborators from the University of Pennsylvania discovered the fossils in 2001, on an expedition for dinosaur bones. They found a dinosaur tail bone, fossil plants and the crab, all within a foot-and-a-half of each other. Because there have been informal (though never published in peer-revie
Contact: Tony Fitzpatrick
Washington University in St. Louis