The New York Times' Science column Trilobites has a story about a new theory as to how Spinosaurus made a living. Spinosaurus lived about 100 million years ago, during the Cretaceous Period, in what is now North Africa. Its bones were first discovered in 1915. Ever since, due to some bizarre features, there have debates about how the animal lived. Back in 2014, paleontologist Nizar Ibrahim announced the discovery of a new specimen and proposed that it lived an aquatic lifestyle, partially due to its dense bones, tail configuration, and short hind limbs. Last year, Dr, Ibrahim's team bolstered that theory when they published another paper. This one described the discovery of a finned, eel-like tail. Now, a new paper in the journal Palaeontologica Electronica co-authored by Dr. Thomas Holtz and Dr. David Hone, proposes that Spinosaurus lived like a gigantic wading bird.
“Real aquatic pursuit predation is a very challenging lifestyle,” said Thomas Holtz Jr., a predatory dinosaur specialist at the University of Maryland and a co-author of the new paper. Aquatic predators like otters, sea lions or sharks have compact, smooth bodies that reduce underwater drag.
According to David Hone, a paleontologist at Queen Mary University of London and a co-author with Dr. Holtz, earlier research by Dr. Ibrahim’s team had shown that spinosaurus had a relatively small number of tail muscles, Dr. Hone said, even fewer than crocodiles, which also tend to have trouble with drag and aren’t particularly effective at pursuing prey underwater. With its tall sail and bulky limbs, spinosaurus would have produced tremendous drag in anything but the deepest water, making swift subaquatic chases extremely difficult.
Instead, the team points to a different set of traits. Spinosaurus had nostrils back on its long snout, like a heron, Dr. Hone said, rather than atop its face, like a crocodile. It had broad feet, like a stork, as well as a head and neck adapted for a strong downward strike. Isotopic evidence from spinosaurus teeth also suggests that at least some individuals were eating fully terrestrial prey, perhaps including other dinosaurs.
