From Science:
As a northeasterly wind whips against the shore, a meters-long dinosaur plunges into the shallow lake. Working hard, the predator takes strong strides with its hind limbs through the shoulder-deep water. The current is so strong that the beast must constantly fight to stay on course, but it succeeds, heading straight across the water. That’s the story told by a remarkable set of fossilized footprints, described in the June issue of Geology, that provide the first hard evidence of predatory dinosaurs traveling in water.
The 125-million year-old trackway was discovered in 2004 during excavations at a famous fossil site in Northern Spain, called the La Virgen del Campo track site. The site had yielded many tracks of dinosaurs walking on land, so a team led by paleontologists Rubén Ezquerra of the Fundación Patrimonio Paleontológico de La Rioja, Spain, and Loïc Costeur of the Université de Nantes came looking for more in an untapped layer of rock. To their surprise, they found a set of footprints unlike any they had seen before.
With three telltale toemarks on each print, the tracks clearly belonged to a major group of bipedal, carnivorous dinosaurs called theropods. But the tracks themselves were different. When theropods walk on land, they typically leave claw marks and an imprint of the foot itself. The lack of the footprint suggested that this animal was not supporting its weight. A sedimentologist on the team confirmed that ripple marks in the stone had been created by currents in water 3.2 meters deep.
More here.