Sauropods had soft pads to help them support their massive weight

Ask people to think of a dinosaur, and they'll probably name Tyrannosaurus Rex, the carnivorous antagonist that features prominently in Jurassic Park and Jurassic World film franchises. But an equally well-known clade of dinosaurs are the herbivorous sauropods, which include Brachiosaurus, Diplodocus, Apatosaurus, Argentinosaurus, and Brontosaurus. According to a new paper published in the journal Science Advances, Australian paleontologists have digitally reconstructed these plant-munching giants to better understand how their feet managed to support their enormous weight.

"We have finally confirmed a long-suspected idea and provide, for the first time, biomechanical evidence that a soft tissue pad, particularly in their hind feet, may have played a crucial role in reducing locomotor pressures. and bone stresses," said co-author Andreas Jannel, who worked on the project while pursuing doctoral studies at the University of Queensland. "It's mind-blowing to imagine that these giant creatures could have supported their own weight on earth."

Sauropods (clade name: Sauropoda, or "lizard-footed") had long-necked, long-tailed bodies that made them the longest animals to walk the Earth. They had thick, powerful hind legs, club-shaped feet with five toes, and thinner forearms. It is rare to find complete sauropod fossils, and even those that are mostly complete still lack heads, tail tips, and limbs. Scientists have nevertheless managed to learn a lot about them, and digital reconstruction is proving to be a valuable new tool to further advance our knowledge.

For example, in 2013, researchers digitally reconstructed the Argentinosaurus to test its locomotion abilities. Previous assessments of the likely speed of the sauropod relied heavily on the study of bone histology and evidence from trace fossils (particularly footprints). The digital skeleton took into account the location (and overlap) of muscles and joints when calculating the animal's gait and speed. The team concluded that Argentinosaurus would have had a top speed of around 5 mph (2 m/s) just because of its size and weight.

[embedded content] Sauropods were thought to walk like elephants, but a new way of analyzing footprints shows that their gait most resembled that of a hippopotamus.

Many paleontologists had assumed that sauropods walked with a gait similar to that of elephants. But a study published earlier this year by British scientists challenged that assumption, arguing that the sauropod's frame was too large to maintain balance with such a gait. They based their conclusion on a new method of footprint analysis that examines how footsteps vary from stride to stride to determine the timing of each step. They compared the tracks of sauropods with those of various modern animals.

The gait of the sauropod did not match any of them, although the gait of the hippopotamus - another heavy animal with widely spread legs - was the closest. As for the elephant, its gait was actually the opposite of a sauropod. Elephants walk sideways, but if sauropods walked that way, there would be too much side-to-side rocking for stable locomotion. Instead, sauropods probably walked with a diagonal gait, with the front foot touching the ground just before the opposite hind foot. In this way the...