Discovery News - Herds of dinosaurs once wandered Arabia and have left behind some footprints in what's being called the first set of trackways discovered on the Arabian Peninsula.
The approximately 165 million-year-old tracks in Yemen appear to have been made by at least two types of dinosaurs, with young and old dinos traveling together along what was once a coastal mud flat.
"It's a bit of a dinosaur highway," said paleontologist Anne Schulp of the Natuurhistorisch Museum Maastricht in Maastricht, The Netherlands. He is the lead author of a paper describing the discovery in the May 20 issue of the journal PLoS One.
No less than 11 parallel tracks of adult and juvenile sauropod dinosaurs were identified, plus some lone and scattered footprints from ornithopods and some other sauropod dinos. Sauropods are those four-footed, long-necked plant-eating behemoths of the dinosaur world. Ornithopods were generally smaller plant-eating dinosaurs that walked or at least ran on two legs and grazed in all fours.
"The identity of the sauropods was based both on the shape of the hand prints, and by the spacing of the foot prints," explains coauthor Nancy Stevens of Ohio University in Athens, Ohio.
"The impressions of the hand were much wider than long and were U-shaped in outline, suggesting that the hand bones were arranged into an arc-shape, which is a feature observed in the group of sauropod dinosaurs known as the Neosauropoda."


They haven't honed it down to a species level of identification, but they narrowed it down impressively, considering all they had to go on were footprints. Like other dino trackways in the world, these newly found tracks provide glimpses of what dinosaurs were doing, rather than how they were put together.
"When you get a trackway like this you get a chance to do research at the next level -- behavior," said Matthew Carrano, curator of dinosaurs at the Smithsonian Institution's National Museum of Natural History.
The parallel tracks of different-aged dinosaurs offer insight into social groups since they suggest the animals were roaming in large herds. They even shed some light on parenting behaviors, he said, showing that smaller sauropods walked alongside the big dinos, keeping up with quicker, shorter steps.
"These trackways are distinctive because they provide the most evocative window to date into Yemen's dinosaurian evolutionary history: an ornithopod together with a beautiful example of sauropod herding behavior," said Stevens.
The discovery also reinforces the idea that there are probably lots of undiscovered dinosaur fossils on the Arabian Peninsula. In fact, Stevens says she is planning to investigate more trackways near the first site with her colleagues Schulp and Mohammed Al-Wosabi of Sana'a University, Sana'a, in the Republic of Yemen.
"It's a place where future research could be productive," agreed Carrano.