Researchers have discovered three dinosaur track sites dated to around 150 million years ago that contain dozens of preserved footprints, according to a study.
The scientists found the track sites in the Imilchil-Outerbat region, Morocco, located in the heart of the North African nation’s central High Atlas mountains. The sites lie within the Isli geological formation, which is between 167 and 145 million years old—a period of time that falls within the Jurassic Period.
The sites contain a diverse range of dinosaur tracks that scientists have described in a study published in the journal Royal Society Open Science. Among the tracks the researchers documented were those made by theropod, sauropod, and ornithopod dinosaurs, some of the major groups in the dinosaur family tree.
Ornithopods were a group of herbivorous animals that were one of the most successful and enduring dinosaur lineages. They originally started out as small, bipedal grazers, growing in size and number over time.
Oussou et al. / Royal Society Open Science 2023
The sauropod group of dinosaurs includes the largest land-dwelling animals ever to walk the Earth, with some species estimated to have weighed more than 90 metric tons. These dinosaurs tended to have very long necks, long tails, small heads and four thick legs.
Theropods, meanwhile, were carnivorous dinosaurs that ranged in size from the 2-foot-long Microraptor to the 40-foot Tyrannosaurus rex. Modern birds are descended from one lineage of small theropods, meaning they are also members of this group.
The first track site described in the latest study extends for almost 200 feet and contains six sauropod trackways, one ornithopod trackway and 11 theropod trackways.
A trackway is a series of two or more preserved tracks made by the feet, tail, or other body parts of an animal.
The second track site that the researchers documented measures more than 30 feet in length and features an intriguing set of very small, juvenile theropod tracks, along with two isolated medium-sized theropod tracks.
Researchers also found an isolated track at the site that was potentially made by a pterosaur—a group of flying reptiles that roamed the skies during the age of the dinosaurs. They were the first group of vertebrates to develop powered flight.
The third track site extends for around 16 feet and showcases a “well-preserved” bird-like theropod trackway, Ahmed Oussou, an author of the study with Sidi Mohamed Ben Abdellah University in Fez, Morocco, told Newsweek.
Despite the diversity of the tracks that the researchers found, identifying specific species from these footprints has been challenging for the researchers since the region is lacking in dinosaur body fossils.
The most common way that dinosaur tracks are preserved is via the process of sedimentation.
“This is when a track is filled with sediment, such as mud or sand, and then buried. Over time, the sediment compacts and hardens into rock, trapping the track. The rock can then be eroded to reveal the track,” Oussou said.
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In the case of the track sites in the High Atlas mountains, alternating deposits of flood-plain mud and river sands created an “ideal setting” for the preservation and fossilization of tracks, Oussou said. At the time the dinosaur tracks were created, the Imilchil-Outerbat region would have looked “completely different” from how it does today.
“This area used to be lowlands with rivers and lakes, similar to the present-day Okavango Delta in Botswana, southern Africa, or the Taquari area in Brazil,” Oussou said.
The study, the researchers said, sheds new light on the paleobiology of Jurassic-era dinosaurs in the region, as well as the interactions between these animals and their environment.
“Dinosaur body fossils are unknown from the Middle to Late Jurassic of the Imilchil area, and are rare across the whole of north Africa,” the authors wrote in the study. “The discovery of these three new track sites increases our knowledge of the richness and diversity of the dinosaurs from Morocco in particular and north Africa in general.”
“The tracks described here and previously from the central High Atlas indicate that Middle to Late Jurassic ecosystems in Morocco were far more diverse than is indicated by the body fossil record.”
