More than 85 well preserved dinosaur footprints – made by at least seven different species – were discovered in East Sussex, representing the most diverse and detailed collection of these Cretaceous fossil traces found in the UK to date.
Footprints were identified by University of Cambridge researchers between 2014 and 2018 following periods of coastal erosion along the cliffs near Hastings. Many of the footprints – ranging in size from less than 2 cm to over 60 cm – are so well preserved that fine details of skin, scales and claws are easily visible.
Footprints date from the Late Cretaceous, between 145 and 100 million years ago, with impressions of herbivores, including Iguanodon, Ankylosaurus, a species of stegosaurus and possible examples of the sauropod group (which included Diplodocus and Brontosaurus); as well as meat eating theropods. The results are reported in the journal Paleogeography, Paleoclimatology, Palaeoecology.
Over the past 160 years, there have been sporadic reports of fossilized dinosaur footprints along the Sussex coast, but no major new discoveries have been described in the last 25 years and the earlier discoveries were much less varied and detailed than those described in the current survey. .
The area around Hastings is one of the richest in the UK for dinosaur fossils, including the first known Iguanodon in 1825, and the first confirmed example of fossilized dinosaur brain tissue in 2016. However, traces of fossils like footprints that may help scientists learn more about the composition of dinosaur communities are less common in the area.
"Full-body dinosaur fossils are incredibly rare," said Anthony Shillito, a doctoral student at the Cambridge Department of Earth Sciences and the first author of the article. "Normally you only get small pieces, which do not say much about how this dinosaur may have lived. A collection of footprints like this helps to fill in some of the gaps and infer things about which the dinosaurs were living in the same place at the same time. "
The footprints described in the current study, which Shillito was co-authored with Dr. Neil Davies, were discovered during the last four winters when heavy storms and storms led to periods of collapse of the sandstone and lamestone cliffs.
In the Cretaceous Period, the area where the footprints were found was probably near a water source, and in addition to the footprints, several fossilized plants and invertebrates were also found.
"To preserve the footprints, you need the right kind of environment," Davies said. "The soil needs to be & # 39; sticky & # 39; enough for the footprint to leave a mark, but not so wet that it is washed. You need that balance to capture and preserve them. "
"In addition to the great abundance and diversity of these prints, we also see absolutely incredible details," Shillito said. "You can clearly see skin texture and scales, as well as four-fingered claw marks, which are extremely rare.
"You may have some idea about which dinosaurs made them from the shape of the footprints – comparing them to what we know about dinosaur feet from other fossils allows us to identify the important similarities. When you also look at footprints from other locations, you can begin to join the species that were the main participants. "
As part of his research, Shillito is studying how dinosaurs may have affected river flows. In modern times, large animals such as hippos or cows can create small canals, diverting part of the flow of the river.
"Given the size of many dinosaurs, they are very likely to have affected rivers in a similar way, but it is difficult to find a" smoking gun "since most of the footprints would have just been taken away," he said. said Shillito. "However, we see some evidence to a lesser extent of its impact; in some of the deepest footprints you can see bushes of plants that were growing. We also found evidence of footprints along the banks of the river channels, so it is possible that the dinosaurs played a part in the creation of these channels. "
There are likely to be many footprints of dinosaurs hidden in the eroded sandstone cliffs of East Sussex, but building sea defenses in the area to slow or prevent the process of coastal erosion may mean that they remained locked inside the rock.
The research was funded by the Natural Environment Research Council (NERC).