Five things to know about newly found dinosaur stomping grounds in the UK

Palaeontologists suggest that a series of tracks on a public beach “point to the presence of large, long-necked dinosaurs in Wales over 200 million years ago”. They believe the tracks may have been made by a large sauropodomorph dinosaur, looking at their large size and shape.

In a paper published in Geological Magazine, they say the dinosaur footprints, called tracks if they are single and trackways if they are in a series, are the most likely explanation for a series of natural dents on the beach at Penarth, south of Cardiff.

The trackways were discovered by a member of the public, Kerry Rees, who alerted the Angela Marmont Centre in 2020, and a team of scientists from the UK and France – from Cardiff University, National Museum Wales, Natural History Museum, Liverpool John Moores University and the University of Lyon – collaborated in the research.

What are the takeaways from this discovery? Let’s explore together.

Not sedimentary structures but dinosaur tracks

The researchers write that the total exposed surface is about 50 metres long and two metres wide, and split into northern and southern sections by a small fault. They say they “interpret these impressions as tracks, rather than abiogenic sedimentary structures” because of the possession of “marked displacement rims” and their relationship to each other, with regularly spaced impressions forming what are considered to be trackways.

Not much is known about the dinosaurs that made the tracks

The track impressions are large, up to about 50 cm in length, but due to erosion and other natural causes, are poorly preserved, and “retain little information about track-maker anatomy”. The researchers believe the tracks originate from an early ancestor of the giant diplodocus, dating back to the Triassic Period, which began 252 million years ago and ended 201 million years ago, bookended by the Permian and Jurassic Periods.

Prof Paul Barrett, who researches dinosaurs at the National History Museum and co-authored the paper, says: “There are hints of trackways being made by individual animals, but because there are so many prints of slightly different sizes, we believe there is more than one trackmaker involved.

“These types of tracks are not particularly common worldwide, so we believe this is an interesting addition to our knowledge of Triassic life in the UK. Our record of Triassic dinosaurs in this country is fairly small, so anything we can find from the period adds to our picture of what was going on at that time.” 

We don’t know exactly how many tracks there are

Because of erosion, and overprinting of tracks, the scientists say an accurate count of individual tracks is “difficult”. Yet they note that track density is “clearly high”, with more than 40 impressions on the southern surface and more than 60 impressions on the northern surface, “equating to approximately four tracks per square metre of exposed surface”.

This may not be the first time the tracks were discovered

Because fossils of dinosaur footprints are left on site and are not brought into museums for display, they have been left open to the elements. Rocks are “uplifted and eroded through time” bringing to the surface “tracks which have been buried for millions of years”. This happens often near the sea as the waves erode the rock surrounding the fossils.

The trace fossils at Penarth (also known as ichnofossils), have emerged more than once over the years, going back to at least 1879. Yet as the sea shifts sand and pebbles, the tracks become covered and uncovered through time, allowing for rediscovery.

Are they? Or aren’t they? (Dinosaur tracks)

While the impressions looked like dinosaur tracks to the scientists, who didn’t have much to go on in terms of site research but depended a lot on photographs taken in 2019, they could have been many other things.

For example, minerals such as gypsum can leave behind footprint-like cavities as they dissolve, or small mud volcanoes can create what appears to the naked eye as a rim of a footprint. Alternatively, ancient rays feeding would also leave marks similar to fossil tracks.

Yet the scientists believe that the tracks were made by dinosaurs, in what is referred to as a trample ground. Trample grounds are often “found along herd movement routes and bodies of water where many animals would be found close together”.

The tracks’ narrowness suggests they were probably made by a biped.

“We think the tracks are an example of Eosauropus, which is not the name of a particular dinosaur species but for shape of a type of track thought to have been made by a very early sauropod or a prosauropod,” Barrett says. “We know these kinds of dinosaur were living in Britain at the time, as bones of the sauropod Camelotia have been found in Somerset in rocks dated to the same age.  

“We don't know if this species was the track maker, but its presence nearby was another smoking gun which suggested something like it could have made these tracks.” 

THUMBNAIL IMAGE: Detail images of individual tracks.

HEADLINE IMAGE: Possible trackways observed on the northern surface. Tracks with approximately equal distancing are highlighted in black and connected with dashed lines. Other tracks are in red.