|An individual footprint of a sauropodomorph dinosaur on the foreshore near Penarth, south Wales, the United Kingdom. Credit: Peter Falkingham, Natural History Museum, London.|
Paleontologists have discovered the footprints of large sauropodomorph dinosaurs on the shoreline near Penarth in south Wales, the United Kingdom.
The Penarth footprints are part of the Blue Anchor Formation and date from the Late Triassic epoch, over 200 million years ago.
The total exposed surface is about 50 m long and 2 m wide, and is split into northern and southern sections by a small fault.
The tracks occur on a single surface at the top of a 15-cm-thick gray, dolomitic siltstone. Small gypsum nodules occur near the top of the bed.
The tracks are deeply impressed into the top surface and are partially infilled with a green siltstone with orange stringers.
The impressions are highly variable in shape and size. They are all highly weathered, exhibiting both broken and smoothed surfaces, breakage being facilitated by numerous diaclases in the bedding plane.
They are roughly circular to elliptical in outline, and almost entirely lack clear impressions of either individual digits, claws or footpads.
The footprint outlines are highly irregular, but some impressions do reveal possible anatomical information. They range over 20-60 cm in maximum diameter. Depth is likewise variable, but ranges mainly over 5-10 cm.
“We believed the impressions we saw at Penarth were consistently spaced to suggest an animal walking,” said Professor Paul Barrett, a paleontologist in the Department of Earth Sciences at the Natural History Museum, London.
“We also saw displacement rims where mud had been pushed up. These structures are characteristic of active movement through the soft ground.”
Professor Barrett and his colleagues from the United Kingdom and France think that the Penarth footprints are an example of the ichnogenus Eosauropus, which is a name not of a dinosaur but a type of track thought to have been made by a sauropodomorph dinosaur.
“We know early sauropods were living in Britain at the time, as bones of Camelotia, a very early sauropod, have been found in Somerset in rocks dated to the same period,” said Dr. Susannah Maidment, a paleontologist in the Department of Earth Sciences at the Natural History Museum, London.
“We don’t know if this species was the track maker, but it is another clue which suggests something like it could have made these tracks.”
“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,” Professor Barrett said.
“The 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.”