Ancient Eurypterid Trackway Discovered in Fife
330 million-year-old tracks made by a giant arthropod which was longer than a man have been discovered in Fife (south-eastern Scotland). The trackway which consists of three parallel lines representing the feet and in between a “scooped” out shape indicating that the tail was dragged; have been preserved in sandstone and were discovered by chance when Dr Martin Whyte from the University of Sheffield was out walking.
The tracks have been ascribed to a sea scorpion called Hibbertopterus, fossils of which have been found in the area. Sea scorpions, or to be more precise eurypterids (pronounced You-ree-ip-ter-ids) were Chelicerate arthropods that evolved around 480 million years ago and flourished worldwide in marine and freshwater environments until their demise towards the end of the Permian.
Fossils of eurypterids are relatively common in ancient marine strata, particularly, as like trilobites, they had to shed their body armour (exoskeleton) when they grew and the cast shells had a high preservation potential. Most eurypterid fossils are not the fossilised carcase of a dead animal but instead the fossilised remains of a cast shell from a moult.
Some types of eurypterids grew to enormous sizes and until the rise of vertebrates such as fish, they were some of the top predators of the Palaeozoic. To read an article about the discovery of an enormous three-metre-long sea scorpion: Claws! Giant Sea Scorpion of the Devonian.
This Scottish discovery is the largest known walking trackway of an arthropod, or indeed any invertebrate discovered to date.
The tracks were probably made as this huge animal hauled itself out of the water. Eurypterids with their simple gills were adapted to absorb oxygen from both water and the atmosphere. It is likely these animals moved into the shallow margins in order to breed, just like a relative of these creatures, the Horseshoe Crab does today.
The tracks are already quite badly eroded but removing the sandstone rock in which they are preserved may be too difficult. Instead, Scottish Natural Heritage, is funding a project to create silicone copies of the trackway which will enable these ancient “footprints” to be studied in detail. A spokesperson for Scottish Natural Heritage, described this discovery as “unique and internationally important because the creature was gigantic.”
Richard Batchelor from Geoheritage Fife, commented:
“The trackway is in a precarious situation, having been exposed for years to weathering. The rock in which it occurs is in danger of falling off altogether. Removing it and housing it in a museum would be prohibitively costly but moulding it in silicone rubber and making copies for educational and research purposes means that we can still see and research this huge creature’s tracks in years to come.”
The person stood next to the trackway in the photographs is pointing to the impression (groove as the fossil has been made by infilling sediment), made by the tail dragging over the sand, the scale of trackways can clearly be seen when compared in size to the person stood adjacent to them. The trackways suggest that they were made by an animal at least 1 metre wide. The three rows of crescent shaped footprints on each side of a central groove made by the tail can be clearly made out. The length of the entire trackway is approximately 6 metres.
A geologist for Scottish Natural Heritage, Colin MacFadyen stated:
“Helping to conserve this important find is vital for our understanding of this period in evolution. Such finds as this highlight that all over Scotland there are no doubt other geological treasures awaiting discovery.”
The sandstone has been dated to approximately 330 million years ago (mid Carboniferous). This area of eastern Scotland is world famous for its Carboniferous fossil sites. For example, at East Kirton a number of important fossil rich Mississippian (Lower Carboniferous) strata are known. It seems that around 330 million years ago, this area of Scotland was low lying with many freshwater lakes. Many early tetrapod fossils as well as numerous invertebrate fossils and plants are known from this region.