Wednesday, 16 December 2020

Prehistoric Jobbies: examining Skara Brae coprolites

Fewer words are more enjoyable in Scottish slang than 'jobbie'. So it's a special pleasure for me to get to work on fossil poo, and legitimately say 'jobbie' when talking about actual science.

A couple of years ago I micro-CT scanned a bunch of jobbies at the University of Edinburgh. The scans were carried out by Ian Butler, who runs the scanner there, and the honours student I was supervising, Carla Willars. It was part of a project I devised and was co-supervising with Stig Walsh at National Museums Scotland. We were scanning scat from across the country: squidgy fresh ones, shrivelled-up old ones, and some truly ancient ones, looking at bone preservation in poo (as you do).

Skara Brae (Pic: by John Allan, via Wikipedia)
Among the scan material were some precious pieces of preserved poop from the collections at National Museums Scotland. They had been collected in the 1970s at the world heritage site of Skara Brae in Orkney: a human settlment older than Stonehenge that captures an exquisite slice of Neolithic life. It includes eight beautifully preserved dwellings inhabited around 5000 years ago, built entirely of stone.

The CT scans showed that the coprolites contained a smattering of vertebrate bone shards. Sharing them with colleagues at National Museums Scotland, we decided to try and work out who or what deposited these jobbies, and what animals the bones inside them belonged to. It blossomed into a larger analysis led by Andrzej Romaniuk, and we published the results recently in Archaeological and Anthropological Sciences

In our paper we combined traditional and modern methods for analysing specimens. As well as using the original CT scan data, we included both regular microscopy and scanning electron microscopy. The latter is basically a microscope that looks at specimens using a beam of electrons, rather than just visually through regular lenses. It allowed us to look at the surface of the coprolites and the bones that were sticking out from them, and see fine details such as the damage that results from digestive acids. Another analysis we carried out was to examine preserved lipids and proteins. This involved taking small samples of one of the coprolites, and analysing it using a mass spectrometer, which can identify what kinds of proteins are in a sample. We can them match them to an organism. 

A scanning electron microscope image of a vole upper jaw bone and teeth, found among the coprolites at Skara Brae.

Using all of these methods, we discovered that these wee jobbies belonged to a prehistoric pooch - one of the many dogs that lived with humans in Neolithic Orkney. The bones inside the coprolites - and found alongside them during excavation - included chunks of cancellous bone, the spongy tissue that makes up the 'honeycomb' structure inside bones. There were also pieces of the hard outer bone coating, called cortical bone, and some teeth. Some of the larger fragments could be identified as belonging to hoofed animals like sheep, which we know were kept as food by the inhabitants of the settlment. But there were also very small bones and teeth belonging to voles.

Ilustration of Skara Brae in the Neolithic, by Colin MacNeil. Note the dog sitting by the old man.

These results suggest that people in Skara Brae were either feeding their dogs on butchery scraps, or the dogs scavenged them from midden heaps (or both). The remains of voles in their faeces shows they ate them too, perhaps helping to play a role in pest control. As well as this, our study showed the power of combining multiple techniques when investigating specimens - and hopefully minimising the destruction or damage of samples during scientific analysis.

 

References

Romaniuk AA, Panciroli E, Buckley M, Chowdhury MP, Willars C, Herman JS, Troalen LG, Shepherd AN, Clarke DV, Sheridan A and van Dongen BE. 2020. Combined visual and biochemical analyses confirm depositor and diet for Neolithic coprolites from Skara Brae. Archaeological and Anthropological Sciences 12: 1-15.

  


Tuesday, 20 October 2020

Skye's Ancient Ecosystem: non-technical summary

Last month I published a non-technical summary of the scientific paper describing Scotland's new dinosaur discovery, StEiggosaurus. This month I'd like to do the same for another of my papers: Diverse vertebrate assemblage of the Kilmaluag Formation (Bathonian, Middle Jurassic) of Skye, Scotland, which came out online at the end of July 2020. It summarises discoveries made to date from part of the rock series on the Isle of Skye - the Kilmaluag Formation, one of the most fossiliferous sites in the UK for vertebrate animals - and compares this with other sites around the world.

Below is a non-technical summary of the paper. No matter your background you can find out about the scientific discoveries being made in Scotland!

Introduction

The Middle Jurassic (164-174 million years ago) is a pivotal time for many land-living animal groups. Not only is there an expansion in the number and kinds of animals (including dinosaurs), but we can also trace the origins of groups that are still alive today. These include mammals, squamates (lizards and snakes) and amphibians. To understand how these groups emerged, and the evolutionary changes that led to their success and diversity in later time periods, we need to study their fossils. 

Looking around the world, the fossils of Middle Jurassic land animals are quite rare compared to other parts of the Jurassic, and the Cretaceous which followed. Some of the best-known examples come from China, Russia, and the British Isles. In the UK, the fossils from sites in Oxfordshire and Gloucestershire in England have been among the most studied and celebrated to date. They have been especially rich in very small backboned animals, the exact groups that scientists are so keen to understand because of their long-standing role in Earth's ecosystems.

There is a series of rocks on the Isle of Skye collectively called the Great Estuarine Group. It is one of the most fossiliferous rock layers in the UK, and as such is legally protected as a SSSI (Site of Special Scientific Interest) and through Scotland's new NCO (Nature Conservancy Order). All work on these rocks requires a permit, and fossils can only be collected for scientific purposes. Work has been carried out on the fossils in these rocks in the Southern part of Skye since they were first discovered in 1971 by Michael Waldman. Since that time many different researchers have worked there, notably Robert Savage (University of Bristol), Susan Evans (University College London) and Paul Barret (Natural History Museum, London). In the last decade Stig Walsh (National Museums Scotland), Roger Benson (University of Oxford), Richard Butler (University of Birmingham) and I have been the main team working on the Kilmaluag Formation.

Our research shows that the fossils from this layer of rocks are globally significant in terms of their completeness and preservation. This makes them vitally important for ongoing studies into the origins of multiple animals groups, and places these Scottish rocks among the most important Middle Jurassic localities in the world.


Geology of the Kilmaluag Formation

The Kilmaluag Formation is one of seven rock formations in the Great Estuarine Group, found in the Inner Hebrides of Scotland. It dates to the Bathonian, around 166 million years ago. This series of rocks captures a changing landscape as the area lifted and fell due to geological processes, causing the land to dip above and below sea level. This periodically created shallow seas, or more terrestrial lagoon environments and deltas. Much later in the Palaeogene around 55 million years ago, these rocks were covered by volcanic eruptions, which also cut through and heated the rock in places. Now the Great Estuarine Group is only visible where the volcanic rock has been eroded by water and ice to reveal the older rocks underneath. This happens predominantly along the shoreline.

The Great Estuarine Group, which includes the Kilmaluag Formation (circled in red).

The Kilmaluag Formation is found on the Isles of Skye, Eigg and Muck, and is up to 25 metres thick. It's named for the village of Kilmaluag on the north coast of Skye, but although you can find some of these rocks there, the largest exposed parts of the Kilmaluag Formation are on the Strathaird Peninsula in the South of the Island. The rocks are Late Bathonian in age, and they are unique because unlike the rest of the Great Estuarine Group, they represent an almost entirely freshwater environment. We know this from the numbers of freshwater organisms preserved in them, including small crustaceans called ostracods (the Kilmaluag Formation used to be called the Ostracod Limestone).

In the north of Skye, the Kilmaluag Formation mostly comprises sandstones, whereas in the south of Skye and on Eigg and Muck, it is mostly limestone. There are cracks running through some of the beds, showing us that there were periods when the sediments dried out completely and cracked, before being filled-in during wetter climate cycles. The presence of muds with lots of clay and carbonates tells us this was once a landscape covered in freshwater lagoons. The layers that yeild the most vertebrate fossils were probably just above the shoreline, and dried out from time to time before being flooded again.


Fossil Plants and Animals from the Kilmaluag Formation

Plants

There hasn't been much work on the plant fossils from the Kilmalag Formation. There are some small bits of bark and stem visible in the rock, but they are very broken up. A study carried out in 1991 looking at the small spores left by plants in the fossil record from Skye, found pollen in the rocks on the north of the island. The pollen mostly came from plants like conifers, cycads (gymnosperms) and ferns (pteridophytes).

Invertebrates

There are lots of invertebrate animals in the Kilmaluag, mostly in the form of ostracods (Darwinula and Theriosynoecum), conchostracans (Anthronestria and Pseudograpta), gastropods (Viviparus) and bivalves (Unio). There are some trace fossil burrows that are thought ot have been made by some kind of crab or shrimp. 

I discovered the first insect fossils from the Kilmaluag in the north of island in 2017 - mostly beetle wing cases - and more have been found since then. They're currently being studied by researchers at National Museums Scotland in Edinburgh, and the Huntarian in Glasgow.

Fish

A lot of fish fossils are found in the Kilmaluag Formation. Fossil sharks, Hybodus and Acrodus are commonly represented by their teeth, and they are some of the only non-marine Jurassic Acrodus fossils in Europe, and youngest in the world. The scales of other kinds of fish have also been found, and there are also some skeletons which are now being studied.

Amphibians

There are two species of salamander known from the Kilmaluag Formation: one called Marmorerpeton, and the other known only as 'Kirtlington salamander A'. Both of these were previously found at the English fossil locality called Kirtlington Cement Quarry, in Oxfordshire. Marmorerpeton is a relatively large (around 30 cm in length) aquatic salamander. It was previously only known from just a few scattered pieces of bone, but there are now several partial skeletons from Skye, which are being studied by our group and our collaborators. It's significant because it belongs to the very earliest group of salamanders that evolved in the Middle Jurassic, so knowing more about its skeleton will help us understand the emergence of the whole group.

Another amphibian found on Skye is Anoualerpeton. It belongs to a group called the albanerpetontids, which went extinct just 2 million years ago. There are no frogs known from the Kilmaluag Formation at the moment - we'll keep looking!

Lepidosaurs - 'Small Reptiles'

The lepidosaurs are the taxonomic group that include snakes, lizards and the tuatara (found in New Zealand). Although often colloquially referred to as 'small reptiles', some of them can grow very large. Their main uniting trait is that they have overlapping scales on their bodies. 

There are lots of early ancestors of lepidosaurs in the Kilmaluag Formation - these fossils are really important for our knowledge of the evolution of this animal group, which is now common throughout the world. Most of these lepidosaurs are known from jaws and some pieces of the skeleton. One of the most common on Skye is Marmoretta, which is now known from lots of jaw bones as well as a partial skeleton - the most complete in the world to date. Other lepidosaurs include Balnealacerta, Bellairsia and Parviraptor. Partial skeletons of these animals are all currently being studied by our group and our collaborators.

Turtles

The Kilmaluag Formation yeilded Scotland's very own Jurassic turtle: Eileanchelys waldmani. It was found in 2004, and represents one of the earliest aquatic turtles in the fossil record, and one of the very few known from this time period around the world. It belongs to near the base of the family tree of living turtles, so it's anatomy helps us understand the evolution of turtles in the time of dinosaurs. Turtle bones are relatively common in the Kilmaluag Formation.

A selection of fossils from the Kilmaluag Formation (clockwise from top left): the teeth of a shark; the jaw of a mammal; the jaw of a lepidosaur' the toothof a dinosaur; the head of a turtle; the tooth of a close mammal relative.

Choristoderes

Choristoderes became extinct around 20 million years ago, but they had their roots some time prior to the Middle Jurassic. They were semi-aquatic reptiles, and mostly quite small (hand sized). Their exact relationship to other reptiles is not certain, partly because of a lack of more complete fossil material. The choristodere Cteniogenys is found on Skye, including bits of the skeleton and a small skull. This is the most complete material known for this animal, and is currently being studied to see what it reveals about the group.

Unidentified Small Reptiles

There are at least four unidentified types of reptile in the Kilmaluag Formation, but unfortunately they don't have any of the features needed to place them in their own genus or species. Hopefully future discoveries will make it possible to name them, and tell us more about what group they belong to.

Crocodiles

A partial skeleton was found in the Kilmaluag Formation and described in 1996. It includes parts of the limbs, ribs, vertebrae and osteoderms, the hardened scales that made up the skin. Some teeths and other bits of crocodile have been found, but mostly not figured or described yet.

Pterosaurs - Flying Reptiles

There are two pterosaur skeletons known from the Kilmaluag Formation, both partial. These are the first flying reptiles to be found in Scotland, and are currently under study.

Dinosaurs

Very little dinosaur material has been found in the Kilmaluag Formation so far. A single tooth belonging to a sauropod, a tooth belonging to a theropod, and an incomplete limb bone, are all that is currently known. Footprints have been found in the northern part of the island, including large and small theropod prints which might represent adults and their young.

Mammals and Kin

The first Jurrasic mammal from Scotland was found in the Kilmaluag Formation in 1971, Borealestes serendipitus, along with the first close relative to mammals, an animal called a tritylodontid. Since then many different early mammals have been found on the island. 

A jaw from Borealestes, found a few years ago. Only the tips of the teeth were visible on the surface, the rest was seen and studied by CT scanning the rock.

Borealestes belongs to a group called the docodontans, which are an early offshot of mammals. They interest scientists because we've dicovered in the last 20 years that despite being from such an early part of the mammal tree, they had evolved very specialised adaptations to their environment - something we thought was exclusive to more recent mammal groups. The partial skeletons of several docodontans are currently under study (a new paper on this should be out very soon!) and should tell us more about their evolution.

Another early-branching mammal is Wareolestes, which is known from Skye from a single jaw. The jaw had replacement teeth just emerging, indicating it was a young animal about to replace it's milk teeth. Other mammals discovered from the Kilmaluag Formation are closer relatives to living groups. They include Palaeoxonodon, which is known from a near-complete jaw found in 2015 (and some other pieces of jaw). The specimen told us that many of the species identified previously from Oxfordshire based on individual teeth, were actually the same animal. The differences in tooth shape were due to the position of the tooth along the tooth row, rather than being fundamental differences between species. This has a knock-on effect for our estimates of how diverse the mammals were in this time period. 

My collaborators and I are currently studying some partial skeletons of several species of mammal from the Kilmaluag Formation.

Comparisons With the Rest of the World

Looking at the animals found on Skye and comparing them to other localities globally, we can see that Skye has a really diverse number of vertebrate fossils. Many of the same species are found at Kirtlington Cement Quarry in Oxfordshire, which dates to the same time period in the Middle Jurassic. But the fossils from Skye are generally more complete than those in England, and so provide new information about the anatomy of these creatures. In many cases, the fossil material found on Skye is the most complete example of these species, especially the small reptiles, salamanders and mammals.

Some groups known from England haven't been found yet on Skye, including frogs, the group of lepidomorphs called rhynchocephalians, and haramiyid and multituberculate mammals. It might be that the English site represents a slightly different environment where these animals didn't live, but it could also be that differences in how we collect fossils on Skye (see Collecting below) account for these differences.

Similar animals are found in Middle Jurassic sites in Russia (Itat Formation) and Morocco (Guel el Ahmar Fauna). The similarities with Russia are strongest, except that there are haramiyid and multituberculate mammals in Russia (and not Scotland, yet). The Middle Jurassic of Morocco is still only poorly known, but it is interesting that there could be similarities, because it was separated from Skye in the Middle Jurassic by the growing Atlantic Ocean. Hopefully more material from this and other sites from the Southern continents will provide more information.

The Jurassic fossils of China are certainly the most spectacular examples of their kind in the world. Although much younger than those on Skye (late Jurassic in Age), they include some of the same groups, such as  small reptiles, pterosaurs, theropod dinosaurs and the docodont mammals. There is a much higher diversity of dinosaurs in China, but there are more small reptiles in Scotland, and similar numbers of mammal species. Most of the fossils from China are exceptionally complete, but they are preserved and collected quite differently from those in Scotland. Their spectacular appearance can give the impression that China held an ultra-diverse and unusual collection of animals with lots of unique specialisations. However the same types of animals are known from elsewhere, they are simply much less complete athan those in China.

Other Late Jurassic sites include the Morrison Formation (Late Jurassic, USA) and Alcobaça Formation (Guimarota, Portugal). Collecting has taken place in the Morrison Formation for a long time, and the list of animals found from those layers is huge. As in Scotland, choristoderes, fish, salamanders, crocodiles, pterosaurs, dinosaurs and mammals are known from the Morrison Formation, but there are lot more species known than in Scotland. The Alcobaça Formation in Portugal also has some similarities with the Kilmaluag Formation: similar species of fish, small reptiles and mammals are known. Both sites also have crocodiles, pterosaurs and dinosaurs, but in greater numer os species in Portugal to date. 

The Purbeck Formation in England is another site worth comparing: it is Late Jurassic to Early Cretaceous, and is very diverse, being one of the most diverse vertebrate fossil Formaton in the UK. Although similar groups of animals are represented there, there are very few crossovers with the Kilmaluag in terms of the actual species - except for some of the fish, and the squamate, Parviraptor

One interesting thing when comparing the geologically later sites like the Morrison, Alcobaça  and Purbeck Formations, with the older Kilmaluag Formation, is that the mammal groups change noticably. In these later Formations there are fewer of the early-branching groups of mammals like docodontans, and more members of more modern groups, including multituberculates and haramiyidans.

Collection Methods and Potential Biases

Of course when comparing the Kilmaluag Formation animals with other sites, we have to bear in mind the methods used to find and extract fossils. These methods effect what palaeontologists find at a site, and so must be taken into account when assessing the fossil assemblage compared to other locations. In the Kilmaluag Formation fossils are found only when they are visible on the rock surface. They are extremely difficult to remove from the site due to the nature of the rock and the location (and they are also only collected when deemed scientifically valuable, to limit our impact on this sensitive area). Once extracted, they can mostly only be studied by CT scanning them, and are not easily removed from the rock with acid.

At most other sites, people actively dig the layers to find fossils. They are easier to remove, and can be prepared from the rock and therefore studied much more easily. In many cases, rock can be bulk processed: dissolving the rock and seiving out the contents. In this way, it's possible to find a lot more fossils, which increases the likelihood of discovering new species and groups. The sites in Oxfordshire and Gloucestershire produce lots and lots of single teeth and bones.

However there is a plus side to the less copious discoveries from Scotland. The fossils in the Kilmaluag Formation - especially of the crucial, small-bodied animals - are often much more complete. Whereas bulk processing means most fossils are reduced to shrapnel, the method in Scotland of studying fossils with CT scanning allows us to keep the skeletons in their original position, and study them in three-dimensions, digitally. This is a huge advantage for the amount of information we can gain from each specimen. Most of the material found to date, although not from new species, represent the most complete examples of these animals known, particularly for the small reptiles, salamanders and mammals.

Looking at the collecting done by the three main groups that have worked on the Kilmaluag Formation since 1971, there are some interesting differences. Collecting in the 1970s resulted in more mammal material, whereas collecting in the early 2000s produced a lot more fish. Our work in the last decade has produced the most lepidosaur material. Overall, mammals and their close relatives, and lepidosaurs, are the most commonly found vertebrate fossils in the Kilmaluag Formation.

The numbers of different groups found in the Kilmaluag Formation is likely to shift as we identify more of the fossils we've collected, and publish those that are currently in the pipeline.


Conclusions

It's clear that the Kilmaluag Formation contains the richest vertebrate fossil material in Scotland, and is one of the most diverse and important in the world. Although at first glance it may seem less diverse than other Middle to Late Jurassic sites around the world, this is likely more to do with the way in which fossils are found, collected and studied, which limits the volume of material we can process. However, what we do have is extremely complete and provides a wealth of new information on the animals of this time period.

Comparing sites around the world with that in Scotland, we can see the distribution of animal groups in this time period, helping us understand ecosystems over 150 million years ago. There are many more fossils from the Kilmaluag Formation being studied and to be published in the coming years. This shows that protection of the shorelines of the Isle of Skye is vital to safeguard our nation's geological heritage, preserving it not only for science, but for the public, and the generations to come.




Monday, 14 September 2020

Eigg Dino Paper: non-technical version

I’ve had a few requests for a non-technical summary of the paper describing the recent discovery from the Isle of Eigg. Our paper, titled First dinosaur from the Isle of Eigg (Valtos Sandstone Foration, Middle Jurassic) Scotland, was published in the scientific journal Earth and Environmental Science Transactions of the Royal Society of Edinburgh in August 2020. There are 13 co-authors, each bringing their own specialism to the mix, with myself as lead author. 

But scientific papers are often a bit opaque for non-specialists. So below I've written a walkthrough of the science, written for the general public. In it, I tease out the details of our discovery and research for everyone to enjoy. If you have any Qs, please ask!

Introduction

The Middle Jurassic (174-164 million years ago) is a special time in the evolution of life on Earth. Many groups appeared at this time or shortly before, and they split into lots of new families, and exploited new ways of life. This evolutionary pattern is also true for dinosaurs. However, scientists struggle to understand how and why this happened because fossils from the Middle Jurassic are so rare. Almost five times as many fossils are known from the Late Jurassic as the Middle! As a result, every Middle Jurassic fossil is a vital clue to life at this time, and scientifically significant.

Although dinosaurs have been found in Scotland already, all of them have come from the Isle of Skye. This is because there are fossil-rich Jurassic rocks on the island dating to around 166 million years ago. As well as dinosaur limb bones, teeth, and footprints, scientists have found fossil crocodiles, turtles, pterosaurs, mammals and marine reptiles, as well as invertebrate fossils like ammonites and belemnites.

The Isle of Eigg, which lies south of Skye in the Inner Hebrides (west coast of Scotland), is also known for its Jurassic fossils. However, these are all from marine animals and mainly comprise reptiles (like plesiosaurs), fish, and sea-living invertebrates. Fossils have been found on Eigg since the early 19th century, but in 200 years of searching no-one had ever found terrestrial animal fossils.

Our paper describes the first dinosaur bone found on Eigg, which I discovered during National Geographic funded fieldwork by the University of Edinburgh in 2017. Our small team was given permission to work on the Island by the Isle of Eigg Heritage Trust. Eigg is owned by the residents, so we had to seek their permission to work there. We found the bone on the shore where there are a series of rocks called the Great Estuarine Group. This is the same group that yields fossils on Skye. It includes many different layers formed under different conditions: some when the Inner Hebrides was a shallow sea, and others from lagoons and deltas when the land was just above sea-level. The Eigg dinosaur was in a layer called the Valtos Sandstone Formation, which was formed on an ancient Middle Jurassic shore where rivers met the sea, perhaps in a brackish (mixed salt and fresh water) lagoon.

The stratigraphy of the Great Estuarine Group, and location of the Isle of Eigg.

The Fossil

The dinosaur bone is now part of the collections at National Museums Scotland (specimen number NMS G.2020.10.1). It was removed from the shoreline using rock saws, and the bone carefully extracted from the remaining rock by expert preparator, Nigel Larkin. The Eigg bone is half a metre long, and each end is missing, which makes it hard to identify what it is. There are tooth marks on the surface, which tells us it was scavenged after death. Nigel used a kind of glue to reinforce the bone and prevent it from breaking further. There was a section of the bone missing in the middle, so Nigel used the indent in the rock as a cast, reconstructing this missing part. 

The Eigg bone, NMS G.2020.10.1. A) the bone within the rock, partly excavated, and B-C) the bone reconstructed and removed from the rock.
Matthew Humpage photographed the fossil so that we could use the pictures for the paper, then he made a photogrammetry model of the bone, which is online and free to access on a site called Sketchfab. The fossil was also studied by thin-section, allowing us to look at the internal structure. This was done by Gregory Funston, who cut a thin slice through the bone in cross-section. He ground and polished this slice down to make it thin enough to pass light through, then examined it with a microscope. We used the information about the bone structure, along with comparisons with dinosaur bones from across the UK and rest of the world, to work out what kind of animal it belonged to.

Bite marks in the Eigg Dino Bone.

Identity of the Eigg Dinosaur

Our team had to work together to figure out what animal the Eigg bone belonged to, and which bone it could be. Because there have been many marine reptile fossils found on Eigg, marine reptile expert Davide Foffa compared it to these extinct ocean-going creatures. Swimming animals have special adaptations in their bones for their way of life, including having very short, wide limb bones, and thickened internal bone structure. Not only was the Eigg bone not the same shape as a marine reptile bone - it was too long and slender – it was not thickened like a marine animal bone. This meant we could be sure it wasn’t a marine reptile, and must be some kind of dinosaur.

Next we compared the bone to the three main groups of dinosaurs: theropods, sauropods, and ornithiscians. Co-authors Stephen Brusatte, Femke Holwerda, and Susannah Maidment are all dinosaur experts, and so were able to work systematically through all the possible identifications, narrowing it down. Because it was badly damaged, the Eigg bone didn’t have any diagnostic features (features that help identify the species) to guide us. Instead, we had to use detective work to narrow down the possibilities. It didn’t match the shape of theropod bones, but bore some resemblance to sauropod fibulae – the smaller of the two lower hind leg bones. It was also similar to a sauropod femur, but it would have to have been a particularly small, slender sauropod. Overall, the Eigg bone bore the closest resemblance to an ornithiscian fibulae, having the same length and width, and similar shape in cross-section. Ornithiscians include Stegosaurus and other armoured dinosaurs, which are already known from the Jurassic of the Northern Hemisphere, including sites in England.

Top) the skeleton of a Stegosaurus (from Natural History Museum London) showing the lower hind leg bones. Bottom) the cross-section of the Eigg Dino Bone, used to study the microscopic structure.
Greg’s cross section of the bone gave us the final clues we needed to identify it. He could tell from the fine detail of the bone structure that it was most likely an ornithischian – specifically a thyreophoran, which includes animals like Stegosaurus. The holes left behind by blood vessels told us that it had a relatively slow growth rate – unlike sauropods which grow very quickly to large sizes. There was a lot of secondary remodelling in the bone, which is when the bone alters as the animal grows. Very similar patterns are seen in stegosaurs like Hesperosaurus, Kentrosaurus and Stegosaurus.

Another thing Greg could see in the bone structure were lines that accumulate as the animal matures. These are known as LAGs (lines of arrested growth), and are found not only in bones, but also in teeth. The Eigg bone had a single LAG, which tells us it was older than one year in age, perhaps just a few years older – a youngster by dino standards. There was no sign that growth had stopped, so it was probably still actively growing before it died.

Conclusions

Putting all of this information together, we can tell that this is a limb bone from a stegosaur-like dinosaur. It is most likely a fibula, or hind lower leg bone. The animal was only young when it died, and was washed into a lagoon by the sea, or perhaps just off-shore, where it was chewed-on by marine reptiles.

Although dinosaur fossils in Scotland are few, and much less complete than those found in more famous Jurassic exposures in England, they are equally important. They add data to our Spartan picture of this time period. The bone from Eigg is also significant for Scotland as the first dinosaur fossil outside of Skye, and the first belonging to a stegosaur-like, thyreophoran dinosaur. It backs up the suggestion made recently by Paige dePolo and her co-authors that fossil trackways found on Skye belonged to thyreophorans.

It has taken 200 years of searching to find this dinosaur fossil on Eigg, but hopefully it won’t take as long to find the next one! Our team is grateful to our sponsors and the people of Eigg for their support – hopefully there are many more fossil discoveries to be made in the Inner Hebrides to enrich our understanding of life in the time of dinosaurs.

Thursday, 3 September 2020

On Finding a Dinosaur

They tell me I’m good at finding things. Word searches, jigsaw puzzles - they are unintentional brain-training to isolate patterns in chaos. When looking for fossils it takes a few attempts to recognise what you’re seeking. Then they say you ‘get your eye in’, or that you ‘have the eye’ for it. I tell them, I have two.

I found my first dinosaur on a glorious sunny day in the Inner Hebrides. I leapt from boulder to boulder across the foreshore of the Isle of Eigg, sprinting like a mountain goat back to my teammates. With each jump I looked down to place my feet securely on dry Jurassic sandstone, which Velcro-gripped the soles of my tattered hiking boots. The stench of sulphur was making me dizzy – a nearby pool choked in marine algae was festering in the hot May sunshine. To avoid it, I moved up shore. As I flew down from a high platform into a small shingle inlet, I saw a silhouette. Long, with a bulbous end. Pattern recognition. 

Shoreline on Isle of Eigg, with Isle of Rum in the distance.
Momentum carried me several steps further along the clattering shingle before I fully registered what I’d seen. I skidded and turned back. The shape was nestled in a boulder tucked below the sandstone outcrops. I crouched down and reached out, running my fingertips across the rough surface. The electric-thrill formed a Bifröst to the ancient past.

Most fossils are not worth collecting, and that’s where scientific knowledge comes in. It was my fourth palaeontological expedition with teams working in my home-country of Scotland. That day in 2017 I recognised the black splodge on the rocks of the foreshore as the remains of a limb bone. It looked like burnt charcoal, the surface cracked as though oven-baked. Where the bone was damaged I saw the tell-tale honeycomb of a structure once-living; the strut of biological architecture, nature’s engineering exposed. A portion of the long mid-shaft was gone, leaving a ghostly indent in the rock. A million frozen grains of sand encased one end of the bone, reluctant to let it go. This stone had carried it for 166 million years like a time-capsule. It was a dinosaur limb bone. I took photographs, then turned and sped South again. 

The Eigg dinosaur bone, or StEiggosaurus, moments after I found it.
When I found my team mates I told them I’d found something. What is it? they asked. I knew how disappointing it was when your ‘fossil’ find turned out to be a bit of driftwood, or a splatter of solidified tar, so I replied that I wasn’t sure, but maybe a limb bone... What kind of limb bone? They pressed. I sheepishly mentioned some possibilities, non-commitally mumbling dinosaur.

I led them back along the shore. When they caught up and saw it, their faces exploded like grin-grenades. They knelt and examined it, agreeing it was indeed a dinosaur limb bone. The first dinosaur I’d found, and the first dinosaur ever found on the Isle of Eigg.

We took photographs and notes, planning how it could be collected. In the following weeks a team arrived by boat to slice through the shore and cut out its dinosaur heart. This bone - which had drifted offshore in the Jurassic sea and come to rest in a sandy bed for a geological nap - now drifted once again, southwards to the lab of our colleague, Nigel Larkin. He carefully removed the surrounding sandstone, exposing the limb bone for us to study.

My artwork showing the kind of dinosaur the Eigg bone belonged to. It may have died crossed a river or delta, and been washed out to sea.
It was scarred by scavengers, and the ceaseless surf of Eigg had made off more than half the evidence, one granule at a time. To figure out to which animal it belonged, I worked with palaeontologists who specialise in different groups of extinct reptile: Femke Holwerda (sauropod-lover), Susannah Maidment (queen of stegosaurs), Davide Foffa (marine reptile chaser), Stephen Brusatte (theropod enthuser). With so little of the bone left to study, we turned to the tell-tale biological structure for further clues. Gregory Funston examined the microscopic structure of the bone, a codex for an animal’s growth. The evidence combined to tell us that this was the leg bone of a stegosaurian dinosaur, a plate-backed herbivore of the Jurassic. An early resident of Eigg, now at rest in the National Museum of Scotland in Edinburgh.

By the time the whole team had assembled to look at the discovery on the shoreline that Summer’s day, I was already elsewhere. I’m restless as a wave, prefering movement. Hopefully life will always find me leaping along fermenting shorelines and shuffling below cliffs. I revel in zenful hours squinting at glinting surfaces, with salt spray scratching my lips and flaying my fingertips, sifting through ancient sands for fragments of Jurassic Scotland. 

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Panciroli, E., Funston, G. F., Holwerda, F., Maidment, S. C. R., Foffa, D., Larkin, N., Challands, T., dePolo, P., Goldberg, D., Humpage, M., Ross, D., Wilkinson, M., Brusatte, S. L. 2020. First dinosaur from the Isle of Eigg (Valtos Sandstone Formation, Middle Jurassic), Scotland. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 1-16.

Monday, 16 September 2019

Scottish Fossil Workshops Programme

This summer I delivered a programme of Fossil Workshops to schools across the Highlands of Scotland, funded by the Palaeontological Association. Covering 1,500 miles and speaking to over 300 pupils, I shared stories of Scotland’s amazing fossils, taught pupils about the science of palaeontology, and encouraged them to protect their precious natural heritage.


I grew up in the rural Scottish Highlands, in a geographically remote location famed for its geology. Our primary schoolwhich at its zenith had about nineteen pupils in totalrarely received visits from outreach programmes, and I don’t remember ever meeting a scientist. Despite knowing the landscape intimately, our community was cut-off from the research and teaching being carried out in our hills.

To address the disconnect between rural communities and science, I put together the Scottish Fossil Workshops programme, and secured funding from the Palaeontological Association’s Engagement Grant scheme. The aim was to reach schools in parts of Scotland that don’t regularly receive outreach, either because their location is distant from towns and cities, or due to low pupil numbers. It’s never difficult to get children excited about fossils, what’s more challenging is widening their interest beyond the toothy trappings of Tyrannosaurus. Scotland has an incredible fossil heritage, brought into the public spotlight in recent years by media attention on the Jurassic materialparticular dinosaur footprintsfound on the Isle of Skye, where my team and I carry out our research. But there are so many more tales told by Scottish fossils that extend well beyond terrible lizards: preserved bodies in rocks that whisper to us about our changing environment and the evolution of life on earth

To create the workshops I enlisted the help of Matt Humpage, a graphic designer and digital artist I’ve recently worked with on the geological-themed anthology, Conversations in Stone (with co-editor Larissa Reid). Matt volunteered to design a bespoke colour scheme and logo for the workshops, creating banners and headers for use in promotional material. Together we compiled an activity booklet for participating schools that included geological colouring-in and drawing activities, a Scottish fossil wordsearch, puppet making, and much more. I received many generous donations of books, leaflets and posters about fossils and geology for inclusion in the activity pack. The PalAss funding was used to 3D print a selection of Scottish fossils, and these augmented real fossils for the children to handle, on loan from the Natural Sciences department at National Museums Scotland (NMS)

Each fossil was a gateway to talk about extinct life and evolution.
Pupils were encouraged to ask lots of questions!
Matt and I set off at the start of May for our workshop tour. It’s a logistical challenge reaching widely dispersed rural schools, so I set the achievable goal of delivering two workshops per day over two weeks. Workshops were two hours in length, and comprised three components: an interactive PowerPoint presentation, a fossil-handling session, and a fossil-themed game. This structure helped balance listening activities with practical components, keeping children aged between five and twelve engaged with the content.

‘Great balance between focused, practical, and active tasks.’ - Teacher

The pupils were overjoyed to have a palaeontologist visit, and the fossil-handling session was a massive hit. I had selected the fossils to complement the presentation, which was split into: 1) What are Fossils?; 2) Fossils of Scotland; and 3) Being a Palaeontologist. I tied content into the Scottish curriculum for Excellence (CfE), particularly evolution, scientific enquiry, skills building, ecosystems, climate change, and digital technologies. This meant the content could be integrated into the wider teaching framework of the school. Each school was given a 10x enlarged 3D print of our recently published complete Borealestes jaw Scotland’s first-discovered Mesozoic mammalalong with a fact sheet about it, and the process of digital printing.

Scotland’s fossils provide a vivid storyline about environmental change and the evolution of vertebrate life. I chose key examples to illustrate this: the Devonian fossil fish of Caithness and Orkney; the first animals on land from the Carboniferous Borders; the strange desert-dwelling Permo-Triassic synapsids of Elgin; and finally, the rich lagoon fauna of Jurassic Skye. For each one I linked the fossils both to Scotland’s landscape and to us, telling the tale of the emergence of the mammal lineage. 

Fossils included plants and trace fossils as well as bones and 3D prints.
Schools were given a free 3D print of Borealestes, a Jurassic mammal first found on the Isle of Skye.
To emphasise the diversity of people and subjects in palaeontology, my presentation included a range of scientists from different ethnic and socio-economic backgrounds. We talked about the various research themes palaeontologists follow, and the many skills scientists employincluding less obvious ones such as art, teamwork, and communication. Teachers commented that this emphasis on a wide range of skills was inclusive and helpful for them to link taught subjects to their practical applications.

Arguably the most important goal of the workshops was to encourage the pupils to be responsible citizen scientists. Most of them had already collected fossils from local sites, and some brought examples to show me, such as ammonites and crinoids. One way to address the problems that can arise from unregulated collecting is to educate young people to protect their local natural heritage. To achieve this I incorporated the Scottish Fossil Code (created by Scottish Natural Heritage, SNH) into the talk, simplifying the message into four bullet points: Ask an Adult (don’t collect without checking it’s okay with landowners); Be Responsible (look after yourself and look after nature); Be a Good Scientist (take notes about what you find); and Tell and Expert (if you find something, show it to someone!) The children were extremely receptive to the idea that by behaving responsibly they were being like real scientists, as well as looking after their environment.

Our parting gift to the teachers was to over-excite their pupils with the role-playing Fossilisation Game. Adapted from a simpler version I found online, this game taught them about taphonomy and fossil bias. Pupils were allocated animals from Jurassic Skye, and encouraged to role-play as their animal (you can imagine the chaos). After a few minutes, we yelled at them to all ‘drop dead!’ As they lay giggling in dramatic death poses on the floor, I circulated a bag of cards to draw from randomly, and these told them if they became a fossil or not, and why. We then looked at how representative the remaining fossils were of the original animal assemblage, and the ‘best’ ways to become a fossil. 

I adapted a fossilisation game I found online to make it Jurassic Skye themed.
Anyone who does regular outreach work in schools will know how intense and exhausting it is. Between visits we spent hours on the road, often only able to pick up basic food from petrol stations or supermarkets and eating it in the car on the way to our next location. But the results, and the excitement of the pupils, were more than enough reward for the effort.

‘Yes! It’s fab for kids here to experience visits like this! We’re so far away from cities!’ - Teacher
‘Thank you! The kids all LOVED the workshops – please come again soon!’ - Teacher 

In the following months pupils entered our Scottish Fossil Art Competition. We received 127 entries, and there were four winners and 18 highly commended entries, chosen in consultation with the Natural Sciences department at NMS. The prizes included books, stickers, and postcards of extinct animals, and a ‘Palaeontologist’s Starter Kit’, with hand lens, notebook, and identification guides. As well as this, one overall winner received a rock collection for their school to learn from, containing the main rock types found in Scotland (generously donated by Angus Miller of the Scottish Geodiversity Forum).

The winners of the Scottish Fossil Art Competition.
Winners received this pack of prizes.
The overall winner also won a Scottish rock collection for the whole school to enjoy.
It was an amazing experience, made possible by PalAss funding (grant number PA-OE201801). I couldn’t have done it without the generous support and donations from NMS, SNH (especially Colin MacFadyen), the Scottish Geodiversity Forum, the STEM team at the University of the Highlands and Islands (esp. Mairi Stewart),  Dunedin Academic Press (esp. Anthony Kinahan), and the British Geological Survey in Edinburgh. Thanks to Roger Benson and Steve Brusatte for providing additional Skye fossils to print. I’m so grateful to everyone who supported me, and of course to Matt Humpage for helping design the content and deliver the workshops.

With an increased interest in Scotland’s fossils, it’s important to share the science of palaeontology with as many people as possible. It would be amazing if the workshops could continue, ideally expanding to reach the rest of Scotland. Hopefully more of us will take our research back into communitieswho knows, maybe it will inspire the next generation of citizen scientists to pursue careers in research and conservation?