Distinctly Scottish Palaeoart: Borealestes Clan Crests

My colleagues and I recently published a new species of mammal from Jurassic Scotland, Borealestes cuillinensis. On the run up to publication I produced a palaeoart reconstruction using traditional methods (pencil, ink, paint), but when I saw the digital reconstructions by Matthew Humpage, I put mine aside in favour of his incredible work.

But I couldn’t stop thinking about my little beasties from Skye. Their evocative names, their discovery, and how these ancient beasts were wound into the rich cultural heritage of the Isle of Skye. Ruminating on all this, I ended up creating what I'm calling Borealestes Clan Crests. 

Borealestes Lucky Star, Clan Crest, by Elsa Panciroli

These palaeoart reconstructions were inspired in part by a mixture of Celtic and Pictish art and carving, and Scottish clan crests (e.g MacDonald, MacIntosh). Below, I’ll take you through the story behind each design. If you'd like a copy of the line-drawings of the images to colour-in (great activity for kids!) get in touch.

Borealestes of the Cuillin, Clan Crest, by Elsa Panciroli

The Borealestes Clan

The core of both images is a classic Celtic knot, seen in multiple sources. It forms a circle with a Pictish emblem at the top centre. The Picts were the people who lived in Scotland prior to the arrival of Gaelic-speaking peoples from Ireland, their culture having been merged into the Celtic and Norse that followed. The Pictish symbol is modelled on those found carved into stones on Skye, for example at Diurinish or Tote. It comprises a crescent with a V-rod through it, a symbol found elsewhere in Scotland as well.

Duirinish Pictish Stone (Source). Note the crescent and V-rod symbol at the top.

It’s not known what this symbol meant to the Picts – the meaning of Pictish carvings is lost to us. But it is thought that many Pictish symbols denoted particular tribes. I’ve used the idea here for the Borealestes ‘tribe’, or clan. I placed a Borealestes lower tooth at the apex of the V points, to show the shape of the lower molar, diagnostic for this genus. Within the crescent are two claw shapes pointing in opposite directions, traced from the actual fossil claw of B. cuillinensis (soon to be published), with a disc between them, symbolising the two species belonging to this genus.

The script around the top of the Celtic knot is based on Gaelic script, with some modifications. Gaelic script is a typeface used for printing Gaelic from the 16^th-18^th Century in Scotland (it survived a little later in Ireland). In the original script, a lower case ‘s’ resembled what in English is an ‘r’. This would have been confusing for modern readers, so I changed it to a smaller version of an upper case ‘S’.

Example of Gaelic Script (Source)

Borealestes serendipitus Crest

The dominant colour for this image is green, which matches the colour used in the paper for the figures of B. serendipitus. The name Borealestes means northern rogue (or brigand), so the dirk (a small Scottish dagger) pays tribute to this. It’s based on a specimen held at National Museums Scotland that came from the Highlands, and dates to the 18^th Century – truly, a time of rogues! The hilt of the original is wooden, but I’ve recreated it in horn.

An 18th Century dirk (small dagger) from the Scottish Highlands (NMS H.LC 63: source)

The wee bandit has the species name B. serendipitus, alluding to the serendipity of this lucky find (although it was not luck, Michael Waldman had done his research before seeking fossils there). To indicate this ‘luck’, I decided to incorporate a ‘lucky star’. I thought that seeing as this was the northern rogue, it’s lucky star would be Polaris, the northern star. It is the brightest star in the constellation Ursa Minor. 

Simplified constellations. Polaris is part of Ursa Minor, and can be found by orienting yourself using Ursa Major. (Source: Pintrest)

To honour the good luck of those who found this skeleton, I’ve depicted the constellations as they would have appeared looking directly north from Skye as darkness fell (at around 10pm) on the day the fossil was discovered (the 28^th of May, 1972, the fossil was collected the following year). I did this using a planisphere. The constellations depicted are, left to right: Ursa Major, Ursa Minor (with Polaris the ‘lucky star’), Draco above it, Cepheus, and finally Cygnus.

Behind the constellations, an aurora borealis glows green, signifying again that this is the northern rogue. It is an additional symbol of luck, because you need to be kind of lucky to see this phenomenon!

Borealestes cuillinensis Crest

The dominant colour for this image is blue, which matches the colour used in the paper for the figures of B. cuillinensis. This crest is simpler than the other, and focuses on the species name. The animal is named for the Cuillin, a mountain range on Skye famous for their beauty. These are the peaks in dark blue below this image. I traced the outline of their iconic ridge from my own photographs, taken during fieldwork. The sun is just setting behind them, creating a warm glow on the Western horizon.

Me enjoying the sunset, with the Cuillin mountains behind, above Loch Scavaig. (Photo: my own)

New Species of Jurassic Mammal from Scotland

This week my colleagues and I published a new species of fossil mammal, found in the Jurassic-aged rocks on the Isle of Skye. It's a sister to Scotland's first Jurassic mammal, Borealestes serendipitus, but is smaller, with differences in the upper teeth and bones of the skull. We named it for the stewards of the landscape, the Cuillin mountains, that watch over our team during fieldwork. We named it, Borealestes cuillinensis.

This is a publication I've been working towards for a long time. It incorporates some material from my PhD, which included mammal material from the richest vertebrate fossil site on the Isle of Skye, on the Strathaird Peninsula. The main specimen I was interested in was a fossil mammal skeleton, found in 1972 (collected in 1973) by Dr Michael Waldman (Stowe School) and Prof Robert Savage (University of Bristol), and their fieldwork team. Despite it being the most complete mammal from the Mesozoic known in the UK, this skeleton wasn't studied, but remained in the collections at National Museums Scotland (NMS). In the 1990s researchers at the museum rediscovered it, and then Drs Nick Fraser and Stig Walsh at NMS later teamed up with Dr Stephen Brusatte at the University of Edinburgh to offer a PhD on the fossil. I was the lucky candidate.

The skeleton belonged to B. serendipitus. It proved difficult to CT scan due to the size of the rock that contained it, so Stig and I (along with Dr Ian Corfe) took it to the European Synchrotron Radiation Facility (ESRF), where Dr Vincent Fernandez obtained amazing scans of the fossil. I've now used those to study the skeleton. With my co-authors I've gone on to publish papers on its ear bones, jaws, and now the skull.

The fossils of Borealestes serendipitus (left), and Borealestes cuillinensis (right). Above are digital reconstructions from ct and synchrotron scans, showing the skull bones inside the rock. Below are the skull reconstructions. The coloured areas (blue and green) show which bits are preserved in the specimens.

But there is a lot more to our new paper than just this specimen. The team I work with on the Isle of Skye - comprising researchers from National Museums Scotland and the Universities of Oxford and Birmingham - discovered another amazing mammal skeleton from the same locality. It was found by Prof Richard Butler (University of Birmingham) in 2018, and upon first examination appeared to be another B. serendipitus skeleton. But when we CT scanned it, I realised this was a new species of Borealestes. The upper teeth were slightly differently shaped, and in the skull the sutures between the very front of the upper jaw (premaxilla) and the main part of the upper jaw (maxilla) were in a different position. Along with other minor differences, and the smaller size of the animal, we realised we had a new species!

The fossil of Borealestes cuillinensis, moments after discovery. Only the tiny jaw was visible on the surface, Richard has great eyesight to spot such a wee beastie! (Photo by Elsa Panciroli)

The rest of the skeleton is still being studied, but the skulls are now published in the Zoological Journal of the Linnean Society. In the paper we outline the diagnostic features for the two species, and use the jigsaw of the broken skull to reconstruct the crania. As well as erecting this new species, we also realised that a species previously assigned to Borealestes, 'B.' mussettae, doesn't belong in that genus at all, so we renamed it Dobunnodon mussettae, after the Iron Age Celtic tribe that occupied the area in Oxfordshire where it was found, the Dobunni.

The molar tooth of Dobunnodon mussettae (previously 'Borealestes' mussettae), the new genus named for the Celtic tribe, the Dobunni.

One thing that threw us at first, is that the lower teeth of these two species are incredibly similar. Usually, we expect lower molar teeth (the ones at the back) to be different, which helps us name new species. But these are almost indistinguishable. We are certain the new specimen is a new species though, as I said previously, because the upper teeth are different, and the sutures in the skull are not the same. Also, we know the new fossil is an adult because it has all of it's teeth fully erupted, so it's not just a young serendipitus! This discovery teaches us that we might not be making accurate estimates of the number of species at a locality if all we have to go on are isolated fossil lower teeth and jaw fragments. Only with more complete skeletons can we be sure... but they are so rare, so we just have to do our best!

The digital reconstructions by Matt Humpage are exceptional. They show Borealestes serendipitus (left) and Borealestes cuillinensis (right), with a 5 pence coin for scale.

The incredible digital reconstructions are by Matt Humpage, and they really blow all my amateurish attempts at drawing extinct animals (as I did for previous publications) out of the water! I highly recommend you check his work out. He also does beautiful digital renders of plants, and he produces videos (including the one for this paper) - plus he's open for commissions!

Stay tuned for more wonderful fossil discoveries from Scotland!

 

Reference

Panciroli E, Benson R, Fernandez,V, Butler RJ, Fraser NC, Luo Z-X and Walsh S. 2021. New species of mammaliaform and the cranium of Borealestes (Mammaliformes: Docodonta) from the Middle Jurassic of the British Isles. Zoological Journal of the Linnean Society [online].

 

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.

Scotland's First Jurassic Mammal - our paper is out!

The first mammal fossil ever found from the ‘time of dinosaurs’ was announced almost 200 years ago*. It was a small jaw just a couple of centimetres across, which emerged from Middle Jurassic rocks in Oxfordshire, England. It was 150 years later that the first such beast was found in Scotland. This week my colleagues and I described that Scottish specimen in detail for the first time, along with stunning new material from the same species.

The most complete Mesozoic-aged mammal jaw found in Scotland so far, belonging to Borealestes serendipitus, a small insectivorous animal.

The animal these fossil bones belong to is delightfully called Borealestes serendipitus, the ‘northern rogue, found by chance’. But it was not just luck, its founder Dr Michael Waldman tells me. Mike was leading a group of school pupils on an outdoor skills trip to the Isle of Skye in the 1970s, and he knew from his research that there were fossils in the area. He never imagined they would be so spectacular or rare of course. Upon finding the first jaw, Mike brought the tiny fossil, no bigger than a thumbnail, to his mentor and friend, Professor Robert ‘Bob’ Savage at the University of Bristol. Together they returned to Skye find more fossils from Scotland’s Jurassic heyday.

Since the first publication on Borealestes in 1972, very little work has been done on it. Several jaws, a partial skeleton, and some isolated teeth were found, but only two partial jaws were published, and the descriptions were sparse. This new paper in the Journal of Vertebrate Paleontology is part of my ongoing research on the mammals of Jurassic Scotland, begun while I was at National Museums Scotland (NMS) and the University of Edinburgh. I’m part of a team from NMS and the Universities of Oxford and Birmingham who have been working on the Isle of Skye since 2010, and finding yet more of this animal and the many creatures that lived alongside it.

A new fossil jaw I found in 2016. Only the tooth tips were protruding from the rock.

Our paper is first and foremost anatomical, clarifying the identification (diagnosis) of Borealestes. In other words, how do you recognise Borealestes if you find it? This is predominantly based on the shape of the teeth. In 2003 a close relative, Borealestes mussettae, was named from isolated teeth from the English Jurassic-aged site of Kirtlington. Our new paper sets out the differences between the two species, and re-evaluates all previously known specimens in light of this new information (some were previously misidentified). 

The fossil specimens are quite exceptional. They include the most complete Mesozoic mammal jaw found so far in Scotland: a very long and slender dentary with delicate jaw hinge and perfect insect-munching teeth. There is also a Borealestes specimen I found myself during fieldwork and so feel a personal connection to, as well as the upper tooth row of a partial skeleton that I’m currently completing work on with my colleagues (watch this space!) 

The micro CT-scan of the jaw I found in 2016 revealed the rest of the bone hiding below the surface. Without computed tomography (CT) it is unlikely we could have studied this fossil intact.

This publication is the next in a series of papers on Borealestes. In 2018 my colleagues and I described the ear bones of this Jurassic animal, whereas this paper focuses on the jaw and dentition. With five jaws figured in this publication, all from micro CT-scans, the upper molar row and incisors known for the first time, and countless individual teeth re-evaluated, this paper expands our understanding of this modest docodontan, and adds significantly to the number of Mesozoic mammal specimens known from Scotland. 

*The jaw belonged to Phascolotherium. Other mammal jaws were found previous to this one, but it was the first one recognised for its significance, and was announced (alongside Megalosaurus) during the inaugural address of the Geological Society of London by its first President, William Buckland, in 1824.

References

Panciroli, E, Benson, R, and Luo, Z-X. 2019. The mandible and dentition of Borealestes serendipitus (Docodonta) from the Middle Jurassic of Skye, Scotland. Journal of Vertebrate Paleontology. https://doi.org/10.1080/02724634.2019.1621884

International Women's Day: Frances Mussett

I was recently asked by a reviewer to amend the name of one of the animals my colleagues and I were re-describing, Borealestes mussetti. ‘It should be B. mussettae’ the reviewer explained, ‘as it honours Frances Mussett’. I’d encountered Mussett’s name many times in my research, but through my own subconscious gender bias, had assumed Mussett was a man. It turns out that the original description of Borealestes mussetti used the wrong gender when erecting this species, and so Frances Mussett became masculinised both through taxonomy and assumption. 

This is one of the subtler ways in which women can be written out of science, and out of history. With International Women’s Day, 8^th March, on our doorstep yet again (and Women and Girls in Science Day just passed, 11^th February) it feels right not only to amend her namesake species (paper coming soon!), but to share some of the achievements of Mussett’s scientific career, and her role in early mammal palaeontology.

Despite being on so many of the most significant papers on Mesozoic mammals, Frances Mussett is poorly biographed. She is frequently mentioned as the assistant of Kenneth Kermack (1919-2000), one of the big names in Mesozoic mammal palaeontology, but seldom as a researcher in her own right. Mussett was a work colleague and friend of the Kermacks (a married couple and both significant palaeontologists), as well as carrying out field work with them. Her publications included co-authorship of papers on two of the most important early mammaliaforms, Kuehneotherium and Morganucodon, and although she didn’t hold a PhD she was undoubtedly a capable researcher and meticulous writer.

Reconstruction of Morganucodon by Bob Nicholls

After her bachelors degree at Birkbeck, Universoty of London, Mussett joined the thriving team of palaeontologists at University College London (UCL), collecting fossils and publishing in the 1950s-70s. The team included Professor Kenneth Kermack, Dr Doris Kermack, Jackie Papworth, Patricia Ferguson (née Lees) and Mussett, the latter two women employed by the department as Kenneth Kermack’s research technician and assistant, respectively. While Ferguson and Mussett’s roles overlapped, Mussett was more heavily involved in manuscript preparation, as well as some teaching. Mussett suffered from diabetes, and had to be strict in order to manage the condition. Restrictions at the time mean that due to her diabetes Musset was not allowed to drive, and so Lees did any driving necessary during fieldwork. 

In the 1960s the UCL team worked regularly at the Welsh fissure fills – a series of cracks in Carboniferous rocks that are filled with sediment from the Late Triassic to Early Jurassic. This sediment has proven rich in fossil material, and Kermack, Kermack and Mussett named a new genus of one of the very earliest mammaliaforms, Kuehneotherium, from among these finds (1968). 

Kermack, Mussett and Rigney (1973) were the first to realise that the Late Triassic and Early Jurassic mammals with triconodont teeth (where the main cusps are arranged in a line along the tooth axis) were a separate group from mammals with the same tooth arrangement that lived later, in the Middle Jurassic to Early Cretaceous. These were once collectively known as ‘Triconodonta’ (Osborne, 1888), but the team divided them into sub-groups, calling their earlier ones Morganucodonta, and the later ones Eutriconodonta. This was an important shift in our understanding of early mammal relationships, and later it was realised the two suborders were completely distinct (Kielan-Jaworowska et al., 2004).

One of the most famous and pivotal early mammals is Morganucodon. It belongs right at the base of the mammaliaform tree, is well-known in terms of fossil material. Along with Kuehneotherium and Sinoconodon, this genus is a touchstone for Mesozoic mammal palaeontologists. Mussett co-authored two major monographs on Morganucodon’s skull and jaw with Kenneth Kermack (1973,1981). Professor Kielan-Jaworowska, one of the most important Mesozoic mammal palaeontologists of all time, said ‘in addition to this wonderful skull, Kenneth and Frances had at their disposal thousands of isolated bones of Morganucodon watsoni from the fissure fillings in Wales’ (Kielan-Jaworowska, 2013: p80). 

The research Mussett was involved in through her role at UCL spanned much of the synapsid family tree, including examining the jaw articulation of docodonts, erecting the name Eupantotheria (Kermack and Mussett, 1958), and looking at the ears of Permian synapsids (Kermack and Mussett, 1983). In the 1970s the UCL team began work at Kirtlington Cement Quarry, a Middle Jurassic locality in England rich in small vertebrate fossils. This led to publications on the mammals from this site (Kermack, Lee Lees, Musset, 1987), as well as lissamphibians (Evans, Milner and Mussett, 1988, 1990). As an important member of the team, Mussett was part of the fieldwork, as well fullfilling her vital role assisting in manuscript preparation and editing.

After the Kermacks retired, Frances Mussett stayed on at UCL, carrying on teaching and other work, but she never published independently. Upon retirement, she donated many specimens to UCL as well as the Natural History Museum in London. Collected between 1961 and 1994 and unusually well-documented (even including the day of collection in some cases), these finds included material from the Isle of Wight, such as the bones of marine reptiles. There were also specimens of Morganucodon, Kuehneotherium and the many other exceptional mammals and small vertebrates collected during her career working alongside the Kermacks (many of these are part of the Kermack Collection). In 2003, Mussett was acknowledged in the naming of Borealestes mussetti, to recognise the ‘major participation of Dr [sic] Frances Mussett in the accumulation of the Kirtlington fauna’ (Sigogneau-Russell, 2003). 

The holotype lower molar tooth of Borealestes mussettae.

And so we come full circle. Here I am sitting in the Oxford Natural History Museum with specimens of B. mussettae – now emended to the feminine form – glinting up at me from under the lights of the microscope. Mussett herself must have spent uncountable hours this way, gazing down the eyepiece at tiny perfections of anatomy from the dawn of mammals. I wonder if she ever saw her namesake species? Undoubtedly the many hours she and women like her have spent contributing to science deserves recognition, not just on International Women’s Day, but every day.

(Note: this blog was emended as previously Pat Lees and Patricia Ferguson were listed as seperate lab members, but they were one and the same: Patricia 'Pat' Lees married John Ferguson, a senior technician at UCL and took his surname. The university Mussett attended was aldo added, and the information about her diabetes. 10/3/19 Thanks to Pam Gill for this extra information.)

References

Evans SE, Milner AR and Mussett F. 1988. The earliest known salamanders (Amphibia, Caudata): a record from the Middle Jurassic of England. Geobios, 21: 539-552.

Evans S.E, Milner AR and Mussett F. 1990. A discoglossidfrog from the Middle Jurassic of England. Palaeontology, 33: 299-311.

Gabriel N. 2018. Specimen of the Week 337: The Mussett Collection.

Kielan-Jaworowska Z, Cifelli RL and Luo Z-X. 2004. Mammals from the age of dinosaurs: origins, evolution, and structure. Columbia University Press.

Kielan-Jaworowska Z. 2013. In pursuit of early mammals. Indiana University Press.

Kermack KA and Mussett F. 1958. The jaw articulation of the Docodonta and the classification of Mesozoic mammals. Proceedings of the Royal Society of London. Series B-Biological Sciences, 149(935), pp.204-215.

Kermack DM, Kermack KA and Mussett F. 1968. The Welsh pantothere Kuehneotherium praecursoris. Journal of the Linnean Society of London Zoology, 47: 407–423.

Kermack KA, Mussett F and Rigney HW. 1973. The lower jaw of Morganucodon. Zoological Journal of the Linnean Society, 53: 87–175.

Kermack KA, Mussett F and Rigney HW. 1981. The skull of Morganucodon. Zoological Journal of the Linnean Society, 71: 1–158.

Kermack KA and Mussett F. 1983. The ear in mammal-likereptiles and early mammals. Acta Palaeontologica Polonica, 28.

Sigogneau-Russell D. 2003. Docodonts of the British Mesozoic. Acta Palaeontologica Polonica, 43: 357-374.