Tag: discoveries

Skye fossil discovery reveals mammals grew more slowly in the Jurassic than they do today

Two unique Jurassic fossil discoveries from the Isle of Skye have shown that mammals in the time of the dinosaurs grew more slowly and lived longer than mammals today. 

A new study in Nature by an international team of researchers led by National Museums Scotland describes two Krusatodon kirtlingtonensis fossils, one adult and one juvenile, both discovered in Skye.

These mouse-sized mammals lived around 166 million years ago. The specimens represent the only juvenile Jurassic mammal skeleton known to science, while the adult is one of the most intact mammal skeletons from this time period in the world. 

The discovery of a juvenile and adult of the same species of early mammals is unique and has allowed groundbreaking comparative analysis into their growth and life history. The ages of the specimens at death were determined using X-ray imaging to count the growth rings in their teeth.

The adult was found to be around 7 years old and the juvenile between 1 – 2 years, and still in the process of replacing its baby teeth.  This was possible thanks to X-ray computed tomography carried out in several laboratories, including the European Synchrotron (ESRF).

Today, small mammals have significantly shorter lifespans, some living as little as 12 months, and maturing quickly, losing their baby teeth and weaning within months of birth. The Krusatodon fossils reveal for the first time that the earliest mammals didn’t finish replacing their teeth until well into their second year of life, possibly later. This tells us that a fundamental shift in the growth patterns and life expectancy of mammals must have taken place during or after the Middle Jurassic. 

The specimens were discovered decades apart, with the adult being one of the earliest Jurassic finds on Skye in the 1970s, while the juvenile was discovered in 2016.  

Dr Elsa Panciroli, lead author and Associate Researcher of Palaeobiology at National Museums Scotland, said: “These fossils are among the most complete mammals from this time period in the world. They give us unprecedented insights into the lives of the first mammals in the time of dinosaurs.

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“Although on the outside Krusatodon looked like a shrew or mouse, on the inside it was quite different; it grew more slowly and lived much longer than small mammals do today. As a result, it probably had quite a different physiology and life history as well. Skye’s fossils are really putting Scotland firmly on the map when it comes to understanding mammal evolution.

“This is just the tip of the iceberg in terms of what they can tell us.” 

Dr Stig Walsh, Senior Curator of Vertebrate Palaeobiology at National Museums Scotland and co-author on the study, said: “Even in the context of the amazing palaeontological finds on Skye in recent years, these fossils are remarkable. 

“Mammal fossils of this age are exceptionally rare worldwide, and most are just single teeth found by sieving sediment. To find two such rare fossil skeletons of the same species at different growth stages has rewritten our understanding of the lives of the very earliest mammals. 

“We’re thrilled they are both now part of Scotland’s National Collection, an important part of the global fossil record, and will be preserved for generations of researchers to come.” 

In addition to National Museums Scotland, the study also involved researchers from the American Museum of Natural History, University of Chicago, European Synchrotron Radiation Facility, and Queen Mary University of London. 

Prof. Roger Benson from the American Museum of Natural History said of the fossil found in 2016:  “When we found the tiny juvenile skull I didn’t realise what we’d found right away.

“The part of the fossil that was sticking out of the rock was blasted by erosion, surrounded by barnacles, and looked just like a piece of ash. I used micro-CT scanning, a form of 3D X-ray imaging, and was very surprised to see a whole skull in the rock. For science,

“it’s really remarkable to have this fossil and it told us a lot about growth and life history in some of the earliest mammals” 

Dr Elis Newham, a Postdoctoral Research Associate at Queen Mary University of London said: “Our study benefited greatly from a new technique we developed using synchrotron X-ray technology.

“This allowed us to analyse growth patterns in the teeth of these fossils, much like counting tree rings. It was surprising to discover that Krusatodon, while showing a similar development pattern to modern mammals, grew much slower and lived longer.

“This research emphasises the value of studying juvenile fossils, and the X-ray cementochronology technique offers a powerful tool for unlocking these secrets from the past.”

The paper was published in Nature yesterday, 24 July 2024. 

University researchers shine new light on the secrets of Stonehenge

Geophysical sensors, excavations and computers reveal millennia of prehistoric land use at Stonehenge

Researchers from the University of Birmingham and Ghent University (Belgium) have discovered hundreds of possible large prehistoric pits – and thousands of smaller ones – at the heart of the Stonehenge landscape, challenging our understanding of land use through time at the most intensively investigated prehistoric site in the world.

A large pit, over 4 metres wide and 2 metres deep dug into chalk bedrock, stands out as the most ancient trace of land use yet discovered at Stonehenge.

Over 10,000 years old, it bears witness to hunter-gatherers roaming the landscape during the early Mesolithic, when Britain was re-inhabited after last Ice Age. This is only one of many new sites and unexpected patterns of prehistoric activity detected at Stonehenge by the Ghent-Birmingham research team.

These results were achieved by combining – uniquely – the first extensive electromagnetic induction survey undertaken in the Stonehenge landscape with evidence from over 60 geoarchaeological boreholes, 20 targeted archaeological excavations, and computer-generated analyses of thousands of subsurface features, such as pits, revealed by the geophysical data.

Philippe De Smedt, Associate Professor at Ghent University said: “Geophysical survey allows us to visualize what’s buried below the surface of entire landscapes. The maps we create offer a high-resolution view of subsurface soil variation that can be targeted with unprecedented precision.

“Using this as a guide to sample the landscape, taking archaeological ‘biopsies’ of subsurface deposits, we were able to add archaeological meaning to the complex variations discovered in the landscape.”

The combination of novel geophysics and ‘traditional’ archaeology has revealed otherwise elusive archaeological evidence around Stonehenge. From 2017, the team carried out excavations to evaluate just how accurate the results of the geophysical survey mapping and interpretation had been.

These samples provided information for developing a model of types of archaeological evidence revealed in the geophysical data, resulting in computer-generated maps of traces of prehistoric activity.

Henry Chapman, Professor of Archaeology at the University of Birmingham said: “When used correctly, geophysical sensors do not ‘lie’. They represent a physical reality. Converting that observed reality to archaeological knowledge, however, is not a straightforward process.

“As archaeologists, we need information on aspects such as chronology and function as a basis for understanding past human behaviour. That puzzle contains pieces that can only be retrieved through excavation.”

A striking result of the project has been the identification of over 400 potential large pits (each over 2.5 metres in diameter), of which six were excavated in the course of the project, ranging in date from the Early Mesolithic (c.8000 BCE) to the Middle Bronze Age (c.1300 BCE).

While each of these sites adds to our knowledge of prehistoric activity in the Stonehenge landscape, the Mesolithic pit stands out as exceptional. The size and shape of the pit suggest it was probably dug as a hunting trap for large game such as aurochs, red deer and wild boar.

Dating to 8200-7800 BCE, it is not only one of the earliest of the very few Mesolithic sites near Stonehenge (predating, for instance, the Blick Mead occupation site 1.5 kms away), it is also the largest known Early Mesolithic pit feature in north-west Europe. 2/5 Mapping of the large pits also shows that they cluster in parts of the landscape that were repeatedly revisited over millennia, notably on the higher ground to the east and west of Stonehenge.

The social contexts of this activity changed radically over time, yet the spatial distribution of these pits suggest similar interests in locales that allowed extensive vistas overlooking the site of Stonehenge.

The implications of this research for rethinking the spatial extents, temporalities and sensory qualities of diverse kinds of prehistoric behaviour beyond the obvious ceremonial monuments, are highly significant for understanding Stonehenge and its landscape setting.

Paul Garwood, Senior Lecturer in Prehistory at the University of Birmingham: “What we’re seeing is not a snapshot of one moment in time. The traces we see in our data span millennia, as indicated by the seven-thousand-year timeframe between the oldest and most recent prehistoric pits we’ve excavated.

“From early Holocene hunter-gatherers to later Bronze Age inhabitants of farms and field systems, the archaeology we’re detecting is the result of complex and ever-changing occupation of the landscape.”

While the Stonehenge landscape is unique, the research methods used are relevant to all archaeological environments. Sensor technologies and computer-based analysis are increasingly important aspects of archaeological research, providing new ways to explore ancient landscapes.

At the same time, they must be integrated at every stage with evidence recovered by excavation to provide us with the rich cultural, environmental, and chronological information that we need to interpret our findings.

As this project shows, these methods can radically change our understanding of ancient landscapes even in a setting as intensively investigated as that at Stonehenge.

Much of the research and excavation for the project was carried out on land owned by the National Trust.

Dr Nick Snashall, Archaeologist for the Stonehenge & Avebury World Heritage Site, said: “By combining new geophysical survey techniques with coring, and pin point excavation, the team has revealed some of the earliest evidence of human activity yet unearthed in the Stonehenge landscape.

“The discovery of the largest known Early Mesolithic pit in north-west Europe shows that this was a special place for hunter-gatherer communities thousands of years before the first stones were erected.”

Reference to published results: De Smedt, Philippe, Paul Garwood, Henry Chapman, Koen Deforce, Johan De Grave, Daan Hanssens, and Dimitri Vandenberghe. “Novel Insights into Prehistoric Land Use at Stonehenge by Combining Electromagnetic and Invasive Methods with a Semi-Automated Interpretation Scheme.” Journal of Archaeological Science, 2022.