In the basement of the Natural History Museum, London, you will find a veritable treasure trove of remarkable stories yet to be told.  

'NHMUK PV R6795', that is the designation of a partial, disarticulated fossil skeleton. Some vertebrae, the radius and ulna from a right forelimb, parts of the hindlimbs, and other bones and fragments. 

Though the exact origin is unknown, the find was marked as being from near the village of Mkongoleko in the Ruhuhu Basin of southern Tanzania in 1933.

It is one of many such specimens from the expeditions of Francis Rex Parrington. The diversity of the extinct species found in the region by Parrington and others has been key to understanding how dinosaurs evolved during the Middle Triassic period. This particular find was subsequently studied by Alan Charig, former Curator of Fossil Reptiles, Amphibians and Birds at the Natural History Museum in the 1950s.

Yet, over eighty years later, the specimen is still throwing up surprises for palaeontologists. 

“We were studying material from the Tanzanian collection, aiming to provide the first scientific descriptions of some of these important fossils, and came across something truly special,” explains Richard Butler, Professor of Palaeobiology at the University of Birmingham. “Not only could we confirm that the specimen represents a new species, but it is a very important new species that fundamentally challenges our models of what the close relatives of dinosaurs would have looked like.”

In a 2017 letter in Nature , the team formally named and identified the significance of Teleocrater rhadinus

It roamed the Earth during the Triassic Period about 245 million years ago – pre-dating the first definite fossils of true dinosaurs by around ten million years – and appears in the fossil record just after a large group of reptiles, known as archosaurs, split into a crocodile branch (eventually leading to today’s alligators and crocodiles) and a bird branch (leading to dinosaurs and eventually birds). Teleocrater belongs to the archosaurs and is one of the oldest fossils lying along the bird branch, close to the immediate ancestry of dinosaurs.   

“Understanding how dinosaurs first evolved and became so successful has been somewhat obscured by the scarcity of well-preserved fossils,” continues Professor Butler. “This sort of find can tell us a lot about early dinosaur evolution. Yet the process from initial discovery to the naming of the species took decades. That is actually quite common because there is so much hiding in collections for us to uncover.”

It speaks to an issue that Professor Butler is keen to stress. For all of the innovation and advances in technology, the field of palaeontology is still rooted in traditional methods of discovery – be that rummaging through museum collections or through field work.

“Traditional field work is going to keep turning up new surprises. In a sense, we collect fossils in the same way that we have done for 200 years. We go out walking in areas we think might contain fossils and we excavate. Whether it is in a basement or out in the field, there is still a buzz when you think you are on the cusp of finding something new.”

Getting under the skin of fossils

Whereas methods of discovery have remained largely the same, the analysis and interpretation of specimens has made significant strides.

“Our community is pretty good at applying new techniques as they appear,” says Professor Butler. “One of the biggest transformations we have seen in the last twenty years has to be the advances made in the imaging of fossils, it has revolutionised what we do, really.”

He details how computerised tomography (CT) scans have become standard practice to help researchers understand fossils, improving the accuracy of 3D models and allowing exploration of specific questions about the internal anatomy. Synchrotron x-ray imaging, photogrammetry - it is a far cry from the techniques available to the likes of Parrington.

“It is quite like detective work, actually,” adds Professor Butler. “A lot of palaeontology is piecing together fragments of evidence. The fossil record is incomplete. We have snippets of information about the environments these extinct animals and plants lived in, their diets and behaviours, and we try to reconstruct from there. The advances in imaging help us to draw in more lines of evidence, and that has been supported by the field becoming far more interdisciplinary.” 

“We have seen a lot of people coming in from a more diverse range of scientific backgrounds in recent years – from biology, engineering and elsewhere. That has been of great benefit to the field.”

Such advances are reflected in a boon of new discoveries, now at the fastest rate on record. Professor Butler estimates that it might be pushing towards an average of one new dinosaur species discovery every week. 

“People refer to a dinosaur renaissance. We certainly seem to be seeing that, people are really curious to know more about our work and discoveries, and the advances we have made help us uncover more about our finds than ever before. I actually think movies like Jurassic Park were a significant factor in that!”

A mention of Spielberg’s iconic film evokes ideas of the well-known species; Brontosaurus, Tyrannosaurus, Velociraptor – species long since extinct. 

For the Birmingham group, the methodologies have opened up new avenues by which to understand a diverse range of vertebrate fossils, some of which feel a lot closer to home.

Part of a bigger picture

“People often refer to crocodiles as living fossils,” says Professor Butler, “but I don’t like that term. Yes, they have a very long fossil record, going back over 200 million years, but they were quite different in the past.”

Today, crocodiles are largely aquatic predators. However, our current crocodilians are just a small remnant of an incredibly diverse past. Some lived in fully marine environments, some were smaller with long greyhound-like limbs, and were probably capable of running quickly, and some were much larger, fully terrestrial predators. 

Dr Felipe Montefeltro, from São Paulo State University (UNESP), has been working with Professor Butler and other University of Birmingham researchers including Dr Stephan Lautenschlager over a number of years, but more recently has spent time in Birmingham on a Rutherford Fellowship. His key focus has been using some of the new imaging techniques to explore crocodilian fossils and see what more we can learn about their functional morphology.

The scans have allowed the team to reconstruct the anatomy of crocodilian skulls and apply computer modelling techniques used in engineering to answer key questions about their functions. What happens when you apply forces? How strong is the jaw? What can that tell us about behaviour and diet?

“We know that in Cretaceous ecosystems in Brazil – about 80 to 90 million years ago – crocodilian reptiles are the main land predators,” explains Professor Butler. “It is a role that, in other parts of the world, is being filled by large predatory dinosaurs like tyrannosaurs. So by comparing them explicitly to large-skulled dinosaurs rather than other crocodilians we hope to find out more about their function and their importance to the broader ecosystem.”

Much as detective work is needed to gather evidence about individual species in a focused study, Professor Butler stresses the equal importance that the hundreds and thousands of small scale studies play in laying the groundwork for ‘bigger picture’ work – investigating changes within ecosystems over millions of years.

“In the aftermath of the Permian-Triassic mass extinction event, about 250 million years ago, around ninety percent of species went extinct. You have this significant transformation of ecosystems in its aftermath with the emergence of the dinosaurs and the origins of modern groups such as mammals. For me, discoveries like Teleocrater rhadinus are another piece in the jigsaw for our understanding of the recovery from this extinction, and for understanding how and why dinosaurs became so successful.”

“Crocodilian diversity is a further example of that. In the last 60 million years they have gone from being incredibly diverse to what we now see where they occupy this aquatic, quite conservative niche. To understand why, you need a more complete picture of the environments they lived in. The work Felipe is doing helps us to build our knowledge base in that regard.”

Getting to grips with long-term change in ecosystems takes on greater meaning amid what is being labelled as a modern biodiversity crisis, the sixth mass extinction event. 

The longitudinal, historical perspective provided by the Birmingham group and collaborators across the globe helps to explain how ecosystems recover from, and how they are transformed by, mass extinction events.

A 2019 paper in Nature Ecology and Evolution, examined how the diversity of land vertebrate species has changed over the last 375 million years through the analysis of nearly 30,000 fossil sites. Tellingly, the research found that biodiversity on land may have been broadly similar for the last 60 million years, since soon after the extinction of the dinosaurs. Such insight provides valuable context for current trends.

Equally, their work can help shine a light on how climate change over time can affect vertebrate evolution. 

“I am always a bit cautious about how much we can extrapolate that climate data,” warns Professor Butler. “We talk about change over millions of years and the climate change we are seeing at the moment is happening over hundreds of years. That said, there are definite lessons we can learn.”

A strategic research partnership

That need to understand global trends is only possible through international collaboration. 

One such relationship, between the UK and Brazil, has proven to be particularly fruitful in building our understanding of vertebrate evolution. The University of Birmingham has hosted a number of PhD students and visiting fellows from Brazilian institutions, and research links between the two countries continue to grow.

The links with UNESP have generated strong results, and Professor Butler speaks of a desire to build further links with the Federal University of Pampa (UNIPAMPA) in the most southerly part of Brazil to undertake fieldwork along the border with Uruguay, home to the Sanga do Cabral Formation – with its wealth of fossils from the immediate aftermath of the Permian-Triassic mass extinction.

An ongoing collaboration with the president of the Brazilian Palaeontological Society, Professor Max Langer of the University of São Paulo (USP) was at the heart of a recent find. Dr Julio Marsola, whose PhD was split between USP and a year in Birmingham, was the lead scientist on a find from the Santa Maria Formation that was described in an early 2019 paper in the Journal of Vertebrate Paleontology.

 

Plenty can be understood from the name of the new dinosaur, Nhandumirim waldsangae. The generic name combines the Portuguese derivatives of the indigenous Tupi-Guarani words ‘Nhandu’ (running bird, common rhea) and ‘Mirim’ (small), in reference to the size and habits of the dinosaur. The specific epithet name refers to the Waldsanga site, the historic outcrop in the Santa Maria Formation that yielded the new species.

“What excites me about this find is that is displays some typical theropod characteristics that we see in better known bipedal predators, but from very early on in the chain of dinosaur evolution,” enthuses Professor Butler. “It might even be the oldest record of the group found in Brazil so far.”

“Whether it is in the field, or the depths of a museum basement, these fossils continue to help us piece together the ecosystems of the past and, perhaps, show us more about where we are going.”

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