FOSSILS/DINOS
Quarter-ton marsupial roamed long distances across Australia’s arid interior
3D scans lead to naming of a new genus of diprotodontid
Peer-Reviewed PublicationIMAGE: LOCATION OF THE SKELETAL REMAINS view more
CREDIT: FLINDERS UNIVERS
One of Australia’s first long-distance walkers has been described after Flinders University palaeontologists used advanced 3D scans and other technology to take a new look at the partial remains of a 3.5 million year old marsupial from central Australia.
They have named a new genus of diprotodontid Ambulator, meaning walker or wanderer, because the locomotory adaptations of the legs and feet of this quarter-tonne animal would have made it well suited to roam long distances in search of food and water when compared to earlier relatives.
Researchers say the skeleton of Ambulator keanei, found on the Australian Wildlife Conservancy’s Kalamurina Station in northern South Australia by Flinders University researchers in 2017, belongs to a species in the family Diprotodontidae, a group of four-legged herbivores that were the largest marsupials to ever exist.
“Diprotodontids are distantly related to wombats – the same distance as kangaroos are to possums – so unfortunately there is nothing quite like them today. As a result, palaeontologists have had a hard time reconstructing their biology,” says Jacob van Zoelen, a PhD candidate at the Flinders University Palaeontology Laboratory.
The largest species, Diprotodon optatum, grew to the size of a car, weighing up to 2.7 tonnes. Diprotodontids were an integral part of Australian ecosystems until the last species became extinct about 40,000 years ago.
During the period when Ambulator keanei was alive (the Pliocene), there was an increase in grasslands and open habitat as Australia became drier. Diprotodontids likely had to travel much greater distances to obtain enough food and water to keep them going.
“We don’t often think of walking as a special skill but when you’re big any movement can be energetically costly so efficiency is key,” says Mr van Zoelen.
“Most large herbivores today such as elephants and rhinoceroses are digitigrade, meaning they walk on the tips of their toes with their heel not touching the ground.
“Diprotodontids are what we call plantigrade, meaning their heel-bone (calcaneus) contacts the ground when they walk, similar to what humans do. This stance helps distribute weight when walking but uses more energy for other activities such as running.”
Diprotodontids display extreme plantigrady in their hands as well, by modifying a bone of the wrist, the pisiform, into a secondary heel, Mr van Zoelen explains.
This ‘heeled hand’ made early reconstructions of these animals look bizarre and awkward, he says.
“Development of the wrist and ankle for weight-bearing meant that the digits became essentially functionless and likely did not make contact with the ground while walking. This may be why no finger or toe impressions are observed in the trackways of diprotodontids.
“So, diprotodontids such as Ambulator may have evolved this morphology to traverse great distances more efficiently. This morphology also allowed for greater weight to be supported, allowing diprotodontids to get very big indeed.
“Eventually, this led to the evolution of the giant and relatively well-known Diprotodon.”
Most studies on the group have focused on the skull, as associated skeletons are rare in the fossil record. As such, the newly described skeleton is of great importance and is even more special as it is the first to be found with associated soft tissue structures.
Using 3D-scanning technology, the Flinders team was able to compare the partial skeleton with other diprotodontid material from collections all over the world.
Encasing the foot of the individual was a hard concretion that formed shortly after death. By CT scanning the specimen, soft tissue impressions preserving the outline of the footpad were revealed.
Note to editors: The specimen was 3D-scanned and the files are now freely available for anyone to download and look at online. They will also be included in the new Virtual Australian Museum of Palaeontology (VAMP), to be launched by Flinders Palaeontology researchers and associates on the 1 June, 2023.
Reassembled partial skeleton Ambulator keanei (SAMA P54742) with silhouette demonstrating advanced adaptations for quadrupedal, graviportal walking.
Analysis of the partial skeleton Ambulator keanei
CREDIT
Jacob Van Zoelen (Flinders University)
Flinders palaeontology researcher Jacob Van Zoelen with the partial skeleton from Australia's interior.
CREDIT
Flinders University
The new article, Redescription of the Pliocene marsupial Ambulator keanei comb. nov. (Diprotodontidae) from inland Australia and its locomotory adaptations (2023) by Jacob D van Zoelen, Aaron B Camens, Trevor H Worthy and Gavin J Prideaux has been published in the Journal of Royal Society Open Science DOI: 10.1098/rsos.230211
https://dx.doi.org/10.1098/rsos.230211
Acknowledgements: This research was funded by the Australian Government Research Training Program Scholarship (Excellence). Travel to collections was partially funded by the Royal Society of South Australia small grant scheme 2018, the Univerasity of California Museum of Palaeontology Doris O. and Samuel P. Welles Fund 2019, Flinders University Higher Degree Research International Conference Travel Grant 2019 and the North American Palaeontology Conference Student Travel Grant. For assistance in the field at Kalamurina Station, we thank Tess McLaren and Keith Bellchambers from the Australian Wildlife Conservancy.
METHOD OF RESEARCH
Computational simulation/modeling
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
Redescription of the Pliocene marsupial Ambulator keanei comb. nov. (Diprotodontidae) from inland Australia and its locomotory adaptations
ARTICLE PUBLICATION DATE
31-May-2023
Spinosaur Britain: Multiple different species likely roamed Cretaceous Britain
IMAGE: (A) SCHEMATIC GEOLOGY OF THE LOWER CRETACEOUS DEPOSITS OF THE WEALD SUB-BASIN (SOUTHEAST ENGLAND), HIGHLIGHTING PUBLISHED SPINOSAURID FINDS (CHARIG & MILNER, 1997; SALISBURY & NAISH, 2011; TURMINE-JUHEL ET AL., 2019). BASED ON AUSTEN & BATTEN (2018: FIG. 2). NOTE THAT VARIOUS ADDITIONAL SPINOSAURID TEETH ARE KNOWN FROM THE REGION BUT REMAIN UNDESCRIBED IN DETAIL (FOWLER, 2007). (B) SIMPLIFIED STRATIGRAPHIC COLUMN OF THE WEALD GROUP IN SOUTHEAST ENGLAND, BASED ON BATTEN & AUSTEN (2011: FIG. 3.2). NOTE THAT THE GRINSTEAD CLAY FORMATION, WHICH SUBDIVIDES THE TUNBRIDGE WELLS SANDS FORMATION IN BATTEN & AUSTEN (2011) AND FROM WHICH THE “SUCHOSAURUS CULTRIDENS” TYPE SPECIMEN WAS DISCOVERED (SALISBURY & NAISH, 2011), IS DOWNGRADED TO A MEMBER OF THE LATTER FORMATION IN OTHER WORKS (HOPSON, WILKINSON & WOODS, 2008) AND HAS NOT BEEN INCLUDED IN THIS COLUMN. view more
CREDIT: SPINOSAURID SILHOUETTE COURTESY OF DAN FOLKES (CC-BY 4.0).
Analysis of a British spinosaur tooth by palaeontologists at the EvoPalaeoLab of the University of Southampton shows that several distinct spinosaur groups inhabited Cretaceous Britain.
Stored within the collections of the Hastings Museum and Art Gallery in East Sussex, the fossil that forms the basis of the new study was gifted to the museum in 1889. It was collected from the local Lower Cretaceous rocks of the Wealden Supergroup, a thick, complicated rock sequence deposited across south-eastern England between 140 and 125 million years ago.
The Wealden is famous for its spinosaur fossils. Baryonyx – discovered in the Wealden of Surrey in 1983 – is one of the world’s most significant spinosaur specimens, since it was the first to reveal the true appearance of this crocodile-headed, fish-eating group. Less impressive spinosaur remains – isolated teeth – are common throughout the Wealden, and have often been identified as belonging to Baryonyx. However, some experts have long suspected that this is incorrect, and such is confirmed by the new study published in PeerJ Life & Environment.
“We used a variety of techniques to identify this specimen, in order to test whether isolated spinosaur teeth could be referred to Baryonyx”, said lead author Chris Barker, whose PhD focuses on the spinosaurs of southern Britain. “The tooth did not group with Baryonyx in any of our data runs. It must belong to a different type of spinosaur”.
The results show that distinct and distantly related spinosaur types lived in the region during Early Cretaceous times. This backs up research by the EvoPalaeoLab team, who argued in previous studies that the spinosaurs of southern England are more diverse than previously thought. In 2021, they named the ‘hell heron’ Ceratosuchops from the Isle of Wight, and in 2022 announced the discovery of what might be Europe’s largest ever land predator, a giant known only as the White Rock spinosaur. These several spinosaurs did not all live at the same time, but inhabited the region over the course of more than 15 million years.
“Museums themselves are places to make exciting discoveries as our understanding of specimens changes from the time they were deposited. What this work highlights is the importance of keeping collections alive, and developing our understanding of them. Curators are essential to help us navigate the cupboards and displays, helping us to unpick the often-incomplete records- either never fully written, or lost to time. The diversity of palaeoenvironments is not always hidden in rocks, it is often waiting in a museum, its importance waiting to be rediscovered!” - Dr. Neil Gostling
“Dinosaur teeth preserve numerous anatomical details, and we can use various analytical techniques to see how similar, or different, they are to other teeth. Our new study shows that previously unrecognised spinosaur species exist in poorly known sections of the Wealden’s history, and we hope that better remains will be discovered that improves our knowledge. Here’s another reminder that even well-studied places like southern England have the potential to yield new dinosaur species”. - Dr. Darren Naish
(A) Lingual, (B) basal, (C) mesial, (D) distal and (E) labial view. (F–G) Close up of the enamel texture on the labial tooth surface. Abbreviations: ca, carina; ce, cervix; co, crown; ent, enamel texture; flu, flute; puc, pulp cavity (infilled); ro, root. Scale bars (A–E): 10 mm, (F–G): 1 mm.
CREDIT
CC BY 4.0
JOURNAL
PeerJ
ARTICLE PUBLICATION DATE
31-May-2023
Multiple species of semi-aquatic dinosaur may have roamed pre-historic Britain
IMAGE: THE SPINOSAUR TOOTH FROM THE WEALDEN IN SOUTH EAST ENGLAND SEEN FROM TWO DIFFERENT ANGLES. view more
CREDIT: HASTINGS MUSEUM AND ART GALLERY
Palaeontologists at the University of Southampton (UK) studying a British dinosaur tooth have concluded that several distinct groups of spinosaurs – dinosaurs with fearsome crocodile-like skulls – inhabited southern England over 100 million years ago.
The team, from the University’s EvoPalaeoLab, carried out a series of tests on the 140 million year old tooth, discovered in the early 20th century, in a thick, complicated rock structure named the Wealden Supergroup. The Wealden lies across south-eastern England and was formed around 140-125 million years ago.
The scientists conducted statistical analysis on the tooth, which is stored at the Hastings Museum and Art Gallery in East Sussex. They meticulously compared its characteristics with other species in the spinosaur ‘family’ of dinosaurs to which it belongs. Their findings, published in the journal PeerJ, confirm the tooth doesn’t match that of any identified spinosaur species.
Project supervisor, Dr Neil Gostling explains: “While we can’t formally identify a new species from one tooth, we can say this spinosaur tooth doesn’t match any of the existing species we know about. Given how many individual teeth exist in collections, this could be just the tip of the iceberg and it’s quite possible that Britain may have once teemed with a diverse range of these semi-aquatic, fish-eating dinosaurs.”
The Wealden is famous for its spinosaur fossils. Baryonyx – discovered in Surrey in 1983 – is one of the world’s most significant spinosaur specimens, since it was the first to reveal the true appearance of this crocodile-headed group. Less impressive spinosaur remains – isolated teeth – are common throughout the Wealden, and have often been identified as belonging to Baryonyx. However, some experts have long suspected that this is incorrect.
“We used a variety of techniques to identify this specimen, in order to test whether isolated spinosaur teeth could be referred to Baryonyx”, said lead author Chris Barker, whose PhD focuses on the spinosaurs of southern Britain. “The tooth did not group with Baryonyx in any of our data runs. It must belong to a different type of spinosaur.”
The results show that distinct and distantly related spinosaur types lived in the region during Early Cretaceous times. This backs up research by the EvoPalaeoLab team, who argued in previous studies that the spinosaurs of southern England are more diverse than previously thought.
In 2021, they named the ‘Hell Heron’ Ceratosuchops from the Isle of Wight, and in 2022 announced the discovery of what might be Europe’s largest ever land predator, a giant known only as the ‘White Rock’ spinosaur. These several spinosaurs did not all live at the same time, but inhabited the region over the course of more than 15 million years.
“Museums themselves are places to make exciting discoveries as our understanding of specimens changes from the time they were deposited,” said Dr Neil Gostling. “What this work highlights is the importance of keeping collections alive, and developing our understanding of them. Curators are essential to help us navigate the cupboards and displays, helping us to unpick the often-incomplete records – either never fully recorded, or lost to time. The diversity of palaeoenvironments is not always hidden in rocks, it is often waiting in a museum, its importance waiting to be rediscovered!”
Co-author Darren Naish said “Dinosaur teeth preserve numerous anatomical details, and we can use various analytical techniques to see how similar, or different, they are to other teeth. Our new study shows that previously unrecognised spinosaur species exist in poorly known sections of the Wealden’s history, and we hope that better remains will be discovered that improves our knowledge. Here’s another reminder that even well-studied places like southern England have the potential to yield new dinosaur species.”
Ends
Artist illustration of a previously identified spinosaur on the Isle of Wight.
CREDIT
Anthony Hutchings
Notes to Editors
- The paper, ‘Isolated tooth reveals hidden spinosaurid dinosaur diversity in the British Wealden Supergroup (Lower Cretaceous)’ is published in the journal PeerJ, DOI: 10.7717/peerj.15453 and can be viewed here: https://peerj.com/articles/15453
- For interviews, please contact Peter Franklin, Media Relations, University of Southampton – press@soton.ac.uk +44 23 8059 3212
- Additional contacts:
Dr Neil Gostling, EvoPalaeoLab, University of Southampton n.j.gostling@soton.ac.uk 07528498792
Chris Barker, EvoPalaeoLab, University of Southanpton ctb1g14@soton.ac.uk
- The University of Southampton drives original thinking, turns knowledge into action and impact, and creates solutions to the world’s challenges. We are among the top 100 institutions globally (QS World University Rankings 2023). Our academics are leaders in their fields, forging links with high-profile international businesses and organisations, and inspiring a 22,000-strong community of exceptional students, from over 135 countries worldwide. Through our high-quality education, the University helps students on a journey of discovery to realise their potential and join our global network of over 200,000 alumni. www.southampton.ac.uk
JOURNAL
PeerJ
METHOD OF RESEARCH
Data/statistical analysis
SUBJECT OF RESEARCH
Animals
ARTICLE TITLE
Isolated tooth reveals hidden spinosaurid dinosaur diversity in the British Wealden Supergroup (Lower Cretaceous)
ARTICLE PUBLICATION DATE
31-May-2023
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