A new species of mammal the size of a shrew which lived alongside dinosaurs in Purbeck during the Cretaceous era has just been discovered at Durlston Bay in Swanage, Dorset.
Bones from the prehistoric species which survived the mass extinction of dinosaurs caused by an asteroid striking Earth 65 million years ago, were found by an undergraduate paleontology student from the University of Portsmouth.
A paleontologist’s impression of the creature, which would have been the size of a modern day shrew
Confirmed as an entirely new species
Ben Weston made the remarkable discovery while he was carrying out fieldwork at Durlston and the tiny jawbone he collected from the cliffs was later confirmed to be a completely unknown species.
The 16.5 millimetre long jaw – the size of a modern day shrew or mouse – was characterised by a long pointed incisor at the front, followed by a gap and then four razor sharp premolars.
Although it superficially resembled a tiny rabbit’s jaw, the pointed incisors and sharp premolars identified it as belonging to an extinct group of mammals – the multituberculates – dating back 140 million years.
It is the first jaw of any animal from the multituberculate group found at Swanage since Victorian times, and its unique size and shape confirmed it as an entirely new species when details of the discovery were published in Proceedings of the Geologists’ Association in July 2025.
The new species has been named by Ben Weston as Novaculadon mirabilis, with ‘novacula’ describing its razor like back teeth and ‘mirabilis’ referring to the miraculous preservation of the specimen.
The point in Durlston Bay where the amazing discovery was made
Durlston Bay viewed from Peveril Point, looking towards Durlston Head
“Literally the very last hour on the beach”
Undergraduate paleontology student Ben Weston said:
“Multituberculate animals are basically the Mesozoic equivalent of rodents. The earliest fossils we have are from the middle Jurassic from the UK, Russia and Germany, but it is believed they probably evolved a bit earlier than this.
“They lived past the extinction that killed off the dinosaurs before they were eventually outcompeted by other mammals like rodents and died out about 30 million years ago.
“This fossil I discovered was from the very beginning of the Cretaceous, so about 140 million years ago. In this lagoon area where Swanage is today, we would have had pterosaurs, turtles, crocodilians and some therapods and sauropods roaming around.
“I was basically just walking on this beach in Swanage in the summer of 2023 doing fieldwork for my third year dissertation around pterosaurs – but on the very last day, literally the very last hour I was on the beach, I came across this big block and just poking out of it was a specimen.
I was looking at rocks of the Lulworth Formation that are exposed there – I had been given a scrappy little fossil of a pterodactyl found at Durlston Bay to work on, and as a part of that study, was collecting environmental and sedimentological data.
Ben with a 3D printed model of the jaw he discovered at 10 times its real size
“Dinosaurs are stomping about”
Ben added:
“I just gave the top of the rock a tap and it fell out straight into my hand. Multituberculates are the most common mammal in these rocks, but there are not many of them – this is only the 10th species to come out of the Purbeck rock and the first species known from a jaw since Victorian times.
“Because the jaw is so robust, it was probably feeding on tough foods like seeds, nuts, berries and tubers, but also on insects and other little grubby things as well.
“If you picture the creature in this lagoon environment where tides are coming in and out and dinosaurs are stomping about, the skeleton is going to get broken up quite quickly.
“It’s good that the jaw and teeth are so robust because they are covered in enamel and less likely to fall apart than the rest of the skeleton. I instantly had my suspicions of what the jaw was when I found it at the beach, but couldn’t have imagined where the discovery would take me.
“Durlston Bay is really quite a special place specifically because of the extensive history of mammal fossils that emerged during the Victorian era – it was one of the few places worldwide with mammal fossils from the age of the dinosaurs.
“The Dorset coastline has been hugely important in fostering my love for palaeontology: I found my first ever fossil, an ammonite, on Charmouth beach, and have often visited the area since, including for the Lyme Regis Fossil Festival that goes on there every year.”
Ben took part in the recent Lyme Regis Fossil Festival along with other students from the University of Portsmouth
“This is a remarkable find”
This was not the first time a student has made a once in a lifetime discovery in Dorset.
In 2017, Portsmouth University undergraduate Grant Smith recovered fossils of two new species of humankind’s earliest ancestors from rocks exposed in cliffs near Swanage.
Honorary research fellow Dr Steve Sweetman, who specializes in rare early Cretaceous mammal fossils from the Isle of Purbeck, said:
“This is a remarkable find that reminds me of when Grant found those extraordinary eutherian mammal teeth.
“When I first saw Grant’s specimens, my jaw dropped, and I had exactly the same reaction to Ben’s multituberculate jaw. It’s incredible that Durlston Bay keeps delivering such significant mammal discoveries by our undergraduate students.”
Dr Roy Smith said the discovery was an amazing find
“No discovery like this since Victorian times”
And research supervisor Dr Roy Smith added:
“The fossil is quite fragile, so we decided to CT scan it in super high resolution, in order not to damage it, then compiled the data into a 3D printed model.
“It is absolutely amazing technology, really cool that you can get so much data without any risk to the fossil when it is only a few millimetres in length.
“This discovery is a fantastic fossil and when Ben showed me it I was completely amazed. He was really lucky to find this wonderful specimen – there hasn’t been a discovery like this in the Purbeck region from these rocks since Victorian times.
“It is an incredibly significant find in the way it has furthered our knowledge of the mammals which lived at this time in the age of the dinosaurs with implications for the diversity and the evolution of this long lasting lineage.”
Herds of sauropods would have lived around the shallow lagoons which covered Purbeck 140 million years ago
Evolved over 130 million years on Earth
At the time this creature lived, Swanage would have been covered by a freshwater lagoon and would have been much warmer than today. Herds of brachiosaurs are known to have lived here, as more than 100 of their footprints were discovered in Keates Quarry near Langton Matravers.
Creatures like Novaculadon mirabilis would have been living in wooded swaps at the edge of the lagoon, carving out their own ecological niches while giant dinosaurs roamed nearby.
Multituberculata was the most diverse order of Mesozoic mammals, with over 200 known species ranging from mouse sized to beaver sized, which evolved over their 130 million years on Earth to find safety and food by burrowing into the ground or climbing trees like squirrels do today.
Portsmouth paleontology student Hamzah Imran created an artistic reconstruction showing the animal as a small, furry creature with speculative spots and stripes, believing they would have given the protection of camouflage amongst the trees.
Brachiosaurus footprints have been discovered in a former quarry near Langton Matravers
An artist’s impression of life around the Purbeck lagoon in the Cretaceous era
Further information
- The full research is published at sciencedirect.com
