Ancient Triassic Seas of South West England Teemed with Life

An ancient coastal landscape has been brought to life thanks to the dedicated research of an undergraduate from Bristol University.  Klara Nordén has explored the diversity of animal life that inhabited the shorelines of south-western England 200 million years ago (Late Triassic), using fossils collected by Gloucester-based geologist Mike Curtis back in the 1980s.

Late Triassic Landscape

The student from the School of Earth Sciences (Bristol University) examined material from Late Triassic sediments at the Marston Road Quarry, near the town of Nunney in Somerset.  This site is well known for its microfossils and many types of fossil teeth.  Although Mike Curtis collected the material back in the 1980s the fossils have not been formally studied until now.

The paper published in the “Proceedings of the Geologists’ Association” highlights the diverse fauna that once existed in this part of south-western England.  The palaeoenvironment consisted of a shallow, tropical sea with many small islands close by.  It was on these islands that Bristol’s very own dinosaur the Thecodontosaurus roamed.

Triassic Fauna

Thecodontosaurus was the fourth dinosaur to be officially described (actually it was described before the term Dinosauria had been erected).  Although a number of specimens were lost when Bristol City Museum was bombed in World War II, enough fossil material has been collected to make this little Sauropodomorpha one of Britain’s best known early Mesozoic dinosaurs.

To read an article about Thecodontosaurus: Bristol Remembers Thecodontosaurus.

The study revealed a total of six species of bony fish and a further six species of shark, as well as the presence of a placodont, a type of marine reptile believed to be distantly related to the plesiosaurs and a member of the Sauropterygia.  The placodont has been identified as Psephoderma alpinum.  Described as being lizard-like with an armoured shell, this reptile fed on shellfish and other invertebrates found in the sediment on the seabed.

Psephoderma alpinum

An Artist’s Drawing of the Placodont Psephoderma alpinum

An illustration of the Triassic placodont Psephoderma.

Picture credit: James O’Shea

Predatory Marine Reptiles

In addition, the study revealed the presence of a number of predatory marine reptiles including a crocodile-like animal in the shallow coastal waters (Pachystropheus rhaeticus), a semi-aquatic reptile first described in 1935, nearly one hundred years after the fossils of Thecodontosaurus were scientifically studied.

Commenting upon her research into this ancient Somerset archipelago, student Klara stated:

“We were excited to find teeth from a placodont, which are rare in British sediments.  The presence of placodonts indicates that the area was once a coastal environment, with shallow waters and abundant invertebrate prey.  Placodonts were in decline in the Late Triassic and the placodont teeth from Marston Road mush come from some of the last of these reptiles to exist on Earth.”

The strata in this part of the world associated with the Upper Triassic (Rhaetian faunal stage), is well-known for its bone beds containing abundant remains of fish and reptiles.  It is not just marine fauna that has been preserved, fluvial processes have resulted in the long distance transport of the remains of land animals around at the time becoming deposited into the shallow marine strata being laid down.

The study also revealed the presence of sphenodontians that would have co-existed on the tropical islands alongside the dinosaurs.

Sphenodontians Alongside Dinosaurs

Sphenodontians inhabited the islands in the archipelago, which they shared with Thecodontosaurus, the famous ‘Bristol dinosaur’.  These small animals resemble lizards but they are not members of the Order Squamata.  They represent a very ancient reptilian lineage that probably originated in the Early Triassic.  Like lizards and snakes, they are diapsids and the sphenodontians are classified along with snakes and lizards in the SuperOrder Lepidosauria but on a distinct branch from the Squamata, (the Rhynchocephalia – meaning “beak heads”).  This study documents the first time that sphenodontian fossils have been recorded in British marine sediments.

Although once diverse, there is only one genus of Sphenodontian living today, the remarkable Tuatara that can be found on a few New Zealand islands (there are attempts being made to introduce this little reptile back to the New Zealand mainland).

To read an article about a genetic study into these ancient reptiles: The Tuatara Has a Surprise in its Genes.

The Triassic Fauna of a Coastal Landscape

Klara’s supervisor is Professor Michael Benton (School of Earth Sciences), he explained that the fossils reveal the details of a coastal landscape that existed some 200 million years ago and they paint a very different picture from today, after all, the Bristol Channel can hardly be regarded as a tropical sea.

The Professor stated:

“It’s really unusual to find remains of land-living animals mixed in with the marine fishes and sharks.  They must have been washed off the land into the shallow sea and this provides evidence to match the age of the marine and terrestrial deposits in the area.”

Co-author of the report, published in the “Proceedings of the Geologist’s Association”, Dr Chris Duffin added:

“I began working on these fossils from the Bristol area forty years ago and it’s great to see such wonderful work by a Bristol undergraduate.”

For models and replicas of Triassic dinosaurs and other prehistoric animals: CollectA Age of Dinosaurs Models and Figures.

Dinosaur Fossils Go on Display at Local Museum

Iconic locations such as the Badlands of Montana, the Hell Creek Formation and the exotic sounding Tendaguru Beds are the sort of places that most people would associate with spectacular dinosaur discoveries, but residents of East Sussex (southern England), don’t have to travel too far to explore life in the past.  The fossilised remains of a large, plant-eating dinosaur have just gone on display at Bexhill Museum.  The bones not only represent a dinosaur, but one of the most successful kinds of dinosaur, or indeed, any land vertebrate that has ever existed.

Hypselospinus Fossils

Say hello to Hypselospinus (Hypselospinus fittoni), a member of the Iguanodon-like group of dinosaurs, (Iguanodontia clade), fossils of which have been found all over the world.  Plant-eating dinosaurs such as the iguanodontids existed on our planet from the Middle Jurassic right up to the end of the Cretaceous, that’s a time span of some ninety million years or so.

Putting things into context, the Bexhill Museum specimen represents a type of herbivorous dinosaur the like of which roamed Earth over a period of time some four hundred times longer than our own species has existed.  Hypselospinus was a medium sized iguanodontid, it may not have been the largest of its kind, but with an estimated length of six metres and a body mass perhaps around the two tonnes mark, Hypselospinus was a sizeable beast!

Fossils on Display at the Museum

140-million-year-old dinosaur bones on display.

Picture credit: Bexhill-on-Sea Observer

Hypselospinus fittoni

Hypselospinus (H. fittoni) is known from a variety of post cranial fossil material, all of it (we think), found in East Sussex.  The Hypselospinus fossils on display at Bexhill Museum consist of a number of limb bones and other material such as a beautifully preserved caudal vertebra (tail bone).  Local palaeontologists Peter and Joyce Austen are credited with the discovery, but it was David Brockhurst, an amateur fossil hunter, perhaps most famous for his work on Europe’s smallest known dinosaur, the curious “Ashdown Maniraptoran” who was responsible for the excavation.

The independent, voluntarily-run museum located in Egerton road, just an Argentinosaurus length away from the picturesque sea front, has a number of important fossils found in the local area on display.  It might be difficult for residents of Bexhill-on-Sea to believe, but back in the Early Cretaceous this part of England was home to a variety of dinosaurs and also flying reptiles (Pterosaurs).

An Iguanodontid

Hypselospinus was typical of an iguanodontid. It had a rectangular shaped skull, which ended in a broad muzzle with a beak that was well suited to cropping vegetation.  It spent most of its life ambling around on all fours, but it could, if it so wished, rear up onto its powerful back legs and adopt a bipedal stance.  Large neural spines associated with the dorsal vertebrae (back bones) suggest that Hypselospinus had a steeply arching back, this feature distinguishes this dinosaur from other iguanodontids associated with southern England.

A Model of a Typical Iguanodontid (Iguanodon)

A typical Iguanodontid dinosaur.

Picture credit: Everything Dinosaur

To view models and replicas of iguanodontids and other Early Cretaceous dinosaurs: CollectA Prehistoric Life Figures.

The Bexhill Hypselospinus

The Bexhill Hypselospinus fossils are being written up by Dr David Norman (Cambridge University), a palaeontologist who has studied a number of iguanodontid species and even has a plant-eating dinosaur, possibly another type of iguanodontid, but this time one that roamed China a few million years after Hypselospinus existed, named after him (Equijubus normani).  We look forward to reading Dr Norman’s appraisal of the Bexhill material.

Bexhill Museum curator, Julian Porter commented:

“We have got most of the parts, including the arms and legs.  One thing which is missing, however is the “thumb spike”.  Either we have not looked in the right place or it may be that this particular species didn’t have the thumb spike like other Iguanodonts.”

Perhaps, Everything Dinosaur can help to clear up the “thumb spike” issue, the Natural History Museum (London), has within its extensive ornithischian dinosaur collection a partial right forearm with an thumb spike measuring around eight centimetres in length.  This specimen (NHMUK R1832) has been assigned to Hypselospinus fittoni.

Checking Details in a Book

It’s a good job we had our “Dinosaurs of the British Isles” book (Dean Lomax and Nobumichi Tamura), handy to cross reference our notes on Hypselospinus fossil material.

If this is correct, than just like the more famous Iguanodon, Hypselospinus had a thumb spike, this spike probably served as a defensive weapon, very helpful, as large meat-eating dinosaurs also roamed around this part of East Sussex during the Early Cretaceous.

To learn more about Bexhill Museum: Bexhill Museum.

To read more about the “Ashdown Maniraptoran”, the cervical vertebra of which is on display at the museum: Europe’s Smallest Dinosaur.

Biologist Provides Fresh Insight into Early Cretaceous Dinosaur Tracks

Many of us, will this summer, go for a stroll along the beach whilst on a visit to the seaside.  It seems this pastime may have been popular with theropod dinosaurs too.  Biologist Pernille Venø Troelsen of the University of Southern Denmark, has provided a fresh perspective on a set of fossilised dinosaur tracks, part of an extensive set of dinosaur trackways uncovered in Lower Cretaceous sediments at Münchehagen, twenty miles northwest of the city of Hanover (Germany).  The scientific paper on these footprints formed part of her Masters degree.

Meat-Eating Dinosaur Tracks

The exposed strata forms part of the Bückeberg Formation, which in turn is part of the Lower Saxony basin of northern Germany and the eastern Netherlands.  The rocks laid down represent sandstones and silts in a brackish environment as this part of Europe during the Early Cretaceous (Berriasian to Valanginian faunal stages), was on the coast of a shallow, tropical sea, which stretched up into the Arctic circle and covered most of what is now Germany, the Low Countries and parts of France.

The footprints have been dated to around 142 million years ago (Early Cretaceous) and they represent tracks made by a large theropod dinosaur and a second, much smaller theropod.

An Illustration of a Typical Theropod Dinosaur

The image above comes from the excellent “Dinosaurs of the British Isles” book.

Picture credit: Nobumichi Tamura

The image of a theropod dinosaur strolling along a beach is from the front cover of the highly informative “Dinosaurs of the  British Isles” by Dean Lomax and Nobumichi Tamura.

More details about this dinosaur book can be found here: Siri Scientific Press.

Hundreds of Dinosaur Tracks

Although many hundreds of dinosaur footprints have been uncovered in this part of northern Germany, for Pernille, these tracks give her the opportunity to infer aspects of dinosaur behaviour, that many people might not associate with ferocious predatory dinosaurs.  For example, the theropods were ambling along, seemingly in no hurry.  The impressions made in the wet sand and now fossilised preserve a tiny fragment of life in the Early Cretaceous, from time to time, the dinosaurs skid on the wet sand and these slips and skids have been preserved in the sandstone.

The larger of the two meat-eaters, stood around 1.6 metres high at the hips, the smaller animal had hips that were around 1.1 metres high.  Hip height can be calculated by measuring the stride length of each dinosaur.  Both dinosaurs are moving in a south-easterly direction.

Mapping Dinosaur Footprints (Early Cretaceous Dinosaur Trackways)

T3 is the large theropod track, T2 represents the smaller theropod. The iguanodontid track is highlighted in green.

Picture credit: Pernille Venø Troelsen (University of Southern Denmark) with additional annotation by Everything Dinosaur

In the picture above, the tracks of the large theropod (T3) are highlighted in orange.  The smaller theropod (T2) is in red.  Each footprint has been numbered, more than fifty individual footprints were included in the study under taken by Penille Venø Troelsen.  Her interpretation of the inferred behaviours was presented at the thirteenth annual meeting of the European Association of Vertebrate Palaeontologists, last month, in Opole, Poland.  The paper was presented to the conference on the 10th of July.

Different Types of Dinosaur Represented

At some point, a large ornithopod, probably an iguanodontid wandered across the beach.  The trackway has been mapped onto the photograph above by Everything Dinosaur team members and the direction of travel noted.  It is not known whether this big, plant-eating dinosaur walked over the beach, before or after the theropods.  No interaction between the herbivore and the theropods is inferred.

Trace fossils such as dinosaur footprints provide evidence of the activity of organisms.  Unlike body fossils, in which the carcase of an animal might be transported many miles after death (by river currents for example), most trace fossils show direct, in situ evidence of the environment at the time and the place where the animal lived.

If you were to step into the footprints made by these dinosaurs you would be literally “walking with dinosaurs”, but for the sake of preservation we would urge readers not to do this should the opportunity arise (take a photograph instead).

Important Information Obtained from the Meat-eating Dinosaur Tracks

From a biologist’s perspective a lot of information can be obtained from such an extensive set of tracks.  Behaviour can also be inferred.  The average speed of the large theropod has been calculated at around 6.3 km/hour, a comfortable walking pace for most people.  The lighter, smaller theropod was travelling on average, a little faster, around 9.7 km/hour.  The footprints were first uncovered in 2009, they are part of a series of Early Cretaceous dinosaur tracks and individual footprints found in this part of Germany, more than 200 individual prints have been mapped to date.

The smaller theropod occasionally crossed its legs as it trotted across the sand.  Pernille puts forward a number of possible explanations for this, perhaps the little dinosaur got buffeted by a strong inshore breeze or perhaps it had found something to eat or was snapping at an insect that was bothering it.

There is another intriguing possibility.  For a biologist, these two tracks could have been made a the same time, that is, this was a large dinosaur and a smaller dinosaur, possible the same species moving together.  Could these be the tracks of a mother and its young?

Pernille Venø Troelsen suggested:

“As a biologist, I can contribute with knowledge about behaviour of individual animals.  If so, this may illustrate two social animals, perhaps a parent and its young.”

Social Dinosaurs

There is an increasing amount of fossil evidence to suggest that dinosaurs were social animals that they exhibited complex behaviours.  For example, a number of dinosaur nest sites have been discovered indicating that many different types of dinosaur nested in colonies, just like many species of birds do today.  Other fossil evidence such as extensive trackways show that dinosaurs moved in herds and that these herds had a structure, adult animals moving on the outskirts of the group to protect the juveniles who were clustered towards the centre of the herd.

False Colour Image of One of the Smaller Theropod Dinosaur’s Footprints

The different colours signify different depths of the footprint.

Picture credit: Pernille Venø Troelsen

The picture above shows a false colour image of one of the smaller theropod dinosaur’s tracks.  The different colours illustrate the depth of various parts of the footprint.

Commenting on the study, a spokesperson from Everything Dinosaur stated:

“It is intriguing to think of these footprints representing an adult and juvenile dinosaur moving together, exploring the beach, perhaps looking out for any unfortunate animals that may have been stranded.  Or maybe moving along the open beach was easier than having to make progress through the surrounding woodland and scrub.”

The spokesperson added:

“Many large animals today, use beaches as natural highways, however, as far as we understand, it is not possible to state with any degree of certainty that these two separate tracks were made at the same time.  Given the parallel nature of the trackways and their relative sizes we can understand why the adult and juvenile dinosaur scenario has been inferred.”

Identifying the Species

As for the species of theropod, the lack of any body fossils found in association with the tracks prevents any identification being made.  In these cases, when an organism is known from just trace fossils, an ichnogenus is erected, that is, any animal known from just trace fossils such as burrows, coprolites or in this case footprints.

For models and replicas of Early Cretaceous dinosaurs and other prehistoric animals: Wild Safari Prehistoric World Models.

The tracks of the meat-eating dinosaurs have both been assigned to the ichnogenus Megalosauripus (Megalosauripus maximus).  However, whether these fossils were made by megalosaurid theropods remains open to debate, just like the dinosaur genus Megalosaurus, the ichnogenus Megalosauripus is a bit of a taxonomic waste basket when it comes to large, tridactyl theropod tracks found in Europe.

Everything Dinosaur acknowledges the help of the University of Southern Denmark in the compilation of this article.