Siats meekerorum – The Carcharodontosaurid that Kept the Tyrannosaurs in Check

The trouble with dinosaur fossils is that there is most certainly not anything like a record of dinosaur evolution and development throughout their time dominating terrestrial environments.  True, palaeontologists have been able to build up a remarkable degree of knowledge and some ancient ecosystems are quite well understood.  This said, we really have only the merest glimpse of the Dinosauria, or indeed of other terrestrial vertebrates for much of the Mesozoic.  Take for example, the United States.

Dinosaurs from the USA

A tremendous amount of dinosaur fossil material has been discovered and indeed thanks to the likes of the Morrison Formation, scientists have been able to build up a detailed impression of life in the Late Jurassic.  With the wonderful Dinosaur Park Formation of Alberta, palaeontologists have an insight into an ecosystem from the Campanian faunal stage of the Cretaceous.  The likes of the Badlands and Hell Creek have provided evidence of the dinosaur fauna that roamed at the very end of the Cretaceous period, but what about all the bits in between?

Apex Predators

Take for example, the issue of apex predators.  Allosaurids such as Allosaurus fragilis and Saurophaganex maximus may have been the largest meat-eating dinosaurs in the western United States during the Late Jurassic whilst the tyrannosaurids such as Daspletosaurus (D. torosus) and the recently described Lythronax argestes topped the predator tree towards the end of the Age of Dinosaurs.  Of course, thanks to the Hell Creek Formation, we can be fairly certain that at the very end of Cretaceous the likes of T. rex ruled.

Siats meekerorum

Step forward Siats meekerorum,  a newly described apex predator that roamed Utah approximately 98 million years ago.  Here is evidence of an apex predator, a dinosaur approaching perhaps 3,000 kilogrammes in weight and at least ten metres long, possibly the apex predator in this part of the world during the Cenomanian faunal stage.

Terror of the Tyrannosaurs – Siats meekerorum

Fearsome Cenomanian predator.

Picture credit: Jorge Gonzales

New Dinosaur Discovery

This new dinosaur discovery, (recently new that is, as the fossils were found in 2008), may help explain a mystery surrounding the tyrannosaurs of northern latitudes.  Although, this particular group of meat-eating dinosaurs had their origins back in the Jurassic, they seem not to have grown really big and become apex predators until towards the end of the Cretaceous.  Dinosaurs such as the fearsome Siats meekerorum, pronounced see-atch me-ker-roar-rum, may be the reason why.

Scientists from the Field Museum (Chicago), North Carolina State University and the North Carolina Museum of Natural Sciences, set about exploring the strata in the Cedar Mountain Formation of Utah.  The team’s work, published in the academic journal “Nature Communications” outlines the discovery of a carcharodontid dinosaur, one that was around ten metres in length and a candidate for the top predator position in this part of the western United States around 98 million years ago.

A Partial Specimen

The partial specimen, consisting of elements from the pelvis, a femur, fragmentary lower leg bones, toe bones and some vertebrae including caudal vertebrae represents only about 4% of the entire skeleton but from this largely disarticulated and scattered material, the researchers were able to determine that they had found evidence of a formidable predator.  This dinosaur gets its genus name from Siats, a mythical man-eating monster from local, Native American tribal legend.

The species name honours the Meeker family for their long-term financial support of the palaeontology department of the Field Museum.  It was Lindsay Zanno (Director of Palaeontology at the North Carolina State University/North Carolina Museum of Natural Sciences), who made the discovery.  It took two summer expeditions to carefully remove the fossil material and prepare them in the laboratory.

Carcharodontosauridae Family

Siats meekerorum has been classified as a member of the Carcharodontosauridae family, a group of large to gigantic carnosaurs with strong affinities to the allosaurs which lived in the Western Hemisphere, Europe, Africa and Asia.  Little is known about the majority of the members of the Carcharodontosauridae family, but one thing is for sure, a number of them were massive, bigger than Tyrannosaurus rex and potentially amongst the largest terrestrial predators that have ever lived.

Siats meekerorum is only the second member of this dinosaur family to have been discovered in North America.  The first carcharodontosaur was Acrocanthosaurus atokensis, fossils of which have been found in Maryland, Texas and Oklahoma.  It has been estimated that the fossils of S. meekerorum are ten million years younger than those of the youngest Acrocanthosaurus material, thus the carcharodontosaurids existed in North America later than previously thought.

A Model of Acrocanthosaurus (A. atokensis)

Fierce meat-eater – the dinosaur Acrocanthosaurus.

Picture credit: Everything Dinosaur

Acrocanthosaurus

Remarking on the fact that Acrocanthosaurus was named and described back in 1950 Dr Zanno stated:

“It’s been sixty-three years since a predator of this size has been named from North America.  You can’t imagine how thrilled we were to see the bones of this behemoth poking out of the hillside.”

Dr Peter Makovicky, from the Field Museum of Natural History assisted Dr Zanno in the collection, and study of this fossil material.  The researchers were able to establish that although the fossil bones represented an individual over ten metres in length, and perhaps weighing as much as 3,000 kilogrammes, this dinosaur was not fully grown when it died.  Analysis of the partial femur that was excavated reveals that had the bone been complete, it would have been only about ten centimetres smaller than that of Acrocanthosaurus, so it could be speculated that when fully grown Siats meekerorum may have matched the early carcharodontosaurid Acrocanthosaurus in size.

A spokesperson from Everything Dinosaur commented:

“Size estimates for A. atokensis vary, but most palaeontologists agree that this dinosaur may have reached lengths in excess of twelve metres and perhaps weighed 4 tonnes or more.  Although, slimmer and more lightly built than the very last of the tyrannosaurs these meat-eaters were formidable predators and it is quite likely that a fully grown Siats meekerorum would have been around twelve metres in length too.  This means that S. meekerorum is vying with Acrocanthosaurus for being the second largest Cretaceous theropod dinosaur discovered in North America.”

Representing Different Subfamilies

Although Siats and Acrocanthosaurus are both members of the Carcharodontosauridae family, they represent different sub-families.  There is a lot of debate with regards to the taxonomic affinities of carcharodontosaurs but in this instance, Siats seems to have affinities to the neovenatorids, a sub-family of carcharodontosaurids that are geographically dispersed with fossils found in Europe, South America, China, Japan and Australia.  This is the first neovenatorid known from North America.

For Dr Zanno, who specialises in studying theropod dinosaurs, this discovery helps fill a gap in the apex predators of North America from the allosaurids of the Jurassic, to the earlier carcharodontosaurids such as Acrocanthosaurus, with Siats meekerorum following on before the emergence of the robust, heavy-set tyrannosaurs such as Daspletosaurus, Teratophoneus and Tyrannosaurus rex.

Dr Zanno added:

“This thing is gigantic.  There is nothing even close in this ecosystem to the size of this animal that could have been interpreted as an apex predator.”

Theropod Dinosaurs

There were other theropods in this Cenomanian ecosystem.  Teeth found in the same strata indicate the presence of tyrannosauroids, the distant ancestors of the mighty T. rex.  However, these tyrannosaurs were small-bodied, fast running, cursorial predators and simply no match for Siats meekerorum.  There has been no evidence found in this strata to suggest the presence of an equal sized tyrannosaur challenging the likes of Siats for the apex predator position.

For models and replicas of theropods and other dinosaurs: PNSO Age of Dinosaurs Models and Replicas.

The spokes person from Everything Dinosaur explained:

“Think of Siats meekerorum as the “lion of the Cenomanian” with the much smaller Tyrannosauroids the equivalent of jackals.  Tyrannosaurs may well have fed of the remains of kills but they would have been no match for Siats and probably stayed well clear of such a large carnivore, which was many times their body weight.”

Wary Tyrannosaurs Stay Clear of the Dominant Siats meekerorum

Siats meekerorum has nothing to fear from these two tyrannosaurs.

Picture credit: Julio Lacerdo

The discovery of Siats meekerorum extends the time when allosaurids were present in North America by ten million years.  It also provides evidence of large allosaurs sharing the same environment as small-bodied tyrannosauroids.  This research supports the hypothesis that the extinction of the Allosauridae in terrestrial ecosystems of North America permitted the rise of the tyrannosaurs which went onto become the dominate, apex predators of Late Cretaceous food webs.

It is likely that the presence of such a large carnivorous dinosaur indicates that a very rich faunal ecosystem may have been preserved in the rocks of the Cedar Mountain Formation.  Everything Dinosaur expects announcements of other dinosaur discoveries from excavations carried out, possibly the naming and describing of a number of new herbivorous dinosaur species.

Study of the Brains of Alligators and Birds Leads to the Inference that Dinosaurs were Capable of Complex Behaviours

Palaeontologists have got the bones of dinosaurs to study, but it is rare for any soft tissues of dinosaurs to be preserved in the fossil record.  True, scars on bones can provide scientists with information on musculature and ligament placement but it is only through comparative analysis of animals alive today that any understanding of the layout, placement and size of organs of the Dinosauria can be deduced.  For example, much work has been done regarding the study of dinosaur brains, even though no fossilised Dinosauria brain material is known from the fossil record.

Dinosaur Brain

Team members at Everything Dinosaur have been fortunate to work with endocasts of the brains of ancient reptiles.  Endocasts are internal moulds of the brain cavity and other areas of the skull.  By piecing the skull bones carefully together, scientists can work out the size, shape and volume of the spaces left inside.  For example, the shape of some tyrannosaur brains have been calculated using this method.  However, endocasts do not provide much information on the brain’s internal structures or what sort of behaviours dinosaurs were capable of.

Last month, Everything Dinosaur team members reported on the research being undertaken concerning an attempt to map the neural pathways and nerve structure of a Cambrian-aged arthropod fossil that had been discovered in China.

To read more about this research: Ancient Arthropod Brain and Nervous System Revealed.

New Study into the Brains of Dinosaurs

A new study, conducted by a team of international researchers at Duke University in North Carolina (USA), has enabled neuroscientists to create a detailed map of the brain of Theropod dinosaurs.  From this work the team have deduced that these animals were capable of complex behaviours and perhaps even used sounds to communicate with each other just as some birds do today.

Were Dinosaurs Like T. rex Capable of Sophisticated Behaviours?

A close-up view of the Nanmu Studio Alpha T. rex in the brown colouration.

Picture credit: Everything Dinosaur

To view the Nanmu Studio Jurassic Series range of prehistoric animal models: Nanmu Studio Jurassic Studio Models and Figures.

Dr Erich Jarvis, a neuroscientist and one who specialises in looking at how brain function can help vocalisation and learning commented:

“In the popular mind, dinosaurs may be underrated in the complexity of their behaviour.”

For Dr Jarvis, a lead author of the dinosaur brain study that has just been presented at the Society of Neuroscience meeting in California , added that as soft tissues were rarely preserved in the Dinosauria and that fossilised brain material was unheard of then researchers had to infer dinosaur brain function and morphology by studying extant species that represent close relatives of the dinosaurs.

Capable of Complex Behaviours

Having conducted such a study on alligators and birds it can be inferred that dinosaurs were capable of complex behaviours with parts of the brain specialising in processing visual data, auditory information and assisting with vocalisation.

Asked to comment on the team’s findings, Dr Jarvis said that amongst other skills, dinosaurs had sufficient brain complexity to communicate with sounds but, “did it really happen?  That we do not know.”

To gain an insight into how dinosaurs thought and communicated, the U.S. based research team studied the brains of alligators, as crocodilians are thought to be the most closely related to the dinosaurs of all the types of living reptile today. In addition, the scientists analysed the brains of birds.

Studying the Brains of Crocodilians and Birds

Birds are essentially avian dinosaurs, the Aves being very closely related to parts of the theropod group of the Dinosauria.  From the work on extant creatures the team could piece together an approximation for a typical theropod dinosaur brain and infer its capabilities.

Using a technique that involves mapping gene activity in different parts of the brain as the animal is subjected to certain stimuli, the researchers were able to gain an insight into the function of alligator brains and those of birds.  From this work the map of the dinosaur brain was re-created.  Some genes are permanently on in the brain, whilst others are only switched on in response to certain stimuli, for example, some genes are only activated for a fraction of a second in response to sounds, particularly in that part of the brain associated with the hearing function and interpretation of sounds.

Examining the Auditory Regions of the Brain

To plot  the auditory regions of the brain, Dr Jarvis and his team quietened the animals down in a darkened room and then played bird songs to birds and alligator calls to the alligators.  The team then swiftly removed their brains, froze them, sliced them, and looked at the genes that had switched on in different regions.  Naturally, this was what we palaeontologists term a “destructive” form of research, unfortunately the animals had to be killed before the second phase of the research could be undertaken.

The genetic data that had been retained in the brain slices enabled the research team to make highly detailed maps of the bird and the alligator brains.  They could work out how the brain was organised and which parts had been stimulated by the earlier experiments.  Using the bird and alligator models as templates, the researchers created an amalgam of the two to represent the brain of a typical theropod dinosaur using endocasts from Tyrannosaurus rex and a Late Jurassic theropod called Allosaurus fragilis.  In addition, the bird brain of Archaeopteryx lithographica was re-created.

Six Distinct Regions Identified

The result of this research enabled the scientists to identify six distinct regions within the dinosaur’s brains and a similar structure in that of the early bird Archaeopteryx.  One of these regions, called the mesopallium, would have been involved in processing complex data, given the Dinosauria the capacity for sophisticated behaviour.

An Endocast of the Brain of Archaeopteryx (A. lithographica)

The brain cast of Archaeopteryx lithographica, one of the earliest known birds, partitioned into neuroanatomical regions: brain stem (yellow), cerebellum (blue), optic lobes (red), cerebrum (green), and olfactory bulbs (orange).

Picture credit: AMNH/Dr. Balanoff

Dr Jarvis explained:

“It suggests that the dinosaur brain had the capacity for complex sensory motor processing, just like we see in birds and alligators.”

However, whilst a large number of today’s birds, the passerines (perching birds), have the ability to produce very complicated vocalisations and even learn shared “songs”.  It can only be inferred that members of the Dinosauria were also able to do this as all the brain sub-divisions that support such vocal learning seem to present.

Dr Jarvis, went onto to state:

“We don’t have any evidence that there was a dinosaur out there that did this, that shared vocal learning with songbirds.  But all the brain subdivisions to support vocal learning are there, so I’d argue the capacity to evolve vocal learning did exist in dinosaurs.”

Crocodiles have some of the most sophisticated and complex behaviours of all the reptiles known today.  Certainly, male Alligators (Alligator mississippiensis) are capable of making very loud noises as they ward of rivals and call to attract a mate in the breeding season, perhaps Tyrannosaurus rex did something similar.

Second Major Dinosaur Fossil from Alberta in a Month

Residents of Leduc, a town approximately eighty miles north of Drumheller (Alberta) and just about ten miles to the south of the Province’s capital Edmonton, have found themselves very much on the palaeontological map of Canada with the discovery of duck-billed dinosaur fossils.  Construction workers from a company called Degner Construction, who were digging a trench as part of the ground works for a new housing development, uncovered the dinosaur remains, believed to be Hypacrosaurus.

Dinosaur Fossil

Experts from Drumheller’s Royal Tyrrell Museum were despatched to confirm the discovery.  This is the second major dinosaur fossil find in about a month from Alberta, as in October, Everything Dinosaur reported the discovery of the tail of another duck-billed dinosaur (hadrosaur), on that occasion by a team of construction workers building a pipeline.

To read more about the October discovery: Pipeline Workers Find Dinosaur Fossils.

Articulated Hadrosaur Fossils

The fossils, some of which are articulated, are lying approximately six metres below the surface, a preliminary examination has revealed the presence of caudal vertebrae (tail bones) and part of the pelvic girdle.

Heather Klimchuk, the Minister of Alberta Culture commented:

“This tremendous find will give us an event greater insight into the dinosaurs that lived in central Alberta.  Alberta’s ability to be successful in preserving and protecting valuable palaeontological resources depends on the co-operation of industry as well as the general public.  Degner Construction is to be commended for recognising and taking the right steps to alert the Royal Tyrrell Museum.”

With the Museum staff supervising, the construction crew were able to use a large excavator to carefully remove topsoil and some of the overlying rock.  Then with great care, the block of sediment containing the fossil remains was removed and transported back to Drumheller for study.

Block Containing Fossils Safely Removed

Leduc’s Deputy Mayor, David Mackenzie stated:

“Leduc will now be acknowledged in the natural history of Alberta in a significant way and we’re pleased future generations of Albertans can benefit from this exciting discovery.”

There is nothing like a major dinosaur fossil discovery to put a place firmly on the map.  Many of the Province’s construction projects will be closed down shortly with the onset of the harsh Canadian winter.

A Hadrosaur Fossil Skeleton on Display (Edmontosaurus)

Duck-billed dinosaur on display similar to the fossils found by the construction workers. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

For models and replicas of Albertan dinosaurs including hadrosaurs: CollectA Deluxe Prehistoric Life Scale Replicas.

However, 2013 has proved to be a great year for the Royal Tyrrell Museum with a number of significant dinosaur fossil finds, perhaps more this year than in other year of the Museum’s twenty-eight years existence.

Once the fossils have been properly cleaned and prepared, it is likely that some elements of the Leduc find will be able to go on show in the Museum’s ornithischian galleries.

Lythronax argestes – New Species of Tyrannosaurid from Southern Utah

An amazing new species of tyrannosaurid has been put on display at the Natural History Museum of Utah (Salt Lake City, Utah).  Fossils of this fearsome predator have been excavated from the Grand Staircase-Escalante National Monument in southern Utah.  Elements of the skull, jaws and part of the hip indicate an animal approximately eight metres in length.  The fossils come from the middle member of the Wahweap Formation and have been dated to approximately 80 million years ago (Middle Campanian faunal stage).

“King of Gore”

This new member of the tyrannosaurid family has been named Lythronax argestes, the creatures’ wide and powerful skull indicate that it was a formidable predator, the genus name means “King of Gore” and the species name is taken from the Greek Homeric wind that blows from the south-west, a reference to the location of the fossil find within North America.  The geographical location of this fossil find, has helped palaeontologists to propose a new theory regarding the evolutionary diversification of the tyrannosaurids of the Late Cretaceous.  It seems the origins of the likes of Tyrannosaurus rex and Tarbosaurus bataar may be somewhat more provincial than previously thought.

Lythronax argestes

An analysis of the skull of L. argestes indicates that this particular tyrannosaur most likely comes from branch of the Tyrannosauridae that includes T. rex.  The snout is short, but stout with the posterior part of the skull quite wide.  The orientation and relative position of the orbits suggest powerful stereoscopic vision.  Until, this dinosaur was described, palaeontologists had thought that this wide-skulled form of tyrannosaurid only evolved during the very last few million years of the Dinosauria (Maastrichtian faunal stage).  Unfortunately, fossilised remains of the forelimbs have not been found to date, so scientists can only speculate on the forelimb proportions and the ratio of upper arm bones to lower arm bones and the digits.  The only limb material excavated from the site so far represent elements from the lower left leg.

To view the CollectA Prehistoric Life model collection in stock at Everything Dinosaur: CollectA Prehistoric Life Models and Figures.

Collaborative Authors

The study, funded in large part by the Bureau of Land Management and the National Science Foundation, was led by Dr Mark Loewen, research associate at the Natural History Museum of Utah, and adjunct assistant professor in the Department of Geology and Geophysics at the University of Utah.   Additional collaborative authors who worked on this analysis which also covered fossils of another slightly later tyrannosaur called Teratophoneus curriei,  include Dr Randall Irmis (Natural History Museum of Utah and Deparment of Geology and Geophysics, University of Utah), Dr Joseph Sertich (Denver Museum of Nature and Science).  Also involved were Dr Philip Currie (University of Alberta), and Dr Scott Sampson (Denver Museum of Nature & Science).

Reconstructing the Skeletons of Two of Utah’s Tyrannosaurs

Picture credit: PLoS One/Loewen et al

 Teratophoneus curriei

T. curriei is known from more complete fossil material which includes elements from the skull, upper jaw, vertebrae and the hip girdle.  This dinosaur was officially named and described in 2011.  It was an agile, cursorial predator, perhaps approaching six metres in length.  The genus name translates as “monstrous murderer”, the species name honours Philip Currie.  Teratophoneus curriei is known from Upper Campanian aged strata (Kaiparowits Formation), of southern Utah, it is a later tyrannosaur, having lived approximately 76 million years ago.  Both types of tyrannosaur lived on the huge, isolated landmass that comprises today’s western parts of North America.  This landmass is known as Laramidia.

For much of the Cretaceous, North America was split into several landmasses, by the formation of the Western Interior Seaway.  Recent studies of the Dinosaurian palaeo-communities that made up the fauna of Laramidia suggest that this part of the world was a hot bed for dinosaur evolution, with many regions supporting their own distinct dinosaur genera.  Different parts of Laramidia had similar types of Ornithischian dinosaur but there were differences at the genera level.  A lot of debate has taken place over the last couple of years as to why this arrangement of speciation may have come about.

North America During the Late Cretaceous

Picture Credit: Dr Ron Blakey of Colorado Plateau Geosystems, Inc

To read an article that looks at the distribution of horned dinosaurs on Laramidia: A Surge in Mountain Building May Have Caused Laramidia’s Unique Dinosaur Faunas.

Studying Tyrannosaurids

The work of this research team also indicates that the branch of the tyrannosaurids that led to the evolution of Tyrannosaurus rex most likely evolved in relative isolation on the southern portions of Laramidia.   Just like with the ornithischian dinosaurs, where plant-eating dinosaurs from the southern part of Laramidia differed from those species found in the northernmost areas, the tyrannosaurids show a similar pattern.  Lythronax argestes and its relatives from southern Laramidia are more closely related to each other than the long-snouted tyrannosaurs known from the northern areas of the landmass.

Dr Joseph Sertich, (Denver Museum of Nature and Science), a co-author of the scientific paper that has just been published in the online, academic journal PLoS One, explained:

“Lythronax may demonstrate that tyrannosaurs followed a pattern similar to what we see in other dinosaurs from this age, with different species living in the north and south at the same time.”

In contrast to the research undertaken into the distribution of ornithischian genera, the researchers suggest that mountain building may not have formed the physical barrier that led to the relative isolation of tyrannosaurs that encouraged such speciation and the evolution into a number of different Late Cretaceous forms.  For them, rising sea levels may provide the answer.

Dr Randall Irmis, another co-author of this fascinating study, pointed out that by examining  the evolutionary relationships, geologic age, and geographic distribution of tyrannosaurid dinosaurs on Laramidia a link can be proposed between tyrannosaurid diversification and the incursion of the Western Interior Seaway.  Large parts of Laramidia would have been flooded, leaving isolated islands of dinosaurs, allowing different species of dinosaurs to evolve separated from other groups.  A similar example can be taken from the Galapagos Islands of the Pacific, where different species of animal have evolved from a shared, common ancestor, after many thousands of years of separation.

Sea Level Change and the Timing of the Diversification of the Tyrannosauridae

Picture credit: PLoS One/Loewen et al.

As the Seaway retreated, exposing more land, these differences in the local faunas could have been exacerbated by climatic variations, differences in prey components and the flora.  This hypothesis helps to explain why the iconic Late Cretaceous dinosaurs of western North America are so different from those of the same age on other continents.  tyrannosaurs may have originated in Asia, but it seems that the most famous of them all, Tyrannosaurus rex has its roots in the “good ole southern USA”.

The scientific paper: “Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans” by Mark A. Loewen, Randall B. Irmis, Joseph J. W. Sertich, Philip J. Currie and Scott D. Sampson published in PLoS One.

Suffolk Man Finds Out About Pliosaur Fossils at the Bottom of His Garden

It pays to keep a sharp look out when working in the garden, as you never know what might turn up when digging.  For example, a strange object discovered in 1997 when builders were digging a trench in the garden of Suffolk resident John Lambert, has turned out to be a fossilised bone from a giant, carnivorous marine reptile.

The village of Tuddenham St Martin, approximately two miles north-east of Ipswich (in the county of Suffolk, East Anglia, UK), may have had very little in common with the Jurassic coast until now and John remained unaware of the significance of his discovery until he took it along to the Colchester and Ipswich Museum to have it examined some sixteen years after the unusually shaped object was found.

Pliosaur Fossil

Mr Lambert, a retired banker, had thought his discovery might have been something very exciting, but he just never got round to getting the specimen checked over by a fossil expert,  that was, until last month.  The fossil is most probably a humerus (upper arm bone) from a large type of marine reptile known as a pliosaur.  It is not possible to identify the genus from a single bone such as this, but one thing is for sure, it was a large animal for the bone measures 42 centimetres in length.

Pliosaurs, otherwise known as short-necked plesiosaurs had large skulls and enormous jaws armed with long, triangular or conical teeth.  They propelled their streamlined bodies through the water using four paddle-like limbs.  Just how big some of these pliosaurs could have been is open to speculation, although recent discoveries such as the Svalbard specimen, or the remains of the jaws and skull of pliosaur found in Dorset indicate that some species could have grown to lengths easily in excess of fifteen metres.

These creatures had their heyday in the Jurassic, survived into the Cretaceous but become increasingly rare in the fossil record towards the end of the Mesozoic.

An Illustration of a Typical Jurassic Pliosaur

Apex predator of the Jurassic.

Picture credit: Everything Dinosaur

Liopleurodon

The genus known as Liopleurodon (the name means “smooth-sided tooth”), is illustrated in the picture above.  It has the typically massive jaws and powerful flippers of this family of reptiles.  Some of the teeth in the lower jaw measured nearly twice the size of an adult T. rex tooth.  A number of scientists have estimated that these creatures may have had some of the strongest bites of any known vertebrate.

Ann Ainsworth, assistant curator of natural history at the Colchester and Ipswich Museum, commented that the fossil was in very good condition, however, she stated:

“Marine reptiles are not animals you would expect to find as fossils in Suffolk as the local rocks are not the right age.”

So the question is, how did the fossil end up buried in a Suffolk garden?

Ann has suggested that the fossil “could have been collected by someone else previously and left in the garden.”

This is very plausible, as fossils do turn up in some very strange places.  For instance, last year Everything Dinosaur wrote a short blog article about a Frenchman who discovered a dinosaur’s foot bone in his garden.  Back in 2011, Everything Dinosaur reported on the discovery of an iguanodontid dinosaur bone turning up in Sunderland (north-east England).

To read more about the Sunderland fossil find: Strange Place to Find a Dinosaur Bone.

A Result of Deposition

Another explanation put forward by the researchers at the museum and one that Everything Dinosaur team members happen to agree with, is that this fossil find is as a result of re-deposition.  Re-deposition occurs when strata which contains fossils is disturbed and the fossils end up being moved from the location where they were originally sited.  Much of East Anglia has deposits of glacial clays, the result of movements of ice sheets during the Quaternary.  In 1959, isolated fossils believed to have come from another Pliosaur were discovered in a ploughed field close to the village of Wrentham on the Suffolk coast.  Four years ago, a single dorsal vertebra was found at Theberton Airfield about twenty miles north-east of Tuddenham St Martin.

A spokes person from Everything Dinosaur commented:

“It is quite likely that this particular fossil originates from Lower Jurassic deposits which can be found elsewhere in England.  Lower Jurassic strata forms a narrow belt along the western margins of the Yorkshire Wolds continuing into Lincolnshire and into the Midlands.  One of our team members once spotted a plesiosaur limb bone that had been exposed as a pond dried up.  It is quite likely that this fossil bone originated from this Jurassic aged strata.”

Speaking about his lucky fossil find, Mr Lambert exclaimed:

“It’s rather fun.  I’ve been here 29 years, we’ve got eight acres of ground, we are quite keen on the gardening side and I can honestly say we’ve found nothing whatsoever of any kind of value apart from rubbish, so it’s really fun to have found this.”

It is likely that the fossil will be donated to the Colchester and Ipswich Museum, it may not be part of the geology of Suffolk, but thanks most likely to glaciation and re-deposition, evidence of an apex Jurassic marine predator has been uncovered in a sleepy Suffolk village.

To view the range of prehistoric animal marine reptile models including plesiosaurs and pliosaurs in stock at Everything Dinosaur: Sea Monsters and Models of Marine Reptiles.