All about dinosaurs, fossils and prehistoric animals by Everything Dinosaur team members.
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3 04, 2012

Aquatic Dinosaur Theory Rises to the Surface Once Again

By | April 3rd, 2012|Dinosaur and Prehistoric Animal News Stories, Dinosaur Fans, Palaeontological articles|6 Comments

Cell Biologist Challenges Theory of Largely Terrestrial Dinosaurs

In a paper published in the scientific journal “Laboratory News” Professor Brian J. Ford has put forward a theory to help explain how these very heavy animals were able to move around – they lived in water.  Using an assessment of the potential loadings on limbs in comparison with the largest land animals alive today; in combination with studies of dinosaur track-ways that show that their heavy tails were in most cases held off the ground, Professor Ford has concluded that as terrestrial animals – “Dinosaurs don’t work.”

Had this paper been published on Sunday April 1st – then Professor Ford’s hypothesis would have been in danger of being consigned to that taxonomic waste-basket where all April Fool’s get sent, but this is a legitimate and thought provoking piece that has even been discussed on the Radio 4 programme “Today”.

Professor Ford, a cell biologist writes:

“The immense size of the largest genera places impossible loadings on their extremities.  A single limb would have to support many tonnes – this would not be compatible with the agility we associate with dinosaurs.  We accept the remains of their footprints with demur, although for such gigantic creatures, the imprints that we observe in rocky strata make no sense.  The prints are roughly as deep in the layers of Liassic mud as ours might have been, although the high mass of an adult dinosaur would cause it to sink up to its knees.  The footprints seem to be those of an altogether lighter organism.”

Unless of course, these are the footprints made as huge creatures, waded across shallow lakes.  If this were the case, Professor Ford argues, then this would explain why the heavy tails do not drag on the ground, they would have been supported by water and held out behind the animal.

For Everything Dinosaur team members this is a case of “deja vu”, many of our team members can remember the theories that were still postulated by some scientists forty years ago, that the largest of the dinosaurs, the long-necked Sauropods lived an aquatic lifestyle, with their great weight supported by the water column.

Many scientists in the 19th Century and indeed into the later part of the 20th Century believed that the very largest dinosaurs, the herbivorous, Sauropods were aquatic.  Opening a child’s dinosaur book from the 1950s and 1960s would often reveal a scene of these huge leviathans happily munching water weeds in a shallow lake or swamp.

Theory on Aquatic Dinosaurs Comes to the Surface

Swimming Dinosaurs Anyone?

Picture Credit: Lindahall.org

Over the last fifty years or so, new scientific methodologies and fossil discoveries has led to the idea that the largest dinosaurs such as the Sauropods were suited to a life in water, being disregarded by most palaeontologists.  Anatomical studies, assessments of limb strength and other research has led to the conclusion that the vast majority of large dinosaur genera were very probably terrestrial.  Scientists set about examining other aspects of Dinosauria anatomy, for example how did the Sauropods, dinosaurs like Brachiosaurus and Apatosaurus support their long-necks.

To read more about the debate over the posture of Sauropods: Swan-neck Posture of Sauropods

Professor Ford, goes further than the early 20th Century scientists who confined their water-based dinosaur theories to the super-heavy-weights of the Sauropodomorpha.  In the article published in Laboratory News, the professor discusses the suitability of Tyrannosaurus rex to a watery habitat.

When discussing the fore-shortened front limbs found in many Late Cretaceous Theropods, professor Ford suggests:

“The diminished forelimbs are equally well accounted for… In land animals, like the elephant, hippo and rhinoceros, each of the four limbs is load-bearing and evolutionary pressure has been against the reduction in size that we observe in flesh-eating dinosaurs like Tyrannosaurus.”

Tyrannosaurus rex – A Predator of Lakes and Rivers?

Splashing towards its Next Meal

Picture Credit: Everything Dinosaur

So if you are bipedal and a predator, perhaps you might have been at home in a shallow lake where the weight of the water could help support your body mass and make it more energy efficient for you to move around.

Concerning T. rex professor Ford states:

“If the large dinosaurs are conceived as primarily aquatic, however, then the specialisation of the forelimbs would be towards manipulative dexterity. The fact that the limbs became foreshortened is entirely reasonable.  Animals like to inspect their food as they eat, and holding it closer to the face is normal behaviour.  Conventionally, conceived the small forelimbs of T. rex make no sense – however, if we envision the animal as an aquatic, carnivorous species, this adaptation becomes entirely reasonable.”

This is certainly an interesting point of view. Ironically, many of the facultative bipeds that shared the Late Cretaceous with the Tyrannosaurs – the Hadrosaurs (duck-billed dinosaurs), for example, were thought by some scientists in the 19th and 20th Centuries to be aquatic.  The bizarre looking hollow crests on some of these dinosaurs were thought to act as air reservoirs or snorkels, enabling these plant-eaters to run into deep water to escape the attentions of a predator such as Tyrannosaurus rex.

Duck-billed Dinosaurs Take to the Water to Escape a Predator

New Hypothesis Suggests Large Dinosaurs were Aquatic

Picture Credit: Rudolph F. Zallinger
The illustration shows two duck-billed dinosaurs (Corythosaurus and Parasaurolophus) swimming underwater to escape a predator. This picture is taken from a beautiful book about dinosaurs and other prehistoric animals first published in 1966, when the theory of some dinosaurs being aquatic was still propounded by a number of scientists and academics.
Interestingly, professor Ford does draw inspiration for this theory from recent studies of another Theropod (meat-eating dinosaur) – Spinosaurus.  Chemical analysis of Spinosaurid teeth by Romain Amiot and colleagues at the University of Lyon revealed that Spinosaurs may have spent a large part of their lives near or in water.  Isotope analysis revealed a similar pattern as found in extant reptiles today that are aquatic – crocodiles and turtles.
Swimming Spinosaurs

Aquatic Dinosaurs – Does the theory hold water?

Picture Credit: Marc Simonetti

To read an article suggesting a more aquatic life-style for Spinosaurids: Swimming Spinosaurs

When asked to comment on the paper, a spokesperson from Everything Dinosaur stated:

“What goes around comes around, sometimes new evidence emerges that leads palaeontologists to question accepted scientific thinking.  However, there is a significant amount of research that suggests that the Dinosauria, even the largest genera, were very well adapted to a life on land”.

Time will tell, perhaps new fossil finds and further developments in research techniques will reveal more conclusive evidence, in the meantime, we at Everything Dinosaur, whilst acknowledging the contribution of Professor Ford to this debate, still believe that dinosaurs were largely terrestrial animals.

You could say, that, for the moment at least, the aquatic dinosaurs theory does not hold water.

To read Professor Ford’s article: Aquatic Dinosaurs

2 04, 2012

World Autism Awareness Day

By | April 2nd, 2012|Educational Activities, Press Releases|0 Comments

World Autism Awareness Day 2012

Today, April 2nd is the fifth annual World Autism Awareness Day.  Every year, for the past five years, organisations with an involvement in autism or in related fields such as Asperger Syndrome on this day celebrate the uniqueness of these conditions.  Market research undertaken by the National Autistic Society in the UK a couple of years ago postulated that there were perhaps 500,000 people in the country with some form of autism.

Autism is very debilitating  affecting the way that people with this condition interact and communicate with the rest of the world.  They can find it difficult to make sense of the world around them and can be over-sensitive to sensory stimuli.  A lot of research has been undertaken over recent years to try to understand these complex conditions.   One thing that now seems certain, neither Autism or other related conditions such as Asperger’s are related to low intelligence.

Children on the autistic spectrum, may have a tendency to obsess on certain objects or subjects.  Very young children, in our experience can become fixated with cartoon shows or television programmes, or indeed characters seen in these programmes.  Some older children obsess about dinosaurs and prehistoric animals, much to the vexation of their parents and guardians who struggle to keep up.  We at Everything Dinosaur try to assist where we can.  After all, we do supply a lot of dinosaur toys and games for autistic children.  For example, one of the attractions of dinosaurs to children on the Autism Spectrum are the long names and all the complicated facts associated with these prehistoric monsters. Some children on the spectrum, seem able to retain vast amounts of information related to their favourite dinosaurs and can recite an astonishing amount of factual information about these prehistoric creatures.  Team members send out fact sheets and pronunciation guides to parents/guardians who in turn pass these on to their charges.  We handle enquiries, answer specific questions, provide advice, email over drawing materials, send out fact cards – all sorts of things as with some of our team members coming from a teaching background we recognise the importance of offering such support.

Today, on this special day our thoughts are even more with those sufferers and with their families, we celebrate the uniqueness of the individual.

The National Autistic Society (UK): National Autistic Society

Celebrate World Autism Awareness Day on Facebook: World Autism Awareness Day on Facebook

True to our word, whilst teaching at a school in London one of the T As (Teaching Assistants) approached us requesting some assistance for her daughter who taught at a special school in the capital that catered for the needs of children on the autistic spectrum.  Within 24-hours of our visit, we had emailed a teaching contact with a dinosaur themed alphabet and our own set of prehistoric fact cards that could then be forwarded on to the teacher concerned.

1 04, 2012

Exploding Prehistoric Animal Carcasses as they Rot – New Evidence

By | April 1st, 2012|Dinosaur and Prehistoric Animal News Stories, Educational Activities, Palaeontological articles|0 Comments

Gas Build Up in Rotting Prehistoric Animal Remains did not Cause them to Explode

A new study by scientists from the University of Zurich (Switzerland) has dispelled the theory that putrefaction gases produced by decomposition caused some dinosaur and other prehistoric animal carcasses to explode before they were fossilised.

A number of animals preserved in the fossil record, their subsequent body fossils had puzzled scientists as to how the bones had come to be positioned in relation to other parts of the preserved skeleton or skeletons.  In particular, the fossilised remains of a pregnant Ichthyosaur (marine reptile) found in the Lower Jurassic deposits of Holzmaden (southern Germany), has intrigued researchers.  The skeleton of the adult, is preserved with the majority of the bones in articulation, in the same relative positions as when the animal was swimming around in the Jurassic sea.

The bones of the Ichthyosaur embryos, preserved with this specimen however, are very different.  For the most part, they lie scattered outside the body of the mother.  Such peculiar bone arrangements are repeatedly found in Ichthyosaur skeletons excavated from the finely, grained Holzmaden deposits.

Ichthyosaurs are believed to have evolved the ability to give birth to live young – viviparity.  These reptiles did not lay eggs like crocodiles and turtles, but they kept their embryos inside them, until they had reached a certain size before giving birth to independent young.

To read an article on a controversial fossil discovery that suggests that other marine reptiles such as Plesiosaurs were also viviparous: Does Plesiosaur Fossil show Evidence of Viviparity?

Holzmaden “Exploded” Ichthyosaur Skeleton

Puzzling Ichthyosaur Fossil

Picture Credit: University of Zurich

The picture above shows a photograph of the Ichthyosaur fossil and an interpretative line drawing of the fossil showing underneath it.  The beautifully preserved adult skeleton is articulated but the fossils of the embryos are scattered over a large area.  The scale bar in the photograph represents twenty centimetres.

Most scientists thought that the position of the embryo fossils and their disarticulation was due to the carcase having exploded as gases caused through the process of putrefaction built up in the body cavity.  These gases, created as a body decomposes would cause the carcass to swell up and become bloated before finally bursting.  It had been thought that through such explosions, even the bones of embryos would have been ejected out of the body.  The Zurich based researchers have challenged this hypothesis by carrying out a series of  elaborate  measurements and an analysis of the physical-biological parameters.  The scientific team, which included sedimentologists, palaeontologists and forensic scientists has put forward new evidence that may dispel the myth of exploding prehistoric animal remains.

In order to gauge the pressure of the particular gases that can actually develop inside a putrefying remains of an Ichthyosaurus, the researchers sought comparative models and found one in a surprising area of science – the forensic study of human corpses.  Humans and many Ichthyosaur are similar in size and as vertebrates we do have roughly the same body plan and digestive tract.  As a result, the formation of similar amounts of putrefaction gas can be expected during decomposition of the dead body.   At the Institute of Forensic Medicine in Frankfurt, Germany, a manometer (device used to measure pressure) was inserted into the abdominal cavity through the umbilicus in one hundred corpses.

A Beautiful Ichthyosaur Fossil

Viviparity in Ichthyosaurs

Picture Credit: Natural History Museum

The putrefaction gas pressures measured were only 0.035 bar.  In the case of the Ichthyosaur remains that came to rest in depths between fifty and one hundred and fifty metres of water, however, putrefaction gas pressures of over five to fifteen bar would have been necessary to cause a body to explode.

Zurich based palaeontologist Christian King, one of the researchers involved in this macabre study believes that gas pressures strong enough to cause a carcase to explode in this depth of water are impossible to achieve.

He stated:

“Large vertebrates that decompose cannot act as natural explosive charges.  Our results can be extended to lung-breathing vertebrates in general.”

So what did cause the anomaly of the adult body remaining virtually intact whilst the remains of any embryos associated with the fossil specimen to be scattered?

According to the researchers, the fate of Ichthyosaur bodies can be reconstructed, they have theorised as follows:

Normally, the bodies sank to the seabed immediately post mortem.  In very deep, hospitable waters, they were broken down completely through putrefaction, scavengers, bone-destroying organisms and dissolving processes, in exactly the same way that marine mammal carcases are broken up today.  In shallower water (up to fifty metres in depth) and a temperature of over four degrees Celsius, however, the corpses often rose back to the surface on account of the putrefaction gases accumulating inside the body.   As the gases built up, they made the corpse buoyant forcing the body to rise to the water surface,  just like a cork when placed in a bucket of water floats to the top.  At the surface, exposed to the waves and scavengers, such as fish, Pterosaurs and other marine reptiles, the bodies decomposed within anything from a few days to weeks and the bones which were not eaten whole by the likes of a Pliosaur were scattered over a wide area on the seabed as they sank.

However, the scientists believe that under very special conditions, Ichthyosaur bodies would remain preserved more or less in their anatomical position.  A lack of oxygen, medium water depths and insignificant bottom water currents could lead to the fossils that we see today.  Because only under these conditions were the putrefaction gases compressed strongly enough through the high water pressure and dissolved in the bodily fluids, and the carcasses not completely broken down due to a lack of scavengers on the seabed.  The carcass of the Ichthyosaur female from Holzmaden, dated to around 182 million years ago, probably sank to the bottom of the sea, which was up to 150 metres deep, where it decomposed.  It was the action of minor underwater currents on the sea floor that carried the decomposing bodies of the embryos out of the mother and scattered their remains around the larger body.  The bigger bones of the adult Ichthyosaur were less affected by the sea currents and therefore remained in situ.

The Hozmaden deposits have yielded some of the world’s best fossils of marine reptiles, especially Plesiosaurs and Ichthyosaurs.  This new study provides further information on how to interpret fossil vertebrate remains and can help shed light on the potential water depths at which these fossils came to rest.

To read about the discovery of a new species of European Ichthyosaur earlier this year: New Ichthyosaur Species Swims into View

 

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