Category: Palaeontological articles

New Research Suggests Multicellular Life Started Earlier

Evidence Suggests Multicellular Life 60 Million Years Earlier than Previously Thought

Researchers from the Virginia Tech College of Science in collaboration with counterparts from the Chinese Academy of Sciences have published new data on one of the most fundamental and significant changes that occurred in the history of life on our planet.  At some time during the Proterozoic Eon, multicellular life forms evolved.  These organisms evolved from single-celled entities and in a paper published in the academic journal “Nature”, the researchers propose that multicellular life forms evolved some sixty million years earlier than previously thought.

The team suggest that they have found fossil evidence of complex multicellularity in strata dating from around 600 million years ago, although microscopic fossils are known in Precambrian strata from several locations around the world (Australia, South Africa as well as China), this new research is helping to clarify some long-standing interpretations of micro-fossils.

Professor of Geobiology at the Virginia Tech College of Science, Shuhai Xiao explained the significance of this new fossil discovery:

“This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way.  Fossils similar to the ones in this study have been interpreted previously as bacteria, single-cell eukaryotes, algae and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals.  This paper lets us put aside some of those interpretations.”

It has long been known that simple, multicellular organisms evolved before more complex ones, such as red algae and sponges.  If a biological hierarchy existed (and most scientists believe that this is the case), then at some point in the past, single-celled organisms began to evolve into much larger, more complicated multicellular organisms.  The trouble is, with the paucity of the fossil record and the difficulties involved in interpreting Ediacaran fauna there is a lot of debate amongst biologists and palaeontologists as to when the solo living cells began to fuse into more cohesive, complex forms.

Evidence of Complex Multicellular Organisms from the Doushantuo Formation

Evidence of multicellular structures in 600 million year old rocks.

Evidence of multicellular structures in 600 million year old rocks.

Picture Credit: Virginia Tech College of Science

The researchers examined microscopic samples of phosphorite rocks from the Doushantuo Formation in Guizhou Province (south, central China).  This formation represents extensive marine sediments that were deposited from around 635 million years ago to around 550 million years ago.  They preserve a unique record of microscopic life (Metazoan life – animals) that existed during the Ediacaran geological period, the period in Earth’s history defined as immediately before the Cambrian and that marks the end of the Precambrian or the Proterozoic Eon.

What is an Eukaryote?

The scientists were able to identify a number of three-dimensional multicellular fossils that show signs of cell-to-cell adhesion, cells potentially performing different functions and programmed cell death.  These qualities are all found in complex eukaryotes, the organisms that dominate visible life on Earth to day, the fungi, animals and plants.  Eukaryotes range in size from single-celled amoebas to giant sequoias and blue whales.  We (H. sapiens) belong to the Domain Eukarya.   Eukaryote cells are complex, they have a distinct nucleus surrounded by a membrane.  The nucleus contains most of the genetic material.  The nucleus itself is a specialised area of the cell, it is referred to as an organelle.  Eukaryote cells have a number of specialised areas within them (other organelles as well as a nucleus).

Professor Xiao and his colleagues admit that these are not the first multicellular fossils found, nor are they probably the oldest, but the exceptional preservation permits the researchers to draw certain conclusions.  For example, it had been previously thought that these multicellular characteristics had started to develop much later in Earth’s history, perhaps as recently as 545 million years ago, a time shortly before the great Cambrian explosion.

What was the Cambrian Explosion?

The Cambrian explosion refers to the period in Earth’s history around 545 to 542 million years ago when there was a sudden burst of evolution as recorded by extensive fossil discoveries.  A wide variety of organisms, especially those with hard, mineralised body parts first appear.

This new research may help to shed some light on when multicellularity arose, but the reasons for this significant change remain unclear.  The complex multicellularity shown in these Chinese fossils is not consistent with that seen in simpler forms such as bacteria.  The scientists note, that whilst some earlier theories can be disregarded these three-dimensional structures can be interpreted in many ways and more research is required to construct the complete life cycle of these ancient organisms.

In summary, these fossils may show some affinity towards the stem-groups that led to the first members of the Kingdoms we know as Animalia, Fungi and Plantae, but much more data is needed to establish a more thorough phylogenetic relationship.

Spinosaurus “Four Legs are Better than Two”?

Spinosaurus – Steps into the Spotlight (Once Again)

And so, the long awaited paper that re-evaluates the fossil data on the Spinosaurus genus and specifically S. aegyptiacus was published in the academic journal “Science” yesterday.  Time to open a new chapter on this, one of the most enigmatic, mysterious and bizarre of all the known Theropoda.  Since the paper’s submission in the summer, there has been a lot of debate in scientific circles with regards to what this new study will show.  The paper’s title “Semi-aquatic Adaptations in a Giant Predatory Dinosaur”, is almost an understatement, when this is contrasted with the lurid headlines we have seen from a large number of media outlets.

Re-examining What We Thought We Knew About Spinosaurus

In very brief summary, the dedicated team of international researchers have re-assessed the known fossil material on Spinosaurus.  They have been able to track down the location in Morocco from which a number of Spinosaurus bones were excavated and sold via a fossil dealer.  The team have then re-examined this site and found further material.  Their efforts has led to a considerable re-think in terms of what this animal looked like and how it moved.  This new study interprets Spinosaurus as a sixteen metre plus dinosaur, that considered itself more at home in the water than on land.  Although capable of terrestrial locomotion, unlike every other large Theropod, a new rendering sees Spinosaurus as an obligate quadruped.  Here is a meat-eating dinosaur that walked on all fours.

A Semi-Aquatic Obligate Quadruped – Spinosaurus

Very much at home in the water.

Very much at home in the water.

Picture Credit: Davide Bonnadonna, Nizar Ibrahim, Simone Maganuco

In the picture above, a web-footed Spinosaurus pursues a prehistoric swordfish, known as Onchopristis.  Earlier studies and research based on other members of the Spinosauridae suggest that fish may have made up a substantial proportion of their diet.  Instead of perching on the river bank, attempting to claw fish out of the water like some form of giant, prehistoric Grizzly bear, an ecological niche trumpeted by ourselves to the CGI team helping with the rendering of Spinosaurus for an episode of the BBC television series “Planet Dinosaur” back in 2011, this latest interpretation goes a lot further.

Beyond “Planet Dinosaur” – The Transformation of Spinosaurus aegyptiacus

From paddler to swimming the "evolving" image of Spinosaurus.

From paddler to swimming the “evolving” image of Spinosaurus.

Picture Credit: BBC

Building Up a New Picture

Having re-visited what records and remaining photographs that exist of the original Stromer material excavated from the Western desert of Egypt around a 100 years ago, the dedicated research team then set about mapping previously known Moroccan finds including jaw bone fossils that had been discovered in the mid 197o’s.  To this eclectic mix they added information obtained from the fossils from the newly “rediscovered” Moroccan site, which itself makes up what is now known as the neotype for Spinosaurus aegyptiacus.  A neotype is a specimen that is deemed to represent a species in the absence of the holotype material that has either been lost or destroyed.  Add a pinch of material not known from the Spinosaurus genus but described from related animals baryonychids, spinosaurids and so forth, combined with a soupcon of inferred parts of the anatomy as the bones are not known at all in the fossil record and you have a “composite” view of the animal.

The Latest Interpretation of Spinosaurus (S. aegyptiacus)

Life-size reconstruction and supplemental figure

Life-size reconstruction and supplemental figure

Picture Credit: Davide Bonnadonna (top) Ibrahim et al (bottom)

The illustration (top), depicts Spinosaurus as a dinosaur that walked on four legs, in this new study the centre of gravity is positioned further forward, the pelvic girdle is estimated to have been much smaller and the hind limbs with their robust but very short femur  reflect the adaptations of a paddler more than that of a bipedal walker.

The picture below, referred to by a colleague as the “Spinosaurus colour chart” is a figure from the scientific paper’s supplementary data.  The colour coded bones illustrate the composite nature of this digital reconstruction.

The “Spinosaurus Colour Chart” Key

RED = the neotype fossils (FSAC-KK 11888)

ORANGE = the original bones from Stromer’s expeditions

YELLOW = isolated fossil material ascribed to Spinosaurus spp. from the same geological Formation as the neotype (Kem Kem Formation)

GREEN = scaled up bones derived from better known spinosaurids

BLUE = additions to help complete the skeleton based on no known fossils but derived from adjacent bones in the digital restoration

We at Everything Dinosaur applaud the efforts of the international team responsible for this new reconstruction.  A revaluation of the known Spinosaurus fossil material has been long overdue and this is the first time that palaeontologists have been able to relocate the bones from a private fossil collection to the actual site where they were excavated.  We commend the team for their perseverance.

Taking a Different Perspective

However, as with all good science, a number of counterpoints have already been made.

Scott Hartman, addresses these concerns in his web log: There’s Something Fishy About Spinosaurus

Scott, with a background in anatomy, and an expert in skeletal reconstructions, makes a number of excellent points in his article.

The dinosaur referred to as Spinosaurus aegyptiacus was one of the last of the Spinosauridae.  There is a British connection to this story.  One of the spinosaurids used in the comparative study was Baryonyx (B. walkeri).  When this dinosaur, whose bones were found in a Surrey clay pit, was formally described back in 1986 it was depicted as a semi-aquatic dinosaur, fish scales found in the body cavity suggested that fish made up at least a portion of its diet.

Commenting on this new research, Dean Lomax, (Honorary Visiting Scientist: School of Earth, Atmospheric and Environmental Sciences, The University of Manchester) and author of the recently published “Dinosaurs of the British Isles” which includes extensive information on the Baryonyx fossil finds, stated:

“The new discovery is very interesting as it potentially confirms what had been suspected for quite some time, that Spinosaurus lived a semi-aquatic lifestyle.”

For further information on the book “Dinosaurs of the British Isles” by Dean Lomax and Nobumichi Tamura, which includes some fantastic skeletal drawings by Scott Hartman visit: Siri Scientific Press

This new paper, marks a new chapter in the story of Spinosaurus, but it’s not the end of the story that’s for sure.  Ironically, although Stromer originally depicted S. aegypticacus as a biped, we recall that in the distant past (the 1970′s), Spinosaurus had previously been thought of as a dinosaur that walked on all fours.

An Illustration of Spinosaurus from 1976

Spinosaurus as a terrestrial quadruped.

Spinosaurus as a terrestrial quadruped.

Picture Credit: Giovanni Caselli (from the book “The Evolution and the Ecology of the Dinosaurs” by L. B. Halstead)

We suspect there are going to be a few more twists and turns in the Spinosaurus story.

Fossil Damaged at Dinosaur National Monument (Utah)

Dinosaur Fossil Damaged and a Piece Stolen from Dinosaur National Monument

It once was a near perfect fossil of the upper arm bone of a Sauropod dinosaur, now it is broken and damaged with a fist-sized chunk missing.  Rangers at the Dinosaur National Monument in Utah have reported the vandalism and theft of part of a humerus.  It is extremely sad to have to report on yet another theft of a dinosaur fossil, officials at the Monument are appealing to members of the public to help them trace the culprit(s).

The Damaged Portion of the Dinosaur Fossilised Bone

The damaged dinosaur bone.

The damaged dinosaur bone.

Picture Credit: National Parks Service

The picture above shows the missing section of the dinosaur bone, the bone seems to have been deliberately smashed.

The Dinosaur National Monument is well-named.  Managed by the United States Department of the Interior National Parks Service, the park covers some 85,000 hectares and overlies the border between the states of Colorado and Utah (although the main dinosaur quarry site is in Utah, close to the town of Jenson).  The Monument is world famous for its amazing collection of dinosaur and other vertebrate fossils which date from the Upper Jurassic.  At least ten different types of dinosaur genera are known from the Morrison Formation exposures.  The Utah sequence represents high energy riverine deposits and on show at the visitor centre is a sandstone “wall” that reveals some 1,500 dinosaur bones.  Dinosaurs were probably swept away and drowned during floods.  At bends in the river as the current slowed down, so debris, including the carcases of dinosaurs was deposited.  The Dinosaur National Monument preserves these “log jams” of dinosaur bones.  Genera associated with the Monument include Camarasaurus, Allosaurus, Stegosaurus, Apatosaurus, Diplodocus and Dryosaurus.

On Tuesday, September 2nd , a park ranger was leading a tour party along the Fossil Discovery Trail when the damaged bone was noticed.  The vandalism and theft probably took place sometime between the Monday guided walk along the Fossil Discovery Trial and Tuesday morning.  The Fossil Discovery Trail is a 1.2 mile trail that runs between the Quarry Visitor Centre and the Quarry Exhibit Hall where the famous sandstone “wall”of dinosaur bones that we described above, is located.  The trail is unique as it is one of the few places where visitors can hike to see and touch dinosaur fossils and fragments in situ.  It allows visitors to experience what it may have been like for palaeontologist Earl Douglass (Carnegie Museum of Natural History), when he discovered the first fossils in what is now the Monument.

A spokes person from Everything Dinosaur commented:

“This is such a shame as the Dinosaur National Monument is going to celebrate its centenary next year and to have fossils damaged and stolen is deeply upsetting.  Although the fossils along the trail are of limited scientific value they provide a wonderful opportunity for members of the public to get up close to real dinosaur fossils.”

The Sauropod Humerus (before and after) Photographs

Two photographs showing the fossil before and after the theft.

Two photographs showing the fossil before and after the theft.

Picture Credit: National Parks Service

The picture above shows two photographs, the picture of the humerus without the damage (left) and a close up showing the damaged portion (right).  Although our dinosaur experts cannot be certain, the bone portion in question looks like the distal end of a left humerus, probably part of a Camarasaurus.  Park officials are seeking help from the public and anyone with information regarding this theft are invited to contact staff on (435) 781-7715.  A reward of $750 USD has been put up by the Intermountain Natural History Association for information that leads to a conviction.

The Part of the Fossil Discovery Trail where the Bone was Situated

The arrow shows the position of the damaged dinosaur bone.

The arrow shows the position of the damaged dinosaur bone.

Picture Credit: National Parks Service

Everything Dinosaur would like to take this opportunity to stress that visitors to the Dinosaur National Monument are not allowed to collect/damage any fossils or rocks.  Under Federal law, all features, artifacts and resources are protected. No collection of park geological resources for commercial sale, private collections or for classroom educational purposes is permitted.  We advise all visitors to National State Parks of America to familiarise themselves with the various protection laws and polices that relate to that particular location.

A Little Detail on a Great Big Dinosaur – Dreadnoughtus

Dreadnoughtus schrani – A Dinosaur on a Massive Scale

And so the announcement came this week about the discovery of a super-sized, South American dinosaur that weighed as much as thirteen, bull African elephants.  Dreadnoughtus was so named as the huge bones (and for a change when it comes to the Titanosauria, there are quite a lot of them), reminded the scientists of the impervious super-structure of turn-of-the-Century battleships.  This was a plant-eating dinosaur that was simply too big to be vulnerable to attack from predators.  Invulnerability would have been very handy for this immense creature as this dinosaur would have been preoccupied with eating, trying to cram enough calories into its enormous digestive system to keep its house-sized body functioning.

A Dinosaur on a Massive Scale - Dreadnoughtus schrani

Huge dinosaur from southern Patagonia.

Huge dinosaur from southern Patagonia.

Picture Credit: Jennifer Hall

Many articles have already been written about this new Titanosaur, the scientific paper was published by the Nature Publishing Group on the 4th September, this paper has already received more than 20,000 page views and the story has been picked up by dozens of news outlets.  We at Everything Dinosaur, had known about this research for some time, there are more exciting titanosaurid discoveries from South America still to be announced, so this blog article hopes to recap the main points about the significance of this study and to focus on a couple of areas that may not have been covered by other media outlets.

Firstly let’s deal with the size – this is a real “elephant in the room” moment, as with all large dinosaur fossils, this seems to be the most prominent and frequently asked question – just how big was this dinosaur?

The Size and Scale of the Dinosaur Discovery

Heavier than a 737 Jet.

Heavier than a 737 Jet.

Picture Credit: Dr. Ken Lacovara

Although D. schrani may not be the very biggest of all the dinosaurs that ever existed.  It is certainly right up there, with an estimated body mass of 59,300 kilogrammes (the actual measurement was 59,291 kilogrammes but some rounding has taken place in the media).

How do Scientists Estimate the Body Mass?

This leads us to one the most important points to note about this discovery.  The international research team led by Drexel University’s Dr. Kenneth Lacovara was able to recover around 45% of the total skeleton of a single individual specimen, including cranial material (skull bones).  Most of the rear portion of the animal was excavated including a left humerus (upper arm bone) and femur (thigh bone).  These limb bones hold the key to estimating body size.  Earlier studies have shown that an analysis of the these limb bones and measurements of their circumference, corresponds to relative body mass in terrestrial quadrupeds.

Put simply, imagine weighing several different herds of cows before they are slaughtered for meat.  The cows would be of different sizes and therefore there would be some variance in total body weights.  Once the cows had met their demise, the upper arm bones and thigh bones could be collected for each animal.  The mid shaft circumference for these bones would then be measured and recorded.  A correlation would most likely be found between the mid shaft circumference measurements and the body weight recorded earlier.  For instance, bigger circumference equals a heavier animal.

This correlation provides accurate data on the body mass estimates of four-limbed, terrestrial animals that are alive today.  So the theory goes, that if it works for animals that are extant (living today), then it should also work for extinct animals such as the Dinosauria.  This correlation is extremely useful as the Sauropods and the later Titanosaurs are so different from living creatures that anatomical comparisons are just not relevant.

The preservation of these limb bones which have been found to scale with body mass, permits the scientists to make an estimate of the body mass of Dreadnoughtus schrani.  The same equation has been used to estimate the body masses of a number of other substantial dinosaurs, but none of them quite match the bulk of Dreadnoughtus.  It therefore suggests that the Dreadnoughtus schrani holotype material represents an individual titanosaurid that was much heavier than other Titanosaurs and indeed much more massive than most other Sauropods.

Dreadnoughtus Compared to Other Sauropoda (Limb Circumference Analysis)

Dreadnoughtus - the most complete skeleton of a giant titanosaurid dinosaur discovered to date.

Dreadnoughtus – the most complete skeleton of a giant titanosaurid dinosaur discovered to date.

Table Credit: Everything Dinosaur, data compiled from Nature Publishing Group and Benson et al.

Still Growing?

Astonishingly, of the two specimens found together, the largest one, the Dreadnoughtus that was estimated to be heavier than a Boeing 737 aircraft was probably not yet fully grown.  Identifying when a dinosaur reached its maximum size is a complicated business (related to indeterminate growth), however, the research team found that it was likely that this super-sized dinosaur was still growing at the time of its death.  The scapula (shoulder blade) had not fused completely to the coracoid bone.  The posteromedial margin of the coracoid foramen (small opening, located in the middle of the coracoid), was butted up against the distal portion of the shoulder blade.  Palaeontologists have cited these conditions as indicating that the individual was still growing.  A study of the humerus supports this hypothesis, the lack of lines of arrested growth indicate that this dinosaur was immature at the time of death.  Although some scientists have questioned the validity of these indicators, whatever the outcome, the larger individual of the two Dreadnoughtus specimens found to date, represents the biggest dinosaur known to science for which a robust body mass has been calculated.

Not reported by many media sources but for the record the femur length is in excess of 1.9 metres and the humerus is 1.6 metres long.

Dinosaur Fossils Found in Southern Patagonia

Another, significant point we wanted to make concerns the location of the dinosaur fossils.  Whilst Patagonia may now be synonymous with dinosaur discoveries, Argentinosaurus, Giganotosaurus et al, many of these fossils come form the northern and central parts of this vast region.  These fossils come from a relatively unexplored part of south-western Patagonia.  The fossil material was excavated from the Cerro Fortaleza Formation, an exposure on the eastern bank of the Río La Leona, (Santa Cruz Province), this is more than 750 miles (1,200 kilometres) away from the location of other major Cretaceous-aged dinosaur fossil finds.  We at Everything Dinosaur are unaware of any radiometric dating and although Campanian-aged biostratigraphical material is associated with some horizons of the Cerro Fortaleza Formation, the precise age of these fossils remains unclear.  They are between 83 million and 66 million years old, with some sources stating 77 million years of age (Campanian to Maastrichtian faunal stages).

Location of the Dreadnoughtus Quarry

The site of the fossil discovery.

The site of the fossil discovery.

Picture Credit: Map de la provincia de Santa Cruz

A Team Effort

Last but not least, the 116 fossils, some of which do show potential evidence of scavenging by Theropod dinosaurs, have been excavated, prepared and digitally mapped by a dedicated team of researchers.  This has certainly been a colossal undertaking, yes, we know the tail itself measures some thirty feet in length, (the total length of Dreadnoughtus schrani has been estimated at 26 metres) and the skull (only one fragment of which has been found) was around eighty-eight centimetres in length.  It is quite right to focus on the huge size of this member of the Titanosaur family, but we at Everything Dinosaur would like to take this opportunity to thank all the researchers for their hard work.

The first fossil was spotted during a expedition back in 2005, the femur we think. From 2005 to 2009 a series of field trips took place to excavate the two individual specimens, since then a great deal of preparatory work and fossil prep has been carried out by scientists from Drexel University, a number of graduates from this institution but also with the aid and support of the likes of the Carnegie Museum of Natural History,  the Museo Argentino de Ciencias Naturales, Argentina and Laboratorio de Paleovertebrados, Universidad Nacional de la Patagonia (also Argentina).

Even a scientist from the University of Manchester (Dr. Victoria Egerton), a lecturer in Applied Palaeontology, was involved.   Our congratulations to everyone who has participated in this amazing study, an exceedingly rare opportunity to learn about one of the largest terrestrial vertebrates that is known to science.

Walking Fish Provides Clues to the First Tetrapods

Researchers Study Living Fish to Gain Insight Into Fossil Record

Arguably one of the most significant events in the history of life on Earth occurred when the first vertebrates walked on land.  The date when types of prehistoric fish made the move to land and began the evolutionary journey that would lead to the Tetrapods keeps changing in the light of new fossil discoveries.  Tetrapods are vertebrates, this group includes the amphibians, reptiles, birds and mammals and that means, we are Tetrapods too.  One of the most important fossil discoveries in recent years, was made in a limestone quarry in Poland.  On one stone slab scientists discovered strange track-like marks about fifteen centimetres wide.  These were controversially interpreted as having been made by the limbs of an animal capable of moving around on land.  It was envisaged that whatever strange creature made these marks, it must have been more than two metres long.  This trace fossil suggests that the first animals walked on land around 400-395 million years ago, some thirty-five million years earlier than previously thought.

To read more about this Polish discovery: Clues to the First Land Animals?

A team of researchers from McGill University (Montreal, Canada), have turned to a living fish in order to gain a better understanding of the evolutionary changes that must have taken place to allow certain types of fish such as the Sarcopterygians to adapt to a more terrestrial lifestyle.  If, sometime around 400 million years ago (Lower Devonian Epoch), a group of fish began exploring terrestrial environments, the first stage on the long evolutionary journey to the Tetrapods, how did these fish do it?  What changes to their bodies and fins took place to allow them to adapt to this new habitat?  Helping to answer these questions was the aim of the research team at McGill University and to do this they turned to a living (extant) fish called Polypterus.

Little Fish Takes Part in “Ground Breaking” Experiments

A giant leap for fish-kind!

A giant leap for fish-kind!

Picture Credit: McGill University

There are ten or so species in the Polypterus genus, as far as we at Everything Dinosaur know, they are all African and freshwater fish.  Polypterus is the only vertebrate known to science that possesses lungs and is capable of breathing air but has no trachea.  These little fish have been studied for more than one hundred and fifty years, Thomas Huxley no less was involved in some of the earliest research.  He placed them in the Order Crossopterygii, now regarded as a synonym of the Sarcopterygii – although this classification has now been largely disproved.  The first successful domestic breeding programme commenced in 2005, this paved the way for laboratory studies.

The McGill team in collaboration with the University of Ottawa, studied Polypterus fish to show what might have happened when fish first attempted to walk out of the water.  These air breathing fish can “walk” on land, (really it is a bit of shuffle), but they do superficially resemble Devonian Sarcopterygians, (hence Huxley’s classification).  The scientists raised juvenile Polypterus on land for nearly a year, with an aim of revealing how these “terrestrialised” fish looked and moved when compared to Polypterus specimens raised in a more normal environment.

Project leader, Emily Standen, a former McGill University post-doctoral student stated:

“Stressful environmental conditions can often reveal otherwise cryptic anatomical and behavioural variation, a form of developmental plasticity.  We wanted to use this mechanism to see what new anatomies and behaviours we could trigger in these fish and see if they match what we know from the fossil record.”

The team discovered that these fish underwent remarkable anatomical and behavioural changes in response to their stressful environment.  These fish walked more effectively by placing their fins closer to their bodies, lifted their heads higher and kept their fins from slipping as much as fish that were raised in water.

Polypterus Showed Anatomical and Behavioural Changes

Helping to explain the evolution of Tetrapods.

Helping to explain the evolution of Tetrapods.

Picture Credit: McGill University

Fellow researcher, Trina Du (McGill University PhD student) explained:

“Anatomically, their pectoral skeleton changed to become more elongate with stronger attachments across their chest, possibly to increase support during walking and a reduced contact with the skull to potentially allow greater head or potential neck motion.”

Hans Larsson, Canada Research Chair in Macroevolution at McGill and an Associate Professor at the Redpath Museum added:

“Because many of the anatomical changes mirror the fossil record, we can hypothesise that the behavioural changes we see also reflect what may have occurred when fossil fish first walked with their fins on land.”

The “terrestrialised” Polypterus is unique and provides fresh ideas on how fossil fishes may have used their fins in a terrestrial environment and what evolutionary processes may have been involved.  Hans Larsson went onto to say that this experiment was the first example that they were aware of, that demonstrated developmental plasticity may have facilitated a large-scale evolutionary transition, by first accessing new anatomies and behaviours that could later be genetically fixed in the population by natural selection.

The study was conducted by Emily Standen, University of Ottawa, and Hans Larsson, Trina Du at McGill University and supported by the Canada Research Chairs Program, Natural Sciences and Engineering Research Council of Canada (NSERC) and Tomlinson Post-doctoral fellowship.  It has been published in the journal “Nature”.  Everything Dinosaur acknowledges the help of McGill University in the compilation of this article.

Dinosaur Footprints Damaged

Welsh Dinosaur Footprints Vandalised

They might be as much as 200 million years old but the thoughtless actions of fossil hunters have damaged a number of dinosaur footprints preserved at a site of special scientific interest (SSSI) in Wales.  A number of prints have been damaged including one that was filled with plaster of paris in a bid to make a cast and then an attempt was made to hammer the cast out of the rock.  The fossilised footprints form part of an important palaeontological site in the Vale of Glamorgan.  The prints can be found on a stretch of exposed coastline between the towns of Barry and Sully on the northern coast of the Bristol Channel, the trace fossils are the oldest known dinosaur tracks to found anywhere in the British Isles.

One of the Vandalised Fossilised Dinosaur Footprints

Three-toed dinosaur footprint with marks showing attempt to remove print from site.

Three-toed dinosaur footprint with marks showing attempt to remove print from site.

Picture Credit: Media Wales Ltd

The picture above shows one of the three-toed (tridactyl) prints with marks around it where an attempt was made to cut out the fossil from the surrounding rock.

The fossils, which are located in strata that form the Mercia Mudstone Group have been subjected to vandalism before.  Sadly, authorities and conservation bodies face a dilemma, do they permit free access to the site so that walkers can view the fossilised footprints and tracks in situ or should the trace fossils be removed and stored in a secure facility to prevent vandalism and fossil thefts?

Back in August 2012, Everything Dinosaur team members reported on the theft of footprint fossils from the same area, fortunately the fossils were recovered a few weeks later.

To read about the earlier fossil theft: Dinosaur Footprints Stolen from the Vale of Glamorgan

This new damage was discovered by South Wales archaeologist Karl-James Langford whilst he was conducting students around the SSSI.

Mr Langford, the founder of Archaeology Cymru (Archaeology Wales) stated:

“I took a group of ten students to give them the tour of the dinosaur footprints.  I could not hide my horror at the damage which had been deliberately caused.   We examined one print that had been filled with plaster of paris.  On a visit to inspect the damage with another group later that same day, somebody had deliberately tried to smash it out with a breeze block, damaging the 200 million year old print in the process.”

It has also been reported that fires had been lit around the site and rubbish left, calls were made last night to provide this extremely important fossil site with greater protection.

What’s so Special About this Location?

The mudstones exposed on this stretch of the coast running along the northern edge of the Bristol Channel were laid down towards the end of the Triassic Period (Upper Triassic – Norian to Rhaetian faunal stage), dinosaur footprint fossils from this time in Earth’s history are extremely rare and the site is one of the world’s most important in terms of recording the activities of Late Triassic dinosaurs.  This was an area of mud flats and silts leading towards the edge of a shallow tropical sea to the south-west.  Many different types of ancient reptile crossed these mud flats and their footprints and tracks were preserved.  Hundreds of individual prints have been recorded and something like sixty trackways have been mapped.  Most of the dinosaur tracks represent a small, three-toed, Theropod which has been given the ichnogenus Grallator.  An ichnogenus is a name given to an organism that has left trace fossils, usually tracks, prints or burrows.  Other types of dinosaur footprints have been recorded, including tracks representing a large meat-eater (Theropod) and a series of trails left by plant-eating Prosauropods.

Field Photograph Showing Preserved Trace Fossils at Barry (Vale of Glamorgan)

Dinosaur Tracks from the Late Triassic.

Dinosaur Tracks from the Late Triassic.

Picture Credit: Tom Sharpe (Dinosaurs of the British Isles)

The photograph above shows a number of rounded footprints and tracks.  The rounded prints are believed to have been made by a Prosauropod dinosaur.  Many of the tracks are quite difficult to spot, the best time to see them is in the evening when the low sun casts shadows on those tracks which represent natural casts.  In addition, if there has been recent rain, or a high tide many of the trackway depressions will be filled with water and this makes observing the prints much easier.

Team members at Everything Dinosaur would like to echo the comments made by a number of other organisations with regards to this damage.  It is essential that sites such as this are protected and safeguarded and we urge all readers to remember that this is a SSSI and as such it is an offence for any person or persons to intentionally or recklessly damage or destroy any of the features of special interest of an SSSI!

If any visitor to this location sees suspicious activity, such as damage to footprints, attempts to make casts or actions that could lead to the theft of a print, please alert the Countryside Council for Wales, the Geology Department of the National Museum of Wales or the Geologists’ Association South Wales Group.

Useful Contacts

For the Geology Department of the National Museum of Wales telephone +44 (0)29 2057 3213

Email: the Geologists’ Association of South Wales Group: webmaster@swga.org.uk

For the Countryside Council for Wales, try Natural Resources Wales (Mon-Fri) on 0300 065 3000

Laquintasaura – What Does it all Mean?

Notes on the Newly Described Dinosaur – Laquintasaura

Over the last day or so, the popular science media has carried a vast array of articles detailing the discovery of a new type of dinosaur from the continent of South America.  There have been radio interviews with some of the scientists behind the academic paper, news reports and of course, a number of video news stories too.   The great majority of the press outpourings have been excellent.  The naming of a new dinosaur is a big story, the general public seems to have an ever-lasting fascination with these ancient animals.  Palaeontologists and science editors far cleverer than ourselves have provided a comprehensive overview of Laquintasaura venezuelae, so rather than dwell on describing this animal, we at Everything Dinosaur will try to place this dinosaur discovery in context and cover some of the issues raised in the scientific paper that were not necessarily picked up by the general media.

The Illustration of the Newly Named Dinosaur L. venezuelae

Small, Early Jurassic, bird-hipped dinosaur

Small, Early Jurassic, bird-hipped dinosaur

Picture Credit: Mark Witton/Natural History Museum

Why Saura and Not Saurus?

First of all, let’s deal with the name Laquintasaura venezuelae.  The fossil material (and there is lots of it), comes from a single bone bed located at a dig site which is effectively a road cutting between the two small towns of Seboruco and La Grita in  Táchira State, western Venezuela, just a few miles from the border with Columbia.   The horizon from which the fossils were excavated form part of the La Quinta Formation, which outcrops in western Venezuela and eastern Columbia.  So the  name is pronounced La-quin-tah-sore-rah  ven-ee-zway-lay and it translates as “Venezuela’s lizard from the La Quinta”, but note the ending of the genus, it is “saura” and not the much more common “saurus”, what’s going on here?

Saura is the female form of the Greek word saurus, it still means lizard and a number of dinosaurs have been given genus names which take the female form of saurus, examples are the likes of Maiasaura (means “good mother lizard”), or the small Cretaceous Ornithopod Leallynasaura which was named after the daughter of the discoverer.  There is nothing particularly feminine about Laquintasaura, it is very likely that the bone bed represents the remains of both males and females, in this case, we think the name has come about as the rock formation “La Quinta” has a female root.

Early Jurassic – So What?

The majority of the rocks that make up the La Quinta Formation are sandstones, accurately dating these rocks is made all the more difficult due to the lack of marine deposits and the more abundant zonal fossils that help to date them.  However, the scientists involved in this study have been able to date the age of the fossils with a very high degree of confidence.  Zircon crystals found very close to the fossilised bones permitted highly accurate radiometric dating techniques to be applied.  Essentially, these crystals are abraded by acids, cooked at very high temperatures and then the proportion of uranium isotopes is measured.  Radioactive elements such as uranium begin to decay from the moment they are formed.  They decay and form “daughter” isotopes by shedding electrons at a consistent, regular rate.  By measuring the proportion of isotopes in these minute zircon crystals the rock formation can be accurately dated.  The fossils of Laquintasaura are 200.91 million years old, plus or minus half a million years or so.

Very few dinosaur fossils have been found that can be dated so accurately to this period in Earth’s history.  The vast majority of the dinosaur fossils that have been dated to around 200 million years or so, are lizard-hipped dinosaurs (Saurischians), Laquintasaura is a member of that other group of dinosaurs, the bird-hipped dinosaurs (Ornithischia).

Photographs of Some of the Fossil Material and Outline Body Shape

Abundant fossil finds.

Abundant fossil finds.

Picture Credit: Proceedings of the Royal Society B.

What’s so Special about Laquintasaura?

The picture above shows an outline of the body shape of Laquintasaura.  It was estimated to be about a metre long, but half of its body length was made up of the tail.  It was lightly built and probably a fast runner, roughly the size of a common Red Fox (Vulpes vulpes).  The drawing also indicates the sort of fossil material that has been found.  Most of the fossils are isolated teeth, or represent bones from the hip area or fragments of rib.  However, other fossils representing parts of the skull, the limb bones and vertebrae have also been found but these elements are much rarer.  The fossils represent the remains of at least four individuals, but probably many more.

Key to the Picture

  • (a) Triangular cheek tooth
  • (b) Neck bones
  • (c) Dorsal vertebrae
  • (d) Left shoulder blade
  • (e) Part of the ankle bone
  • (f) Left ischium (bone from the hip)
  • (g and h) Views of the femur

This is the first early Ornithischian bone bed containing the bones of a number of individual dinosaurs found anywhere in the world.  Studies of the bones suggest that the fossils represent a group of animals that ranged from about three years to twelve years of age.

Although the bones are jumbled up, they do not show any obvious signs of having been transported a long distance perhaps by a river in spate.  Palaeontologists interpreting this fossil deposit have suggested that this bone bed was not formed over a long period, where single dinosaur carcases were deposited in the same location as a result of seasonal, violent floods.   The fossils seem to have been transported and deposited in a low-energy water environment, perhaps a slow moving river and it has been suggested that this group of dinosaurs died in a single catastrophe.  It is unclear whether they all died as a result of becoming stuck in the water, or whether the water transport occurred after death.   This suggests that this was a social group, a small herd or a flock if you prefer.

Most palaeontologists are confident that later Ornithischians, the likes of the Iguanodonts, duck-billed dinosaurs and the horned dinosaurs lived in herds.  If Laquintasaura is a social, bird-hipped dinosaur, then these fossils have provided the earliest known evidence for the evolution of complex social groups in the Ornithischia.  This social behaviour in Ornithischian dinosaurs is being seen around fifty million years earlier than previously thought.

Weird Teeth

The teeth are unlike any other teeth associated with Ornithischian dinosaurs.  They are quite prominent, and although triangular in shape, the edges are curved and slightly concave in appearance.  The edges of the crown (the tooth that sticks out of the gum) are coarsely serrated.  This suggests that this little dinosaur was most probably a herbivore eating tough ferns and horsetails.  It probably also grabbed at passing insects or small reptiles from time to time, hence the bug eating Laquintasaura depicted in Mark Witton’s excellent illustration (see above).

A Close up of One of the Teeth of Laquintasaura (various views)

Strange teeth indicate herbivorous habit.

Strange teeth indicate herbivorous habit.

Picture Credit: Barrett et al, Proceedings of the Royal Society B.

Venezuela’s First Dinosaur – Dinosaurs Thrived Around the Equator

Much has been made of the fact that this is the first dinosaur ever to be discovered in Venezuela.  Indeed, this is the first dinosaur to be named and described from the northern portion of South America.  Two hundred million years ago, Venezuela formed part of the central portion of the giant super-continent Pangaea.  Laquintasaura seems to have thrived in a habitat close to the equator in the centre of this huge land mass.  Very few dinosaur fossils have been found in what is termed the palaeoequatorial region.  It had been thought that much of this part of the world in the Late Triassic/Early Jurassic was too hot and dry to support extensive, complex ecosystems.  Much of this area was thought to have been covered by vast, inhospitable deserts.  However, the finding of the fossils of Laquintasaura suggests that dinosaurs and most likely other types of vertebrate did live in these regions.

The Location of the Laquintasaura Fossils (Palaeoequatorial Environment)

Spatial distribution of early bird-hipped dinosaurs.

Spatial distribution of early bird-hipped dinosaurs.

Picture Credit: Proceedings of the Royal Society B.

The diagram (b) shows the location of dinosaur fossil finds mapped onto a picture of the world from the Late Triassic.  The yellow line indicates the position of the equator.  Diagram (c) shows the position of dinosaur fossil finds known from the very Early Jurassic.  Arrows indicate Ornithischian dinosaur finds.  Note the scarcity of palaeoequatorial dinosaur finds and the very limited palaeobiogeographical distribution of Ornithischians in the Late Triassic and their subsequent spread in the Early Jurassic.  The red dot in diagram (c) indicates the site of the Laquintasaura fossils.  As these dinosaurs were small, around one metre in length, it is highly unlikely that these dinosaurs could have migrated long distances, this and the fact that the fossil bones show little sign of long distance transport indicates that Laquintasaura lived close to the equator.

The discovery of Laquintasaura suggests that there were Ornithischian dinosaurs living close to the equator around 200 million years ago.  Their presence (and the discovery of two Theropod teeth at the same site), indicates that western Venezuela supported a diverse and flourishing ecosystem.

What Does it Mean for Dinosaur Evolution?

The fossils of Laquintasaura come from just a few hundred thousand years after the end Triassic extinction event.  The period of deep time marked by the end of the Triassic experienced a mass extinction event.  The type and diversity of terrestrial vertebrates altered dramatically with many kinds of reptile and amphibian becoming extinct.

Palaeontologist Dr. Paul Barrett of the Natural History Museum (London) and one of the lead authors of the scientific paper commented:

“Laquintasaura lived very soon after the major extinction at the end of the Triassic Period, 201 million years ago, showing dinosaurs bounced back quickly after this event.  It is fascinating and unexpected to see they lived in herds, something we have little evidence of so far in dinosaurs from this time.”

Either the dinosaurs did recover quickly after this extinction event or they were not too badly affected when compared to other vertebrates.

In addition, scientists are aware that by the Middle Jurassic, the bird-hipped dinosaurs had begun to diversify into a range of body types.  There were the likes of the ancestors of the Camptosaurs, heterodontids and the first of the armoured dinosaurs.

This research carried out by the University of Zurich and the Natural History Museum is helping to piece together the origins and the subsequent diversification of this group of the Dinosauria that led them to become the dominant terrestrial herbivores of the Mesozoic.

Unravelling an Ammonite Mystery

Why did the Ammonites go Extinct but the Nautilus Survive?

A team of international researchers led by scientists from the American Museum of Natural History (New York), have been trying to unravel one of the great mysteries of invertebrate palaeontology.  Why did the Ammonites go extinct but their relative the Nautilus survive the Cretaceous extinction event?  Building on previous research, lead author of the scientific paper, published this week in the journal “Geology”, Dr. Neil Landman believes that over specialisation and limited geographic distribution led to the downfall of this particular group of chambered shelled molluscs.

 A Nautilus Compared to an Extinct Ammonite

Similar creatures but only the Nautilus is around today.

Similar creatures but only the Nautilus is around today.

Picture Credit: Everything Dinosaur/Safari Ltd

 Ammonites belong to the Class Cephalopoda and they seem to have been entirely marine, pelagic animals (living above the sea floor).  Although more closely related to today’s cuttlefish, Ammonites and their living relative the Nautilus both had coiled, chambered shells.  The first Nautiloids can be traced back to the Late Cambrian, whilst the Ammonites are believed to have originated in the Devonian geological period.  There are two extant genera of Nautilus alive today.  These animals tend to be found in deep water (up to seven hundred metres, although more usually around three to four hundred metres) and they inhabit the deeper slopes of coral reefs in the Indo-Pacific.  They are believed to be scavengers feeding on a variety of dead animal matter.

In this new study, the researchers including scientists from the Royal Belgian Institute of Natural Sciences, Saint Petersburg State University, Polska Akademia Nauk (Warsaw), Bowling Green State University (Ohio) and the Natural History Museum of Maastricht (Holland) as well as Dr. Landman, mapped all the locations of Ammonite fossil finds in the last half a million years or so of the Cretaceous (Maastrichtian faunal stage).  They then compared this data with the occurrences of the Nautiloid genus Eutrephoceras over the same period.  The scientists also included information from a recently published study that looked at Ammonite genera that appear to have briefly survived beyond the Cretaceous into the Palaeogene.

What? Evidence of Ammonites surviving beyond the Cretaceous extinction event we hear you ask!  There is some evidence to suggest that a few types of Ammonite did indeed survive into the Age of Mammals.  Perhaps the very last of this great group of marine invertebrates lived for a hundred thousand years or so before they too finally became extinct.  In a few, very special locations the sequence of strata that was led down at the end of the Cretaceous (Maastrichtian faunal stage) and the first deposits of the Palaeogene (Palaeocene epoch, Danian faunal stage) can be identified.  One such location is the cliffs at Stevns Klint on the Danish island of Sjaelland.  Fragmentary fossils representing two different genera of Ammonite have been identified from the strata immediately above the thin, dark line that marks the end of the Cretaceous.  Dr. Landman has been at the forefront of these studies and he believes as many as six species may have lingered, sort of “dead clades swimming”.

Fragmentary Fossils of Ammonites from Stevns Klint

Fragmentary fossils indicate survival of some species into the Palaeocene Epoch.

Fragmentary fossils indicate survival of some species into the Palaeocene Epoch.

Picture Credit: PLOS One

 The picture above shows Ammonite fossilised remains found in the Palaeocene aged strata at Stevns Klint and surrounding area.  Pictures A, B and D-H are fossils of the Ammonite Baculites vertebralis whereas picture C represents the species Hoploscaphites constrictus.  The white arrows in pictures A and C indicate voids left after the dissolution of the original aragonite shell.

To read more about Stevns Klint being granted UNESCO World Heritage status: Famous KT Boundary Gets UNESCO World Heritage Status

The research team plotted the fossil data against two criteria, firstly they looked at all the occurrences of each genus and secondly they looked at the maximum distance between occurrences for each genus, an examination of geographical distribution based on an assessment of world geography at the end of the Mesozoic.  The scientists discovered that most of the Ammonite genera at the very end of the Maastrichtian were restricted in their geographic distribution.  This may have made the Ammonites more susceptible to an extinction event.  This idea is reinforced when the geographical spread of those genera that may have briefly survived into the Palaeocene is examined.  These genera have a significantly greater geographical spread when compared to non-surviving Ammonite genera.  The research team suggest that those types of Ammonite that were more broadly distributed had a greater chance of survival, at least for a little while longer.  This pattern is further emphasised when the distribution of the Nautiloid  Eutrephoceras is considered.  The scientists found that the distribution of Eutrephoceras was as broad as that of the most widely distributed Ammonites at the end of the Cretaceous.  However, even the most geographically dispersed Ammonites became extinct in the Palaeocene, whereas Eutrephoceras survived.  This new paper proposes that a broad geographical distribution may have initially protected some Ammonites against dying out, but it was no guarantee of their ultimate survival.

Ammonite Fossils are Popular with Fossil Collectors

Examples of fossil Ammonites.

Examples of fossil Ammonites.

Picture Credit: Everything Dinosaur

The restricted distribution of Ammonites may have contributed to their extinction.  Other studies have also helped shed light on the reasons for the demise of the Ammonoidea, Dr. Landman and his colleagues at the American Museum of Natural History have been at the forefront of many of these research projects.  Many scientists now agree that Ammonite numbers and the range of species was in decline before the end of the Cretaceous and this Sub-Class of Cephalopods would have been devastated by the aftermath of the extraterrestrial impact event.  Large amounts of acid rain falling into the sea would have significantly altered the pH balance of marine environments, this would have had a major impact on Ammonite numbers.

Dr Landman stated:

“The Ammonites petered out due to more than one disastrous change caused by the impact.  Ocean acidification likely dissolved the shells of their microscopic young, which floated on the ocean’s surface early in their life-cycle.  Fossil records also show the impact event devastated plankton species, the primary food source for adult Ammonites.  These effects may have only lasted a hundred years or so, but that would have effectively starved some of the Ammonites.”

To read a related report by Everything Dinosaur into studies of the prey of Ammonites: The Last Supper of an Ammonite

In contrast, the deeper living Nautiloids may have been less affected by changes at the ocean’s surface and as they are less reliant on plankton as a staple source of food they could have ridden out the cataclysmic events.  This may explain why there are two genera of Nautiloids around today but as far as anyone knows, not one species of Ammonite remains.

Everything Dinosaur’s Review of the Recently Introduced Wild Safari Ammonite Model

Video Credit: Everything Dinosaur

To view Everything Dinosaur’s range of Safari Ltd prehistoric animal models:  Wild Safari Dinosaurs and Other Prehistoric Animal Models

Downsizing Dinosaurs – The Key to Survival

Sustained Miniaturisation in the Dinosauria the Key to their Survival as Birds

A new study led by the University of Adelaide but involving scientists from a number of universities including Bristol University and the University of Southampton has mapped the evolution of meat-eating dinosaurs and identified how these large creatures gave rise to the birds (Aves).  The Theropoda, or at least parts of this meat-eating dinosaur group kept shrinking in size for at least fifty million years before the evolution of Archaeopteryx.

Archaeopteryx may not have been the first bird, but the dozen or so fossils of this enigmatic dino-bird, all of which come from Germany, provide evidence of a transitional creature that shows anatomical features of both dinosaurs and birds.  Most scientists now accept that birds are descended from the dinosaurs, one particular group of meat-eating dinosaurs called the Maniraptora.  Dinosaurs in the family Dromaeosauridae, fearsome, aggressive predators such as Velociraptor (V. mongoliensis) are members of the Maniraptora clade, but over what time period did the evolutionary changes take place to result in a small bird from larger Dinosaurian ancestors?

 Shrinking Dinosaurs over Fifty Million Years Gave Rise to the Birds

Sustained miniaturisation gave rise to the birds.

Sustained miniaturisation gave rise to the birds.

Picture Credit: Davide Bonnadonna

The international research team, led by Associate Professor Michael Lee (School of Earth and Environmental Sciences, Adelaide University), including Gareth Dyke and Darren Naish (both from the University of Southampton) and Andrea Cau (from the University of Bologna and Museo Geologico Giovanni Capellini), have published their work in the latest edition of the academic journal “Science”.  Professor Michael Benton (Bristol University) provides an adjunct to this research “How Birds Became Birds”.

In professor Benton’s perspective he explains the importance of this new study by placing it into the context of existing research into Theropoda evolution.  Professor Benton states that although it is now widely accepted that the birds evolved from a particular branch of the dinosaur family tree, it is not certain how quickly this evolutionary transition took place.  One of the first birds known from the fossil record (A. lithographica) from the Upper Jurassic of Germany, was thought to have evolved its wings, feathers and the ability to fly within just ten million years or so.  However, over the last two decades, scientists have been able to trace the thirty or so characteristics that distinguished the small, Archaeopteryx with its aerial abilities from its larger, ground-dwelling dinosaur ancestors back through the Theropoda.  This new study reinforces the thinking that the anatomical changes needed to convert a terrestrial predator into an agile, creature capable of powered flight began to emerge much earlier in this group of meat-eating dinosaurs.

Mathematical Models to Trace the Evolution of Archaeopteryx

New from Papo for 2014 a model of Archaeopteryx.

New from Papo for 2014 a model of Archaeopteryx.

Picture Credit: Everything Dinosaur

How much earlier?  This new work suggests that changes began to take place in the Theropoda at least fifty million years before Archaeopteryx.  This means that as far back as 200 million years ago, at the beginning of the Jurassic, evolutionary changes in meat-eating dinosaurs were beginning to occur that would eventually lead to today’s birds.

The team used a complex mathematical modelling technique more associated with the study of the geographical spread and evolution of viruses to assess the changes in the skeletons of Theropod dinosaurs.  In total 1549 skeletal, anatomical characteristics were mapped from over 120 specimens of Theropod dinosaurs and birds.  Two main drivers leading to the transition of dinosaurs into birds were identified.  The group of Theropod dinosaurs directly related to the birds undergoes sustained miniaturisation across fifty million years.  Average body weights are gradually reduced from around 160 kilogrammes in Early Jurassic direct Theropod ancestors to the very light Archaeopteryx, estimated to have weighed less than one kilogramme.  Secondly, this particular group of dinosaurs seems to have been evolving skeletal adaptations such as feathers and wishbones up to four times faster than other types of dinosaur.

A spokes person from Everything Dinosaur stated:

“This highly informative new research, has applied a sophisticated mathematical model to help unravel the evolutionary relationship between the birds and their dinosaur ancestors.  Instead of thinking about dinosaur/bird evolution as a quick leap into the air derived from a relatively small component of the Dinosauria, it seems like dinosaur/bird evolution is more akin to a long runway leading to an eventual take off”.

The distinct and prolonged miniaturisation of the Theropod/bird stem across tens of millions of years would have facilitated the evolution of many unique characteristics associated with smaller body size.  This would have permitted these dinosaurs to exploit a variety of different ecological niches which their larger cousins could not.  Small size also infers a more agile lifestyle, faster reactions, sharper senses – steps towards the evolution of enhanced balance, large eyes and more sophisticated brains that could eventually manage the complex body movements required to coordinate powered flight.

New Study Examines the Dinosaur to Bird Evolutionary Pathway

Maniraptora evolving faster than other types of dinosaur.

Maniraptora evolving faster than other types of dinosaur.

Picture Credit: Everything Dinosaur

Associate Professor Michael Lee, the lead author on the mapping of this part of the Dinosauria family tree commented that the branch of the Theropoda that gave rise to the Aves was the only group of dinosaurs that kept getting smaller.

He explained:

“Birds evolved through a unique phase of sustained miniaturisation in dinosaurs.  Being smaller and lighter in a land of giants, with rapidly evolving anatomical adaptations, provided these bird ancestors with new ecological opportunities, such as the ability to climb trees, glide and to fly.”

It can be argued that these evolutionary characteristics, miniaturisation and more rapid anatomical adaptations were the reasons for the survival of the birds at the end of the Cretaceous.

The University of Adelaide staff member added:

“Ultimately, this evolutionary flexibility helped birds survive the deadly meteorite impact that killed off all their Dinosaurian cousins.”

So why were a group of Theropod dinosaurs able to evolve quicker than other types of dinosaurs.  We may have to look at bird-hipped dinosaurs for an answer.  As far as we know, the lizard-hipped Theropod dinosaurs were the only meat-eating dinosaur group.  The bird-hipped members of the Dinosauria (Ornithischians) were all plant-eaters.  Their hips evolved in a different direction (literally) to the Saurischians (lizard-hipped forms).  The pubis bone got pushed backwards, purportedly to accommodate a larger gut to help digest all that tough plant material.  A big gut meant a bigger body, so part of the Theropoda, the allosaurids for example, evolved bigger and bigger forms so that they could hunt and kill the herbivores which themselves were getting bigger and bigger.

The Dinosauria Classified as Two Distinct Sub-Groups

Classifying dinosaurs by the shape of their hip bones.

Classifying dinosaurs by the shape of their hip bones.

Picture Credit: Everything Dinosaur

As Associate Professor Lee points out, the Theropod dinosaurs were the only group to continually push the envelope when it came to size of their skeletons.  It is possible that the herbivorous dinosaurs simply could not shrink, since a plant-based diet requires a larger gut for digestion.  In the meantime, the Theropoda could explore alternate resources, habitats and even prey.  All of these new activities, such as chasing insects, climbing trees and gliding would in turn, have led to other novel anatomical adaptations.

“So as the dinosaurs shrank, their other features evolved more quickly, which led to faster shrinking to take advantage of these new abilities and so on.”

There is one further, rather intriguing point to be made when the consequences of this research are considered.  If miniaturisation in a branch of the Theropod dinosaurs began as far back as the Early Jurassic around 200 million years ago, could the ultimate driver for these changes have been the Triassic/Jurassic extinction event that marked the demise of a very large number of terrestrial Archosaur groups?

Did All Dinosaurs Have Feathers?

Kulindadromeus Discovery Gets Palaeontologists into a Flap

The embargo has been lifted and we can now talk about the amazing new fossil discovery from Siberia, details of which has just been published in the academic journal “Science”.  News of the discovery of the first ever plant-eating dinosaur with feathers as well as scales has been announced.  So what does this mean?  Feathered dinosaurs have been discovered before right?  True, but and it is a big “but“, feathers have only been associated with one group of dinosaurs up until now, the Theropods, the group of dinosaurs most closely related to birds.

The dinosaur has been named Kulindadromeus zabaikalicus and at just over a metre in length, it is not going to be breaking any size records when it comes to extinct prehistoric animals.  Indeed, if we had the technology to travel back 175 million years or so, to the area surrounding what was to become the Siberian city of Chita, this little dinosaur would have probably gone almost unnoticed.  However, the publication of this long-awaited scientific paper is very important and over the next few paragraphs we will try to put this fossil discovery into perspective.

The Order Dinosauria (the dinosaurs) can be split into two distinct groups based on the structure and position of their hip bones.  These two sub-divisions are the Ornithischia (bird-hipped dinosaurs) and the Saurischia (lizard-hipped dinosaurs).  Those Theropods many of whom were feathered, belong to the Saurischians.   The Siberian fossils show that a member of the Ornithischian group also had feathers.

Feathers Amongst the Dinosauria

Ornithischians had feathers too.

Ornithischians had feathers too.

Picture Credit: Everything Dinosaur

The picture above shows the dinosaurs split into two groups, on one side of the dinosaur family tree are the lizard-hipped dinosaurs, the long-necked Sauropods and the Theropods, those mainly meat-eating dinosaurs who are the closest related to birds (Aves).  The other part of the Dinosauria consists of the bird-hipped Ornithischians, an almost entirely vegetarian group consisting of the horned dinosaurs, duck-bills, armoured dinosaurs and such like.  Kulindadromeus, described as a neoornithischian dinosaur and definitely amongst the bird-hipped dinosaurs, shows that other types of dinosaurs, not just the Theropods had feathers too.

The terms “bird-hipped” and “lizard-hipped” can be a little confusing, especially when we are trying to identify the ancestors of birds.  These terms were first coined by Henry Govier Seeley in 1887.  He divided the dinosaurs into two groups, based on the fact that all the dinosaurs known at the time (and the majority of dinosaurs discovered to date for that matter), had a pelvis that followed one of two distinctive shapes.  There was a bird-like pelvis, where the pubis bone points backwards and the lizard-hipped configuration where the pubis bone points forward.  It is the lizard-hipped dinosaurs,the Theropoda, that are most closely related to the Aves and indeed one group of Theropods, the Maniraptorans that are the direct ancestors of today’s birds.

Classifying the Dinosauria

Classifying dinosaurs by the shape of their hip bones.

Classifying dinosaurs by the shape of their hip bones.

Picture Credit: Everything Dinosaur

Back in 2010, a scientific team led by Sofia Sinitsa, a geologist at the Institute of Natural Resources, Ecology and Cryology from the Siberian city of Chita, explored some highly fossiliferous strata located in the nearby Kulinda valley.  The site represented a low energy depositional environment with freshwater crustaceans, insect larvae and plant fossils.  The strata was laid down by the edge of a large lake, evidence of ash in the layers of rock indicated that there were volcanoes in the neighbourhood too.  Fragmentary fossils indicating the presence of small dinosaurs were also discovered but their poor state of preservation led the scientists to focus on other fossil material.  Expeditions to the same locality found more fossils of dinosaurs over the next two summers and as a result, Pascal Godefroit, a palaeontologist at the Royal Belgian Institute of Natural Sciences (Brussels) was contacted along with other scientists as the implications of the discovery began to dawn on the Russian team.

Dr. Godefroit commented:

“We were completely shocked by the discoveries.”

Pictures from the Dig Site and Some of the Fossil Material Collected

A vast amount of fossil material was collected.

A vast amount of fossil material was collected.

Picture Credit: Royal Belgian Institute of Natural Sciences

Bristle-like and brush-like structures had been identified in a number of Cretaceous species of Ornithischian dinosaur, most notably in dinosaurs such as Psittacosaurus and Tianyulong, but these quills, brushes and bristles have been described by researchers as representing the very earliest development stage of feathers, what scientists call proto-feathers.

To read an article by Everything Dinosaur on the evidence of quills and bristles in later Ornithischian dinosaurs:

Evidence of feathers in psittacosaurids: Upsetting the Apple Cart

The scientists claim that these new fossils differ from the the bristle-like structures found in much later Ornithischian dinosaurs as they have complex, multi-filamented structures typical of the feathers associated with the Theropoda.

Kulindadromeus zabaikalicus (pronounced Cul-lin-dah-dro-me-us zah-bay-cal-lik-us) had been named after the Kulinda valley locality and from the Greek “dromeus”, which means runner.  The trivial name honours the Zabaikal krai region of Siberia in which the Kulinda valley can be found.

An Illustration of Kulindadromeus zabaikalicus

Feathered dinosaur down amongst the horsetails.

Feathered dinosaur down amongst the horsetails.

Picture Credit: Andrey Atuchin

Dated to around 175 to 160 million years ago (Aalenian to Early Callovian of the Mid Jurassic), this one metre long plant-eater had filamentous structures covering most of its body, including its head, neck and chest.  The more complex feather-like structures are confined to the upper arms and upper legs, an arrangement found in a number of fossils of small Theropod dinosaurs excavated from Cretaceous strata in the famous Lioaning Province of north-eastern China.

Explaining the significance of this discovery, Dr. Godefroit stated:

“For the first time we found more complex, compound structures together with simpler hair-like structures in a plant-eating dinosaur that really resemble the proto-feathers in advanced meat-eaters”.

Multiple Filamentous Structures Associated with the Femur (Thigh Bone)

Complex feather-like structures on the thigh

Complex feather-like structures on the thigh

Picture Credit: Royal Belgian Institute of Natural Sciences/ Dr. Pascal Godefroit

The scientists are confident that these little, fast-running creatures could not fly, so why evolve feathers then?  The answer is quite simple, feathers first evolved for other purposes and they only became adapted for flight much later.  These feathers probably helped to keep these small animals insulated and warm.  This suggests that contrary to popular opinion, most dinosaurs were endothermic (warm-blooded  like mammals and birds) and not cold-blooded like today’s reptiles.  The longer, more complex feather structures may have had some role in display and visual communication.  In total, at least six fossil skulls have been found along with a large number of fossilised bones from many individuals and lots of different growth stages have been recognised.  The abundance of fossil material will give the palaeontologists the chance to study how feathers changed as animals grew and matured.

If this neoornithischian had complex feathers then this also throws up an intriguing set of possibilities.  The common ancestor of both the Ornithischian and Saurischian dinosaurs could have been feathered, or perhaps, feathers evolved in different types of dinosaur, an example of convergent evolution.

Chinese palaeontologist Xing Xu of the Institute of Vertebrate Palaeontology and Palaeoanthropology (Beijing), someone who has intensively studied the Lioaning feathered dinosaurs commented:

“The finds are a fantastic discovery”.

However, he warns against getting too carried away, stating that the fossils are too fragmentary to be certain that the more complex feathery structures actually correspond to those found later in birds.  We suspect that further research is going to be carried out into the nature of these branched integumentary structures, before palaeontologists will agree that feather-like structures were widespread amongst the Dinosauria.

One of the co-authors of the scientific paper, Professor Danielle Dhouailly from the Université Joseph Fourier in La Tronche (France ), has been examining these ancient structures and comparing them to the down and feathers found in modern birds.  The lake sediments also preserved scales, so scientists now have evidence that both scales and feathers could be found on individual dinosaurs.  In addition, scientists now know that the leg scales found in modern birds are essentially aborted feathers.

The Ancient Lake Sediments Preserved Evidence of Scales

Fossilised bone (sandy colour) surrounded by evidence of small scales on the foot.

Fossilised bone (sandy colour) surrounded by evidence of small scales on the foot.

Picture Credit: Royal Belgian Institute of Natural Sciences/ Dr. Pascal Godefroit

Professor Dhouailly added:

“Developmental experiments in modern chickens suggest that  avian  scales are aborted feathers, an idea that explains why birds have scaly legs.  The astonishing discovery is that the molecular mechanisms needed for this switch might have been so clearly related to the appearance of the first feathers in the earliest dinosaurs”.

There is more research to be done, but this discovery has potentially huge implications for our view of the Dinosauria.  Ironically, back in the beginning of 2014, Everything Dinosaur team members were asked to predict what news stories might occur over the year and they did predict that a discovery regarding feathered Ornithischian dinosaurs would be announced.

To read Everything Dinosaur’s full list of 2014 predictions: 2014 Palaeontology Predictions

Team members congratulate all those involved in this exciting fossil discovery and the subsequent research.

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