Detailed Molecular Analysis of Fossilised Tissue Reveals Gradual Evolution of Avian Stance

It may be seventeen years since the release of the multi-award winning film “Crouching Tiger, Hidden Dragon”, but today, we draw similarities between one of director’s Ang Lee’s most successful movies and a new scientific paper published in the on line journal “Nature Communications” that illuminates how the crouched posture of modern birds evolved from their more straight-limbed dinosaur ancestors.  It’s really a case of “standing dinosaur evolves into crouching bird”.  The fossils associated with the study represent Confuciusornis sanctus.

Just like the film released in 2000AD, the research is the culmination of extensive collaboration between China and the West.  A joint study between scientists from the Royal Veterinary College, led by Professor John Hutchinson and Professor Baoyu Jiang (Nanjing University, China) and associates have analysed the perfectly preserved soft tissues around the ankle joint of a 125-million-year-old, early bird called Confuciusornis and used this data to work out the evolutionary path the birds took towards their more crouched posture.

An Model of the Early Cretaceous Bird Confuciusornis (C. sanctus)

“A bird in the hand”, the Confuciusornis model from PNSO. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

To view models and replicas of Confuciusornis and other prehistoric animals: PNSO Age of Dinosaurs Replicas.

The Early Cretaceous Bird – Confuciusornis

Known from hundreds of beautifully preserved specimens excavated from Lower Cretaceous strata associated with the Yixian and Jiufotang Formations of Liaoning Province (north-eastern China), Confuciusornis was a pigeon-sized bird that shows a number of anatomical adaptations over more primitive creatures such as Archaeopteryx.  For example, Confuciusornis had a toothless beak, compressed caudal vertebrae (pygostyle) and a deeper chest to support more powerful flight muscles.  The males possessed a pair of extremely long tail feathers (see illustration above), whilst the females tended to be smaller and lacked long tail feathers.

A Pair of Confuciusornis Fossils (Male and Female)

A pair of Confuciusornis fossil birds (Liaoning Province).

Examining the Lower Leg

The researchers examined the lower leg of one specimen which had soft tissues preserved, including the remnants of cartilage and ligaments, around the ankle joint.  These fossils have been preserved in layers of very finely-grained volcanic ash, enabling exquisite details from animals that lived more than 120 million years ago to be studied.

Dr Jiang stated:

“These soft tissues were not just preserved as an ashen replacement of the former tissue, as sometimes happens.  Rather, the cellular and fibrous structure of the tissues was preserved at a microscopic level.”

Multiple spectroscopic imaging methods in conjunction with X-ray synchrotron analysis enabled the team to examine these tissues at the molecular level.  Some of the bird’s original organic chemistry was identified.  In particular, the team found evidence of fragments of the collagen proteins that made up the leg ligaments, which matched the preservation at the microscopic tissue level of detail.

Tissue Preservation in a Confuciusornis Specimen

The team’s findings concur with an increasing body of evidence that, under certain special conditions, some biological molecules including even amino acids or partial proteins, can persist over millions of years in the fossil record.

To read an article about the discovery of dinosaur proteins in 175-million-year-old Sauropodomorpha: More Dinosaur Proteins Found – Lufengosaurus.

Highly Magnified Image (Micrograph) Showing Organic Structures at the Cellular Level (C. sanctus)

Confuciusornis micrograph of ankle area showing cells (yellow arrows).

Picture credit: Nature Communications

The image above shows a cross-sectional slice of the ankle area with a large area of mineralisation (m) visible in the fibrocartilage within the ankle joint.  The yellow arrows equate to cells, scale bar 10 μm (microns).

Scanning Electron Micrograph of the Fossil Tissue

Soft tissue preservation in a Confuciusornis fossil.

Picture credit: Royal Veterinary College

The image above shows a cross-sectional slice of tendon or ligament fibres (arrow) from a scanning electron micrograph of the fossil tissue (scale not stated).

An Exceptional Fossil

Professor Roy Wogelius (University of Manchester), one of the co-authors of the scientific paper, commented:

“The preservation in this fossil was exceptional and allowed us to resolve subtle but important chemical and structural details within this critical early species of bird.”

The researchers then reconsidered this evidence in light of the whole anatomy of the Confuciusornis leg, and that of its cousins from earlier dinosaurs to extinct and even modern birds.  Using this data, the team were able to obtain more information that potentially maps out how the straight-limbed ancestors of birds (theropod dinosaurs), evolved the crouching gait.

Professor Hutchinson stated:

“Once we were confident that some of the remnants of the soft tissues around the ankle joint still remained around the ankle, we could reconstruct parts of the ankle beyond just the bones.  The new information we gained about the anatomy of the cartilages and tendons show that this early bird had an ankle whose form fits an intermediate function between that of early dinosaurs and modern birds.”

Professor Hutchinson added:

“Overall this reinforced other lines of evidence that the more crouched, zigzag limb posture of birds evolved gradually from early dinosaurs to birds, with even these early birds having limbs that were built and worked differently from those of living birds, but were approaching the modern condition.”

Three-Dimensional Computer Image of the Fossilised Right Lower Leg (C. sanctus)

A three-dimensional, computer generated image of the lower right leg of Confuciusornis.

Picture credit: Royal Veterinary College

An Insight into the Evolution of Modern Birds

This multi-technique study involving scientists from both Chinese and British academic institutions, has provided a new insight into the evolution of modern birds.

The team have essentially plotted the evolution of the ankles of modern birds from their reptilian ancestors.  By comparing the confuciusornithid material with that of later Enantiornithines and those primitive birds believed to be more closely related to modern Aves (Neornithes), such as the Ornithurae, the researchers have shown that as the number of main toes was reduced, the foot narrowed and became more robust.

The hypotarsus process became more prominent and enlarged and the orientation of the foot altered towards a more crouching gait.  This led on to the development of fibrocartilages, mineralisations and ultimately bony ridges and grooves to enhance the leverage of as well as enclose and guide the foot tendons which are seen in most modern birds today.

Everything Dinosaur acknowledges the assistance of a media release from the Royal Veterinary College in the compilation of this article.

Visit Everything Dinosaur’s award-winning website: Everything Dinosaur.

Tracking Down Australia’s Early Cretaceous Dinosaur Ichnofauna

A number of media outlets have covered details of the new scientific paper published in the “Journal of Vertebrate Palaeontology” that maps the extensive dinosaur tracks located on the Dampier Peninsula of Western Australia.  The focus of many of these reports has been on the discovery of giant sauropod footprints, which at around 1.7 metres long, have been dubbed “the biggest dinosaur footprints in the world”.

Biggest Dinosaur Footprint in the World?

Richard Hunter lies next to the giant dinosaur footprint.

Picture credit: University of Queensland

Certainly, the picture of the individual print, with one of the field team, lawman Richard Hunter lying alongside, has captured the public’s imagination.  However, some of the key findings of the academic paper have been somewhat overlooked in the mainstream media.  In this article, we will briefly summarise some of the main points.

The Importance of the Broome Sandstones

The sandstone rocks of the Dampier Peninsula contain a vast amount of very well-preserved dinosaur tracks, prints and trackways.  They have been studied periodically since the 1960s but were and remain, part of the myth culture related to creation for the indigenous people.  The sandstones date from the Lower Cretaceous (Valanginian to Barremian faunal stages), that’s around 140 to 125 million years ago (mya).

The date of these rocks in Western Australia equates to around about the same time as the Wealden Supergroup was being formed, strata that is exposed in southern England, including the Isle of Wight and has yielded a wealth of dinosaur fossil material.

So, the trackways and prints preserved in Western Australia, permit scientists to compare and contrast the different dinosaur faunas that existed in different parts of the world, this is one of the key points from the mapping of the Australian tracks.  In addition, these rocks are much older than the dinosaur fossil bearing strata in other parts of Australia, notably Queensland, the Winton area for example.

Dinosaur Tracks

The trace fossils preserved on the peninsula provide the main record of non-avian dinosaurs in the western half of Australia, this ichnofauna provides the only detailed glimpse of Australia’s Dinosaurian fauna during the first half of the Early Cretaceous.

A Dinosaur Thoroughfare – Extensive Dinosaurian Tracks Mapped

Extensive dinosaur tracks (Broome sandstone).

Picture credit: Queensland University

One of the implications for this study, is that the sauropod tracks provide scientists with an opportunity to research further how such large browsers and grazers shaped the environment and the ecosystem, just as elephants influence the flora to be found in Africa, where these extant herbivores are located in significant numbers (see photograph above, showing extensive Sauropodomorpha tracks – dinoturbation).

The Number of Tracks and the Different Types of Dinosaur They Represent

The research team, which was led by Dr Steve Salisbury (Queensland University), were invited by the area’s Goolarabooloo Traditional Custodians, to map and document the sacred trackways.  From 2011 to 2016, the field team spent hundreds of hours recording, photographing, casting and mapping the trace fossils, a task made extremely difficult by the extent of the trackways and the fact that most of them were only exposed at low tide.  Drones were used to provide an aerial view of the footprints, perhaps one of the most diverse Dinosaurian ichnofaunas found to date.

To read an article about the mapping work: Mapping the Dinosaur Heritage of Western Australia.

Forty-eight discrete Dinosaurian tracksites were identified in this area.  Thousands of tracks were examined and measured in situ and using three-dimensional photogrammetry.  Tracksites were concentrated in three main areas along the coast: Yanijarri in the north, Walmadany in the middle, especially around James Price Point and Kardilakan–Jajal Buru in the south.

Dinosaur Tracks and the Palaeoclimate

The researchers describe the palaeoclimate as a large braided river system within a flood plain that was periodically flooded, located close to the sea.  Most of the dinosaur tracks are found in horizons that represent layers generated between the periodic floods.

Of the thousands of tracks studied, 150 could be assigned to the type of dinosaur likely to have made them.  At least eleven and possibly as many as twenty-one different track types were recorded:

• Five different theropod tracks
• More than six types of sauropod tracks – including those 1.7 metre long prints left by the giant form.
• Six types of armoured dinosaur tracks
• Four types of ornithopod tracks

Eleven of these track types could formally be assigned or compared to existing or new ichnotaxa, whereas the remaining ten represent morphotypes that, although distinct, are currently too poorly represented to confidently assign to existing or new ichnotaxa.

One of the Newly Described Ichnotaxa – A Giant Eight-Metre-Plus Ornithopod Named Walmadanyichnus hunteri

A giant Early Cretaceous ornithpod Walmadanyichnus.

Picture credit: Queensland University

The Diversity of Theropod Dinosaur Tracks Mapped

Broome sandstone theropod track types.

Picture credit: Queensland University

Describing the Ichnotaxa

The researchers from Queensland University in collaboration with their associates at James Cook University, demonstrate that only two of the ichnotaxa described in this new paper, relate to already described dinosaur species.  Tracks assigned to the small theropod Megalosauropus broomensis and the fleet-footed ornithopod Wintonopus latomorum have been described before.

The team have identified a total of six new ichnotaxa:

• One new theropod ichnotaxon – Yangtzepus clarkei (see illustration above).
• Two new ornithopod ichnotaxa – Wintonopus middletonae and the eight-metre-long giant Walmadanyichnus hunteri (see photograph of track in this article).
• One new sauropod ichnotaxon – Oobardjidama foulkesi (see illustration below).
• Two new thyreophoran ichnotaxa – Garbina roeorum and Luluichnus mueckei (see illustration further down this page).

Sauropod Trackmakers (Broome Sandstone)

The sauropod biota of the Dampier Peninsula (Early Cretaceous, western Australia).

Picture credit: Queensland University

The Importance of the Armoured Dinosaurs (Thyreophora)

The researchers conclude that the trace fossils preserved on the Dampier Peninsula provide a unique insight into the dinosaur dominated biota of this portion of Gondwanaland in the Early Cretaceous.  Both the sauropods and ornithopods seem to be diverse and abundant, with the armoured dinosaurs, the only fully quadrupedal bird-hipped dinosaurs recorded.

Importantly, the scientists report trackways associated with stegosaurids and overall, a higher density of armoured dinosaurs as well as many different types of theropod (carnivorous dinosaur), including at least two substantial meat-eaters (Broome theropod morphotypes B and C), which probably were apex predators.  These large carnivores had plenty of prey, the paper, published in the “Journal of Vertebrate Palaeontology” also alludes to large bodied ornithopods as well as, giant sauropodomorphs.

Illustrating the Dinosaur Biota of the Dampier Peninsula Based on Tracksite Evidence

The Broome sandstone dinosaurs.

Picture credit: Queensland University with additional annotation by Everything Dinosaur

For models and replicas of stegosaurs, ornithopods and theropod dinosaurs: PNSO Age of Dinosaurs Models.

A Giant Stegosaurian Indicated by Dinosaur Tracks

Note the giant stegosaurid dinosaur, depicted in the illustration above.  Some of the stegosaurid prints are around eighty centimetres long and approximately seventy centimetres across.  This armoured dinosaur rivals the Broome sandstone sauropods in terms of size.  Assigned to the ichnogenus Garbina, the trackways indicate a truly huge armoured dinosaur.  Although Everything Dinosaur team members, having read the scientific paper, cannot find any specific size calculations for this dinosaur, the tracks are considerably bigger than those assigned to the ichnotaxon Garbina roeorum.  This stegosaurid, could be one of the largest armoured dinosaurs yet described, with a body length exceeding eleven metres.

A Biota More Representative of the Late Jurassic than the Early Cretaceous

In many respects, the biota represented by the Broome sandstone tracks suggest a carryover of typical megafauna from the Late Jurassic, a time when the majority of Dinosaurian clades had a more cosmopolitan distribution prior to the break up of the super-continent of Pangaea.  Although the fossil record for the Lower Cretaceous of Gondwana is very poor, a similar mix of taxa occurs in the Barremian–lower Aptian La Amarga Formation (Argentina) and the Berriasian–Hauterivian Kirkwood Formation of South Africa.  The persistence of this fauna across the Jurassic-Cretaceous boundary in South America, Africa, and Australia might be characteristic of Gondwanan Dinosaurian faunas more broadly.

The Dampier Peninsula tracksites suggest that the extinction event that affected dinosaurs in the Northern Hemisphere across the Jurassic/Cretaceous boundary may not have been as severe further south (Gondwana).  The disappearance of stegosaurids from Australia as indicated by the lack of fossils in younger Cretaceous strata and the apparent decline in Theropoda diversity by the middle Cretaceous indicates that, similar to what may have happened in South America, Australia passed through a period of faunal turnover from 140 mya to around 125 mya.

The Tracks of a Large Stegosaur (Garbina ichnogenus)

Field worker Louise Middleton and a stegosaurid trackway (Garbina).

Picture credit: Queensland University

The World’s Biggest Dinosaur Footprint

If we briefly side step (no pun intended), the issue as to whether the Sauropodomorpha belong within the Order Dinosauria (see our article posted up on March 23rd, which explains about a potential re-classification of dinosaurs), is one of the Broome sandstone prints the biggest dinosaur footprint yet described?

To read an article from 2016 about a dinosaur titanosauriform print found in Mongolia: Giant Dinosaur Footprint from the Gobi Desert.

For an early article on the  mapping of the Broome sandstone dinosaur tracks: Mapping the Dinosaur Heritage of Western Australia.

The Sauropodomorpha Track with a Scale Drawing of the Potential Size of the Dinosaur

Richard Hunter provides the scale next to the giant sauropod print. Scale depiction of dinosaur provided below.

Picture credit: Queensland University

The picture above shows the actual image released by Queensland University to illustrate the potential size of the dinosaur which made the series of prints which measure up to 1.7 metres in length.

Assessments of stride length suggest a sauropod dinosaur with a hip height of around 5.3 to 5.5 metres.  The line drawing provides scale, potentially the long-necked dinosaur that made these tracks could have exceeded twenty-five metres in length.

Unable to Assign an Ichnogenus from the Sauropod Dinosaur Tracks

There is not enough information at the moment to assign an ichnogenus to this sauropodomorph, it has been named “Broome sauropod morphotype A”.  Certainly, these 1.7 metre long prints are amongst the biggest yet found.

In October 2009, Everything Dinosaur reported on the discovery of a series of huge sauropod tracks in eastern France, to read about this: On the Trail of France’s Sauropod Big Foot.

The scientific paper: “The Dinosaurian Ichnofauna of the Lower Cretaceous (Valanginian–Barremian) Broome Sandstone of the Walmadany area (James Price Point), Dampier Peninsula, Western Australia”, by Salisbury, S. W., A. Romilio, M. C. Herne, R. T. Tucker, and J. P. Nair.  Published in Journal of Vertebrate Palaeontology.

Visit Everything Dinosaur’s award-winning website: Everything Dinosaur.

Massive Increase in Visual Range Preceded the Origin of Terrestrial Vertebrates

One of the most significant steps (no pun intended), in vertebrate evolution took place some 385 million-years-ago when some types of sarcopterygian fish evolved rudimentary limbs and started to clamber around on land.  These fish were the ancestors of all the tetrapods (four-legged vertebrates), amphibians, reptiles, birds, mammals and of course ourselves.  It could be argued that our species, Homo sapiens, is nothing more than a highly modified fish!  How and why the transition from living in a watery world to one of a terrestrial lifestyle took place is hotly debated by palaeontologists.

Tetrapod Evolution

One team of researchers from the Northwestern University (Illinois), in collaboration with colleagues from the Natural History Museum of Los Angeles County and optical imaging specialists, have come up with a remarkable theory that explains the move from the water to the land.

Note the Eyes Located on the Top of the Skull in this Early Tetrapod

Meet our next of fin. An illustration of an early tetrapod.

Improvement in eyesight was the driver for the momentous leap from water onto land and not limb evolution linked to a better ability to clamber about on terra firma.

For models and replicas of early tetrapods: CollectA Age of Dinosaurs (Prehistoric Life) Models.

Looking at the Position of the Eyes

The scientists which included corresponding authors Malcolm MacIver and Lars Schmitz (Northwestern University), spent a year running simulations comparing many different types of fossil.  The researchers noticed that there was a dramatic increase in fish eye size, the eyes tripled in size and they shifted from the sides of the head to the top of the skull.  These adaptations took place long before the first modified fins looking like limbs evolved.

The team speculate that before permanent life on land came about, certain types of fish became ambush predators, hunting terrestrial invertebrates using similar tactics to modern-day crocodiles.  Eyes near the top of the head would have allowed these creatures to observe the land without giving themselves away.  They could spot potential prey on the land.  Being able to spot potential food provided a distinct advantage and as light travels better in air than it does in water, these fish could see a lot further.  Natural selection led to the evolution of bigger eyes and better eyesight.

The “buena vista” (good view) hypothesis that the study proposes states that being able to see food opportunities far away provided a stimulus to drive the evolution of locomotion to reach the potential prey.  This aided the natural selection for improved, stronger limbs, first for brief forays onto land to ambush prey and later for a life in a terrestrial environment.

The Evolution of Bigger, Better Eyes Capable of Seeing Further Preceded the Conquest of the Land

Video credit: Northwestern State

Hunting on Land

Hunting on land was a mental game changer for the early tetrapods and we applaud the team behind the research who have collaborated with animators to produce a very helpful explanatory video.  The video written and produced by Kristin Pichaske with the collaboration of Malcolm MacIver is provided here and it is great to see research summarised in such a way so as to make it much more accessible.  Our congratulations to everyone involved in the study and also to the team behind this most informative video.

For an article on the evolution of tetrapod locomotion: Walking Fish Provides Clues to the First Tetrapods.

Visit the Everything Dinosaur website: Everything Dinosaur.

Chinese Authorities Make Arrests in “Crack Down” on Dinosaur Egg Thieves

Official Chinese State media has reported the arrest of a man accused of stealing dozens of fossilised dinosaur eggs.  A number of specimens have been recovered but many more are, as yet, unaccounted for.  China has some of the strictest regulations and laws in the world, when it comes to protecting rare artefacts including fossil remains.  Sadly, despite the very best efforts of the authorities there is a thriving black market in illegally acquired fossils, with huge sums of money being exchanged for dinosaur fossils including teeth, bones and fossilised eggs.

A Photograph of a Dinosaur Egg (Liverpool Museum)

A fossilised dinosaur egg (Theropoda). Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Dinosaur Egg Thief Arrested

The media report states that a Chinese citizen with the surname Wang has been accused of stealing eighty dinosaur eggs from a collector in Zhejiang Province on the night of January 9th 2017.  Three other accomplices are believed to have been involved according to the report from the Xinhua News Agency.  Mr Wang had previously visited the collector twice under the pretext of making a prospective purchase, agency sources have stated.

The four suspects are believed to have divided up the stolen property and Mr Wang took home a total of twenty-seven eggs.  Police raided Mr Wang’s home earlier this month after arresting him, during the search of the property in Huanan County (Heilongjiang Province), the authorities were able to recover the stolen eggs, the remaining fossils, an estimated fifty or so specimens, have yet to be recovered.

Protoceratops Dinosaur – Eggs from These Dinosaurs were the First to be Scientifically Described

A Protoceratops exhibit on display at The Naturmuseum Senckenberg (Frankfurt, Germany). Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

The three accomplices have also been apprehended, Heilongjiang police have confirmed that Mr Wang was in police custody but no further information about the other parties involved was provided.

Visit Everything Dinosaur’s website: Everything Dinosaur.

Increasing Fossil Thefts

Over the last five decades or so, as China’s geology has been explored in more detail, a treasure trove of fossil material has been discovered, including numerous dinosaur fossils.  The Institute of Vertebrate Palaeontology and Palaeoanthropology (IVPP) in Beijing is believed to hold the world’s largest collection of vertebrate fossils.  Sadly, despite it being illegal to export fossils and other material out of China, thefts still occur and many important fossils have been sent overseas to end up in the hands of private collectors.

Fossil protection legislation in the People’s Republic of China is comprehensive, the illegal excavation and export of vertebrate fossils including eggs was covered in the 1982 Cultural Relics Protection Law.  This law was developed from existing rules and regulations that had been in place prior to the Cultural Revolution.  More recently, legislation in this area was reviewed (2010-2013) and a number of Chinese scientific institutions have published guidelines and procedures to help organisations that are based outside China to stay on the right side of the law.

Dinosaur Eggs and Nests are Highly Sought After by Collectors

An Oviraptor and its nest. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

For models and replicas of oviraptor and other prehistoric animals: CollectA Prehistoric Animal Models.

All too often Everything Dinosaur has had to report on this blog incidences of fossil theft, illegal excavations or deliberate vandalism to an important fossil site.

For an article published in 2015 about a seizure of hundreds of stolen Chinese dinosaur eggs: Chinese Authorities Seize Dinosaur Eggs.

To read an article from 2014 about the theft of a dinosaur footprint from Utah (United States): Dinosaur Footprint Stolen.

Nicolas Cage agrees to return stolen dinosaur fossil: Hollywood Star Agrees to Return Tarbosaurus Fossil.