Cooking – A Great Leap Forward in Human Evolution

Processed Food – Not Too Bad After All if our Ancestors are Anything To Go By

The ability to process food, to make it more edible, easier to digest and to breakdown in the human gut to release nutrients, may have helped hominids to gain the upper hand when it came to competing with other predators back in the Pleistocene and earlier.  Indeed, a paper published in the scientific journal “The Proceedings of the National Academy of Sciences”, postulates that processed food, given such a bad press today may have helped humans gain an evolutionary advantage.

Compared to other extant primates, our species H. sapiens spends only one tenth the amount of time eating compared to a chimpanzee.  The new research suggests that processing food without the use of fire may date back more than two million years and it could have accelerated human evolution.  Raw food eating primates such as chimpanzees spend nearly fifty percent of their day eating, modern humans devote less than five percent of each day to this vital task – thanks to our diet and the way that we treat foodstuffs.

As well as spending much less time eating than chimpanzees and other apes, humans have also evolved far smaller teeth, jaws and guts.  The physical changes could not have evolved without the introduction of food processing, say the scientists from Harvard University (USA), a university that has produced a number of scientific papers recently on the cooking and eating habits of our ancestors.

According to the new study, there is evidence that this occurred with the emergence of Homo erectus, a direct ancestor of modern humans that evolved around 1.9 million years ago.  The research team carried out a comparative study using non-human primates, modern humans and fourteen extinct hominids.  The team analysed molar sizes, body masses, DNA, and other characteristics to infer when the pattern of reduced eating times began.  They found that H. erectus, its descendants H. neanderthalensis, and H. sapiens evolved smaller molars compared with other primates; a shift not explicable by the amount of overall evolution in the jaws and heads of these species.  Processing foods with tools and fire would have softened edibles and therefore allowed smaller molars and reduced eating time. The authors’ research suggests that food processing originated after the human-chimpanzee split and before H. erectus.  This study therefore suggests that the likes of H.erectus may have been the first to process food, not cooking as we know today but perhaps by using fire and the bashing of meat to make it more easy to digest.

The stateside based authors, led by Dr Chris Organ, from Harvard University, wrote:

“Food processing would have provided higher caloric intake in the ancestors of modern humans, which likely bestowed significant advantages on reproductive success and survival.  Malnutrition resulting from a committed raw food diet strongly suggests that eating cooked and processed food is necessary for long-term survival of wild foods in Homo sapiens.  This hypothesis explains the small teeth, jaws and guts of modern humans and the universal importance that cooking has played in cultures throughout recorded history.”

Richard Wrangham, also of Harvard University produced a book back in 2009, that examined the evolution of cooking and its role in the development of our own species – a sort of scientific reaffirmation of the old saying “you are what you eat”.

Professor Wrangham (Ruth Moore Professor of Anthropology at and Chair of Biological Anthropology at Harvard), argued that the invention of cooking, even more than agriculture, the eating of meat, or the advent of tools is what led to the rise of humanity.

Wrangham’s book entitled, “Catching Fire: How Cooking Made Us Human,”  makes the case that the ability to harness fire and cook food allowed the brain to grow and the digestive tract to shrink, giving rise to our ancestor Homo erectus some 1.8 million years ago.

Professor Wrangham stated at the time his book was published:

“Cooking is the signature feature of the human diet, and indeed, of human life.  It’s the development that underpins many other changes that have made humans so distinct from other species.”

Drawing on a wide body of research, Wrangham made the case that cooking made eating faster and easier, and enabled our ancestors to gain more caloric benefit from food.  Moreover, he theorises that cooking is vitally important to supporting the outsize human brain, which consumes a quarter of the body’s energy.

This new research builds on some of the earlier Harvard University work.  This new study concludes:

“Humans are able to spend less time feeding because they typically consume higher-quality food than chimpanzees, and because they use cooking and non-thermal processing to render more calories available from food. Cooking and non-thermally processing foods also reduces food particle size and increases starch gelatinisation, which results in earlier bolus formation and swallowing.  These facts suggest that a dramatic increase in caloric intake from cooking and non-thermally processing food played an important role in shaping our evolutionary history.”

Perhaps back in the early part of the Pleistocene epoch, our direct ancestor, the hominid known as H. erectus was enjoying his or her very own version of “Master Chef”.

H. erectus has been the focus of a number of scientific papers this month, a team of experts announced the discovery of a portion of a prehistoric hominid skull, believed to be more than 170,000 years old.  This fragment of skull was unearthed near the French town of Nice, the Lazaret Caves – an excavation site that has yielded over 20,000 fossils.

Students Ludovic Dolez and Sebastian Lepvraud were working on the excavation site and discovered the skull fragment on the 13th August, part of a forehead belonging to a Homo erectus.

Palaeontologist Marie-Antoinette de Lumley, in charge of the dig site stated:

“It belonged to a nomad hunter, less than 25 years old.  He may be able to teach us more about the evolution of his successor, the Neanderthal man.”

The bone was left to dry for a few days where it was discovered, before being removed for a special public announcement attended by the mayor of Nice and other local officials.

The “Mother” of All Placental Mammal Fossils

Milestone in Mammalian Evolution

The Liaoning Province in China is famous for its amazing feathered dinosaur and early bird fossils, however, a team of scientists have published a paper on the discovery of a prehistoric mammal.  A tiny creature that scurried through the undergrowth – the fossils suggests that this may be one of the earliest ancestors of the placental mammals.

This well-preserved fossil discovered in north-east China provides new information about the earliest ancestors of most of today’s mammal species, including ourselves as we to are  placental mammals.  According to a paper published today in the journal “Nature”, the fossil represents a new milestone in mammal evolution that was reached 35 million years earlier than previously thought.

Our Arboreal Ancestor – Juramaia sinensis

Picture Credit: Mark A. Klinger

It fills an important gap in the fossil record and helps to calibrate modern, DNA-based methods of dating evolution.

The paper, by a team of scientists led by Carnegie Museum of Natural History palaeontologist Zhe-Xi Luo, describes Juramaia sinensis, a small shrew-like mammal that lived in China 160 million years ago during the Mid Jurassic.

Juramaia is the earliest known fossil of Eutherians, the group that evolved to include all placental mammals, which provide nourishment to unborn young via a placenta.  As the earliest known fossil ancestor to placental mammals, Juramaia provides fossil evidence of the date when Eutherian mammals diverged from other mammals; the Metatherians ( whose descendants include marsupials such as kangaroos ) and monotremes ( such as the duck-billed  platypus ).

As Luo explains,

“Juramaia, from 160 million years ago, is either a great-grand-aunt or a great-grandmother of all placental mammals that are thriving today.”

The fossil of Juramaia sinensis was discovered in the Liaoning Province in northeast China and examined in Beijing by Luo and collaborators: Chong-Xi Yuan and Qiang Ji from the Chinese Academy of Geological Sciences and Qing-Jin Meng from the Beijing Museum of Natural History, where the fossil is stored.

The name Juramaia sinensis means “Jurassic mother from China.”

The fossil has an incomplete skull, part of the skeleton, and, remarkably, impressions of residual soft tissues such as hair.  The Liaoning Province has a reputation for producing the most exquisitely preserved fossils of animals and plants.

Juramaia’s complete teeth and forepaw bones enable palaeontologists to pinpoint that it is closer to living placentals on the mammalian family tree than to the pouched marsupials, such as kangaroos.

Luo commented:

“Understanding the beginning point of placentals is a crucial issue in the study of all mammalian evolution.”.

Modern molecular studies, such as DNA-based methods, can calculate the timing of evolution by a “molecular clock.”  But the molecular clock needs to be cross-checked and tested by the fossil record.   The idea of a “molecular clock” is that evolutionary changes occur at regular time intervals.  It is assumed that the rate of genetic change (mutation) in an organism’s DNA has not changed over time, or at least can be averaged.  The molecular genetic difference or “distance” between two species can be measured and their rate of genetic change estimated.

Prior to the discovery of Juramaia, the divergence of Eutherians from Metatherians posed a quandary for evolutionary biologists: DNA evidence suggested that Eutherians should have shown up earlier in the fossil record–around 160 million years ago.

The oldest known Eutherian was Eomaia, dated to 125 million years ago (Early Cretaceous).  The primitive mammal Eomaia was originally described in 2002 by a team of scientists led by Luo and Carnegie mammal specialist, John Wible.

The discovery of Juramaia provides much earlier fossil evidence to corroborate the DNA findings, filling an important gap in the fossil record of early mammal evolution and helping to establish a new milestone of evolutionary history.

Chuck Lydeard, Programme Director in the National Science Foundation’s Division of Environmental Biology, which co-funded the research stated:

“These scientists have used the rich fossil mammal record to test evolutionary hypotheses proposed by their colleagues studying living mammals using genetic data.”

Juramaia also reveals adaptive features that may have helped the Eutherian newcomers survive in a tough Jurassic environment.

Juramaia’s forelimbs are adapted for climbing.  Since the majority of Jurassic mammals lived exclusively on the ground, the ability to escape to the trees and explore the canopy might have allowed Eutherian mammals to exploit an untapped niche and to escape from all those cursorial, feathered dinosaur predators that shared their forest home.

Luo supports this perspective:  He stated:

“The divergence of Eutherian mammals from marsupials eventually led to the placental birth and reproduction that are so crucial for the evolutionary success of placentals.  But it is their early adaptation to exploit niches on trees that paved their way toward this success.”

Countdown to Planet Dinosaur

BBC Television Series to be Shown Next Month

The wait for the new BBC documentary series “Planet Dinosaur” is nearly over with team members at Everything Dinosaur being informed that this six-part television series is scheduled to be shown next month, with a date and time yet to be confirmed.

The BBC’s dinosaur portfolio consists of a number of web based activities and complimentary dinosaur themed programmes that will air on the other BBC channels whilst the main series is broadcast on BBC1.  With more dinosaurs having been discovered in the last thirty years or so compared to the preceding one hundred and fifty years, the BBC and their production partners have a lot of new dinosaur material to cover.  Planet dinosaur uses the latest CGI and cutting-edge research to reveal the deadly secrets of these new prehistoric creatures.

For the first time on British television, the very latest dinosaur discoveries have been brought together and brought to life in this ground-breaking series. Featuring a cast of new dinosaurs that will feed the nation’s nightmares, the next generation of children aren’t going to be talking about Tyrannosaurus rex – they are about to meet far bigger, badder, more vicious characters that roamed the Earth 95 million years ago – or so the BBC publicity material goes, although we doubt whether a single television series is going to shake T. rex from the number one dinosaur position.

The series starts in North Africa, where two of the world’s biggest predators once battled for supremacy.  At 13m and 7 tonnes, Carcharodontosaurus was a huge beast, a gigantic lizard-like carnivore with shark-like teeth more than 6 inches long.  It was an efficient hunter that would slash at its prey until it bled to death.

But the discovery of an upper jaw in Morocco revealed an even bigger carnivorous killer – Spinosaurus.  Four metres longer than Tyrannosaurus rex, Spinosaurus is thought to have been one of the biggest killers to ever walk the Earth.  But unlike the meat-eating Carcharodontosaurus, Spinosaurus mainly ate fish, living and hunting almost exclusively in the water.  Team members at Everything Dinosaur provided data and advised the CGI team on how to go about bringing Spinosaurus back to life.

Like all predators that share an environment, the two may once have had to compete for food.  Planet Dinosaur takes a look at what one such deadly battle may have looked like and finds out which giant beast would have been most likely to survive a fight to the death, although no evidence of any conflict between these two apex predators has been preserved in the fossil record.

Looks like the autumn schedule is going to be exciting.

Oldest Fossils on Earth 3.4 Billion Years Old

Scientists Discover Oldest Fossils on Earth

A team of Anglo/Australian scientists have published their findings regarding the discovery of tiny, microbial fossils that could be the oldest fossils ever found on Earth.  The discovery in 3.4 billion  year old sandstone, some of the oldest sedimentary rock known, suggests that bacteria had evolved early in the Archaen Eon a time when the Earth was virtually devoid of oxygen.  The discovery was made at the remote Strelley Pool location, Pilbara (Western Australia).  Not only does this discovery have significant implications for life on our own planet but such a find could help scientists search for evidence of microbial life on Mars.

The Remote and Very Beautiful Fossil Site

Picture Credit: AFP Photo Nature/David Wacey

A picture of the remote fossil location a site synonymous with Archaen microbial fossils.

The new research, published in the scientific journal “Nature Geoscience”, provides solid fossil evidence to date key branching points in the Earth’s evolutionary clock, although as with many microbe fossils, some scientists are challenging whether the tiny tube-like structures that have been discovered are organic remains suggesting that they could have been formed by chemical or other inorganic means.

Scientists based in The University of Western Australia’s Centre for Microscopy, Characterisation and Analysis in collaboration with Oxford University (England) have unearthed arguably the best-preserved pre-three billion year-old micro-fossils on Earth.  These consist of remarkably preserved carbonaceous cells along with the protective tubes (sheaths) that housed some of these cells.

Leading author University of Western Australia Postdoctoral Research Fellow Dr. David Wacey said direct evidence for early life in the form of micro-fossils was exceedingly rare and evidence for what type of life came first had until now proved elusive.  Certainly, from what is known about the Archaen Eon, any life forms that may have lived during this immensely ancient time were likely to have been extremely tough – extreme extremophiles as it were.

Dr.Wacey commented:

“Our research helps to answer the question: How did these microbes survive?  On the early Earth, where free oxygen was rare or absent, evolving life had to employ other means to survive.  Using a combination of electron microscopy and ion probe analysis, we were able to show that these particular microbes had a metabolism that was based on the use of sulphur.  This ability to essentially ‘breathe’ sulphur compounds has long been thought to be one of the earliest stages in the transition from a non-biological to biological world.”

The conditions that early life forms may have evolved in can still be found on our planet today.  Just a few decades ago marine biologists discovered a series of volcanic vents on the bottom of deep oceans.  These “black smokers” as they are called as they belch out columns of dense, black smoke rich in iron sulphides at temperatures of more than 400 degrees Celsius could mirror the conditions where the first life on Earth evolved.   Life may have thrived around such undersea vents, building a sulphur based ecosystem.

Dr. Wacey went onto state:

“By showing the intimate association of these 3.4 billion-year-old micro-fossils with the mineral pyrite (FeS2), we have now provided the earliest direct evidence of micro-organisms employing a sulphur-based metabolism.”

The micro-fossils come from Strelley Pool, a remote region of the Pilbara about 60 kilometres west of the small town of Marble Bar (Western Australia).  They are the oldest micro-fossils ever to be found in sandstones, extending the record of life on Earth in such rocks by about 300 million-years.

A Three-Dimensional Reconstruction of a 3.4 Billion Year Old Micro-fossil

Australia’s First Residents

Picture Credit: David Wacey/Derek Gerstmann

The picture shows a computer generated 3-D model of a micro-fossil about 10 micrometres in diameter from Western Australia (left).  Cross sections through the reconstruction (right) emphasise the spheroidal nature of this ancient cell.

A Highly Magnified Picture of the Tubular Micro-fossils

Picture Credit: AFP Photo Nature/David Wacey

The picture shows a highly magnified collection of tubular micro-fossils (resembling the protective sheaths of modern bacteria) found in between sand grains in a 3.4 billion-year-old sandstone from Western Australia

A team member, Martin Brasier, of Oxford University, made the additional claim that the remains were the Earth’s oldest fossils.

He said:

“At last we have good solid evidence for life over 3.4 billion years ago.”

However, as with a number of such discoveries dating from 3.49 to 3.4 billion years ago this research has attracted controversy.  Although the Strelley Pool area has provided evidence of micro-fossils such as simple bacteria filaments, a number of scientists question the findings.  Professor Brasier has been a leading critic of slightly older fossils, found in the Pilbara in 1993 by a Californian researcher, William Schopf.  He has argued these older fossils are not biological in origin, as Professor Schopf believes.

If the Strelley Pool discoveries are proof of ancient life on Earth then this evidence could assist scientists as they seek to discover if there was life on Mars.  Using this information, they could look for geological features that resemble the Pilbara location on the red planet and then aim to send unmanned probes to sample rock cores to see if the chemical signatures of micro-fossils could be found.

How Decisions about Prehistoric Animal Models get Made

Deciding Which Model to Make

Team members at Everything Dinosaur get asked quite frequently about the decision making process that takes place when manufacturers are deciding which new prehistoric animal models to make.  There are many factors to consider and the process of deciding which replicas to make can be long and drawn out.

With the Kentrosaurus model from Safari Ltd winning the prestigious “dinosaur model of the year award” from readers of Prehistoric Times magazine and that company’s newly introduced Kaprosuchus prehistoric crocodile model widely tipped to win that accolade for 2011 we decided to ask our good friends at Safari how they go about choosing which models to manufacture.

One of the Favourite Models of 2011 – Safari Wild Dinos Kaprosuchus

Picture Credit: Everything Dinosaur

To view Safari’s extensive collection of prehistoric animal models: Dinosaur Toys for Boys and Girls – Dinosaur Models

It seems that this U.S. based company considers many factors before it goes into full scale model production.  Firstly there is supply and demand, a review of existing model sales and popularity can provide a helpful insight. Then there is the many customer requests received by the company, along with the influence of recent fossil discoveries or new theories about already well-known prehistoric animals.  With our estimate that a new dinosaur species is named and described every twenty to thirty days or so then there is always going to be plenty of new prehistoric animals to choose from.  Prehistoric creatures that appear in television documentaries or in movies can also have an influence.

The input from Everything Dinosaur and those people who contact us about model ideas and suggestions do have an important role to play.  Each enquiry we get is passed on to our contacts at the manufacturer and we know that such suggestions and feedback is greatly appreciated by the design team.

A Video Review of Papo Ankylosaurus

New Edition to the Papo “Dinosaures” Model Range – Ankylosaurus

The Everything Dinosaur video review of the new dinosaur model Ankylosaurus introduced by Papo of France.  A fine example of a model of an armoured dinosaur.  In this video we provide a little more information about the discovery of Ankylosaurus magniventris and compare and contrast the model’s features with the known fossil material of the Late Cretaceous herbivore.

The Papo Ankylosaurus Model Video Review

Video Credit: Everything Dinosaur

The Papo “Dinosaures” model range has expanded this year with the introduction of three models, of these the Ankylosaurus is the last to be introduced.  The entire range, more appropriately called prehistoric animals due to the inclusion of replicas of Smilodon, cavemen, a Woolly Mammoth plus a marine reptile and a Pterosaur consists of nineteen models.

To view the dinosaur models available from Everything Dinosaur, including the Papo Dinosaures model range: Dinosaur Models

We are Amongst 8.7 million Species – Give or Take a Million

New Estimate for the Number of Species on Planet Earth

It was the Swedish physician and naturalist Carolus Linnaeus (1707 – 1778), who formed the basis for the classification of organisms in his Systema naturae, first published in 1735.  He grouped organisms with shared features and characteristics into different sets, creating an interrelated hierarchy of life, sometimes referred to as a “tree of life” as a result of its branching structure.  The basic unit in this classification is the species.  A species is defined as a group of organisms whose members have the potential to breed together and produce fertile offspring. Species are grouped into genera, genera into sub-families, families and so on.

Families are grouped into orders, for example our species Homo sapiens is classified with apes, monkeys into the Primates (order).  Orders themselves are grouped into classes, and these in turn are grouped into phyla.  Members of different phyla differ in fundamental features such as body organisation and methods of locomotion and respiration.  Phyla are finally grouped into the largest commonly used classification a kingdom, such as the kingdom plantae (plants) and animalia (animals).

Scientists have argued ever since the time of Linnaeus as to just how many species there are on our planet.  Back in 1975, I recall reading a paper that estimated (conservatively as it turned out) that there were around one million species of insect on the Earth, other estimates have been made over the years using a variety of techniques and the total number of individual species estimated has varied widely, with as many as 100 million species being cited in some literature.

Not knowing how many species inhabit the Earth is one of the most fundamental questions in science.  Efforts to sample the world’s biodiversity to date have been limited and thus have precluded direct quantification of global species richness, and because indirect estimates rely on assumptions that have proven highly controversial.  However, a group of international scientists have used the basis of the classification system first devised by Linnaeus to propose a new calculation for the number of species.  This team calculates that we humans are amongst 8.7 million other species (plus or minus 1.3 million).

In a paper published in the online scientific journal PLoS Biology (Public Library of Science), the team state that the higher taxonomic classification of species (i.e. the assignment of species to phylum, class, order, family, and genus) follows a consistent and predictable pattern from which the total number of species in a taxonomic group can be estimated. Their work was validated against well-known taxa, and when applied to all domains of life, it predicted 8.7 million species in total with a margin for error of +/- 1.3 million eukaryotic species globally (with a nucleus in the cell).  Seventy percent of our planet’s surface may be covered by sea water, but according to these new calculations there are only 2.2 million species present in the sea.

The researchers including scientists from the Department of Biology, Dalhousie University, Halifax, Nova Scotia, Canada, the Department of Geography, University of Hawaii, Honolulu, Hawaii, and the United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, United Kingdom, in conjunction with Microsoft research propose that some 86% of the species on Earth and 91% in the ocean, still await description.

Co-author Boris Worm of Dalhousie University stated that the recently-updated Red List issued by the International Union for the Conservation of Nature assessed 59,508 species, of which 19,625 are classified as threatened. This means the IUCN Red List, the most sophisticated ongoing study of its kind, monitors less than 1% of world species.

Our Planet’s Complex Biodiversity

Picture Credit: Everything Dinosaur

It is important that scientists have an understanding of the biodiversity of planet Earth as without this, it would be very difficult to establish the current rate of extinction.  Many scientists believe that species are dying out at an alarming rate.  In what is known as the sixth mass extinction event, it has been estimated that as many as three species an hour are becoming extinct – many of these organisms are unknown to science.

As co-author of the study, Boris Worm of Dalhousie University points out:

“If we didn’t know – even by an order of magnitude (1m? 10m? 100m?) – the number of people in a nation, how would we plan for the future?  At its most basic, if we don’t know what we’ve got, we can’t protect it, and we can’t even be sure what we’re losing.”

Which was the Largest Crocodile of All Time?

Sarcosuchus, Purussaurus, Deinosuchus or Any Other Candidate?

With a Saltwater crocodile (Crocodylus porosus) at an animal park in Queensland (Australia), being recognised as the largest crocodile kept in captivity, team members at Everything Dinosaur started a debate amongst themselves as to which was the largest crocodilian known from the fossil record.

Crocodiles are certainly an ancient group of reptiles, with their origins predating the dinosaurs.  However, which of these animals would be classified as the largest – this might be difficult to say.

A few days ago, we reported that Cassius, an eighteen foot long “Salty” had been declared the largest crocodile in captivity by the Guinness Book of Records.

To read more about Cassius: Record Breaking Monster Crocodile

However, a number of extinct types of crocodile are known to be much larger.  Indeed, having checked with the Guinness Book of Records, the largest prehistoric crocodile (according to them), is Sarcosuchus (Sarcosuchus imperator), a member of the Eusuchia, fossils of this crocodile are known from Cretaceous strata from Niger (Africa).  Although, there is a lack of fossil material, estimates of length provide a consensus that this reptile may have been ten to twelve metres long.  It has been suggested that this fearsome predator may have weighed eight tonnes.  This would make Sarcosuchus (flesh crocodile) a contender for the largest type of crocodile known.

A Reconstructed Skull of Sarcosuchus (Sarcosuchus imperator)

Picture Credit: Patrina Malone

Then there is the much more recent, South American, giant Purussaurus (Purussaurus brasiliensis).  This prehistoric Caiman is known from a number of fossil locations in South America (Brazil, Peru and Venezuela).  An expedition to the Peruvian Amazon back in 2005 discovered more fossils and from one particular skull, which measures over fifty-five inches in length, it has been estimated that this Caiman from the Miocene may have reached lengths of between ten and thirteen metres.  We think this member of the crocodile family is also known as Mourasuchus amazoniensis, but this is regarded as a junior synonym.

There is also Deinosuchus (Terrible Crocodile) to consider.  Deinosuchus (D. hatcheri) lived during the Late Cretaceous.  Its fossils have been found in the United States.  Once again size estimates are difficult to affirm.  When looking at extant species today, the head length can be assessed as being approximately one eighth the size of the entire animal measured from the tip of its snout to its tail.  This is a useful guide when trying to work out the size of a crocodile or alligator when it it swimming and only a portion of the head is above the water.  Using measurements taken from a huge, nearly complete skull, found in the Big Bend River formation, Texas, and described by the scientists Colbert and Bird back in the 1950s, Deinosuchus was estimated to be over fifteen metres long and to weigh in excess of eight Tonnes.  Since then further analysis of fossil fragments, bones and dermal armour (scutes) has been undertaken and palaeontologists now estimate Deinosuchus to be a little smaller, but it is still a contender for the largest croc of all time.  The jaws are more robust than those of Sarcosuchus, suggesting that Deinosuchus predated upon large animals, perhaps attacking dinosaurs as they came close to water to get a drink.

Which was the Largest Crocodile?

One for the Guinness Book of Records to Contemplate

Picture Credit: Everything Dinosaur

Team members at Everything Dinosaur have had a go at producing art materials and drawings to illustrate the likely candidates for the title of largest crocodile known to science.

Recently, a group of scientists published a paper detailing their study of suspected Deinosuchus coprolites (fossilised dung), thus providing a potential insight into this reptile’s diet:

To read more about Deinosuchus and a follow up article: Ancient Crocodile Poop Provides Information on the Diet of Deinosuchus

Update on Deinosuchus: Update on the Diet of Cretaceous Crocodiles

The crocodiles are indeed an ancient group of reptiles, they evolved into a myriad of forms, some of these were gigantic but as to which genus was the biggest – it looks like we will be debating this for some time.

Cretaceous Mass Extinction – Exterrestrial Object Not Entirely to Blame

International Team of Scientists Consider a Variety of Factors in Demise of the Dinosauria

It was American father and son, Luis and Walter Alvarez who publicised the discovery of a world-wide layer of clay rich in the rare Earth element iridium in rocks known as the K-T  boundary.  The K-T boundary marks the border between the Cretaceous and the Tertiary.  These American scientists argued that the iridium was deposited after an impact event, a collision between our planet and an exterrestrial object such as a meteorite or asteroid.  This global catastrophe has been proposed as one of the main causes of the mass extinction event that marked the end of the Mesozoic and saw something like seventy percent of all life on land wiped out – including the Dinosauria.  Time to reconsider the question: what caused the extinction of the dinosaurs?

Is A Global Impact Entirely to Blame?

Picture Credit: Astro-Virginia.edu

However, other factors may have played a significant role in the demise of the dinosaurs and a team of international researchers have published papers detailing a ten year study into the strata and fossil record of northeastern Asia.  They conclude that rising sea levels, volcanism and climate change were also very significant in the extinction of the mega fauna in this particular part of the world.

These new findings suggest that a prehistoric exterrestrial impact is not solely responsible for wiping out the dinosaur population in northeast Asia sixty-five million years ago.  Chinese media is reporting that the scientists claim that the end of the dinosaur’s reign in some regions of northeast Asia can be linked to several other factors, including volcanic eruption, climate change and dramatic drops in sea level.  The Chinese led study, involving thirty scientists from eight different countries has yielded powerful evidence challenging the dominant, impact theory, although scientists remain fairly confident that the Chicxulub crater in the Yucatan peninsula is evidence of a large impact event approximately sixty-five million years ago.

The study was made public during an ongoing seminar of geology and palaeontology in Jiayin, a county in northeastern Heilongjiang Province, where scientists have found fossils of dinosaurs living just before this group of reptiles extinction.

The scientists, including experts from Russia, the U.S., Germany, Belgium, Britain, Japan and the Republic of Korea, were led by Sun Ge of Jilin University in northeast China. Together, they have spent the past ten years studying the extinction of dinosaurs.

The study showed that in Jiayin the K-T boundary, the geologic boundary between the rocks of the Cretaceous and Tertiary periods, does not contain high-levels of iridium, a radioactive element that linked an asteroid strike to the extinction of dinosaurs.  This may be the case as although, the Chicxulub crater indicates a collision with an object at least ten kilometres in length, the fall out from the resulting explosion may not have reached northeastern Asia, leaving no tell-tale traces of iridium.

Among conflicting and controversial hypotheses explaining dinosaur extinction, the asteroid theory is the only one that has been proven by scientific evidence and is universally recognised by scientists, Sun commented.

Scientists believe a giant asteroid/meteorite that hit the earth about sixty-five million years ago sealed the fate of dinosaurs forever with huge pyroclastic clouds, shock-waves, earthquakes and tidal waves as well as extensive fires.  Many palaeontologists believe that as dust and smoke filled the atmosphere, the sun was obscured and the planet was plunged into a “nuclear winter”.  Most large land animals and many forms of marine life such as the Mosasaurs, Ammonites and Belemnites became extinct.  However, this new study suggests that volcanic activities around that time greatly impacted the environment of the Jiayin area and could be to blame for the mass extinction.  Certainly, these dramatic changes in the climate and atmosphere may well have contributed to environmental stress.

Geologic features of and around the K-T boundary in Jiayin are identical to those of and around the same layer in Russian regions of Siberia and the Far East, said Sun Ge.

This is not the first time (or do we at Everything Dinosaur suspect the last time), the asteroid extinction theory has been challenged.  To read a recent article on this debate: Impact Extinction Theory Challenged – Was it Global Cooling?

Regions in northeast Asia had similar geographic environments sixty-five million years ago, where volcanic eruption, climate cooling and up to 100-metre drops in sea-level might have been the major factors that wiped out the dinosaurs, said Akhmetiev M, a Russian geologist who participated in the program.

According to Sun, the world’s 105 sections of K-T boundary suggest a mega-wipeout sixty-five million years ago that destroyed over seventy percent of all the Earth’s species, including the dinosaurs.

However in conclusion the scientists state that the extinction of dinosaurs was probably caused by different factors in different regions, and an extraterrestrial impact was probably not the single cause of the Dinosauria extinction.

To read another article on the effect of volcanism on the extinction of the dinosaurs: Blame the Deccan Traps

Evolution of the Biggest Mouths in the Natural World

Tiny Whale Fossil Indicates Evolution of Baleen Whales from Toothed Cetaceans

The Baleen Whales, huge creatures such as the Blue Whale (Balaenoptera musculus) and the Grey Whale (Eschrichtius robustus) feed by gulping in huge amounts of water, and straining out small sea creatures such as krill through their plates of bristle-like baleen that hang from the upper jaws.  However, these leviathans may have evolved from huge marine predators that specialised in eating much larger prey.

Museum Victoria palaeontologist Dr. Erich Fitzgerald has made ground-breaking discoveries on the evolution of the world’s largest whales, the Baleen Whales, based on 25 million-year-old fossil jaws found near Torquay in Victoria (Australia).

Published today in the Royal Society’s journal Biology Letters, this important discovery challenges earlier scientific notions by suggesting that  Baleen Whales (e.g. Blue Whales), which feed on small organisms, first evolved their huge mouths for capturing large individual prey animals.

The new fossil evidence comes in the form of the lower jaw bones of Janjucetus,  (Janjucetus hunderi) a 3-metre-long early relative of today’s toothless baleen whales.

Dr. Fitzgerald commented:

“Janjucetus had tightly connected lower jaws and lacked the elastic lower jaw joint that makes it possible for the mouths of modern Baleen Whales to greatly expand and swallow vast volumes of plankton-rich seawater.  What this amounts to is vivid evidence that Janjucetus and the earliest baleen whales could not filter feed.”

Dr. Fitzgerald’s research challenges the belief that the earliest Baleen Whales had the same jaw structure as their modern day relatives.  The newly uncovered fossils suggest that early Baleen Whales had bizarrely shaped skulls structured for sucking prey into their mouths.

Dr. Fitzgerald and the Fossil of the Extinct Whale (Janjucetus hunderi)

Credit: Photograph by Jon Augier, Copyright Museum Victoria

Dr. Erich Fitzgerald cradles the fossil jaws of the tiny extinct whale (Janjucetus hunderi).  With a total body length of only three metres, this Oligocene marine mammal would have been dwarfed by its present day relative, the Blue Whale, a skeleton of which looms in the background.

Dr. Fitzgerald added:

“Their skull, mouth and lips may have acted like vacuum cleaners, hoovering up larger animals, like fishes or octopuses.”

Although this fossil discovery shows Janjucetus had a rigid lower jaw joint, their upper jaws were expansive – a key feature of all Baleen Whales.

According to Dr. Fitzgerald:

“The characteristic large mouth of today’s Baleen Whales is first seen in the upper jaws of non-filter feeding early species, suggesting that the wide upper jaws originally evolved as a specialisation for suction feeding.”

Although the steps by which Baleen Whales evolved from suction feeders into filter feeders remains unclear, this research demonstrates the first evolutionary step towards what are now the biggest mouths in the history of life on Earth.

Painting of Janjucetus Whale Attacking a Shoal of Fish

Picture Credit: Carl Buell, Copyright Carl Buell

Janjucetus hunderi attacking a school of fish in the seas off the coast of south-east of Australia, twenty-five million years ago.

Describing just how big the mouth of a  Blue Whale (Balaenoptera musculus) is, Dr. Fitzgerald stated:

“When fully expanded, a blue whale’s mouth could park a Kombi van.”

Janjucetus hunderi lived about 25 million years ago in coastal seas off south-east Australia.  The fossil jaws of Janjucetus were found near the Victorian township of Torquay in the 1970s by a dedicated amateur palaeontologist. Little had been established about the whale remains until Dr. Erich Fitzgerald started his long-term research on the fossils in 2009.

Dr. Fitzgerald is a palaeontologist specialising in the evolution of marine mammals.  He held a Post-doctoral Fellowship at the Smithsonian Institution and is currently the Harold Mitchell Fellow at Museum Victoria.  Erich also holds an honorary appointment at the Smithsonian Institution in Washington, DC.  This research is a result of two years of study at Museum Victoria and the Smithsonian Institution.

Painting of a Blue Whale (Balaenoptera musculus) Feeding on Krill

Biggest Mouth in the Ocean

Picture Credit: Artwork by Carl Buell, Copyright Carl Buell

Museum Victoria houses the largest collection of fossil marine mammals in Australia and hosts the country’s only whale evolution research program. The paper published in the scientific journal “Biology Letters” is entitled “Archaeocete-like jaws in a Baleen Whale.”

Everything Dinosaur is grateful to Melbourne Museum and Museum Victoria for their help in the compilation of this article.

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