Category: Dinosaur and Prehistoric Animal News Stories

Mammals Quick off the Mark after Dinosaur Extinction

Kimbetopsalis simmonsae – Shedding Light on Ancient Mammals

A newly described species of ancient mammal, one that existed around half a million years or so after the Cretaceous mass extinction event that saw the demise of the dinosaurs, is helping scientists to understand more about how the Mammalia Order radiated and diversified.  The discovery from New Mexico (Nacimiento Formation), has been named Kimbetopsalis simmonsae, it seems that mammals were quick to take advantage of the vacuum left in terrestrial habitats by the dinosaurs.

An Illustration of What Kimbetopsalis simmonsae Might Have Looked Like

An illustration of Kimbetopsalis simmonsae.

An illustration of Kimbetopsalis simmonsae.

Picture Credit: Sarah Shelley

Lucky Find for Student

The fossils, which consist of the back of the jaws, part of the brain case and incisors from the front of the mouth were found during an exhibition to the San Juan Basin of New Mexico last year.  Remarkably, the first evidence, the back of the jaws was found by University of Nebraska-Lincoln student Carissa Raymond, this was her first fossil hunting field trip.  The field team consisted of two other students, recruited by University of Nebraska-Lincoln palaeontologist Ross Secord and Steve Brusatte (University of Edinburgh).  Thomas Williamson, curator of palaeontology at the New Mexico Museum of Natural History and Science, based in Albuquerque and a specialist in Late Cretaceous/Early Palaeocene fauna was also part of the group.

The paper describing this new species of prehistoric animal has just been published in the journal of the Linnean Society.  K. simmonsae was a member of the multituberculates, a group of mammals that first evolved in the Jurassic.  They thrived during the age of dinosaurs, but were mostly small and many described species are thought to have been nocturnal.  Although, building up a more complete picture is difficult as most genera are known from only a few isolated teeth.  This beaver-sized mammal represents a relatively large example of this sub-order of mammals, the animal was named after the Kimbeto Wash area of the New Mexico Badlands, where the fossils were found.

Dr Stephen Brusatte, lead researcher on the study, explained:

“We realised pretty quickly that this was a totally new type of mammal that no-one has seen before, the other part of the name – psalis, means “cutting shears” and is in reference to the blade-like teeth [incisors].”

The Fossils of Kimbetopsalis simmonsae Note the Peculiar Cusps on the Molars and Premolars

Remarkable fossil find from New Mexico - Kimbetopsalis simmonsae.

Remarkable fossil find from New Mexico – Kimbetopsalis simmonsae.

Picture Credit: Dr. Steve Brusatte University of Edinburgh

The Multituberculata Mammals

The multituberculate mammals are generally regarded as the earliest plant-eating mammals to have existed.  The teeth of K. simmonsae are typical of this group, the long chisel-like front teeth and the back teeth, the chewing teeth, with their parallel rows of cusps.  It is these back teeth with their distinctive cusps arranged in either two or three rows that gives the Multituberculata group their name.  This discovery is the first new multituberculate to be found in the San Juan Basin in more than a Century.

Members of the Field Team Pose for a Photograph

left to right

left to right Sarah Shelley, Eric Davidson, Carissa Raymond, Steve Brusatte and Ross Secord

Picture Credit: Thomas Williamson/Reuters

Fossils of another multituberculate from the genus Taeniolabis are known from this area, however, the newly described Kimbetopsalis simmonsae come from a geologically much older stratigraphic layer. Taeniolabis species represent some of the largest Multituberculata so far described, with some specimens estimated to about as big as an Alsatian dog and one species Taeniolabis taoensis possibly exceeding 100 kilogrammes in weight, although they were probably entirely herbivorous.  It has been proposed that Kimbetopsalis simmonsae may have been an ancestor of the Taeniolabis genus, part of a trend towards larger and larger mammals as the Mammalia radiated out and new species evolved to take advantage of the extinction of the dinosaurs.  It seems that the mammals may have been quick off the mark to exploit the niches left after the dinosaur extinction.

Extinction of the Multituberculates

This type of mammal was soon destined to go the same way as the dinosaurs.  By the Late Eocene, these creatures were becoming increasingly rare and by the Early Oligocene Epoch (around 32-30 million years ago), the Multituberculata were extinct.  Why these mammals died out, remains an area of debate amongst palaeontologists.  This group left no living descendants and a number of reasons why they became extinct have been proposed, one of the more plausible and popular explanations is increased competition from placental mammals, particularly rodents.  Rodents are the most diverse and most specious of all the types of mammal living today.  Perhaps it was the evolution and rapid spread of the rodents that finally led to the demise of the Multituberculata, a group that had outlived the Dinosauria.

To read an earlier article that traces the origins of the Multituberculata: Tracing the Origins of the Multituberculates

Commenting on the significance of this fossil discovery, Dr. Thomas Williamson said:

“Finding this new mammal was a pleasant surprise.  It helps fill an important gap in the record of this group of mammals.  It’s interesting that this odd, now extinct group, was among the few to survive the mass extinction and thrive in the aftermath.  It may be because they were among the few mammals that were already well-suited to eating plants when the extinction came.  This new species helps to show just how fast they were evolving to take advantage of conditions in the post-extinction world.”

“Bent Fence Post” Turns out to be Woolly Mammoth Fossils

Farmer Finds Partial Woolly Mammoth Fossil in Field

Farmers in certain parts of the south-west of England can occasionally turn up pieces of Ammonite fossil as they plough their fields, but a farmer from Michigan came up with an elephant-sized surprise when he and a neighbour were digging in their soya bean field.  They have unearthed the partial skeleton of a male Woolly Mammoth, one that is believed to be between 10,000 and 15,000 years old.

James Bristle a resident of Washtenaw County (west of Detroit), thought he had uncovered something a little more prosaic, when he excavated a “wood-like” object, he explained:

“We thought it was a bent fence post.  It was covered in mud.”

However, upon closer inspection the strange object, started to look more like bone.  It turned out to be a rib bone from the extinct elephant.  The grandson came over to take a look and he was speechless, quite a feat when you consider just how noisy most five-year olds are.  Mammoths and Mastodons roamed North America until the latter stages of the Pleistocene Epoch, this specimen may represent one of the last Woolly Mammoths to have lived in this part of this world.  Just a few thousand years, perhaps in this animal’s case, just a few hundred years later, all the prehistoric elephant species of North America had become extinct.

A Model of a Woolly Mammoth

Woolly Mammoth Model without the usual brown coat

Woolly Mammoth model, typical of this type of prehistoric elephant.

Picture Credit: Everything Dinosaur

Confirmed by Palaeontologists

University of Michigan Professor Dan Fisher has been leading the excavation, to remove the animal’s remains before exposure to the air invites further decay of the bones and teeth.  The partial skeleton consists of the skull, pelvis, two, huge curved tusks, the shoulder blades and numerous vertebrae and rib fragments.  About thirty Woolly Mammoth fossilised skeletons have been reported from the State of Michigan.

The Mammoth Remains Having Been Partially Excavated (in situ)

Down in the hole the skull and tusks emerge.

Down in the hole the skull and tusks emerge.

Picture Credit: ITN

Examination of the teeth indicates that the animal was adult and about forty years of age when it died.  Speculating on how the body came to be under a soya bean field, palaeontologists have explained that the surrounding matrix suggests a still body of water.  This animal could have been hunted by humans, butchered and then placed in a pond to help preserve the meat.  Placing a carcase in water to help preserve it, is believed to have been a relatively common practice amongst the human inhabitants of North America.  The water would perhaps have iced over quite soon after the kill and the cold water and ice would have kept the meat relatively fresh.

A spokesperson from Everything Dinosaur commented:

“Consider the site of this discovery as an early example of a freezer.  Storing resources for use at a future date, planning ahead, is one of the traits associated with our species.  This sizeable beast would have provided a huge amount of food to a group of nomadic hunters”

According to Professor Fisher, the soya bean field discovery represents one of the most complete Woolly Mammoth skeletons ever found in the State.  Once all the bones have been removed, they will be carefully examined and a detailed analysis undertaken.  The scientists will hope to find tell-tale marks in the bone to indicate human butchery.

The Skull with its Partial Tusks Intact is Removed from the Hole

On the surface a ventral view of the skull.

On the surface, a ventral view of the skull.

Picture Credit: ITN

The Professor stated:

“Study of the bones may shed light on when humans arrived in the Americas, a topic of debate amongst archaeologists.”

To read an article about the latest research into Mammoths: Woolly Mammoth Genome is Sequenced

Mapping the Lives of a Population of Dinosaurs

Maiasaura peeblesorum – The Maiasaura Life History Project

Years of excavation at the quarries identified as nesting sites for the Hadrosaur known as Maiasaura (M. peeblesorum) has yielded an immense amount of data.  However, a team of scientists from Montana State University, Oklahoma State, and the Indiana Purdue University have taken the field research in a different direction and used an immense fossil deposit covering over two thousand square metres to report on the largest dinosaur population growth study ever undertaken.

The team’s findings make quite sombre reading for any would-be duck-billed dinosaur (not that they could read, we know).  Mortality rates for animals under twelve months of age were nearly 90%, whilst if you got passed your eighth birthday, the odds were beginning to stack up against you for living much longer.  These dinosaurs lived in tough times.  The numbers might sound frightening but mortality rates in extant antelope and other herbivores on the African savannah, are in some cases very similar.  Predatory dinosaurs probably did not fare any better.

Maiasaura peeblesorum – Model by Safari Ltd

Model of "Good Mother Lizard"

Model of “Good Mother Lizard”

Picture Credit: Everything Dinosaur

Maiasaura peeblesorum

Maiasaura was a large, flat-headed, duck-billed dinosaur that inhabited North America during the Late Cretaceous.  The first fossils of Maiasaura were found in the Badlands of western Montana in 1978, by a team of American scientists led by the famous palaeontologist Jack Horner.  The site the team discovered consisted of a number of nests, eggs, baby Maiasaura, juveniles as well as adult specimens.  The area was renamed “Egg Mountain”.  Approximately, 200 individual specimens have been excavated, providing evidence of the nesting behaviour of dinosaurs.  Published papers on these fossils were amongst the first to put forward the hypothesis that some types of baby dinosaurs were altricial, that is, heavily dependent on their parents for food and protection.  Here was evidence of dinosaurs being raised in nests.

This new research published this week in the journal “Paleobiology” provides the most detailed life history of any dinosaur and has created a framework to which all other dinosaurs can be compared.

The Badlands of Montana – Once Home to Thousands of Dinosaurs

The Badlands of Montana.

The Badlands of Montana.

Picture Credit: Holly Woodward Ballard/Karen Chin

Commenting on the significance of the research, Jack Horner, curator of the Museum of the Rockies and a man synonymous with all things Maiasaura stated:

“This is one of the most important pieces of palaeontology involving MSU [Montana State University] in the past twenty years.  This is a dramatic step forward from studying fossilised creatures as single individuals to understanding their life cycle.  We are moving away from the novelty of a single instance to looking at a population of dinosaurs in the same way we look at populations of animals today.”

The research was led by Holly Woodward Ballard, Assistant Professor of Anatomy at Oklahoma State University, who prior to her appointment to this post, undertook her PhD at Montana State University.  Holly specialises in studying osteohistology (growth patterns of animals preserved in bone tissue) to map population growth dynamics in extinct vertebrates.  This data can then be used to create a model for palaeohistologic inferences, examining how individuals vary within a population, growth rates and survival rates.

To complete the research, the team analysed the fossil bone micro-structure (histology) of fifty Maiasaura tibiae (lower leg bones).  The bone histology reveals aspects of growth that cannot be ascertained by observation of the external structure and shape of the bone.  The histology reveals information such as growth rate, metabolism, age of maturity, and the age at death.

Assistant Professor Woodward Ballard explained:

“Histology is the key to understanding the growth dynamics of extinct animals.  You can only learn so much from a bone by looking at its shape, but the entire growth history of the animal is recorded within the bone.”

To a statistician a sample of just fifty may not sound like much, but to a vertebrate palaeontologist where a species can be known from a single bone or even a single tooth the Maiasaura fossil assemblage from the Badlands of Montana represents an absolute treasure trove of dinosaur fossil material.

The published paper provides an insight into how quickly Maiasaura babies grew up.  It had bird-level growth rates throughout most of its life, its bone tissue most closely resembles that of a modern warm-blooded (endothermic) mammal such as an elk.

The speed of growth might have something to do with the fact that the bigger you got the less chance of you ending up as a meat-eater’s lunch.  Everything Dinosaur has reported previously on a study into the histology of another Hadrosaur, called Hypacrosaurus that showed that these herbivores grew faster than the carnivorous dinosaurs that co-existed with them.

To read more about this study: Duck-Billed Dinosaurs Grew Fast to Avoid Tyrannosaurs

The bone histology also recorded major events in the life of individuals such as the different ages when animals died.

Elizabeth Freedman Fowler, curator of palaeontology at the Great Plains Dinosaur Museum in Malta (Montana), conducted the statistical analysis of the research data, she commented:

“By studying the clues in the bone histology, and looking at patterns in the death assemblage, we found multiple pieces of evidence all supporting the same timing of sexual and skeletal maturity.”

With these dinosaurs, they probably were mature enough to breed within the third year of life and had an average adult body weight of 2,300 kilogrammes in eight years.  Life was tough for these herbivorous dinosaurs, especially the very young or the very old.  The average mortality rate for those less than twelve months of age was 89.9%, for individuals eight years and older it was 44.4%.  These figures sound alarming but most of the garden birds hatched this spring will not survive their first winter.

If a Maiasaura made it through two years, they enjoyed a six-year window of peak physical and reproductive fitness, when the average mortality rate was just 12.7%.

Assistant Professor Woodward Ballard added:

“By looking within the bones and by synthesizing what previous studies revealed, we now know more about the lift history of Maiasaura than any other dinosaur and have the sample size to back up or conclusions.  Our study makes Maiasaura a model organism to which other dinosaur population biology studies will be compared.”

Study Shows Considerable Variation with an Extinct Animal Population

The research also highlighted the extent of individual size variation within an extinct population of animals.  Earlier studies had linked age to the size of dinosaur limb bones, this method may not be that accurate based on this new data.  Histology studies examining a subset of dinosaur bones (such as femora or tibiae) had been carried out before with an assumed age for an animal calculated on the length of these key bones.  The length of the bone may be misleading, it is only by exploring the micro-structure of the bone that age details can be revealed.

Holly outlined how their research challenged the findings of earlier studies:

“Our results suggest you can’t just measure the length of a dinosaur bone and assume it represents an animal of a certain age. Within our sample, there is a lot of variability in the length of the tibia in each age group.  It would be like trying to assign an age to a person based on their height because you know the height and age of someone else.  Histology is the only way to quantify age in dinosaurs.”

Assistant Professor Holly Woodward Ballard at the Maiasaura Dig Site

At the Maiasaura bonebed.

At the Maiasaura bonebed.

Picture Credit: Holly Woodward Ballard/Karen Chin

The Maiasaura Life History Project

The Maiasaura research does not end with the publication of this paper.  This is only one of a series of proposed study areas.  Assistant Professor Woodward Ballard intends to lead a number of annual summer excavations up into the Badlands of Montana to collect more specimens.  The scientists want to keep working on the extensive bonebeds and build up a much more complete picture of the daily lives and struggles of these dinosaurs.

Clearly excited about the opportunity the huge bonebed presents, Holly stated:

“Our study kicks off The Maiasaura Life History Project, which seeks to learn as much as possible about Maiasaura and its environment seventy-six million years ago by continuing to collect and histologically examine fossils from the bonebed, adding statistical strength to the sample.  We plan to examine other skeletal elements and make a histological “map” of Maiasaura, seeing if the different bones in its body grew at different rates, which would allow us to study more aspects of its biology and behaviour.  We also want to better understand the environment in which the Maiasaura lived, including the life histories of other animals in the ecosystem.”

We at Everything Dinosaur wish all those involved in The Maiasaura Life History Project every success and we look forward to reporting on further research in the near future.

Why Did Dinosaurs Have Small Eyes?

Small-eyed Dinosaurs Let’s Keep Things in Proportion

Telephone calls and emails into the “dino den” otherwise known as the office at Everything Dinosaur last night, when the popular Radio 2 early evening show, Simon Mayo Drivetime, provided a prehistoric themed poser as part of a regular slot helping out with listener’s homework.  One of the two questions sent in involved the Dinosauria, why did dinosaurs have such small eyes?

Does Everything Dinosaur Have A View on Question B?

Any views on question two?

Any views on question two?

Picture Credit: Simon May Drivetime Facebook

Small-eyed Dinosaurs?

In short, dinosaurs did not have small eyes, in fact, the eyes of some dinosaurs were quite large in proportion to the rest of their body and the word “proportion” is the key here, but more about that later.  You see, (no pun intended), it all depends on the type of dinosaur you look at.  Not all dinosaurs were the bus-sized, meat-eaters so popular with little boys and girls, as shown in the picture above.  That fearsome dinosaur looks like Carcharodontosaurus saharicus (Car-car-oh-dont-toe-sore-us, sa-har-ri-kus) as depicted in the BBC television series “Planet Dinosaur” which was first aired in the autumn of 2011.  The grey, long-necked dinosaurs in the background would have dwarfed even the largest carnivore.  They look like Paralititan stromeri, colossal animals that could have reached lengths in excess of thirty metres or more and perhaps weighed seventy tonnes.

Take a look at a skull of a much smaller dinosaur, a member of the Velociraptor family for example, and you will see that the orbit (the eye socket) is relatively large when the dimensions of the rest of the skull are taken into consideration.

Dromaeosauridae (Family) and Typical Dromaeosaurids such as the Velociraptorinae did not have Small Eyes

Getting into a Flap over Velociraptors

No small eyes here on a Velociraptor

Dinosaurs such as Velociraptor are very closely related to modern birds.  Birds have very large eyes in proportion to their body size.  After all, if you are going to fly, having large eyes coupled with excellent eyesight makes a lot of sense.  Members of the bird Order (Aves), have the biggest eyes relative to their body mass amongst the vertebrates, some species have eyes so large that eye movement is limited within the orbit of the skull, when some birds want to have a good look around they have to turn their heads, the eyes cannot move independently in their sockets.

Turning Your Head to Have a Look Round

Turning your head to look, (a large beak doesn't help).

Turning your head to look, (a large beak doesn’t help).

What about those Really Big Dinosaurs?

This is all very well, some dinosaurs had proportionately big eyes, but what about those really big dinosaurs, animals like  Carcharodontosaurus and the monstrous  Paralititan mentioned earlier?  It’s that word again “proportion”.  In proportion to their bodies, large dinosaurs did have relatively small eyes, this phenomenon is observed in large mammals today, elephants, rhinos and the largest animals of all the Cetaceans (whales and dolphins).  Really big animals tend to have eyes that look small. The actual diameter of the eye might be much bigger than our own, but since the skull is so big compared to ours, then the eye seems much smaller in comparison.

Newly hatched dinosaurs had big eyes in proportion to their body size.  As the animal grew so its body proportions changed and gradually the eye became much smaller when compared to the rest of the body.

Baby Dinosaurs Had Bigger Eyes when Compared to the Adults

Ontogeny in Diplodocids

As dinosaurs grew, their eyes become proportionately smaller.

Picture Credit: Mark A Klinger/ Carnegie Museum of Natural History

It’s worth remembering that despite a common public misunderstanding, dinosaurs were perfectly adapted to their environments and way of life.  As a clade, the Dinosauria has been around for some 800 times longer than our own species.  From what we know of the closest living relatives of the dinosaurs, the birds, these reptiles probably had excellent colour vision and in many cases their visual acuity, ability to see movement and their colour vision spectrum were much better than ours.

Think of it this way, studies of the internal structure of the skull of Tyrannosaurus rex indicate that this ferocious predator had a optic nerve about as thick as an adult man’s thumb.  That’s a lot of data going into that part of the brain dedicated to processing information from the eyes (occipital centre).  The orbits (eye sockets), in the skull of “Sue”, the largest mounted T. rex skeleton, measure nearly 10.5 cm across, this suggests that this dinosaur had eyeballs around 8 cm in size, that’s bigger than a tennis ball.  These eyes were held aloft some four metres in the air, an excellent viewing platform.  In addition, the position of the eyes in the skull gave this Theropod a degree of binocular (stereoscopic vision), probably greater depth perception than ours.  Ideal if you are an ambush predator.

Forward Facing Eyes of an Apex Predator

A three-dimensional reconstruction of a T. rex skull.

A three-dimensional reconstruction of a T. rex skull.

Research into the eyesight of Tyrannosaurus rex, published in 2006 by the University of Oregon concluded that big, Late Cretaceous meat-eaters like the “King of the Tyrant Lizards” may have had eyesight that was at least ten times* better than our own.  Vision may not have been the primary sense of T. rex, but those proportionately small eyes could have very probably spotted you before you had seen it and that’s quite a sobering thought.

Comparing the Orbits of Two Types of Tyrannosauroids

The orbit of a Tyrannosaurus rex is compared to the eye socket of a Raptorex

The orbit of a Tyrannosaurus rex is compared to the eye socket of a Raptorex kriegsteini


Picture Credit: Paul Sereno

Stevens, K.A. 2006 Binocular vision in Theropod dinosaurs. Journal of Vertebrate Paleontology 26(2):321-330. *visual acuity up to thirteen times was stated in the paper.

For dinosaur themed toys, models and games: Visit Everything Dinosaur

One Step Closer to Determining the Colour of Dinosaurs

Bat Study Helps to Confirm Melanosome Detection in Fossils

Melanin is a very widespread, natural pigment found in the animal kingdom.  Different forms of melanin are responsible for the colour of organisms, the black and the brown/reddish hues, for example.  Over the last few years, studies have attempted to identify evidence of melanosomes (the specialised part of the animal cell which synthesises, stores and transports the pigment), within the fossil record, but why is the search for an understanding about the colour of long dead creatures so important?

Colour Holds the Key to Behaviour

In living animals today, colour patterns are closely linked to behaviours and colouration provides information on how these creatures interact with their environments.  From the ornate and beautiful peacock to the striking pigmentation of an okapi, knowledge of the colour of an organism provides scientists with a host of information.  If only we had such insights for long extinct animals, well we do, but the identification of preserved melanosomes in the fossil record has proved controversial.  The interpretation of the structures found has led to some very colourful debates.  Are scientists able to infer pigmentation from these preserved remains?

Shapes of Structures Seen Under Very High Magnification Can Provide a Clue to Original Colour

Interpretation of melanosomes.

Interpretation of melanosomes.

Even the Dinosauria has been dragged into the discussion, back in 2010, Everything Dinosaur reported on research led by Bristol University that attempted to identify the colour of feathers preserved in the fossils of a little Chinese Theropod dinosaur Sinosauropteryx.

To read more about this research: A Ginger Dinosaur

Now a new paper produced by scientists from the University of Bristol in collaboration with colleagues from Virginia Tech and a number of other American academic institutes, backs the earlier research suggesting that the chemical preservation of melanin is possible within the fossil record.  The scientists studied a range of exceptionally well-preserved vertebrate fossils including specimens dating back to the Carboniferous and much more recent fossil material, the bats from the Early Tertiary shales of Messel in Germany, for example, along with some even more recent Miocene fossils.  The team were able to show that melanin is preserved in a number of soft-bodied fossils, but its burial under high pressure and temperature, all part of the fossilisation process does alter its original chemistry.  Other scientists had proposed that the structures thought to be melanosomes preserved in the fossil record, were actually bacteria that had become part of the fossil structure as they preserved the bacterial action of the original organic remains decomposition.  The research team concludes that the relatively widespread occurrence of melanin found allows them to dismiss the suggestion that these structures are microbial in origin.

Dr. Jakob Vinther (Bristol University), one of the authors of the paper published in the PNAS (Proceedings of the National Academy of Sciences – America), replicated the conditions under which fossils form and then subjected the samples to analysis using extremely sensitive ion mass spectroscopy (TOF-SIMS – time-of-flight ion mass spectroscopy), the scientists were able to map how the melanin chemical composition would change over time and then compared their results to what was found in a chemical analysis of the fossil record.

Dr. Vinther stated:

“This is a great leap forward in our understanding of how fossils are preserved.  We now know how melanin is preserved and we have the methods to confidently detect it.”

In short, if scientists now know how the pigment behaves during fossilisation and what its chemical signature should be after the fossilisation process has occurred, then they should be able to identify melanin in fossils by looking for this tell-tale signature.

Two Distinct Types of Melanin

There are two distinct types of melanin, eumelanin is responsible for the colour black and these structures resemble tiny sausage shapes when examined under high magnification.  The second type, responsible for the reddish/brown hues is phaeomelanin and its structures look much more circular when viewed under a microscope.  Importantly, structures which resemble these shapes have been spotted in the fossil record, as they have different chemical signatures, a chemical analysis can be used to back up observations regarding observed melanin structures.

Prehistoric Bats Under the Spotlight

Take for example, those prehistoric bat fossils from the Messel shales which date from the Eocene Epoch.  Two species were studied and microscopic analysis of the beautifully preserved fur showed shapes that looked like the more circular structures associated with phaeomelanin (reds and browns).  The time-of-flight ion mass spectroscopy confirmed this interpretation.  Chemical signatures found support the idea that those circular structures would have meant that when these bats lived some fifty million years ago, the bats would have been reddish-brown in colour.  By using the morphological analysis backed up by the chemical signature study, the team could conclude with a high degree of certainly that these two species of bat were effectively brunettes.

A Fossil Bat – Palaeochiropteryx (Messel, Germany) from the Study

Reddish/brown bats of the Eocene.

Reddish/brown bats of the Eocene.

Picture Credit: Dr. Jakob Vinther

Also involved in this study were scientists from the University of Texas at Austin (Texas), along with Caitlin Colleary, who had done his Masters Degree at Bristol University but was now a PhD student at Virginia Tech.

Outlining the extent of their study, Caitlin said:

“We have now studied tissues from fish, frogs, and tadpoles, hair from mammals, feathers from birds, and ink from octopus and squids.  They all preserve melanin, so it’s safe to say that melanin is all over the place.  Now we can confidently fill in some of the original colour patterns of these ancient animals.”

This area of research is likely to remain controversial for a while longer.  So much depends on how we interpret the morphology of these tiny structures.  This research does provide a chemical method of helping to back up findings, however, we suspect that the debate amongst scientists will rumble on.  After all, in scientific research of this nature, hardly anything is as clear as black and white.

More research into the colour of dinosaurs (August 2015): The Colour of Dinosaurs

Dinosaurs may have laid coloured eggs (May 2015): Did Dinosaurs Lay Coloured Eggs?

Working out the colour of dinosaurs may have become a little more complicated: Working out the Colour of Dinosaurs Just Got Harder

The colour of marine reptiles: Marine Reptiles and their “Little Black Numbers”

Everything Dinosaur acknowledges the help of Bristol University in the compilation of this article.

New Research on the Coelacanth Shows it Has a Vestigial Lung

The Weird and Wonderful Coelacanth – Once an Air Breather

An international team of researchers led by scientists at the Department of Zoology at the University of Rio de Janeiro (Brazil), have discovered that the bizarre “living fossil” Coelacanth has a vestigial lung in its abdomen.  This organ, now obsolete, is an evolutionary left over from when the ancestors of the extant species lived in oxygen poor waters millions of years ago.

The fossil record of the Coelacanths part of the group of predatory Sarcopterygian fishes, dates back to the Devonian (about 410 million years ago), once widespread, living in a variety of freshwater and marine habitats these fish were believed to have died out at around the same time as the dinosaurs.  However two extant species are known, both in the genus Latimeria (Latimeria chalumnae and L. menadoensis).  Latimeria chalumnae is found in deep water between 200 and 400 metres deep off the coast of South Africa with a particular concentration around the Comoros Islands.  The first specimen known to science was caught in 1938.  Latimeria chalumnae is coloured deep blue with white spots.  The second species L. menadoensis, is predominantly brown in colour and it was scientifically described in 1999.  This species seems to be confined to the deep waters off the Indonesian island of Sulawesi.

A Model of a Coelacanth

Ancient fish model - Coelacanth

Ancient fish model – Coelacanth

Picture Credit: Everything Dinosaur

The team of international researchers which also included scientists from France and Japan studied a total of five Latimeria chalumnae specimens a various growth stages and following dissections as well as three-dimensional reconstructions they discovered that the vestigial lung is proportionally much larger in the Coelacanth embryo but the growth of this organ slows down as the fish matures.  This suggests that the ancestors of modern Coelacanths evolved a lung to help supplement their breathing, perhaps as a result of living in low oxygen environments.  The deep water habitat of the two known species alive today are very stable and oxygen levels are relatively constant.  As a result, the lung is not needed and it has become obsolete.  A fatty organ has also been noted, this seems to act as a buoyancy aid.  This research has been published in the journal “Nature Communications”.

Three Dimensional Reconstructions Showing the Development of the Vestigial Lung in Coelacanths

Three-dimensional images showing the development of the Coelacanth lung at different fish growth stages.

Three-dimensional images showing the development of the Coelacanth lung at different fish growth stages.

Picture Credit: Brito et al (Nature Communications)

The picture above shows right lateral views of the specimens in the study showing the development of the lung.  Pictures (a-d), early embryo with approximate length four cm.  Pictures (e-h), embryo with yolk sac around thirty centimetres in length.  Pictures (i-l) an adult animal, approximate length 1.3 metres.  Yellow = oesophagus and stomach, green the fatty organ and red equals the vestigial lung.  The obsolete lung is proportionally much larger in the embryo than in the adult animal.

The presence of a strange, calcified sheath in the abdominal cavity of fossil Coelacanths, has been known for over 150 years.  However, palaeontologists were not sure what these calcified plates represented.  It had been thought that it was some sort of specialised internal organ, perhaps functioning like a swim-bladder.  Only recently has this organ present in fossil Coelacanths been identified as a pulmonary organ (lung), positioned adjacent to the fish’s gut.

Although the anatomy of living Coelacanths has been studied extensively, little evidence concerning the presence of a lung in extant species had been found.  However, it had been noted that adult animals had a large, fatty organ in the location where the lung was thought to be.  How these structures found in modern Coelacanths related to the structures seen in fossils remained unclear.  In this new research, the existence of a vestigial lung in L. chalumnae is confirmed.  In addition, the scientists propose homology (shared ancestry) between this lung and calcified lung found in fossils.  The parallel development of a fatty organ for buoyancy control suggest a unique adaptation amongst the Coelacanth family for living in deep water environments.

Over the long course of this fishes evolution, the adaptation to living in stable, deep water, marine environments with its very low variations in oxygen content, may have resulted in the loss of the lung function.  As the lung becomes proportionally smaller in adult specimens so there is an increase in the size of the fatty organ.  This organ may help to stabilise this relatively large fish in the water column, an adaptation to living at depths of more than 200 metres.

The researchers speculate that adapting to a deep water environment may help to explain the survival of some Coelacanths.  The stable, unchanging, deep water environments might have been much less affected by the global environmental crises marked by the End Cretaceous extinction event.  Late Cretaceous Coelacanths inhabiting shallow marine environments or freshwater may not have been so lucky, hence their extinction.

A Rare Photograph of Latimeria Chalumnae in its Natural Habitat

Latimeria chalumnae photograhed

Latimeria chalumnae photographed off the coast of South Africa

Picture Credit: Laurent Ballesta

The Rediscovering of Australia’s First Cretaceous Dinosaur

Original Quarry where Fossils of Austrosaurus Found Re-Located

More fossils of the very first Cretaceous dinosaur to be described from Australia have been excavated over the winter months and scientists could be on the verge of solving a mystery surrounding whether the Titanosaur named Austrosaurus mckillopi deserves to be a valid genus or not.

The winter months (southern hemisphere), are the best months to conduct field work in Queensland (Australia), although still hot, the daytime temperatures are nowhere near as high as they are in the summer and the months of June through to the early part of September are regarded as the season of field work when volunteers join palaeontologists on organised digs, excavating the rich Mesozoic fossil heritage of this Australian State.  Austrosaurus means (southern lizard), scientists have estimated that this dinosaur may have reached lengths in excess of fifteen metres.

Field Workers at the Dig Site (Summer 2015)

Fieldworkers at the site, the original wooden posts marking the 1932 discovery can be seen in the picture.

Fieldworkers at the site, the original wooden posts marking the 1932 discovery can be seen in the picture.

Picture Credit: Patricia Woodgate

Back in 1932, a farm worker found some fragments of bone that turned out to be vertebrae from a huge Titanosaur.  The fossils were very unusual as the location of the fossil find – Clutha Station close to the settlement of Richmond had provided scientists with some excellent examples of marine reptiles.  The sediments deposited in this area represented a marine environment, however, the carcase of a large, herbivorous dinosaur had been washed out to sea and the fossils had been exposed on the surface due to erosion.  Sadly, the fossil location was lost and although a dinosaur was named based on the fragmentary remains (Austrosaurus), no further material could be recovered.

That was until last year, when the mayor of Richmond John Wharton set out to search the Clutha Station area in a bid to re-discover the fossil site.  Searching by truck did not prove successful, but when a helicopter was hired, two wooden posts in the ground were soon spotted from the air and on further inspection this proved to be the site of the 1932 fossil discovery.  A preliminary investigation led to a full-scale excavation taking place during this year’s field work season.

A number of pinkish-white bones were excavated, including some very well preserved rib bones, the largest of which measure 1.6 metres in length.  These bones are very likely part of the same skeleton as the vertebrae discovered in 1932.  The bones are currently on display at the Kronosaurus Korner museum in Richmond. Further preparation and cleaning will be undertaken and then an analysis carried out comparing this, now more complete skeleton to the fossilised remains of Wintonotitan wattsi, another Australian Titanosaur, whose fossils have been recovered from rocks of a similar age, but the majority of these fossil finds have taken place to the south of the town of Richmond (near to Winton).

An Excavator Hard at Work at the Dig Site with Volunteers

Hard at work excavating the fossil remains.

Hard at work excavating the fossil remains.

Picture Credit: Patricia Woodgate

Dr. Steve Poropat, a scientist from the Australian Age of Dinosaurs Museum (based at Winton), the town after which Wintonotitan was named stated:

“Rediscovering a historical dinosaur dig site was almost more exciting than finding a brand new one.  Once we knew where the site was, we knew we had the chance to find more of the same Austrosaurus specimen and all that was separating us from it was a metre or so of black soil.”

Attempts had been made in the 1970’s and 1980’s to relocate the original Austrosaurus dig site, but they had all been unsuccessful.  Thanks to the dedicated folk of Richmond and the surrounding area, Australian scientists have the opportunity to learn more about the first Cretaceous dinosaur to be described in Australia and to find out whether Wintonotitan and Austrosaurus deserve to be separate genera.

An Illustration of Austrosaurus (Austrosaurus mckillopi)

A scale drawing of Austrosaurus.

A scale drawing of Austrosaurus.

Picture Credit: Everything Dinosaur

In January, Everything Dinosaur predicted that this year would be an important one for Australian dinosaur discoveries.  There have been a number of fantastic fossil finds and it is great to hear the 1932 fossil site has been rediscovered.

Proudly Showing Off One of the Newly Discovered Rib Bones

Showing off a fossil rib.

Showing off a fossil rib.

Picture Credit: Patricia Woodgate

To read more about Everything Dinosaur’s predictions for 2015: Palaeontology and Fossil Predictions for 2015

To read more about other Titanosaur discoveries from Australia including Wintonotitan: A Trio of Aussie Dinosaurs

Potential New Species of Horned Dinosaur Reported

Potential New Addition to the Ceratopsidae Family

Everything Dinosaur has received reports that scientists from the Museum of the Rockies (Bozeman, Montana), may have discovered a new species of horned dinosaur (Ceratopsidae family).  The fossils including elements of the skull were originally found during fieldwork on the Judith River Formation back in 2012, but it was not until this week that researchers realised that the bones could represent a new species of horned dinosaur.

The Judith River Formation, part of the Judith River Group, is famous for its vertebrate fossils and a number of dinosaur genera have been described from the various sub-divisions that make up the Judith River Formation, although, as far as we at Everything Dinosaur there has never been any Sauropod fossils associated with this particular geological feature.  Numerous Ornithischian and Theropod dinosaur fossils have been found, although a number of genera that have been named are based on very fragmentary remains, a consequence of this part of Montana being first explored during the “Bone Wars” of the late 19th Century by scientists such as Edward Drinker Cope.

Some of the Judith River Formation Fossil Material

More research is required to identify this fossil find as a new dinosaur.

More research is required to identify this fossil find as a new dinosaur.

Picture Credit: ABCFOXMontana

As the fossils, which represent about eighty-five percent of one individual, were found very close to the Careless Creek Ranch site where the first fossilised remains of the small horned dinosaur known as Avaceratops (A. lammersi), were discovered back in 1981, it was thought that the bones represented another specimen of Avaceratops.  However, as researchers from the Museum of the Rockies removed the fossils from their protective plaster and burlap jackets it was noted that the skull morphology was somewhat distinctive and different from that seen in the Avaceratops holotype.  In addition, this specimen seemed to lack a nasal horn.  This data has led the researchers to speculate that this could be a brand new species of horned dinosaur.

Commenting on the work carried out so far, John Scannella, Palaeontology Collections Manager for the Museum explained:

“What’s important is that before a new dinosaur species is named that the bones that are supposed to belong to this new species of dinosaur are closely studied by palaeontologists and compared to other specimens that might look similar.”

An Illustration of the Dinosaur Called Avaceratops (A. lammersi)

A scale drawing of Avaceratops.

A scale drawing of Avaceratops.

Picture Credit: Everything Dinosaur

If the fossil represents a new species then it can possibly help palaeontologists to learn more about the radiation of the Ceratopsidae that took place during the Early to Middle Campanian faunal stage (around 79 to 77 million years ago).  If the fossils turn out to be another example of an Avaceratops, than ironically they could have a far greater significance.  The relationship between Avaceratops and other members of the horned dinosaur family tree is not clear (phylogeny).  Avaceratops is regarded as a basal member of the Centrosaurine dinosaurs, but this position has been debated.  In addition, the actual size of this dinosaur remains uncertain.  The holotype material has been regarded as representing a sub-adult, even a juvenile specimen.  In Everything Dinosaur’s illustration we show Avaceratops as being relatively small for a Late Cretaceous member of the Ceratopsidae.  However, other researchers who have looked at more recent fossil finds suggest that this dinosaur could have reached lengths of over four metres and weighed in excess of one tonne.  If these new fossils do indeed represent another Avaceratops, then with eighty-five percent of the skeleton to study, palaeontologists might learn a lot more about how Avaceratops grew and where it fits into the horned dinosaur family.

A spokesperson from Everything Dinosaur stated:

“The problem with horned dinosaurs is that they seem to have changed substantially as they grew up and matured.  As features such as horns and neck frills change, then it can take a very long time to determine whether this is really a new species or just a specimen at a younger or older growth stage than the fossils of an already described species.”

Avaceratops has been very much one of Everything Dinosaur’s “dinosaurs of the week” this week.  During a school visit, we met a young girl called Ava and we explained all about the dinosaur that shares her name. We even sent over a picture of Avaceratops so the class could see what we think this dinosaur looked like.  Avaceratops was named after Ava Cole, the wife of Eddie Cole who found the first fossils of this herbivorous dinosaur.

Latest Dinosaur from Alaska

New Dinosaur Species Suggests Unique Fauna of Late Cretaceous Alaska

Scientists have announced a new species of duck-billed dinosaur that once roamed the polar forests of Alaska.  The dinosaur, named Ugrunaaluk kuukpikensis pronounced 00-grew-na-luck kook-pik-en-sis, reached lengths in excess of nine metres and its discovery further supports the theory that during the Late Cretaceous, Alaska supported a unique dinosaur fauna.

An Illustration of a Herd of Ugrunaaluk (U. kuukpikensis)

Duck-billed dinosaur would have seen the northern lights.

Duck-billed dinosaur would have seen the northern lights.

Picture Credit: James Havens

The fossils, which include the remains of a number of individuals, came from the Liscomb Bone Bed, a highly fossiliferous layer of rock along the Colville River in the Prince Creek Formation.  These rocks consist of flood plain deposits and shed light on life in the far north of the American continent some 69 million years ago (Maastrichtian faunal stage).

The Colville River area has produced evidence of a number of dinosaur species that suggest that the wildlife existing at the very top of the landmass known as Laramidia at the end of the Age of Dinosaurs was not found anywhere else in the world.  Recent fossil finds include teeth of giant Troodontids and a polar Tyrannosaur.

To read more about the tyrannosaurid discovery: Nanuqsaurus – Polar Bear Lizard

One of the lead authors of the scientific paper that details this discovery (published in the quarterly journal Acta Palaeontologica Polonica), Pat Druckenmiller stated:

“Today we find these animals in polar latitudes.  Amazingly, they lived even farther north during the Cretaceous.  These were the northern-most dinosaurs to have lived during the Age of Dinosaurs.  They were truly polar.”

Earth sciences curator at the University of Alaska Museum of the North, Dr. Druckenmiller worked with University of Alaska Fairbanks graduate student Hirotsugu Mori and Florida State University’s Gregory Erickson in order to piece together the fossilised and disarticulated remains.  However, the naming of this dinosaur involved Ronald Brower Senior, an expert on Alaskan native peoples.  The scientists wanted to give their new dinosaur a name that honoured the Iñupiaq people who live along the Colville River.  Mr Brower, a teacher at the University of Alaska Fairbanks Alaska Native Language Centre and an expert on the culture and history of the Iñupiaq, helped the team come up with Ugrunaaluk kuukpikensis, the name translates as “ancient grazer”, a reference to the extensive dental battery these dinosaurs possessed, vital if they were able to cope with a diet of coarse pine needles, fir cones and ferns.

Some of the Duck-Billed Dinosaur Fossil Bones from the Site

Caudal vertebrae (tail bones)

Caudal vertebrae (tail bones)

Picture Credit: Pat Druckenmiller/University of Alaska Museum of the North

Although the Arctic is much colder today than it was back in the Late Cretaceous, these dinosaurs, if they had been permanent residents*, would have endured many months of complete darkness and an average annual temperature of around nine degrees, that’s about the equivalent annual average temperature of Toronto (Ontario, Canada) today.  These substantial herbivores would have been well used to seeing snow and ice.

Dr. Pat Druckenmiller Digging for Dinosaur Fossils

The research team had to endure a variety of extreme weathers including snow falls.

The research team had to endure a lot of extreme weather including snow falls.

Picture Credit: Greg Erickson/University of Alaska Museum of the North

This is the fourth unique dinosaur species to be identified from this part of the world.  The researchers propose that these dinosaurs were specially adapted to survive the harsh climate and that northern Laramidia supported a unique ecosystem.  The absence of any crocodile, lizard or turtle bones from the deposit suggests that ectotherms (cold-blooded reptiles) could not cope with the cold at this latitude.

*As to whether these duck-billed dinosaurs were residents or seasonal migrants has caused some debate amongst palaeontologists.  Some scientists have proposed that these large herbivores migrated up to these latitudes so that they could take advantage of the abundant plant growth in the summer months, when there would have been almost permanent daylight.  However, Greg Erickson believes that the young Hadrosaurs found at the site were too small to be able to undertake such an extremely long migration.  He thinks that the dinosaurs were permanent residents.

The Florida State University scientist explained these dinosaurs may have had physiologies more like birds or mammals.  The researchers hope to study the fossils in more detail so that they can understand more about how such large reptiles were able to survive so far north.

As to where Ugrunaaluk kuukpikensis fits into the Hadrosaur family tree, the dinosaur resembles an Edmontosaurus, but it was ascribed its own genus based on differences in the anatomy of the skull and differences in the morphology of some of the other post cranial fossil material.

Understanding Azhdarchid Pterosaurs

What Role in Ecosystems did Giant Azhdarchid Pterosaurs Have?

Ask a young dinosaur fan to name a flying reptile and in all likelihood they will come out with the name of one of the really large Late Cretaceous Pterosaurs.  Pteranodon will probably feature (member of the Pteranodontia), which once boasted as many as eleven species in this genus, but now most palaeontologists except the revision down to just two (P. sternbergi and the geologically younger P. longiceps).  However, matching Pteranodon in popularity and exceeding it in terms of wingspan come the likes of Hatzegopteryx and Quetzalcoatlus.  These two flying reptiles are representatives of the enigmatic Azhdarchidae and as such could be regarded as the most spectacular of all the flying reptiles known to science.

A Model of the Giraffe-sized Pterosaur Called Hatzegopteryx

The CollectA Hatzegopteryx

The CollectA Hatzegopteryx

Picture Credit: Everything Dinosaur

There is no doubting some of these azhdarchid Pterosaurs were giants, Hatzegopteryx (H. thambema), for example, was taller than a giraffe and its wingspan could have exceeded twelve metres.  Quetzalcoatlus from Upper Cretaceous sediments of Texas, is believed to have been even bigger.  When the huge skull is considered, one of the largest known in the Tetrapods (excluding marine animals such as the Cetaceans), when the robust post cranial fossil material associated with Hatzegopteryx is examined closely, it seems incredible that these large creatures were able to take to the air.  However, when the global distribution of the fossils is considered along with aerodynamic wing shape studies, it seems that most of the Azhdarchidae were indeed accomplished fliers.

An Important Question to Answer

This begs the question, what role in the Late Cretaceous ecosystem did these toothless giants have?  There have been a number of research papers published exploring this area of Pterosaur research.  Recently, Mark Witton, a leading expert on the Pterosauria (University of Portsmouth) collaborated with Darren Naish (University of Southampton) to produce an intriguing paper in the latest edition of the quarterly journal “Acta Palaeontologica Polonica” on this very subject.  Both these eminent British scientists have written extensively on the Pterosauria before, but in this new paper entitled “Azhdarchid Pterosaurs: Water-trawling Pelican Mimics or “Terrestrial Stalkers”?”, they conclude that large azhdarchid Pterosaurs were very probably terrestrial hunters, perhaps filling a role in ecosystems similar to that of the Maribou Stork (Leptoptilos crumenifer) today.   These storks are large wading birds and are widespread in sub-Saharan Africa.  They have a reputation for eating almost anything that can fit into the mouths including rubbish from garbage dumps.  They do feed on carrion and it has been proposed that azhdarchid Pterosaurs were scavengers too, but these heavy birds also stalk and feed upon a variety of small vertebrates such as frogs, lizards, other birds and small mammals.

The idea that the likes of Hatzegopteryx and Quetzalcoatlus were largely terrestrial hunters, stalking prey – has been challenged on a number of occasions, three main concerns over this hypothesis have been raised:

  1. Fossils of azhdarchid Pterosaurs are frequently found in aquatic deposits
  2. Aerial water-trawling, where the beak is pulled through the water to catch food in an enlarged throat pouch like that seen in extant pelicans is a more likely feeding strategy
  3. Large, slow-moving Pterosaurs would have been very vulnerable to attack from other predators as they roamed the land

In this new paper, Mark and Darren examine the evidence for these claims and conclude that the fossil evidence does indeed support the idea that these large animals were indeed terrestrial foragers.  Firstly, the fact that fossils of azhdarchids are found in strata that represent lacustrine, riverine or marine environments is dismissed as having no real significance with regards to the behaviour of these flying reptiles.  Water transport and deposition accounts for a huge proportion of the vertebrate fossil record and therefore, the deposition in aquatic deposits probably has no bearing on the actual lifestyles of these creatures.

Secondly, it is true, that pelicans are very efficient feeders and their pouches do help them forage, but an examination of the joint function of Pterosaur jaws indicates that they are entirely different to those of the jaws of pelicans. Pelican beaks are highly specialised compared to those of all other Tetrapods, studies of azhdarchid jaw (albeit from very crushed remains in most cases), fossils, suggest that these Pterosaur jaws are anatomically very different from those of pelicans.  The researchers cannot find any strong evidence to support the idea that azhdarchids foraged like pelicans.

A Flock of Azhdarchid Pterosaurs Doing What They Do Best – Ground Foraging

Some Pterosaurs were as tall as a giraffe.

Some Pterosaurs were as tall as a giraffe.

Picture Credit: Mark Witton

In addition, the estimated amount of jaw expansion present in azhdarchids was proportionately much smaller when compared to that of pelicans, even when the asymmetrical jaw joints of azhdarchids are considered.  Lots of other reptiles from the fossil record also show evidence of asymmetrical jaw joints, yet there is no evidence to suggest that these creatures too, indulged in pelican-like feeding behaviour.

Finally, the researchers refute the idea of these Pterosaurs being particularly prone to attack once on the ground.  Trace fossils indicate that Pterosaurs were quite capable walkers on land and although encumbered by their wings, they were not completely helpless.  There are lots of birds around today that adopt a terrestrial foraging strategy, the risks to stalking Pterosaurs from a large Theropod attack are probably overstated.  For example, studies of Pterosaur take-offs indicate that these creatures could probably take to the air quite quickly and when you consider that they would have had a pair of sharp eyes perched some five metres off the ground, the likelihood of a meat-eating dinosaur ambushing them would have been considerably reduced.

So, after a careful examination of the available evidence, the researchers conclude that terrestrial foraging for the likes of Hatzegopteryx remains the most likely feeding strategy.  This gives a whole new meaning to the idea of “picking something up for dinner”.

Back in 2013, Mark P. Witton wrote a fantastic book all about the Pterosauria, it was called “Pterosaurs, Natural History, Evolution, Anatomy” and it is well worth purchasing.

Here is Everything Dinosaur’s book review: Pterosaurs Reviewed

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