Hadrosaur Headgear helped Communication for these Herding Herbivores

A new study has just been published into the sound resonating capabilities of ornate head crests of 4 genera of lambeosaurine hadrosaurs, building on earlier American studies from the 1980s and 1990s, time to look at some musical lambeosaurines.

For many years scientists have puzzled over the exact function of the duck-billed dinosaur crests.  Hadrosaurs are split into two main groups, the hadrosaurines (example being Edmontosaurus) animals with small or no head crests and the lambeosaurines (Corythosaurus, Charonosaurus etc.) with flamboyant crests.

Extensive Hadrosaur Fossils

From the extensive hadrosaur fossil remains now known, it can be seen that the size and shape of the crest changed as animals grew and reached maturity.  Also, some lambeosaurine species seem to show differences in crest shape and size between species.  A number of fossil skulls of the species Parasaurolophus walkeri have different sized crests and this may indicate that the males had larger more prominent crests than females.  There are a number of studies and reviews being conducted at the moment to try to identify medullary bone in the hadrosaur fossil record.  Finding evidence of this particular type of bone tissue in duck-billed dinosaurs with their skulls and crests preserved would help scientists to identify females amongst the fossil record.

A Typical Hadrosaurine Fossil Specimen

After much careful fieldwork and preparation a fossil skeleton is ready for display. A typical hadrosaurine fossil specimen. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Medullary bone is a thin layer of very vascular bone that is formed in modern birds during ovulation.  The formation of this bone type is linked to high levels of the female hormone oestrogen.  This type of bone is formed in the leg bones and exists until the last egg has been laid.  It is then re-absorbed by the body.  This tissue provides a source of calcium for the creation of eggshells.  The presence of fossilised medullary bone structures may help scientists to pick out the girls from the boys.  Using this data, a better understanding of head crest shape and morphology could then be derived.

Musical Lambeosaurines

This new research carried out by a team of Canadian and American researchers, and published in the scientific journal “The Anatomical Record”, concludes that duck-billed dinosaurs were capable of producing a variety of sounds, and the size and shape of the crest influenced the sound produced.  They go on to theorise that as these dinosaurs grew and reached sexual maturity their voices altered.  The larger crests of mature animals would help make different sounds compared to the voices of juveniles.

In a way, this is similar to our own species in which the male voice “breaks” prior to the onset of adulthood.

Building on earlier research into hadrosaur vocalisation, the team were able to study crests and nasal passages in great detail using CAT scans to determine the internal structure of these ornate items of dinosaur headgear.  In addition, studies of casts from hadrosaur brain cases were included in the work to help clarify the relationship between these crests and the olfactory part of the brain (sense of smell).  The team’s results seems to confirm one of the earlier theories, that the head crests were used for vocal communication — not to enhance the sense of smell.

And if the research is validated, it would indicate that when a lambeosaurine made calls, air would travel through the nasal passages enclosed by the head crest. Since the sizes and shapes of head crests (and nasal passages) differed among lambeosaurine genera and amongst individuals of a species, this would be evidence that each dinosaur had its own distinct voice.

“Dinosaurs vocalised through their mouths, but because the nose connects to the mouth, the nasal passages act as resonance chambers,” commented researcher Lawrence Witmer of Ohio University’s College of Osteopathic Medicine, one of the authors of the scientific paper.

Four Genera of Lambeosaurine Studied

Four genera of lambeosaurine were studied – Parasaurolophus, Corythosaurus, Hypacrosaurus and Lambeosaurus.  The addition of Hypacrosaurus, regarded as one of the most primitive lambeosaurines discovered to date can be explained by the fact that several near complete fossil specimens of this dinosaur have been found and a number of juvenile specimens are known, permitting scientists to study the growth and development of this particular dinosaur.

By examining the brain-cases of these dinosaurs the scientists were able to speculate on the relationship between the crest and certain specific elements of brain function.

“The shape of the brain can tell us a lot about what senses were important in a dinosaur’s everyday life, and give insight into the function of the crests,” said David Evans, a palaeontologist at the Royal Ontario Museum and the University of Toronto, the lead author of the research paper.

In addition, the team examined such systems in dinosaurs’ closest living relatives, birds and crocodilians.

Their study indicated that the brain region linked with all things olfactory was relatively small and underdeveloped in the lambeosaurines, suggesting, the researchers say, that the dinosaurs’ head crests did not evolve to improve smell.  Instead, the researchers think the dinosaurs used the nasal passages within the crests to make loud bellowing sounds that could have been used to call for mates, express social dominance or as alarm calls to warn others of the approach of predators.

“We have a sense that these animals used low frequency sound, so, very deep sounds that actually travel long distances and they may have been able to use those to communicate”.

The discovery of one of the delicate sound conducting bones of a Corythosaurus (the columella) indicates that these animals may have had sensitive hearing, perhaps more capable of detecting low frequency sounds than many mammal species.

The picture this research paints is of a large herd of animals of different ages, sizes and different levels of maturity moving along filling the Cretaceous air with loud honks, bellows and grunts.  Younger animals would probably have made higher pitched sounds, chirps and squeaks.  Vocalisation may have had a number of important functions within these groups, but it is also worth noting that the crests themselves would have also been used as a form of visual signalling device between individuals.

The joint Canadian and American team re-examined earlier work on the morphology of hadrosaur brains and their new research indicates that some areas of the brain, for example, those linked with social behaviour, problem-solving and higher thought were quite large.  This would have helped these animals decipher complex messages in the form of visual signals and vocalisations.

The research team has stated:

“What it suggests is that they indeed did have the brain power to pull off some of these sophisticated behaviours,”,  in addition, “that they probably did communicate in perhaps fairly subtle ways and they could make sense of it.”

The subtle differences in crest size, such as those seen in the three species of Parasaurolophus currently recognised would mean that different species would have produced slightly different sounds.

To read an article focusing on the work into hadrosaur vocalisation in the late 1990s: Article on Dinosaur Sounds.

This new study does not detract from the work of other research teams, but places a greater emphasis on the crest shape of lambeosaurines to produce different types of sounds.  It links the study of these ornate crests with brain structure.  It is possible that these impressive features served a multitude of purposes.  As they were hollow tubes connected to the nasal passages they could have modified the air that was breathed, perhaps helping to retain moisture or warm the air before it entered the respiratory system.  In some instances, that part of the brain that dealt with the olfactory function does seem to be closely associated with the crest, the crests may have helped these large animals detect slight variations in scents wafting on air currents.  This may have helped them find sources of food or assisted with their migrations.  After all, these huge animals living in massive herds would have consumed a great deal of plant material and so these animals would probably have been on the move constantly in search of fresh feeding grounds.

It is possible that the head crests of hadrosaurs played a function in all these areas.  Perhaps the bigger mystery is why the hadrosaurines such as Edmontosaurus had no crests or solid ones formed by the extension of the nasal bones.

Everything Dinosaur stocks a wide range of duck-billed dinosaur models, including lambeosaurine replicas in the: PNSO Age of Dinosaurs model range.

Pachyrhinosaurs – Bizarre Horns and Bumps Designed to Attract a Mate

The horns, frills, crests and epoccipital bones of the ceratopsids (horned dinosaurs) have fascinated palaeontologists, none more so than the pachyrhinosaurs.  This bizarre ornamentation has been taken to extremes in some genera, such as Styracosaurus with its huge frill of long spikes and Chasmosaurus with its broad, wide head-shield.  However, the discovery of a large ceratopsid bone-bed in Canada may help scientists learn more about ceratopsian head gear.

The discovery of a new species of pachyrhinosaur – Pachyrhinosaurus lakustai found in Alberta, Canada may provide vital information regarding the growth and development of such ornamentation.  Information on the ontogeny (growth and development) of dinosaurs is essential in helping to understand how this ornamentation developed as the animals grew.

New Species of Dinosaur (Pachyrhinosaurus)

To read an article on the discovery of this new species of pachyrhinosaur: New Species of Pachyrhinosaur named in honour of its Discoverer.

The horns, spikes and other bony elements making up the head-shields of these horned dinosaurs may look bizarre to us, but they must have evolved for a particular purpose, with adults passing on these characteristics to subsequent generations and Natural Selection operating to pass on beneficial characteristics.

An Illustration of Pachyrhinosaurs

Picture credit: Mike Fredericks

The illustration above shows two adult pachyrhinosaurs (Pachyrhinosaurus canadensis), scientists are unsure whether the large bump on the snout supported a horn and some illustrators have depicted pachyrhinosaurs with a small nose horn arrangement – such are the difficulties in interpreting the fossil record.

However, these scary faces may look very intimidating to us, but researchers studying the bone-bed  in which this new species was found think that this ornamentation helped pachyrhinosaurs attract a mate.

A Bizarre-looking Dinosaur

Commenting on the species, Scott Sampson of the Utah Museum of Natural History, one of the scientists involved with the study stated:

“It’s one of the most bizarre-looking dinosaurs ever.  It has more bony bells and whistles than just about any animal I’ve ever heard of”.

Around the edge of its large skull plate, referred to as a frill, is a series of forward-curving spikes, each about 1.5 feet (0.45 metres) long.

Despite their less-than-cuddly appearance, the team of North American researchers believe other pachyrhinosaurs would have found the sharp adornments and strange spikes appealing.

Philip Currie, a palaeontologist at the University of Alberta, added:

“it’s generally conceded that these horns on the face and the frill were to make [the dinosaurs] attractive to potential mates.”

Phil Currie led the team that produced the paper describing this new species of dinosaur.  The discovery of at least 27 individuals of the same species, with importantly, 15 skulls within the bone-bed, has helped the team draw some conclusions related to the amazing head gear of these horned dinosaurs.  Regarded as one of the richest bone-beds in the world, scientists estimated that there were over 300 bones per cubic metre of matrix.  The animals excavated represented adults and juveniles of the same species, allowing the scientists to study the development of these facial structures as the animals grew into mature, breeding adults.

“Most dinosaur species are known from one or two typically incomplete specimens, whereas this species is from a massive bone bed that preserved the remains of dozens of individuals and a number of skulls, sampling it from juvenile to adult and showing us the real variation that occurs among a species,” said the Utah museum’s Sampson.

The group found large differences between young and old among these horned dinosaurs. The juveniles seemed to have been relatively smooth-faced, while the adults were spiky, Currie, the lead scientist, explained.

“It was the first really good example showing growth and variation in these animals, where we had the babies looking one way and the adults looking totally different,” Currie commented.

The discovery of so many dinosaurs of one species at one site enables scientists to gain a unique insight into dinosaur growth rates and ontogeny.  The Pachyrhinosaurus find also helps to piece together the ceratopsid family tree.  Although, a number of ceratopsid genera are known, scientists are unsure how they are all related.

Discussing the recent finds in Alberta, Canada, Phil Currie added:

“It’s part of a sequence where we can look at not only the animal itself but all its close relatives, and we’re reaching the point now where we can trace these things from formation to formation and see the evolutionary changes of the lineage.”

Sampson agreed that the new research stands to make a significant advance in the study of horned dinosaurs and their family tree, he referred to the bone-bed discovery as a “landmark” in horned dinosaur research.

Pretty Pachyrhinosaurs

To see a model of Pachyrhinosaurus and other horned dinosaur figures: Dinosaur Models and Toys.

A number of dinosaurs had some amazing adaptations that gave them a rather bizarre appearance.  As well as the horned dinosaurs, there are the bone-headed dinosaurs known as the pachycephalosaurs and curious looking animals such as Cryolophosaurus, a theropod of the Early Jurassic nick-named “Elvisosaurus” due to its bizarre head crest.

A number of these strange animals have been illustrated on a poster entitled “Weird Dinosaurs”, the dinosaurs diversified into a myriad of different forms, each one adapted to a certain ecosystem, habitat and environmental niche.

The “Weird and Wonderful” Dinosaur Poster

Weird dinosaurs.

Picture credit: Everything Dinosaur

Jurassic Walls

There has been a trend in recent years for garden designers to incorporate ammonite replicas in garden plans.  Many garden centres now stock a range of ammonite replicas, usually cast in concrete that can be placed around rockeries to add interest and make a bit of a feature.

However, Brandon Lennon of www.lymeregisfossilwalks.com has sent us some photographs of a real ammonite fossil set in a wall – the ultimate in ammonite sculpture, your very own real fossil to have in your garden.  Brandon tells us that he took a party of keen fossil enthusiasts out on one of his guided walks along the beaches of Lyme Regis Bay and one lucky member of the group found a super ammonite fossil.

Ammonite Fossil

The date was Saturday July 5th and sharp eyed Brandon led the party to a good location to find fossils heading west out of the town, along Monmouth beach to Seven Rocks Point.  The group discovered a super specimen of a Microderoceras ammonite, and Brandon carefully extracted the fossil and carried it back to his workshop to undertake some preliminary cleaning.  The next day, the finder of this beautiful fossil came to collect it and now the Microderoceras has pride of place in a garden wall.

The Wall with the Fossil Ammonite

Picture credit: Piers Hanson

The wall and ammonite fossil certainly make an interesting feature and a talking point in the garden.  After all, there are not many gardeners that can boast that they have 180 million-year-old masonry.

A Close up of the Fossil

Ammonite in a wall.

Picture credit: Piers Hanson

Ammonite Replicas

The fossil looks most impressive and certainly has received a great deal of care and attention from the wall builder.  We are unsure of the scale, so we cannot tell how big the fossil is.  However, specimens of Microderoceras sp. are relatively common at Lyme Regis, in fact this genus is used by geologists and palaeontologists as a zone fossil to aid with biostratigraphic analysis of strata (common fossils help scientist work out the order of deposition).

Ammonite Replicas from Everything Dinosaur

A Bullyland ammonite model is used to help illustrate a display of ammonite fossils. Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Bullyland of Germany have created an ammonite model that is featured in the picture (above).  To view the range of Bullyland models and figures: Bullyland Prehistoric Animal Models.

Although we cannot be certain from the pictures, but it looks like the fossil represents an internal mould of the shell, some fine detail particularly the septae on the inner whorls can be seen.  Had the fossil not been removed, it would have been subjected to weathering and attritional processes and eventually broken up on the beach.

Our thanks to Brandon Lennon and Piers Hanson for allowing us to use these pictures.

To visit: Brandon Lennon’s fossil shop: Lyme Regis Fossils for Sale.

Fossil Evidence of Complex Arthropod Behaviour

A new scientific study examines complex behaviour in Cambrian arthropods. Arthropods are the largest phylum of animals, with a great number of diverse forms and numerous modes of life.  The first arthropods appear in the fossil record around 545 million years ago around the time of a great increase in life on Earth, known as the Cambrian explosion.

Trilobites were among the first arthropods to evolve, and account for approximately one third of all fossils found in Cambrian rocks.  Evolving a hard, outer coat (exoskeleton) which is segmented and paired, jointed legs and other appendages, plus the ability to grow via moulting – characteristics of all arthropods has proved to be a very successful evolutionary strategy.  Arthropods are found in virtually possible habitat on land and water and members of this phylum include crustaceans, millipedes, centipedes, spiders, mites, scorpions and of course the most abundant of all – insects.

Cambrian Arthropods

The trilobite, from humble origins evolved into something like 9 or 10 different Orders.  The Trilobita diversified into a multitude of different forms, although entirely marine, these animals survived right up to the end of the Palaeozoic (end of the Permian) and represent one of the most important faunas in the entire fossil record.

An Illustration of a Typical Trilobite

Picture credit: Everything Dinosaur

Trilobites get their name (it means three-lobed) as their bodies can be divided into three distinct sections both longitudinally and cross-ways.  There is a central axis running down the body, with a left lobe and right lobe.  In cross section, trilobites have a headshield (cephalon), a trunk (thorax) and a tail section (pygidium).

To view fossil replicas including trilobite models: CollectA Prehistoric Life Models and Figures.

It is easy for members of the public to dismiss such animals from Earth’s pre-history as ancient, simple animals, but an amazing fossil from China has provided scientists with an insight into early arthropod behaviour and revealed that these ancient relatives of modern arthropods were capable of the same sort of complex behaviours seen in many extant arthropods today.

Cambrian Fossils

A set of fossils dating from the Cambrian (525 million years ago approximately), indicate that some forms of early marine crustacean gathered together in large groups and were capable of collective behaviour, according to an international team of scientists.

Fossil evidence of collective behaviour is extremely rare. But what makes the find even more intriguing is that it indicates that such behaviour was occurring at the beginning of the Phanerozoic, an eon of time that began around 550 million years ago and marks the stage in the fossil record when hard shells and other structures appear.

The fossils, found in Yunnan province in south west China, were analysed by a team of scientists from Oxford University, the University of Leicester and Yunnan University, China. The find is reported in an article in the journal Science.  During the Cambrian, the country we know as China today, consisted of two separate and submerged continental masses that lay in a warm, tropical sea of the coast of a large landmass called Gondwana.  This shallow sea teamed with life and some elements have been preserved as fossils to create an extensive record of early marine life in this part of the world.

Burgess Shale Deposits

This area rivals the Burgess Shale deposits in British Columbia, Canada, in terms of the exceptionally well-preserved Cambrian fossils that have been found, although the strata is slightly younger than the famous Cambrian fossil bearing strata of the Burgess Shale.

However, the Burgess Shale deposits have been studied for nearly 100 years, whilst these Chinese deposits, first examined in 1984 have yet to be fully explored.

Pictures of the the fossil show a group of shrimp-like animals which have formed a linked line and seem to be travelling together across the sea bed. The close up shows two animals in more detail.

Commenting on this discovery, Professor Derek Siveter of the Oxford University Museum of Natural History and co-author of this study stated:

“What’s unique about the Yunnan fossil material is that it shows individual specimens closely interlocked to form a chain, of which there are several examples.”

These chains may have formed for reproductive purposes, or they may represent a stage in the animal’s life cycle – if so, there are no comparable occurrences in modern arthropods.  However, similar behaviour is seen in some species of crustacea today, such as lobsters.  These animals form chains and move collectively, migrating across the seabed heading for breeding grounds.  Such chains are formed to protect individual animals from predators, whilst they move out in the open.  A large co-ordinated chain may confuse potential attackers and deter them from making an attack.

Migratory Activity

The scientists have speculated that this congregation is likely to be evidence of migratory activity, possibly associated with animals congregating as a defence against predators.  Although, it is difficult to draw conclusions about the behaviour of organisms from fossil evidence.

A Model of a Trilobite

CollectA Redlichia rex trilobite model.

Professor Siveter added:

“The simplest explanation is that what we are seeing is reflecting some sort of migration.  The spiny lobster is one example of this sort of migratory behaviour seen amongst modern arthropods.  These lobsters join together in a kind of ‘train’ with the antennae of one animal sometimes touching the tail of the animal in front. However, the animals represented by the Chinese fossils are much more closely interlocked – they formed ‘chains’ rather than ‘trains’’’.

“This amazingly rich period in the history of life saw the appearance of more or less all the major groups of animals that provide the biodiversity we see around us today.” continued Professor Siveter.

“This find demonstrates that the creatures in our seas 525 million years ago were far from primitive, in fact they were complex organisms exhibiting some very sophisticated behaviour”.

The Yunnan Province will probably yield more amazing discoveries in years to come, providing scientists with a unique insight into an ancient world that existed over 500 million years ago.