Tag Archives: sauropod

Fossil Friday: Australia’s largest known dinosaur identified after a decade of work

A newly-identified titanosaurus, christened Australotitan cooperensis, is one of the 15 largest dino species we’ve ever found. And, so far, it seems to be the largest one ever uncovered in Australia.

Image credits Queensland Museum.

According to estimations from experts, this “southern titan” could likely grow up to 6.5m (21ft) tall and 30m (98.5ft) long, which Google tells me is just a tad longer than a basketball court. Its fossil was discovered on a farm in southwest Queensland almost one decade ago, and paleontologists spent all that time trying to distinguish it from other known species, mostly by comparing scans of it to the bones of known sauropods.

Big-boned down under

The sauropods were a lineage of plant-eating dinosaurs that grew to awesome proportions. Their bulky bodies were fleshed out with very long necks and tails, thin, somewhat stumpy legs, and quite small heads (relative to their overall size). They lived during the Cretaceous period, between 92 to 96 million years ago, and were probably the largest animals to ever walk on dry land.

The new species was christened Cooper (cooperensis means ‘of/from Cooper’ in Latin) for the area where it was unearthed: Cooper Creek. The remote location of this site, as well as the impressive size of the fossils themselves and their condition, made the identification process that much longer. They were unearthed in 2007 on a family farm near Cooper Creek, Eromanga, Australia, on a family farm owned by two of the authors of this paper, Robyn and Stuart Mackenzie.

Artist’s impression of what the dino looked like. Image credits Queensland Museum.

However, enough of the bones were found intact for researchers at the Queensland Museum and the Eromanga Natural History Museum to study and reliably identify.

It is closely related to three known sauropod species: the Wintonotitan, Diamantinasaurus, and Savannasaurus. This would mean that Australia’s largest dinosaur is, appropriately, part of one big family of big animals.

“It’s amazing to think from the first bones discovered by our son, the first digs with the Queensland Museum, through to the development of a not-for-profit museum that runs annual dinosaur digs, all have helped us to get to this point, it’s a real privilege,” Stuart Mackenzie said.

“Australia is one of the last frontiers for dinosaur discovery and Queensland is quickly cementing itself as the palaeo-capital of the nation – there is still plenty more to discover,” said Dr Jim Thompson, chief executive of the Queensland Museum Network.

The paper “A new giant sauropod, Australotitan cooperensis gen. et sp. nov., from the mid-Cretaceous of Australia” has been published in the journal PeerJ.

Global warming cleared the way for long-necked giant dinosaurs during the Jurassic

Illustration of Diplodocus. Credit: Pikrepo.

With their long necks, bulging bodies, and long tails, you had to be blind to not notice a sauropod. These were the largest creatures to ever walk on land — some reaching towering heights of 12 meters (40 feet) — but how they managed to grow to such stupendous scale, outcompeting all other herbivores, has always been a matter of great debate among paleontologists. A new study suggests the timeline of sauropod expansion of range and growth in size corresponds with a major extinction triggered by volcanic eruptions in the Early Jurassic.

How some dinosaurs got their long necks

Earth has been no stranger to global cataclysms that wipe out countless species. Over the last half-billion years there have been five major wipeouts, known as mass extinctions, in which well over half of all living creatures disappeared within a geological blink of the eye. Between these major wipeouts, there were minor extinction episodes, such as the Toarcian Oceanic Anoxic Event, during which a series of carbon dioxide-rich volcanic eruptions plunged the world into global warming roughly 182 million years ago.

Similar to human activity today, the Early Jurassic eruptions introduced excess carbon dioxide into the atmosphere, which made the oceans more acidic, thereby causing a mass extinction of marine life. Although plants have a reputation for being a carbon sink, during that time terrestrial ecosystems were dominated by ferns, cycads, and ginkgoes, which didn’t do too well in the now arid, warmer climate. Instead, the shift in climate proved ideal for conifers, which flourished.

However, only animals tall enough to reach the conifers and with stomachs tough enough to digest the spiny leaves could access the nutritional source. One such creature must have been Bagualia alba, a five-ton heavyweight herbivore and the earliest eusauropod, or “true sauropod”, found to date.

B. alba‘s fossils were described by Argentinian paleontologists for the first time in a study published today in the journal Proceedings of the Royal Society B. The fossils, including a partial skull of the ancient giant, were unearthed in the Cañadón Asfalto Basin in Argentina. They suggest B. alba had similar characteristics to famous sauropods like diplodocus and brontosaurus, such as large legs, long necks relative to the body, thick, spoon-shaped teeth, and broad, strong jaws.

During the Early Jurassic, plant-eating sauropods competed with other herbivores, including members of their own clade with less powerful jaws and shorter necks. It has always been unclear why eusauropods grew in leaps and bounds, but now we have a very reasonable explanation — the new fossils show that the Toarcian Oceanic Anoxic Event provided the perfect storm for the dawn of the long-necked sauropods.

According to the authors of the study, this is the first time that the availability of ancient plants have been linked with the evolutionary development of a dinosaur that included them in their diet.

“We show that eusauropod dominance was established after a massive magmatic event impacting southern Gondwana (180–184 Ma) and coincided with severe perturbations to the climate and a drastic decrease in the floral diversity characterized by the rise of conifers with small scaly leaves. Floral and faunal records from other regions suggest these were global changes that impacted the terrestrial ecosystems during the Toarcian warming event and formed part of a second-order mass extinction event,” wrote the researchers from the Museum of Paleontology Egidio Feruglio in Trelew, Argentina.

Scientists reconstruct the brain of one of the oldest dinosaurs in unprecedented detail

 Artist impression of the skull and brain of the sauropodomorph. Credit: Márcio L. Castro and Rodrigo Temp Müller.

Evolution can oftentimes be unpredictable. Around 230 million years ago, a dog-sized meat-eating dinosaur by the name of Buriolestes schultzi roamed Brazil’s forests. A hundred million years later, this small dinosaur’s cousins, such as Diplodocus and Brachiosaurus, grew to sizes spanning tens of meters in length and could weigh over 100 tons.

In many lineages, relative brain size tends to increase with time — but not in this case. According to paleontologists who performed one of the most accurate brain reconstructions of a dinosaur to date, Buriolestes schultzi‘s brain weighed approximately 1.5 grams or as much as a pea. Its humongous four-legged cousins’ brains, however, were no larger than a tennis ball, much smaller than you’d expect for their size.

The 3D reconstruction was based on three skulls unearthed by Dr. Rodrigo Temp Müller, a Brazilian paleontologist from the Universidade Federal de Santa Maria. Along with colleagues from the Universidade de São Paulo, the researchers employed computed tomography (CT) to draw inferences about the ancient dinosaur’s brain from the cavity left behind.

Buriolestes schultzi brain. Credit: Márcio L. Castro.

The small Jurassic carnivore was one of the earliest dinosaurs, and this shows in its primitively-shaped brain, which resembles the morphology of the crocodile brain.

However, Buriolestes had well-developed brain structures in the cerebellum, indicating superior abilities to track moving prey. It likely hunted using its eyes more than its nostrils, seeing how the olfactory bulb was relatively small, suggesting that smell wasn’t all that important. Conversely, olfactory bulbs grew to become very large in later sauropods and other closely related giant dinosaurs.

A strong sense of smell is associated with complex social behavior in many species. Alternatively, olfactory capabilities play an important role in foraging, and helping herbivores to distinguish between digestible and indigestible plants.

In time, Buriolestes transitioned to a plant-eating diet, which explains why its brain-to-body size ratio actually decreased. Carnivorous animals generally need more cognitive power in order to detect prey, as well as other predators. For slow-moving sauropods, brainpower wasn’t at such a premium.

Indeed, when the researchers calculated Buriolestes schultzi cognitive capability based on its brain volume and body weight, they found higher values than those seen in giant sauropods. However, the cognitive value was lower than that of theropod dinosaurs, suggesting that Buriolestes wasn’t smarter than T. rex or Velociraptor.

Our knowledge of very early dinosaurs is lacking, most paleontologists agree. This is why this study is so important, offering a rare window into the evolution of the brain and sensory systems of one of the earliest dinosaurs, and later some of the largest animals ever to walk on land.

The findings appeared in the Journal of Anatomy.

Huge dinosaurs evolved cooling systems to escape heat stroke

Growing big has its advantages — like escaping those nasty predators — but it also brings new problems. For giant dinosaurs, dealing with overheating was a massive issue, but they managed to overcome it by developing specialized cooling systems.

Detail of a painting of an Upper Jurassic scenery showing a sauropod. Credits: Gerhard Boeggemann.

Dinosaurs were an extremely varied group, and size is one regard in which their variability went off the charts. Some dinosaurs were as small as hummingbirds, weighing only a few grams, while others could weight as much as 100 tons.

Sauropods were the largest and heavier dinosaurs — larger than everything else in their ecosystem, and an order of magnitude more massive than anything that ever walked the Earth until them.

There are several advantages to growing this much. For starters, you can simply outgrow predators, and become too big for predation. Secondly, you can also use energy more efficiently, and also gain significant longevity. But there are a few issues to overcome too. Thermal inertia is such an issue.

“Small dinosaurs could have just run into the shade to cool off,” said study co-author Professor Lawrence Witmer, “but for those giant dinosaurs, the potential for overheating was literally inescapable. They must have had special mechanisms to control brain temperature, but what were they?”

Different dinosaur groups had different physiological strategies to deal with high heat loads in the brain. Small-bodied dinosaurs had a balanced pattern of blood supply with no particular emphasis on any one site of heat exchange whereas larger-bodied dinosaurs had a more focused thermal strategy, emphasizing blood flow to different parts of the head. Credits: Courtesy of WitmerLab at Ohio University.

If you want to cool down, one of the best things you can do is use evaporation. It’s what many creatures do through sweat, and it’s also what air conditioning units do. This process is particularly important around the head, where some of the most sensitive organs (like the brain and eyes) lie. Chemical analyses of fossil sauropod teeth previously suggested that, despite their massive bodies, the animals maintained body temperatures similar to those of modern mammals, so we know that they were successful in their thermoregulation.

“The brain and sense organs like the eye are very sensitive to temperature,” said Ruger Porter, Assistant Professor of Anatomical Instruction and lead author of the study. “Animals today often have elaborate thermoregulatory strategies to protect these tissues by shuttling hot and cool blood around various networks of blood vessels. We wanted to see if dinosaurs were doing the same things.”

In order to see how this process took place, researchers looked at blood vessels — the body’s natural cooling system. Thankfully for the researchers, blood vessels basically inscribe themselves into bones and well-preserved fossils can reveal the ridges associated with blood vessels.

Credits: Courtesy of WitmerLab at Ohio University.

The team started out with carcasses of birds and reptiles, using CT scans to trace blood flow from sites of evaporative cooling to the brain. They also measured the bony canals and grooves that conveyed the blood vessels. They were then able to take what they’ve learned from this process and adapt it to information from dinosaur fossils. They found that different dinosaurs used different cooling strategies.

“The discovery that different dinosaurs cooled their brains in a variety of ways not only provides a window into the everyday life of dinosaurs, it also serves as an exemplar of how the physical constraints imposed by specific environmental conditions have shaped the evolution of this diverse and unique group,” said Sharon Swartz, a program director at the National Science Foundation, which funded the research. “Using a combination of technological innovation and biological expertise, these researchers were able to take a direct reading from the fossil record that provides new clues about how dinosaur skeletal form and function evolved.”

A key factor that decided how dinosaurs regulated their temperature was body size. Smaller dinosaurs had balanced blood flows, whereas larger dinosaurs favored blood flow to different parts of the head — the blood vessel patterns that researchers found goes way beyond what is necessary for simple nourishment. This unbalanced pattern allowed thermal strategies to be more focused, emphasizing one or more cooling regions.

For a while, the team also had a puzzling question. Most of the giant dinosaurs were herbivores, but large predators (such as the 10-ton Tyrannosaurus Rex) also existed — and the researchers’ analysis showed that they had a balanced vascular pattern, like the small dinosaurs.

“This finding had us scratching our heads until we noticed the obvious difference–theropods like Majungasaurus and T. rex had a huge air sinus in their snouts,” Witmer said. But the eureka moment came when the team found evidence that this antorbital air sinus was richly supplied with blood vessels. Witmer had previously shown that air circulated through the antorbital air sinus like a bellows pump every time the animal opened and closed its mouth.

“Boom! An actively ventilated, highly vascular sinus meant that we had another potential cooling region. Theropod dinosaurs solved the same problem…but in a different way,” concluded Witmer.

The team now wants to expand the research to other species of dinosaurs.

The study has been published in the journal Anatomical Record.

Huge sauropod bone discovered in France

There’s big bones, and then there’s this.

The city of Cognac in France is known for the drink named after it — but among the paleontology world, it’s also famous for something else. Close to the southwestern city lies one of the most productive dinosaur fossil sites in the world. Over 7,500 fossils, belonging to over 50 different species, have been found at the site since 2010, including some belonging to the largest animals that ever walked on land.

Paleontologists have been working on the site all summer, and they recently came across a bone buried in a thick layer of clay. Now, after it has been completely excavated, the bone confirmed the researchers’ hunch. The two-meter long femur at the Angeac-Charente site belonged to a sauropod.

Sauropods are a four-legged group of dinosaurs that were widespread in the late Jurassic era some 140 million years ago. They had very long necks, long tails, and small heads relative to the rest of the body. They were herbivorous and grew to enormous sizes.

“This is a major discovery,” Ronan Allain, a paleontologist at the National History Museum of Paris told Reuters. “I was especially amazed by the state of preservation of that femur.”

“These are animals that probably weighed 40 to 50 tonnes.”

It’s unclear just what type of sauropod this was, although further lab analysis will help clarify the issue. Nevertheless, the finding is spectacular — not only through its sheer size but also due to its excellent state of preservation. All fossils are fragile and tend to collapse, but fossils this large are especially vulnerable.

“We can see the insertions of muscles and tendons and scars. This is rare for big pieces which tend to collapse in on themselves and fragment,” Allain added.

Its excellent preservation is owed to a special environment. Angeac-Charente, now a vineyard, used to be a marsh, which offers an excellent fossilization environment.

A sauropod thigh bone found at the same site in 2010 was 2.2m long and weighed 500 kilos, according to local paper La Charente Libre. Other notable findings from the site include bones of stegosaurs and a herd of ostrich-like dinosaurs.

Giant African Titanosaur had a heart-shaped tail

 

 

Titanosaurs belonged to a group of dinosaurs called sauropods — the largest terrestrial creatures that ever roamed the Earth. But while most sauropods disappeared during the Late Cretaceous 100 million years ago, Titanosaurs thrived during that period. However, the early evolution of this group is not that well known because not many fossils have been discovered.

An illustration of two titanosaurs in their natural environment. Image credits: Mark Wutton.

This is where Mnyamawamtuka moyowamkia comes in. Its name is derived from Swahili for “animal of the Mtuka (with) a heart-shaped tail”, in reference to the name of the riverbed (Mtuka) in which it was discovered and due to the unique heart-shape of its tail bones. Mnyamawamtuka was first discovered in 2004 when parts of its skeleton were found high in a cliff wall overlooking the seasonally dry Mtuka riverbed in Tanzania. Excavations continued, at times requiring extreme dedication: often, the digging team was suspended by ropes or climbing gear over the wall. If the digging would have been delayed even by just a few years, erosion might have destroyed much of this skeleton.

Digging the skeleton required a lot of dedication. Image credits: Gorscak & O’Connor.

Researchers note that the finding is particularly important as it provides a much-needed puzzle piece in understanding Titanosaur evolution, as well as the general evolution of African fauna during the Cretaceous.

“Although titanosaurs became one of the most successful dinosaur groups before the infamous mass extinction capping the Age of Dinosaurs, their early evolutionary history remains obscure, and Mnyamawamtuka helps tell those beginnings, especially for their African-side of the story,” said lead author Dr. Eric Gorscak. “The wealth of information from the skeleton indicates it was distantly related to other known African titanosaurs, except for some interesting similarities with another dinosaur, Malawisaurus, from just across the Tanzania-Malawi border,” noted Dr. Gorscak.

An illustration depicting Mnyamawamtuka and the parts of its skeleton which have been uncovered. Image credits: Gorscak & O’Connor.

This isn’t the only important finding from the area. Among others, researchers have found evidence of two other titanosaurs (Shingopana songwensis and Rukwatitan bisepultus), a mammal-like crocodile (Pakasuchus kapilimai), evidence of the monkey-ape split, as well as early evidence of insect farming.

This new find also suggests a close relationship titanosaurs from Africa and South America — two continents which were joined together 180 million years ago.

“This new dinosaur gives us important information about African fauna during a time of evolutionary change,” said Judy Skog, a program director in the National Science Foundation’s Division of Earth Sciences, which funded the research. “The discovery offers insights into paleogeography during the Cretaceous. It’s also timely information about an animal with heart-shaped tail bones during this week of Valentine’s Day.”

Journal Reference: Gorscak E, O’Connor PM (2019) A new African Titanosaurian Sauropod Dinosaur from the middle Cretaceous Galula Formation (Mtuka Member), Rukwa Rift Basin, Southwestern Tanzania. PLoS ONE 14(2): e0211412. https://doi.org/10.1371/journal.pone.0211412

Artistic rendition of Lingwulong shenqi. Credit: Zhang Zongda.

‘Amazing dragon’ fossils in China rewrite the evolution of world’s most massive dinosaurs

The fossils of a newly discovered long-necked dinosaurs are forcing scientists to rethink the origins of one the most iconic dinosaur lineages.

Artistic rendition of Lingwulong shenqi. Credit: Zhang Zongda.

Artistic rendition of Lingwulong shenqi. Credit: Zhang Zongda.

Xing Xu and colleagues at the Chinese Academy of Sciences in Beijing examined the partial skeletons of as many ten individuals belonging to a new sauropod species. Sauropods were among the largest creatures to have ever walked Earth, a family of dinosaurs that includes Brontosaurus or Diplodocus.

The new species was named Lingwulong shenqi, which literally means “amazing dragon of Lingwu”, after the town near where it was found.

What’s special about this new dinosaur is that seems like it’s the oldest Diplodocoid found so far, pushing back the appearance of advanced sauropods by 15 million years. Diplodocoidea is a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like SupersaurusDiplodocusApatosaurus, and Amphicoelias.

Lingwulong wasn’t nearly as large as its most famous cousins, the largest individual identified by the Chinese researchers being about 18 meters (57 feet) long. Like most sauropods, the “amazing dragon” must have congregated in groups and stuck to a vegetarian diet. Because its neck wasn’t as long as other sauropods, scientists think that Lingwulong grazed on low- soft plants with its peg-like teeth.

Being the earliest member of its evolutionary family (Diplodocoidea), the dinosaur’s discovery in East Asia — which lived during a time when the region was still connected to other continents — will likely force palaeontologists to re-evaluate how sauropods appeared and evolved. Before this dinosaur was identified, the prevailing line of thought was that advanced sauropods first appeared in the late Jurassic and quickly spread throughout the planet. Now, it seems like these dinosaurs evolved earlier and spread slower than previously thought.

Neosauropod fossils have been found in North America, Europe, and eastern Africa, but until now, none were older than 160 million years old, nor was any found in Asia.

“The new discovery challenges conventional biogeographical ideas, and suggests that dispersal into East Asia occurred much earlier than expected,” the researchers wrote in the journal Nature Communications. “Moreover, the age of this new taxon indicates that many advanced sauropod lineages originated at least 15 million years earlier than previously realised, achieving a global distribution while Pangaea was still a coherent landmass.”

There are still many unexplored areas in China, which Xu and colleagues hope to investigate them in order to unravel the sauropod family tree even further.

 

Rare dinosaur footprint fossils give clues into a forgotten era

Around 170 million years ago, a group of long-necked sauropods was taking a stroll along a muddy, shallow lagoon in what is now the north-east coast of the Isle of Skye. Using a mixture of modern techniques and good old-fashioned paleontology, researchers have now found and analyzed these footprints, gaining new insight into this ancient period.

The Isle of Skye used to be a dinosaur haven. Image credits: Avery Ng.

Lying just off the coast of Scotland, the Isle of Skye has been inhabited since the Mesolithic period, and its rich history includes a time of Norse rule and a long period of domination by the legendary Clan MacLeod. But before that (way before that), it was a coastal lagoon inhabited by several species of dinosaur.

Researchers from the University of Edinburgh, Staffin Museum, and Chinese Academy of Sciences found 50 footprints in a tidal area at Brothers’ Point, in one of Skye’s numerous small peninsulae. In addition to numerous isolated footprints, researchers identified two pathways which feature footprints from both sauropods and therapods (older cousins of Tyrannosaurus Rex).

Sauropod footprint discovered in Scotland. Image credits: Paige dePolo.

The finding is particularly significant since the footprints have been dated to the mid-Jurassic. Middle Jurassic dinosaur fossils “are exceedingly rare, but new discoveries from the Isle of Skye, Scotland, are beginning to fill this gap,” researchers write. Paige dePolo, who led the study, commented:

“This tracksite is the second discovery of sauropod footprints on Skye. It was found in rocks that were slightly older than those previously found at Duntulm on the island and demonstrates the presence of sauropods in this part of the world through a longer timescale than previously known. This site is a useful building block for us to continue fleshing out a picture of what dinosaurs were like on Skye in the Middle Jurassic.”

Studying Skye isn’t easy — the site’s location in a tidal area made the task extremely difficult. Researchers had to use drone photographs to create a map of the site, in addition to a paired set of cameras and tailored software they used to model the tracks. This allowed the team to assess the shape and orientation of the toes, as well as the presence of claws

But it was well worth it. Skye has already yielded a trove of valuable findings and Dr. Steve Brusatte, of the University of Edinburgh’s School of GeoSciences, who led the field team, says there might be even more in store.

“The more we look on the Isle of Skye, the more dinosaur footprints we find. This new site records two different types of dinosaurs — long-necked cousins of Brontosaurus and sharp-toothed cousins of T. rex — hanging around a shallow lagoon, back when Scotland was much warmer and dinosaurs were beginning their march to global dominance,” said Brusatte.

Journal Reference: dePolo et al. A sauropod-dominated tracksite from Rubha nam Brathairean (Brothers’ Point), Isle of Skye, Scotland. https://doi.org/10.1144/sjg2017-016

The sauropod trackway excavated in Plagne, France. Credit: P. Dumas.

Long-necked sauropod made world’s longest dinosaur trackway

In 2009, paleontologists made headlines after they discovered the world’s largest dinosaur tracks in Plagne, a French village nestled in the Jura Mountains. Since then, scientists have been busy, carefully excavating the site where they uncovered more tracks. Together, the huge dinosaur prints form the longest sauropod trackway found thus far, sprawling over more than 150 meters (490 feet).

The sauropod trackway excavated in Plagne, France. Credit: P. Dumas.

The sauropod trackway excavated in Plagne, France. Credit: P. Dumas.

The initial sauropod prints were discovered by members of the Oyonnax Naturalists’ Society. Between 2010 and 2012, a team supervised by the Laboratoire de Géologie de Lyon explored a meadow covering three hectares. Eventually, the paleontologists learn that the footprints belonged to a 110-step trackway extending over 155 meters.

It was sauropods, the largest dinosaurs ever to have walked the Earth, that etched the trackway. Judging from the limestone layers onto which the trackway was embedded, paleontologists estimate the prints were formed 150 million years ago during the Early Tithonian Age of the Jurassic.

Everything about sauropods was over the top. They were large, four-legged, plant-eating dinosaurs which could grow to 30 meters (100 feet) in length and could weigh up to 50 tonnes. The only things ‘small’ about them were their unusually tiny heads relative to the body, with a comparably small brain.

The tracks excavated at Plagne were left by a sauropod with a foot span of 94 to 103 cm and a total length of up to 3 meters, including the mud ring displaced by each step. The prints are so well preserved that they still feature five distinct elliptical toe marks, while handprints are characterized by five circular finger marks arranged in an arc.

According to a biometric analysis, this sauropod was likely 35 meters long and weighed between 35 and 40 tonnes. Its average stride was 2.8 meters, inching along at a snail’s pace of 4 km/h. It belonged to a species called Brontopodus plagnensis. 

Artist’s impression of Plagne sauropod superimposed on its tracks. Credit: Illustration by A. Bénéteau; photo by Dinojura.

Artist’s impression of Plagne sauropod superimposed on its tracks. Credit: Illustration by A. Bénéteau; photo by Dinojura.

During this time, the region around Plagne looked quite different, sitting on a vast carbonate platform submerged in a warm and shallow sea. The presence of sauropods indicates the region was likely littered by many islands that offered ample vegetation to sustain the huge dinosaurs’ appetite. Land bridges that emerged when the sea level lowered connected these islands and offered animals, large and small, a corridor through which they could migrate.

How some dinosaurs got enormously long necks

The longest creatures to ever walk the Earth were the long-necked, long-tailed dinosaurs known as the sauropods. But why did these huge vegetarians grow such huge necks, reaching up to 15 meters? That’s six times longer than that of the current world-record holder, the giraffe.

 

“They were really stupidly, sauropodabsurdly oversized,” said researcher Michael Taylor, a vertebrate paleontologist at the University of Bristol in England. “In our feeble, modern world, we’re used to thinking of elephants as big, but sauropods reached 10 times the size elephants do. They were the size of walking whales.”

The secret, according to him and his team was mostly hollow neck bones. To find out just how sauropod necks could get so long, scientists analyzed other long-necked creatures and compared sauropod anatomy to that of their closest living relatives – birds and crocodiles.

“Extinct animals — and living animals, too, for that matter — are much more amazing than we realize,” Taylor explained. “Time and again, people have proposed limits to possible animal sizes, like the five-meter (16-foot) wingspan that was supposed to be the limit for flying animals. And time and again, they’ve been blown away. We now know of flying pterosaurs with 10-meter (33-foot) wingspans. And these extremes are achieved by a startling array of anatomical innovations.”

Unsurprisingly, Taylor and his colleagues found several adaptations that supported long necks. The most notable feature was that air often made up 60 percent of these animals’ necks, with some of them as light as birds bones, making it easier to support the giant lengths. The muscles, ligaments and tendons were also positioned in a way that helped maximize leverage, making neck movements more efficient. Furthermore, their giant torsos and four-legged stances helped provide a stable platform for their necks; in contrast, giraffes have really small torsos compared to the rest of their bodies. The number of vertebrae was also important: while most mammals (with the exception of the sloths and manatees) have maximum 7 vertebrae in their necks, sauropods had 19 (which is still not that much comparing the sizes).

sauropod2

Another interesting fact which enabled them to grow such big necks was their small head size; sauropods didn’t even had cheeks to store food for chewing. As a matter of fact, they didn’t even chew food, they just swallowed it and let the gut digest it.

“Sauropod heads are essentially all mouth. The jaw joint is at the very back of the skull, and they didn’t have cheeks, so they came pretty close to having Pac Man-Cookie Monster flip-top heads,” researcher Mathew Wedel at the Western University of Health Sciences in Pomona, Calif., explained. “It’s natural to wonder if the lack of chewing didn’t, well, come back to bite them, in terms of digestive efficiency. But some recent work on digestion in large animals has shown that after about 3 days, animals have gotten all the nutrition they can from their food, regardless of particle size. And sauropods were so big that the food would have spent that long going through them anyway,” Wedel said. “They could stop chewing entirely, with no loss of digestive efficiency.”

But the question remains: why did they evolve like this? Well, there’s no clear answer so far, but there are three theories: either to reach leaves from high trees, either to graze large portions of vegetations by sweeping, with lower effort or… because it made them more sexually attractive. Taylor’s research however, didn’t provide an answer for this question.

sauropod

Large dinosaurs used to migrate across vast distances

sauropodThe art of science is most evident when one manages to accurately assert truths about a given fact with little information provided. A great scientists knows how to properly churn information, turn it over a million sides and correlate it with other related facts to form a clear picture. It’s incredible for instance how astronomers are able to image a whole galaxy or even map the universe only by observing light or radio waves – this astonishes me every time. Maybe not as spectacular, but nevertheless worthy of praise for their investigation, paleontologists claim that the large dinosaurs that once roamed the grate planes of the ancient world  used to travel for great distances, basing their assumption on nothing more than the information provided by tooth analysis.

Simply by analyzing 32 fossilized teeth belonging to two sub-species of the Camarasaurus, excavated from Wyoming and Utah, the researchers were able to tell that these giant sauropods used to embark on long and arduous journeys, some 300 kilometers in any given direction. These giant beasts could grow as large 20 meters in length and 18 tonnes in weight, which caused the food supplies to rapidly deplete around them, and in term required them to migrate far and long in search for other supplies.

“The question of how sauropods got to be so big is one that is still being actively studied. There’s evidence that some of the reason is that they didn’t have the dental morphology to chew their food, so in order to get enough energy their guts got bigger, and they did more processing in their stomachs,” said Henry Fricke, head of geology at Colorado College in Colorado Springs, who led the study.

“Migration could come into the story of gigantism as a feedback process. Once they started to get big, it would be easier for them to migrate and get more food more consistently, which would help them to grow even more,” he added. Moving long distances gets more energetically efficient the bigger strides a creature can take, so it would be highly inefficient for a mouse, for example, but much more efficient for a large dinosaur

An epic Jurassic journey

The team of researchers were able to reconstruct the dinosaurs’ migration patterns by analyzing the  oxygen isotopes found in the fossilized teeth. Oxygen isotopes found in the water they consumed was incorporated in layers of enamel as their teeth developed, however the isotopes are different depending on the water source. The researchers found 2 distinct discrepancies in the oxygen isotopes levels, which they compared with ancient soil samples from their lowland habitats and bordering uplands.

Fricke and his team were thus able to piece together the facts and conclude the sauropods used to migrate for several months each year, in a seasonally fashion. Most of the dinosaurs were pushed to the limit by this extremely long journey, with many not surviving the trip back home.

“What was up in the highlands food-wise we don’t know, the land is weathered away, but the conditions may not have been as hot and dry, and it may even have rained more continuously at the higher elevations,” Fricke said.

“This is a neat example of how we can bring geochemical methods to bear on an issue, how we can learn something about dinosaur behaviour that we can’t learn from looking at the morphology of the fossils themselves,” he added.

The study was published in the journal Nature.

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The fossilized titanosaur egg reveals the sausage-shaped structures that are likely preserved wasp cocoons. Coin added for scaling purposes. (c) Jorge Genise

Ancient wasps used to grow inside rotting dinosaur eggs

The fossilized titanosaur egg reveals the sausage-shaped structures that are likely preserved wasp cocoons. Coin added for scaling purposes. (c) Jorge Genise

The fossilized titanosaur egg reveals the sausage-shaped structures that are likely preserved wasp cocoons. Coin added for scaling purposes. (c) Jorge Genise

A recent discovery made by Argentinian paleontologist uncovered wasp cocoons hidden inside the 70 million year old fossilized egg of a titanosaur sauropod, suggesting that these ancient wasps used to dwell, consume and breed inside of them.

The find was made after researchers carefully analyzed one of the five titanosaur eggs uncovered back in 1989 in the Patagonia region of Argentina, and saw that  one of the broken eggs contained tiny sausage-shaped structures. These structures were an inch long and 0.3 inches wide, making them a perfect match for the shape of a wasp cocoon, namely the  Cretaceous wasp Rebuffoichnus sciuttoi, researchers believe.

Titanosaur was the largest creature to have ever walked the Earth, and while fossils of its eggs and that of wasp cocoons have been found before in considerate numbers, this is the first time they’ve been found together, suggesting a new relationship in the ancient ecosystem.

Diagram showing titanosaur nest excavation and egg laying

Diagram showing titanosaur nest excavation and egg laying

The wasps weren’t responsible for the damage of the eggs, however – they were too small and weak to break the thick titanosaur egg shell. Analyzing the various fractures in the eggshell, as well as other preserved insects found inside the egg, paleontologists theorize that it was open by force by some dinosaur scavenger who would’ve sucked its content dry. A second wave of creatures, likely ancient spiders, then came to dine on the now rotting egg, before finally the wasps attacked the spiders or even the initial scavengers. They would’ve then laid their eggs inside their targets’ bodies. The wasp offspring then spun their cocoons inside the rotting egg.

“Some cocoons have a truncated end that indicate the emergence of adult wasps,” study researcher Laura Sarzetti, of the Museo Argentino de Ciencias Naturales, told LiveScience.

“The presence of wasps, which are at the top of carrion food web[s], suggests that a complex community of invertebrates would have developed around rotting dinosaur eggs,” the researchers write in the journal article.

Now, although the bugs profited off the death of this particular egg, the critters were probably key in keeping titanosaur nests clean overall, added co-author Laura Sarzetti, another entomologist at the museum. For many dinosaurs, egg laying sites were kept in the same relative position for generations, and as such a cleansing of the decaying material left over from previous hatching was extremely important.

The newfound fossil cocoons are described in the July issue of the journal Palaeontology.

Dinosaurs were as warm blooded as today’s mammals

Were dinosaurs slow and lazy, as you see most reptiles today, or active and quick like you see them in the movies? It pretty much depends on their body temperature – if they are cold blooded or not.

The kingdom of T-Rex

It seemed to be a no-brainer that dinosaurs are cold blooded, relying on a very warm environment to survive, and active only a few hours a day. However, more recent research conducted in the past few decades seems to suggest that dinosaurs were much more nimble, like the velociraptor, or even downright fast – like T-Rex. Such feats would require a blood temperature close to that of today’s mammals.

Dinosaurs were an incredibly diverse group of animals that ruled the Earth for some 160 million years, until the great extinction that took place 65 million years ago; considering the fact that we’ve started imposing ourselves as a species some 50.000 years ago, that’s definitely something worth thinking about.

A new approach

It’s pretty amazing to see how many things you can find out about creatures that lived 100 million years ago, if you use modern science and a creative approach. CalTech researchers did just this, analyzing isotopic concentrations in teeth of sauropods, dinosaurs believed to be the biggest land animals to have ever lived, with huge long necks, the team found that the body temperature of dinosaurs was similar to that of modern day animals.

Depiction of size of sauropods relative to a human

“This is like being able to stick a thermometer in an animal that has been extinct for 150 million years,” says Robert Eagle, a postdoctoral scholar at Caltech and lead author on the paper to be published online in the June 23 issue of Science Express.

If their analysis is correct, it’s indeed groundbreaking, shattering a general consensus that measuring dinosaur body temperatures would be impossible.

“The consensus was that no one would ever measure dinosaur body temperatures, that it’s impossible to do,” says John Eiler, a coauthor and the Robert P. Sharp Professor of Geology and professor of geochemistry. And yet, using a technique pioneered in Eiler’s lab, the team did just that

The team analyzed 11 teeth, coming from different parts of the world, including Tanzania and Wyoming, belonging to Brachiosaurus brancai and Camarasaurus. They found that the Brachiosaurus had a temperature of about 38.2 degrees Celsius (100.8 degrees Fahrenheit) and the Camarasaurus had one of about 35.7 degrees Celsius (96.3 degrees Fahrenheit). This is pretty close to human body temperature (36.8 degrees Celsius), warmer than crocodiles and aligators and cooler than birds.

“Nobody has used this approach to look at dinosaur body temperatures before, so our study provides a completely different angle on the longstanding debate about dinosaur physiology,” Eagle says.

Isolated cases, or a general rule ?

The research seems to indicate quite clearly that dinosaurs were warm blooded, thus indicating a warm blooded metabolism, but the issue itself is much more complex. Because sauropods were so huge, they could retain body heat much more efficiently than humans or smaller reptiles.

“If you’re an animal that you can approximate as a sphere of meat the size of a room, you can’t be cold unless you’re dead,” Eiler explains.

So even if you depend on your environment’s heat to survive (which is what reptiles and lizards do), it is still possible to have warm blood.

“The body temperatures we’ve estimated now provide a key piece of data that any model of dinosaur physiology has to be able to explain,” says Aradhna Tripati, a coauthor who’s an assistant professor at UCLA and visiting researcher in geochemistry at Caltech. “As a result, the data can help scientists test physiological models to explain how these organisms lived.”

There are also other matters to take into consideration, mainly the theory of gigantotherms, which implies that dinosaurs maintained high body temperatures simply by being so big, and that they even had to have some cooling mechanism, to prevent them from becoming too hot. They would probably have had lower metabolic rates to reduce the amount of internal heat, especially as large adults. But still, the method is revolutionary, and can be applied to virtually any species, so we will definitely be getting more results for more, smaller species of dinosaurs.

“What we’re doing is special in that it’s thermodynamically based,” Eiler explains. “Thermodynamics, like the laws of gravity, is independent of setting, time, and context.” Because thermodynamics worked the same way 150 million years ago as it does today, measuring isotope clumping is an extrem powerful technique, that can be applied for any setting.