New light shed on behavior of giant carnivorous dinosaur Spinosaurus
New research from Queen Mary University of London and the University of Maryland, has reignited the debate around the behaviour of the giant dinosaur Spinosaurus.
Since its discovery in 1915, the biology and behaviour of the enormous Spinosaurus has puzzled palaeontologists worldwide. It was recently argued that the dinosaur was largely an aquatic predator, using its large tail to swim and actively pursue fish in the water.
The new study, published today in Palaeontologia Electronica, challenges this recent view of Spinosaurus suggesting that whilst it likely fed from the water, and may have swum, it wasn’t well adapted to the life of an aquatic pursuit predator. Instead it was like a giant (if flightless) heron or stork — snatching at fish from the shoreline while also taking any other small available prey on land or in water.
The researchers compared the features of Spinosaurus with the skulls and skeletons of other dinosaurs and various living and extinct reptiles that lived on land, in the water or did both. They found that whilst there were several pieces of evidence that contradicted the aquatic pursuit predator concept, none contradicted the wading heron-like model, and various lines of evidence actively supported it.
Dr David Hone, Senior Lecturer at Queen Mary and lead author on the project said: “The biology and ecology of Spinosaurus has been troubling palaeontologists for decades. Some recent studies have suggested that it was actively chasing fish in water but while they could swim, they would not have been fast or efficient enough to do this effectively. Our findings suggest that the wading idea is much better supported, even if it is slightly less exciting.”
Co-author Tom Holtz, Principal Lecturer in Vertebrae Paleontology, University of Maryland, said: “Spinosaurus was a bizarre animal even by dinosaur standards, and unlike anything alive today, so trying to understand its ecology will always be difficult. We sought to use what evidence we have to best approximate its way of life. And what we found did not match the attributes one would expect in an aquatic pursuit predator in the manner of an otter, sea lion, or short-necked plesiosaur.”
One of the key pieces of evidence unearthed by the researchers related to the dinosaur’s ability to swim. Spinosaurus was already shown to be a less efficient swimmer than a crocodile, but also has fewer tail muscles than a crocodile, and due to its size would have a lot more drag in the water.
Dr Hone said: “Crocodiles are excellent in water compared to land animals, but are not that specialised for aquatic life and are not able to actively chase after fish. If Spinosaurus had fewer muscles on the tail, less efficiency and more drag then it’s hard to see how these dinosaurs could be chasing fish in a way that crocodiles cannot.”
Dr Holtz added: “We certainly add that the evidence points to Spinosaurus feeding partly, even mostly, in the water, probably more so than any other large dinosaur. But that is a different claim than it being a rapid swimmer chasing after aquatic prey.” Though as Dr Hone concludes: “Whilst our study provides us with a clearer picture of the ecology and behaviour of Spinosaurus, there are still many outstanding questions and details to examine for future study and we must continue to review our ideas as we accumulate further evidence and data on these unique dinosaurs. This won’t be the last word on the biology of these amazing animals.”
Originally found in Egypt, Spinosaurus is thought to be one of the largest carnivorous dinosaurs to exist probably reaching over 15 m in length. The first known Spinosaurus fossils were destroyed by Allied bombing during World War II, which has hampered palaeontologist’s attempts to understand these unusual creatures. More recently the dinosaur found fame in the 2001 film Jurassic Park III, where it battles and defeats a Tyrannosaurus rex.
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Journal Reference:
- David Hone, Thomas Holtz. Evaluating the ecology of Spinosaurus: shoreline generalist or aquatic pursuit specialist? Palaeontologia Electronica, 2021; DOI: 10.26879/1110
New skull of tube-crested dinosaur reveals evolution of bizarre crest
The first new skull discovered in nearly a century from a rare species of the iconic, tube-crested dinosaur Parasaurolophus was announced today in the journal PeerJ. The exquisite preservation of the skull, especially the bizarre tube-shaped nasal passage, finally revealed the structure of the crest after decades of disagreement.
Despite its extreme morphology, details of the specimen show that the crest is formed much like the crests of other, related duckbilled dinosaurs. Joe Sertich, curator of dinosaurs at the Denver Museum of Nature & Science and the leader of the team who discovered the specimen said, “This specimen is a wonderful example of amazing creatures evolving from a single ancestor.”
“Imagine your nose growing up your face, three feet behind your head, then turning around to attach above your eyes. Parasaurolophus breathed through eight feet of pipe before oxygen ever reached its head,” said Terry Gates, a paleontologist from North Carolina State University.
“Over the past 100 years, ideas for the purpose of the exaggerated tube crest have ranged from snorkels to super sniffers,” noted David Evans, the Temerty Chair in Vertebrate Palaeontology and Vice President of Natural History at the Royal Ontario Museum. “But after decades of study, we now think these crests functioned primarily as sound resonators and visual displays used to communicate within their own species.”
Among the most recognizable dinosaurs, the duckbilled Parasaurolophus sported an elongate, tube-like crest on its head containing an internal network of airways. Three species of Parasaurolophus are currently recognized, ranging from Alberta to New Mexico in rocks dating between 77 and 73.5 million years old. The new skull belongs to Parasaurolophus cyrtocristatus, previously known from a single specimen collected in the same region of New Mexico in 1923 by legendary fossil hunter Charles H. Sternberg. Both specimens display a shorter, more curved crest than other species, a feature that may be related to their immaturity at death.
The partial skull was discovered in 2017 by Smithsonian Ecology Fellow Erin Spear, Ph.D., while exploring the badlands of northwestern New Mexico as part of a Denver Museum of Nature & Science team. Located deep in the Bisti/De-Na-Zin Wilderness of New Mexico, only a tiny portion of the skull was visible on a steep sandstone slope. Museum volunteers led by Sertich were surprised to find the intact crest as they carefully chiseled the specimen from the sandstone. Abundant bone fragments at the site indicated that much of the skeleton may have once been preserved on an ancient sand bar, but only the partial skull, part of the lower jaw, and a handful of ribs survived erosion.
Today, the badlands of northwestern New Mexico are dry and sparsely vegetated, a dramatic contrast to the lush lowland floodplains preserved in their rocks. 75 million years ago, when Parasaurolophus lived in the region, North America was divided into two landmasses by a broad seaway. Laramidia, the ribbon of land to the west, extended from today’s Alaska to central Mexico, hosting multiple episodes of mountain building in early stages of the construction of today’s Rocky Mountains. These mountain-building events helped preserve diverse ecosystems of dinosaurs along their eastern flanks, some of the best-preserved and most continuous anywhere on Earth. Parasaurolophus shared lush, subtropical floodplains with other, crestless duckbilled dinosaurs, a diverse array of horned dinosaurs, and early tyrannosaurs alongside many emerging, modern groups of alligators, turtles and plants.
“The preservation of this new skull is spectacular, finally revealing in detail the bones that make up the crest of this amazing dinosaur known by nearly every dinosaur-obsessed kid,” said Sertich. “This just reinforces the importance of protecting our public lands for scientific discoveries.”
“My jaw dropped when I first saw the fossil,” said Gates. He continued, “I’ve been waiting for nearly 20 years to see a specimen of this quality.”
“This specimen is truly remarkable in its preservation,” said Evans, who has also worked on this iconic dinosaur for almost two decades. “It has answered long-standing questions about how the crest is constructed and about the validity of this particular species. For me, this fossil is very exciting.”
For decades, the family tree of Parasaurolophus placed the two long, straight-crested species of Parasaurolophus (P. walkeri from Alberta and P. tubicen from younger rocks in New Mexico) as most closely related despite being separated by more than 1,000 miles (1,600 km) and 2.5 million years. Analysis of additional features of the skull excluding the crest, together with information from other Parasaurolophus discoveries from southern Utah, suggest for the first time that all of the southern species from New Mexico and Utah may be more closely related than they are to their northern cousin. This fits patterns observed in other dinosaur groups of the same age, including horned dinosaurs.
The research was funded by the Denver Museum of Nature & Science through generous donations to the Laramidia Project. The paper describing the new skull of Parasaurolophus appears in the January 25, 2021, release of the journal PeerJ.
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Journal Reference:
- Terry A. Gates, David C. Evans, Joseph J.W. Sertich. Description and rediagnosis of the crested hadrosaurid (Ornithopoda) dinosaur Parasaurolophus cyrtocristatus on the basis of new cranial remains. PeerJ, 2021; 9: e10669 DOI: 10.7717/peerj.10669
Dinosaur embryo find helps crack baby tyrannosaur mystery
They are among the largest predators ever to walk the Earth, but experts have discovered that some baby tyrannosaurs were only the size of a Border Collie dog when they took their first steps.
The first-known fossils of tyrannosaur embryos have shed light on the early development of the colossal animals, which could grow to 40 feet in length and weigh eight tonnes.
A team of palaeontologists, led by a University of Edinburgh researcher, made the discovery by examining the fossilised remains of a tiny jaw bone and claw unearthed in Canada and the US.
Producing 3D scans of the delicate fragments revealed that they belonged to baby tyrannosaurs — cousins of T. rex — which, based on the size of the fossils, were around three feet long when they hatched.
The team’s findings suggest that tyrannosaur eggs — the remains of which have never been found — were around 17 inches long. This could aid efforts to recognise such eggs in the future and gain greater insights into the nesting habits of tyrannosaurs, researchers say.
The analysis also revealed that the three-centimetre-long jaw bone possesses distinctive tyrannosaur features, including a pronounced chin, indicating that these physical traits were present before the animals hatched.
Little is known about the earliest developmental stages of tyrannosaurs — which lived more than 70-million-years-ago — despite being one of the most studied dinosaur families. Most tyrannosaur fossils previously studied have been of adult or older juvenile animals.
The study, published in the Canadian Journal of Earth Sciences, was supported by the Royal Society, Natural Sciences and Engineering Research Council of Canada, and National Science Foundation. It also involved researchers from the Universities of Alberta and Calgary, Canada, and Montana State and Chapman Universities, US.
Dr Greg Funston, of the University of Edinburgh’s School of GeoSciences, who led the study, said: “These bones are the first window into the early lives of tyrannosaurs and they teach us about the size and appearance of baby tyrannosaurs. We now know that they would have been the largest hatchlings to ever emerge from eggs, and they would have looked remarkably like their parents — both good signs for finding more material in the future. “
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Journal Reference:
- Gregory F. Funston, Mark J. Powers, S. Amber Whitebone, Stephen L. Brusatte, John B. Scannella, John R. Horner, Philip J. Currie. Baby tyrannosaurid bones and teeth from the Late Cretaceous of western North America. Canadian Journal of Earth Sciences, 2021; 1 DOI: 10.1139/cjes-2020-0169
New starfish-like fossil reveals evolution in action
Researchers from the University of Cambridge have discovered a fossil of the earliest starfish-like animal, which helps us understand the origins of the nimble-armed creature.
The prototype starfish, which has features in common with both sea lilies and modern-day starfish, is a missing link for scientists trying to piece together its early evolutionary history.
The exceptionally preserved fossil, named Cantabrigiaster fezouataensis, was discovered in Morroco’s Anti-Atlas mountain range. Its intricate design — with feathery arms akin to a lacework — has been frozen in time for roughly 480 million years.
The new species is unusual because it doesn’t have many of the key features of its contemporary relatives, lacking roughly 60% of a modern starfish’s body plan.
The fossil’s features are instead a hybrid between those of a starfish and a sea lily or crinoid — not a plant but a wavy-armed filter feeder which fixes itself to the seabed via a cylindrical ‘stem’.
The discovery, reported in Biology Letters, captures the early evolutionary steps of the animal at a time in Earth’s history when life suddenly expanded, a period known as the Ordovician Biodiversification Event.
The find also means scientists can now use the new find as a template to work out how it evolved from this more basic form to the complexity of their contemporaries.
“Finding this missing link to their ancestors is incredibly exciting. If you went back in time and put your head under the sea in the Ordovician then you wouldn’t recognize any of the marine organisms — except the starfish, they are one of the first modern animals,” said lead author Dr Aaron Hunter, a visiting postdoctoral researcher in the Department of Earth Sciences.
Modern starfish and brittle stars are part of a family of spiny-skinned animals called the echinoderms which, although they don’t have a backbone, are one of the closest group of animals to vertebrates. Crinoids, and otherworldly creatures like the sea urchins and sea cucumbers are all echinoderms.
The origin of starfish has eluded scientists for decades. But the new species is so well preserved that its body can finally be mapped in detail and its evolution understood. “The level of detail in the fossil is amazing — its structure is so complex that it took us a while to unravel its significance,” said Hunter.
It was Hunter’s work on both living and fossil echinoderms that helped him spot its hybrid features. “I was looking at a modern crinoid in one of the collections at the Western Australian Museum and I realised the arms looked really familiar, they reminded me of this unusual fossil that I had found years earlier in Morocco but had found difficult to work with,” he said.
Fezouata in Morocco is something of a holy grail for palaeontologists — the new fossil is just one of the many remarkably well preserved soft-bodied animals uncovered from the site.
Hunter and co-author Dr Javier Ortega-Hernández, who was previously based at Cambridge’s Department of Zoology and is now based at Harvard University, named the species Cantabrigiaster in honour of the long history of echinoderm research at their respective institutions.
Hunter and Ortega-Hernández examined their new species alongside a catalogue of hundreds starfish-like animals. They indexed all of their body structures and features, building a road map of the echinoderm skeleton which they could use to assess how Cantabrigiaster was related to other family members.
Modern echinoderms come in many shapes and sizes, so it can be difficult to work out how they are related to one another. The new analysis, which uses extra-axial theory — a biology model usually only applied to living species — meant that Hunter and Ortega-Hernández could identify similarities and differences between the body plan of modern echinoderms and then figure out how each family member was linked to their Cambrian ancestors.
They found that only the key or axial part of the body, the food groove — which funnels food along each of the starfish’s arms — was present in Cantabrigiaster. Everything outside this, the extra-axial body parts, were added later.
The authors plan to expand their work in search of early echinoderms. “One thing we hope to answer in the future is why starfish developed their five arms,” said Hunter. “It seems to be a stable shape for them to adopt — but we don’t yet know why. We still need to keep searching for the fossil that gives us that particular connection, but by going right back to the early ancestors like Cantabrigiaster we are getting closer to that answer.”
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Materials provided by University of Cambridge. The original story is licensed under a Creative Commons License. Note: Content may be edited for style and length.
Journal Reference:
- Aaron W. Hunter, Javier Ortega-Hernández. A new somasteroid from the Fezouata Lagerstätte in Morocco and the Early Ordovician origin of Asterozoa. Biology Letters, 2021; 17 (1): 20200809 DOI: 10.1098/rsbl.2020.0809
All-purpose dinosaur opening reconstructed
For the first time ever, a team of scientists, led by the University of Bristol, have described in detail a dinosaur’s cloacal or vent — the all-purpose opening used for defecation, urination and breeding.
Although most mammals may have different openings for these functions, most vertebrate animals possess a cloaca.
Although we know now much about dinosaurs and their appearance as feathered, scaly and horned creatures and even which colours they sported, we have not known anything about how the vent appears.
Dr Jakob Vinther from the University of Bristol’s School of Earth Sciences, along with colleagues Robert Nicholls, a palaeoartist, and Dr Diane Kelly, an expert on vertebrate penises and copulatory systems from the University of Massachusetts Amherst, have now described the first cloacal vent region from a small Labrador-sized dinosaur called Psittacosaurus, comparing it to vents across modern vertebrate animals living on land.
Dr Vinther said: “I noticed the cloaca several years ago after we had reconstructed the colour patterns of this dinosaur using a remarkable fossil on display at the Senckenberg Museum in Germany which clearly preserves its skin and colour patterns.
“It took a long while before we got around to finish it off because no one has ever cared about comparing the exterior of cloacal openings of living animals, so it was largely unchartered territory.”
Dr Kelly added: “Indeed, they are pretty non-descript. We found the vent does look different in many different groups of tetrapods, but in most cases it doesn’t tell you much about an animal’s sex.
“Those distinguishing features are tucked inside the cloaca, and unfortunately, they’re not preserved in this fossil.”
The cloaca is unique in its appearance but exhibits features reminiscent to living crocodylians such as alligators and crocodiles, which are the closest living relatives to dinosaurs and other birds.
The researchers note that the outer margins of the cloaca are highly pigmented with melanin. They argue that this pigmentation provided the vent with a function in display and signalling, similar to living baboons and some breeding salamanders.
The authors also speculate that the large, pigmented lobes on either side of the opening could have harboured musky scent glands, as seen in living crocodylians.
Birds are one the few vertebrate groups that occasionally exhibit visual signalling with the cloaca, which the scientists now can extend back to the Mesozoic dinosaur ancestors.
Robert Nicholls said: “As a palaeoartist, it has been absolutely amazing to have an opportunity to reconstruct one of the last remaining features we didn’t know anything about in dinosaurs.
“Knowing that at least some dinosaurs were signalling to each other gives palaeoartists exciting freedom to speculate on a whole variety of now plausible interactions during dinosaur courtship. It is a game changer!”
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A new archaeology for the Anthropocene era
ndiana Jones and Lara Croft have a lot to answer for. Public perceptions of archaeology are often thoroughly outdated, and these characterisations do little to help.
Yet archaeology as practiced today bears virtually no resemblance to the tomb raiding portrayed in movies and video games. Indeed, it bears little resemblance to even more scholarly depictions of the discipline in the entertainment sphere.
A paper published today in Nature Ecology and Evolution aims to give pause to an audience that has been largely prepared to take such out-of-touch depictions at face value. It reveals an archaeology practiced by scientists in white lab coats, using multi-million-euro instrumentation and state of the art computers.
It also reveals an archaeology poised to contribute in major ways to addressing such thoroughly modern challenges as biodiversity conservation, food security and climate change.
“Archaeology today is a dramatically different discipline to what it was a century ago,” observes Nicole Boivin, lead author of the study and Director of the Institute’s Department of Archaeology. “While the tomb raiding we see portrayed in movies is over the top, the archaeology of the past was probably closer to this than to present-day archaeology. Much archaeology today is in contrast highly scientific in orientation, and aimed at addressing modern-day issues.”
Examining the research contributions of the field over the past few decades, the authors reach a clear conclusion — archaeology today has a great deal to contribute to addressing the challenges of the modern era.
“Humans in the present era have become one of the great forces shaping nature,” emphasizes Alison Crowther, coauthor and researcher at both the University of Queensland and the MPI Science of Human History. “When we say we have entered a new, human-dominated geological era, the Anthropocene, we acknowledge that role.”
How can archaeology, a discipline focused on the past, hope to address the challenges we face in the Anthropocene?
“It is clear that the past offers a vast repertoire of cultural knowledge that we cannot ignore,” highlights Professor Boivin.
The two researchers show the many ways that data about the past can serve the future. By analysing what worked and didn’t work in the past — effectively offering long-term experiments in human society — archaeologists gain insight into the factors that support sustainability and resilience, and the factors that work against them. They also highlight ancient solutions to modern problems.
“We show how researchers have improved the modern world by drawing upon information about the ways people in the past enriched soils, prevented destructive fires, created greener cities and transported water without fossil fuels,” notes Dr. Crowther.
People also continue to use, and adapt, ancient technologies and infrastructure, including terrace and irrigation systems that are in some cases centuries or even millennia old.
But the researchers are keen to highlight the continued importance of technological and social solutions to climate change and the other challenges of the Anthropocene.
“It’s not about glorifying the past, or vilifying progress,” emphasizes Professor Boivin. “Instead, it’s about bringing together the best of the past, present and future to steer a responsible and constructive course for humanity.”
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Materials provided by Max Planck Institute for the Science of Human History. Note: Content may be edited for style and length.
Journal Reference:
- Nicole Boivin, Alison Crowther. Mobilizing the past to shape a better Anthropocene. Nature Ecology & Evolution, 2021; DOI: 10.1038/s41559-020-01361-4
New flower from 100 million years ago
Oregon State University researchers have identified a spectacular new genus and species of flower from the mid-Cretaceous period, a male specimen whose sunburst-like reach for the heavens was frozen in time by Burmese amber.
“This isn’t quite a Christmas flower but it is a beauty, especially considering it was part of a forest that existed 100 million years ago,” said George Poinar Jr., professor emeritus in the OSU College of Science.
Findings were published in the Journal of the Botanical Research Institute of Texas.
“The male flower is tiny, about 2 millimeters across, but it has some 50 stamens arranged like a spiral, with anthers pointing toward the sky,” said Poinar, an international expert in using plant and animal life forms preserved in amber to learn more about the biology and ecology of the distant past.
A stamen consists of an anther — the pollen-producing head — and a filament, the stalk that connects the anther to the flower.
“This isn’t quite a Christmas flower but it is a beauty, especially considering it was part of a forest that existed 100 million years ago,” said George Poinar Jr., professor emeritus in the OSU College of Science.
Findings were published in the Journal of the Botanical Research Institute of Texas.
“Despite being so small, the detail still remaining is amazing,” Poinar said. “Our specimen was probably part of a cluster on the plant that contained many similar flowers, some possibly female.”
The new discovery has an egg-shaped, hollow floral cup — the part of the flower from which the stamens emanate; an outer layer consisting of six petal-like components known as tepals; and two-chamber anthers, with pollen sacs that split open via laterally hinged valves.
Poinar and collaborators at OSU and the U.S. Department of Agriculture named the new flower Valviloculus pleristaminis. Valva is the Latin term for the leaf on a folding door, loculus means compartment, plerus refers to many, and staminis reflects the flower’s dozens of male sex organs.
The flower became encased in amber on the ancient supercontinent of Gondwana and rafted on a continental plate some 4,000 miles across the ocean from Australia to Southeast Asia, Poinar said.
Geologists have been debating just when this chunk of land — known as the West Burma Block — broke away from Gondwana. Some believe it was 200 million years ago; others claim it was more like 500 million years ago.
Numerous angiosperm flowers have been discovered in Burmese amber, the majority of which have been described by Poinar and a colleague at Oregon State, Kenton Chambers, who also collaborated on this research.
Angiosperms are vascular plants with stems, roots and leaves, with eggs that are fertilized and develop inside the flower.
Since angiosperms only evolved and diversified about 100 million years ago, the West Burma Block could not have broken off from Gondwana before then, Poinar said, which is much later than dates that have been suggested by geologists.
Joining Poinar and Chambers, a botany and plant pathology researcher in the OSU College of Agricultural Sciences, on the paper were Oregon State’s Urszula Iwaniec and the USDA’s Fernando Vega. Iwaniec is a researcher in the Skeletal Biology Laboratory in the College of Public Health and Human Sciences and Vega works in the Sustainable Perennial Crops Laboratory in Beltsville, Maryland.
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Materials provided by Oregon State University. Original written by Steve Lundeberg. Note: Content may be edited for style and length.
“The male flower is tiny, about 2 millimeters across, but it has some 50 stamens arranged like a spiral, with anthers pointing toward the sky,” said Poinar, an international expert in using plant and animal life forms preserved in amber to learn more about the biology and ecology of the distant past.
A stamen consists of an anther — the pollen-producing head — and a filament, the stalk that connects the anther to the flower.