You wait ages for a pterosaur and then four come along at once.

Hot on the heels of a recent paper discovering three new species of pterosaur, University of Portsmouth palaeobiologists have identified another new species—the first of its kind to be found on African soil.

Pterosaurs are the less well-known cousins of dinosaurs. They had adept flying ability—some as large as a fighter jet and others as small as a model aeroplane.

The new species belongs to a group of pterosaurs called tapejarids from the Cretaceous period. Tapejarids were small to medium-sized pterosaurs with wingspans perhaps as wide as four metres, most of which had large, broad crests sweeping up from the front of the skull.

They are well known in Brazil and China, and specimens have also been discovered in Europe, but this is the first time the flying reptile has been found in Africa.

It differs from the three recent species discovered as this one had no teeth—it was ‘edentulous’.

Professor David Martill, from the University’s School of the Environment, Geography and Geosciences, led the study. He said: “The study of Moroccan material shows that we are still far from having found all the paleontological treasures of North Africa. Even fragmentary fossils, like the jaw piece of the new pterosaur, can give us important information about the biodiversity of the past.”

Ph.D. student Roy Smith, one of the co-authors, said: “I feel very privileged to be part of such an exciting discovery. Working in the Sahara was a life-changing experience, and discovering a new species of pterosaur is the icing on the cake.”

The new pterosaur has been named Afrotapejara zouhrii to honour the Moroccan palaeontologist Professor Samir Zouhri. Originally a mammal specialist, Zouhri also contributed to several discoveries of prehistoric reptiles in Morocco, including dinosaurs and pterosaurs.

Professor Martill said: “The opportunity to illuminate the diversity of pterosaurs in Africa while honouring a colleague does not happen every day.”

The research team included Dr. David Unwin from the University of Leicester and Dr. Nizar Ibrahim from the University of Detroit Mercy.

Palaeontologist Dr. Ibrahim, said: “Samir Zouhri has played an important role in the development of Moroccan palaeontology, not only through his publications, but also because he organised scientific conferences in Morocco and edited an entire volume for the Geological Society of France on the subject of vertebrate palaeontology in Morocco.”

The fossil material is part of the collections of the Faculty of Sciences Aïn Chock, Casablanca Hassan II University and the paper was published in Cretaceous Research.

Reference:
David M. Martill et al, A new tapejarid (Pterosauria, Azhdarchoidea) from the mid-Cretaceous Kem Kem beds of Takmout, southern Morocco, Cretaceous Research (2020). DOI: 10.1016/j.cretres.2020.104424

Note: The above post is reprinted from materials provided by University of Portsmouth.

A new feathered dinosaur that lived in New Mexico 67 million years ago is one of the last known surviving raptor species, according to a new publication in the journal Scientific Reports.

Dineobellator notohesperus adds to scientists’ understanding of the paleo-biodiversity of the American Southwest, offering a clearer picture of what life was like in this region near the end of the reign of the dinosaurs.

Steven Jasinski, who recently completed his Ph.D. in Penn’s Department of Earth and Environmental Sciences in the School of Arts and Sciences, led the work to describe the new species, collaborating with doctoral advisor Peter Dodson of the School of Veterinary Medicine and Penn Arts and Sciences and as well as Robert Sullivan of the New Mexico Museum of Natural History and Science in Albuquerque.

In 2008, Sullivan found fossils of the new species in Cretaceous rocks of the San Juan Basin, New Mexico. He, along with his field team of Jasinski and James Nikas, collected the specimen on U.S. federal land under a permit issued by the Bureau of Land Management. The entire specimen was recovered over four field seasons. Jasinski and his coauthors gave the species its official name, Dineobellator notohesperus, which means “Navajo warrior from the Southwest,” in honor of the people who today live in the same region where this dinosaur once dwelled.

Dineobellator, as well as its Asian cousin Velociraptor, belong to a group of dinosaurs known as the dromaeosaurids. Members of this group are commonly referred to as “raptor” dinosaurs, thanks to movies such as “Jurassic Park” and “Jurassic World.” But unlike the terrifying beasts depicted in film, Dineobellator stood only about 3.5 feet (about 1 meter) at the hip and was 6 to 7 feet (about 2 meters) long — much smaller than its Hollywood counterparts.

Raptor dinosaurs are generally small, lightly built predators. Consequently, their remains are rare, particularly from the southwestern United States and Mexico. “While dromaeosaurids are better known from places like the northern United States, Canada, and Asia, little is known of the group farther south in North America,” says Jasinski.

While not all of the bones of this dinosaur were recovered, bones from the forearm have quill nobs — small bumps on the surface where feathers would be anchored by ligaments — an indication that Dineobellator bore feathers in life, similar to those inferred for Velociraptor.

Features of the animal’s forelimbs, including enlarged areas of the claws, suggest this dinosaur could strongly flex its arms and hands. This ability may have been useful for holding on to prey — using its hands for smaller animals such as birds and lizards, or perhaps its arms and feet for larger species such as other dinosaurs.

Its tail also possessed unique characteristics. While most raptors’ tails were straight and stiffened with rod-like structures, Dineobellator’s tail was rather flexible at its base, allowing the rest of the tail to remain stiff and act like a rudder.

“Think of what happens with a cat’s tail as it is running,” says Jasinski. “While the tail itself remains straight, it is also whipping around constantly as the animal is changing direction. A stiff tail that is highly mobile at its base allows for increased agility and changes in direction, and potentially aided Dineobellator in pursuing prey, especially in more open habitats.”

This new dinosaur provides a clearer picture of the biology of North American dromaeosaurid dinosaurs, especially concerning the distribution of feathers among its members.

“As we find evidence of more members possessing feathers, we believe it is likely that all the dromaeosaurids had feathers,” says Jasinski. The discovery also hints at some of the predatory habits of a group of iconic meat-eating dinosaurs that lived just before the extinction event that killed off all the dinosaurs that weren’t birds.

Jasinski plans to continue his field research in New Mexico with the hope of finding more fossils.

“It was with a lot of searching and a bit of luck that this dinosaur was found weathering out of a small hillside,” he says. “We do so much hiking and it is easy to overlook something or simply walk on the wrong side of a hill and miss something. We hope that the more we search, the better chance we have of finding more of Dineobellator or the other dinosaurs it lived alongside.”

Reference:
Steven E. Jasinski, Robert M. Sullivan, Peter Dodson. New Dromaeosaurid Dinosaur (Theropoda, Dromaeosauridae) from New Mexico and Biodiversity of Dromaeosaurids at the end of the Cretaceous. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-61480-7

Note: The above post is reprinted from materials provided by University of Pennsylvania.

The oldest fossil of a modern bird yet found, dating from the age of dinosaurs, has been identified by an international team of palaeontologists.

The spectacular fossil, affectionately nicknamed the ‘Wonderchicken’, includes a nearly complete skull, hidden inside nondescript pieces of rock, and dates from less than one million years before the asteroid impact which eliminated all large dinosaurs.

Writing in the journal Nature, the team, led by the University of Cambridge, believe the new fossil helps clarify why birds survived the mass extinction event at the end of the Cretaceous period, while the giant dinosaurs did not.

Detailed analysis of the skull shows that it combines many features common to modern chicken- and duck-like birds, suggesting that the ‘Wonderchicken’ is close to the last common ancestor of modern chickens and ducks. The fossil was found in a limestone quarry near the Belgian-Dutch border, making it the first modern bird from the age of dinosaurs found in the northern hemisphere.

The fossil doesn’t look like much on first glance, with only a few small leg bone fragments poking out from a piece of rock the size of a deck of cards. Even those small bones attracted the researchers’ interest, since bird fossils from this point in Earth’s history are so rare.

Using high-resolution X-ray CT scans, the researchers peered through the rock to see what was lying beneath the surface. What they saw, just one millimetre beneath the rock, was the find of a lifetime: a nearly complete 66.7-million-year-old bird skull.

“The moment I first saw what was beneath the rock was the most exciting moment of my scientific career,” said Dr Daniel Field from Cambridge’s Department of Earth Sciences, who led the research. “This is one of the best-preserved fossil bird skulls of any age, from anywhere in the world. We almost had to pinch ourselves when we saw it, knowing that it was from such an important time in Earth’s history.

“The ability to CT scan fossils, like we can at the Cambridge Biotomography Centre, has completely transformed how we study palaeontology in the 21st century.”

“Finding the skull blew my mind,” said co-author Juan Benito, also from Cambridge, who was CT scanning the fossils with Field when the skull was discovered. “Without these cutting-edge scans, we never would have known that we were holding the oldest modern bird skull in the world.”

The skull, despite its age, is clearly recognisable as a modern bird. It combines many features common to the group that includes living chickens and ducks — a group called Galloanserae. Field describes the skull as a kind of ‘mash-up’ of a chicken and a duck.

“The origins of living bird diversity are shrouded in mystery — other than knowing that modern birds arose at some point towards the end of the age of dinosaurs, we have very little fossil evidence of them until after the asteroid hit,” said co-author Albert Chen, a PhD student based at Cambridge. “This fossil provides our earliest direct glimpse of what modern birds were like during the initial stages of their evolutionary history.”

While the fossil is colloquially known as the Wonderchicken, the researchers have given it the slightly more elegant name of Asteriornis, in reference to Asteria, the Greek Titan goddess of falling stars.

“We thought it was an appropriate name for a creature that lived just before the end-Cretaceous asteroid impact,” said co-author Dr Daniel Ksepka from the Bruce Museum in Greenwich, Connecticut. “In Greek mythology, Asteria transforms herself into a quail, and we believe Asteriornis was close to the common ancestor that today includes quails, as well as chickens and ducks.”

The fact that Asteriornis was found in Europe is another thing which makes it so extraordinary. “The late Cretaceous fossil record of birds from Europe is extremely sparse,” said co-author Dr John Jagt from the Natuurhistorische Museum Maastricht in the Netherlands. “The discovery of Asteriornis provides some of the first evidence that Europe was a key area in the early evolutionary history of modern birds.”

“This fossil tells us that early on, at least some modern birds were fairly small-bodied, ground-dwelling birds that lived near the seashore,” said Field. “Asteriornis now gives us a search image for future fossil discoveries — hopefully it ushers in a new era of fossil finds that help clarify how, when and where modern birds first evolved.”

The announcement of the Wonderchicken find coincides with a new exhibit at Cambridge’s Sedgwick Museum of Earth Sciences, where visitors can learn more about Asteriornis and see the fossil up close. “Dawn of the Wonderchicken” runs from 19 March to 15 June. Admission is free.

Dr Daniel Field is funded by a UKRI Future Leaders Fellowship. He is a University Lecturer in the Department of Earth Sciences at the University of Cambridge, and a Fellow of Christ’s College Cambridge.

Reference:
Daniel J. Field, Juan Benito, Albert Chen, John W. M. Jagt, Daniel T. Ksepka. Late Cretaceous neornithine from Europe illuminates the origins of crown birds. Nature, 2020; 579 (7799): 397 DOI: 10.1038/s41586-020-2096-0

Note: The above post is reprinted from materials provided by University of Cambridge. Original written by Sarah Collins. The original story is licensed under a Creative Commons License.

A topic of considerable interest to paleontologists is how dinosaur-dominated ecosystems were structured, how dinosaurs and co-occurring animals were distributed across the landscape, how they interacted with one another, and how these systems compared to ecosystems today. In the Late Cretaceous (~100-66 million years ago), North America was bisected into western and eastern landmasses by a shallow inland sea. The western landmass (Laramidia) contained a relatively thin stretch of land running north-south, which was bordered by that inland sea to the east and the rising Rocky Mountains to the west. Along this ancient landscape of warm and wet coastal plains comes an extremely rich fossil record of dinosaurs and other extinct animals.

Yet, from this record, an unexpected pattern has been identified: Most individual basins preserve an abundant and diverse assemblage of dinosaur species, often with multiple groups of co-occurring large (moose- to elephant-sized) herbivorous species, yet few individual species occur across multiple putatively contemporaneous geological formations (despite them often being less than a few hundred kilometers apart). This is in fairly stark contrast to the pattern seen in modern terrestrial mammal communities, where large-bodied species often have very extensive, often continent-spanning ranges. It has therefore been suggested that dinosaurs (and specifically large herbivorous dinosaurs) were particularly sensitive to environmental differences over relatively small geographic distances (particularly with respect to distance from sea level), and may have even segregated their use of the landscape between more coastal and inland sub-habitats within their local ranges.

In their new study published in Geology, Thomas Cullen and colleagues sought to test some of these hypotheses as part of their broader research reconstructing the paleoecology of Late Cretaceous systems.

One of the methods they’re using to do that is stable isotope analysis. This process measures differences in the compositions of non-decaying (hence, “stable”) isotopes of various common elements, as the degree of difference in these compositions in animal tissues and in the environment have known relationships to various factors such as diet, habitat use, water source, and temperature. So the team applied these methods to fossilized teeth and scales from a range of animals, including dinosaurs, crocodilians, mammals, bony fish, and rays, all preserved together from a relatively small region over a geologically short period of time in sites called vertebrate microfossil bonebeds.

By analyzing the stable carbon and oxygen isotope compositions of these fossils they were able to reconstruct their isotopic distributions in this ecosystem — a proxy for their diets and habitat use. They found evidence of expected predator-prey dietary relationships among the carnivorous and herbivorous dinosaurs and among aquatic reptiles like crocodilians and co-occurring fish species.

Critically, says Cullen, “What we didn’t see was evidence for large herbivorous dinosaurs segregating their habitats, as the hadrosaurs, ceratopsians, and ankylosaurs we sample all had strongly overlapping stable carbon and oxygen ranges. If some of those groups were making near-exclusive use of certain parts of the broader landscape, such as ceratopsians sticking to coastal environments and hadrosaurs sticking to more inland areas, then we should see them grouping distinctly from each other. Since we didn’t see that, that suggests they weren’t segregating their resource use in this manner. It’s possible they were doing so in different ways though, such as by feeding height segregation, or shifting where in the landscape they go seasonally, and our ongoing research is investigating some of these possibilities.”

Another important part of their study was comparing the fossil results to an environmentally similar modern environment in order to examine how similar they are ecologically. For a modern comparison, they examined the animal communities of the Atchafalaya River Basin of Louisiana, the largest contiguous wetland area in the continental U.S. The landscape of this area is very similar to their Cretaceous system, as are many elements of the plant and animal communities (not including the non-avian dinosaurs, of course).

From their comparisons, the team found that the Cretaceous system was similar to the Louisiana one in having a very large amount of resource interchange between the aquatic and terrestrial components of the ecosystem, suggesting that fairly diverse/mixed diets were common, and food being obtained from both terrestrial and aquatic sources was the norm. They also found that habitat use differences among the herbivorous mammals in the Louisiana system was more distinct than among those large herbivorous dinosaurs in the Cretaceous system, lending further evidence to their results about their lack of strict habitat use preferences.

Lastly, the team used modified oxygen stable isotope temperature equations to estimate mean annual temperature ranges for both systems (with the Louisiana one being a test of the accuracy of the method, as they could compare their results to directly measured water and air temperatures). The team found that in their Late Cretaceous ecosystem in Alberta, mean annual temperature was about 16-20 degrees C, a bit cooler than modern day Louisiana, but much warmer than Alberta today, reflecting the hotter greenhouse climate that existed globally about 76 million years ago.

Characterizing how these ecosystems were structured during this time, and how these systems changed across time and space, particularly with respect to how they responded to changes in environmental conditions, may be of great importance for understanding and predicting future ecosystem responses under global climate change. The team’s research continues and should reveal much more about the food webs and ecology of the dinosaurs and other organisms that inhabited these ancient landscapes.

Reference:
D.C. Evans, M.J. Ryan, M.B. Goodwin, F. Fanti, L. Huang, U.G. Wortmann, F.J. Longstaffe, T.M. Cullen. Large-scale stable isotope characterization of a Late Cretaceous dinosaur-dominated ecosystem. Geology, 2020; DOI: 10.1130/G47399.1

Note: The above post is reprinted from materials provided by Geological Society of America.

New research finds soot from global fires ignited by an asteroid impact could have blocked sunlight long enough to drive the mass extinction that killed most life on Earth, including the dinosaurs, 66 million years ago.

The Cretaceous–Paleogene extinction event wiped out about 75 percent of all species on Earth. An asteroid impact at the tip of Mexico’s Yucatán Peninsula caused a period of prolonged cold and darkness, called an impact winter, that likely fueled a large part of the mass extinction. But scientists have had a hard time teasing out the details of the impact winter and what the exact mechanism was that killed life on Earth.

A new study in AGU’s journal Geophysical Research Letters simulates the contributions of the impact’s sulfur, dust, and soot emissions to the extreme darkness and cold of the impact winter. The results show the cold would have been severe but likely not devastating enough to drive a mass extinction. However, soot emissions from global forest fires darkened the sky enough to kill off photosynthesizers at the base of the food web for well over a year, according to the study.

“This low light seems to be a really big signal that would potentially be devastating to life,” said Clay Tabor, a geoscientist at the University of Connecticut and lead author of the new study. “It seems like these low light conditions are a probable explanation for a large part of the extinction.”

The results help scientists better understand this intriguing mass extinction that ultimately paved the way for humans and other mammals to evolve. But the study also provides insight into what might happen in a nuclear winter scenario, according to Tabor.

“The main driver of a nuclear winter is actually from soot in a similar type situation,” Tabor said. “What it really highlights is just how potentially impactful soot can be on the climate system.”

The impact and extinction

The Chicxulub asteroid impact spewed clouds of ejecta into the upper atmosphere that then rained back down to Earth. The returning particles would have had enough energy to broil Earth’s surface and ignite global forest fires. Soot from the fires, along with sulfur compounds and dust, blocked out sunlight, causing an impact winter lasting several years. Previous research estimates average global temperatures plummeted by at least 26 degrees Celsius (47 degrees Fahrenheit).

Scientists know the extreme darkness and cold were devastating to life on Earth but are still teasing apart which component was more harmful to life and whether the soot, sulfate, or dust particles were most disruptive to the climate.

In the new study, Tabor and his colleagues used a sophisticated climate model to simulate the climatic effects of soot, sulfates, and dust from the impact.

Their results suggest soot emissions from global fires absorbed the most sunlight for the longest amount of time. The model showed soot particles were so good at absorbing sunlight that photosynthesis levels dropped to below one percent of normal for well over a year.

“Based on the properties of soot and its ability to effectively absorb incoming sunlight, it did a very good job at blocking sunlight from reaching the surface,” Tabor said. “In comparison to the dust, which didn’t stay in the atmosphere for nearly as long, and the sulfur, which didn’t block as much light, the soot could actually block almost all light from reaching the surface for at least a year.”

A refuge for life

The darkness would have been devastating to photosynthesizers and could explain the mass extinction through a collapse of the food web, according to the researchers. All life on Earth depends on photosynthesizers like plants and algae that harvest energy from sunlight.

Interestingly, the temperature drop likely wasn’t as disturbing to life as the darkness, according to the study.

“It’s interesting that in their model, soot doesn’t necessarily cause a much larger cooling when compared other types of aerosol particles produced by the impact-but soot does cause surface sunlight to decline a lot more,” said Manoj Joshi, a climate dynamics professor at the University of East Anglia in the United Kingdom who was not connected to the new study.

In regions like the high latitudes, the results suggest oceans didn’t cool significantly more than they do during a normal cycle of the seasons.

“Even though the ocean cools by a decent amount, it doesn’t cool by that much everywhere, particularly in the higher latitude regions,” Tabor said. “In comparison to the almost two years without photosynthetic activity from soot, it seems to be a secondary importance.”

As a result, high latitude coastal regions may have been refuges for life in the months after the impact. Plants and animals living in the Arctic or Antarctic are already used to large temperature swings, extreme cold, and low light, so they may have had a better chance of surviving the impact winter, according to the researchers.

Reference:

1. Clay R. Tabor et al. Causes and Climatic Consequences of the Impact Winter at the Cretaceous‐Paleogene Boundary, Geophysical Research Letters (2020). DOI: 10.1029/2019GL085572
2. Julia Brugger et al. Baby, it’s cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous, Geophysical Research Letters (2016). DOI: 10.1002/2016GL072241

Note: The above post is reprinted from materials provided by American Geophysical Union. The original article was written by Lauren Lipuma.