Fossil finds give clues about flying reptiles in the Sahara 100 million years ago
Three new species of toothed pterosaurs — flying reptiles of the Cretaceous period, some 100 million years ago — have been identified in Africa by an international team of scientists led by Baylor University.
The pterosaurs, which soared above a world dominated by predators, formed part of an ancient river ecosystem in Africa that teemed with life including fish, crocodiles, turtles and several predatory dinosaurs.
“Pterosaur remains are very rare, with most known from Europe, South America and Asia. These new finds are very exciting and provide a window into the world of pterosaurs in Cretaceous Africa,” said lead author Megan L. Jacobs, a doctoral candidate in geosciences at Baylor University.
The study, published in the journal Cretaceous Research, is helping to uncover the poorly known evolutionary history of Africa during the time of the dinosaurs. The research finds that African pterosaurs were quite similar to those found on other continents. Their world included crocodile-like hunters and carnivorous dinosaurs, with few herbivores. Many predators, including the toothed pterosaurs, preyed on a superabundance of fish.
“For such large animals, they would have weighed very little,” Jacobs said. “Their wingspans were around 10 to 13 feet, with their bones almost paper-thin and full of air, very similar to birds. This allowed these awesome creatures to reach incredible sizes and still be able to take off and soar the skies.”
Pterosaurs snatched up their prey while on the wing, using a set of large spike-like teeth to grab. Large pterosaurs such as these would have been able to forage over hundreds of miles, with fossil evidence showing they flew between South America and Africa, similar to present-day birds such as condors and albatrosses, researchers said.
The specimens — identified by researchers from chunks of jaws with teeth — were obtained from fossil miners in a small village called Beggaa, just outside Erfoud in southeast Morocco. These villagers daily climb halfway up the side of a large escarpment, known as the Kem Kem beds, to a layer of a coarse sand, the most fossiliferous bed.
“They excavate everything they find, from teeth to bones to almost complete skeletons,” Jacobs said. “They then sell their finds to dealers and scientists who conduct fieldwork, ensuring the villagers make enough money to survive while we get new fossils to describe. These pterosaur fragments are unique and can be identified easily — if you know what to look for.”
One of the species, Anhanguera, previously was only known to be from Brazil. Another, Ornithocheirus, had until now only been found in England and Middle Asia.
This year’s find brings to five the total of toothed pterosaurs whose remains have been found in the Kem Kem beds, with the first described in the 1990s and the second one last year, Jacobs said. The specimens will be part of an acquisition in a museum in Morocco.
Story Source:
Materials provided by Baylor University. Note: Content may be edited for style and length.
Journal Reference:
- Megan L. Jacobs, David M. Martill, David M. Unwin, Nizar Ibrahim, Samir Zouhri, Nicholas R. Longrich. New toothed pterosaurs (Pterosauria: Ornithocheiridae) from the middle Cretaceous Kem Kem beds of Morocco and implications for pterosaur palaeobiogeography and diversity. Cretaceous Research, 2020; 110: 104413 DOI: 10.1016/j.cretres.2020.104413
Ancestor of all animals identified in Australian fossils
A team led by UC Riverside geologists has discovered the first ancestor on the family tree that contains most familiar animals today, including humans.
The tiny, wormlike creature, named Ikaria wariootia, is the earliest bilaterian, or organism with a front and back, two symmetrical sides, and openings at either end connected by a gut. The paper is published today in Proceedings of the National Academy of Sciences.
The earliest multicellular organisms, such as sponges and algal mats, had variable shapes. Collectively known as the Ediacaran Biota, this group contains the oldest fossils of complex, multicellular organisms. However, most of these are not directly related to animals around today, including lily pad-shaped creatures known as Dickinsonia that lack basic features of most animals, such as a mouth or gut.
The development of bilateral symmetry was a critical step in the evolution of animal life, giving organisms the ability to move purposefully and a common, yet successful way to organize their bodies. A multitude of animals, from worms to insects to dinosaurs to humans, are organized around this same basic bilaterian body plan.
Evolutionary biologists studying the genetics of modern animals predicted the oldest ancestor of all bilaterians would have been simple and small, with rudimentary sensory organs. Preserving and identifying the fossilized remains of such an animal was thought to be difficult, if not impossible.
For 15 years, scientists agreed that fossilized burrows found in 555 million-year-old Ediacaran Period deposits in Nilpena, South Australia, were made by bilaterians. But there was no sign of the creature that made the burrows, leaving scientists with nothing but speculation.
Scott Evans, a recent doctoral graduate from UC Riverside; and Mary Droser, a professor of geology, noticed miniscule, oval impressions near some of these burrows. With funding from a NASA exobiology grant, they used a three-dimensional laser scanner that revealed the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. The animal ranged between 2-7 millimeters long and about 1-2.5 millimeters wide, with the largest the size and shape of a grain of rice — just the right size to have made the burrows.
“We thought these animals should have existed during this interval, but always understood they would be difficult to recognize,” Evans said. “Once we had the 3D scans, we knew that we had made an important discovery.”
The researchers, who include Ian Hughes of UC San Diego and James Gehling of the South Australia Museum, describe Ikaria wariootia, named to acknowledge the original custodians of the land. The genus name comes from Ikara, which means “meeting place” in the Adnyamathanha language. It’s the Adnyamathanha name for a grouping of mountains known in English as Wilpena Pound. The species name comes from Warioota Creek, which runs from the Flinders Ranges to Nilpena Station.
“Burrows of Ikaria occur lower than anything else. It’s the oldest fossil we get with this type of complexity,” Droser said. “Dickinsonia and other big things were probably evolutionary dead ends. We knew that we also had lots of little things and thought these might have been the early bilaterians that we were looking for.”
In spite of its relatively simple shape, Ikaria was complex compared to other fossils from this period. It burrowed in thin layers of well-oxygenated sand on the ocean floor in search of organic matter, indicating rudimentary sensory abilities. The depth and curvature of Ikaria represent clearly distinct front and rear ends, supporting the directed movement found in the burrows.
The burrows also preserve crosswise, “V”-shaped ridges, suggesting Ikaria moved by contracting muscles across its body like a worm, known as peristaltic locomotion. Evidence of sediment displacement in the burrows and signs the organism fed on buried organic matter reveal Ikaria probably had a mouth, anus, and gut.
“This is what evolutionary biologists predicted,” Droser said. “It’s really exciting that what we have found lines up so neatly with their prediction.”
Story Source:
Materials provided by University of California – Riverside. Original written by Holly Ober. Note: Content may be edited for style and length.
Beetles changed their diet during the Cretaceous period International team decodes 99 million-year-old amber fossils
Like a snapshot, amber preserves bygone worlds. An international team of paleontologists from the University of Bonn has now described four new beetle species in fossilized tree resin from Myanmar, which belong to the Kateretidae family. They still exist today, with only a few species. As well as the about 99 million years old insects, the amber also includes pollen. It seems that the beetles helped the flowering plants to victory, because they contributed to their propagation. In turn, the beetles benefited from the new food source. The results have now been published in the journal “iScience.”
The researchers have described the new beetle species using specimens in four amber pieces from Myanmar (previously known as Burma). The pieces are estimated to be 99 million years old and date from the Cretaceous period, when dinosaurs were a rich and diverse group. Two of the pieces are in the Museum of Natural Sciences of Barcelona (Spain), while the other two specimens are kept in the Institute of Geology and Palaeontology in Nanjing (China).
“Although Myanmar surprises us time and again with finds of great scientific importance, amber pieces containing numerous organisms are not often found there,” says project leader Dr. David Peris, who comes from Spain and is a postdoc at the Institute for Geosciences at the University of Bonn with an Alexander von Humboldt Foundation’s fellowship. He carried out the project with scientists from the USA, Spain, Germany, China and the Czech Republic.
Three of the examined amber pieces contained numerous beetles, while the fourth piece contained only one specimen of this family. Many pollen grains of different groups of seed plants, some of them long extinct, have been preserved with the beetles in the tree resin. Peris: “This close association suggests that the grains were distributed in the viscous lump of resin by the movement of the beetles.”
The beetle family still exists today
The Kateretidae are a small family of beetles with less than 100 described modern species that today live in South America and other temperate and subtropical regions. The species of this family feed on pollen and flower parts. Due to their dietary habits, they are nowadays regarded as pollinators of flowering plants (angiosperms). But in the middle Cretaceous period their rapid development had just begun. Previously, the Earth was colonized by gymnosperms, literally meaning “naked seeds,” which also includes our conifers. “The most important aspect of this study is that the pollen grains in three of the amber pieces do not belong to flowering plants,” says Peris. The pollen grains on the beetle of the fourth piece of amber, however, come from a water lily, a group of very primitive angiosperms that emerged at an early stage.
Living together for mutual benefit
There are other pollinating insects in amber, but almost all of them concern gymnosperms. When flowering plants (angiosperms) began their early development, they represented a new resource that was used by the Kateretidae. The beetles adapted quickly and formed a mutually beneficial symbiosis: The flowering plants served the beetles as a food source and these animals contributed to the propagation of the new angiosperms by pollination.
In earlier studies it was speculated that the beetles might belong to the insect groups that pollinated the earliest flowers. Some of these animals had developed the ability to pollinate gymnosperms well before the appearance of angiosperms. “Our study supports this hypothesis of significant host plant relocation, as there are no Kateretidae associated with gymnosperms today,” says Peris. Adapting to the new resource has proven to be an evolutionary advantage.
Story Source:
Materials provided by University of Bonn. Note: Content may be edited for style and length.
‘Wonderchicken’ fossil from the age of dinosaurs reveals origin of modern birds
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.
Story Source:
Materials provided by University of Cambridge. Original written by Sarah Collins. The original story is licensed under a Creative Commons License. Note: Content may be edited for style and length.
Dinosaur stomping ground in Scotland reveals thriving middle Jurassic ecosystem
During the Middle Jurassic Period, the Isle of Skye in Scotland was home to a thriving community of dinosaurs that stomped across the ancient coastline, according to a study published March 11, 2020 in the open-access journal PLOS ONE by Paige dePolo and Stephen Brusatte of the University of Edinburgh, Scotland and colleagues.
The Middle Jurassic Period is a time of major evolutionary diversification in many dinosaur groups, but dinosaur fossils from this time period are generally rare. The Isle of Skye in Scotland is an exception, yielding body and trace fossils of diverse Middle Jurassic ecosystems, serving as a valuable location for paleontological science as well as tourism.
In this paper, dePolo and colleagues describe two recently discovered fossil sites preserving around 50 dinosaur footprints on ancient coastal mudflats. These include the first record on the Isle of Skye of a track type called Deltapodus, most likely created by a stegosaurian (plate-backed) dinosaur. These are the oldest Deltapodus tracks known, and the first strong evidence that stegosaurian dinosaurs were part of the island’s Middle Jurassic fauna. Additionally, three-toed footprints represent multiple sizes of early carnivorous theropods and a series of other large tracks are tentatively identified as some of the oldest evidence of large-bodied herbivorous ornithopod dinosaurs.
All tracks considered, these two sites expand the known diversity of what was apparently a thriving ecosystem of Middle Jurassic dinosaurs in Scotland, including at least one type of dinosaur (stegosaurs) not previously known from the region. These findings reflect the importance of footprints as a source of information supplemental to body fossils. Furthermore, the authors stress the importance of revisiting previously explored sites; these new sites were found in an area that has long been popular for fossil prospecting, but the trackways were only recently revealed by storm activity.
Lead author dePolo says: “These new tracksites help us get a better sense of the variety of dinosaurs that lived near the coast of Skye during the Middle Jurassic than what we can glean from the island’s body fossil record. In particular, Deltapodus tracks give good evidence that stegosaurs lived on Skye at this time.”
Author Brusatte adds: “These new tracksites give us a much clearer picture of the dinosaurs that lived in Scotland 170 million years ago. We knew there were giant long-necked sauropods and jeep-sized carnivores, but we can now add plate-backed stegosaurs to that roster, and maybe even primitive cousins of the duck-billed dinosaurs too. These discoveries are making Skye one of the best places in the world for understanding dinosaur evolution in the Middle Jurassic.”
Story Source:
Materials provided by PLOS. Note: Content may be edited for style and length.
Journal Reference:
- dePolo PE, Brusatte SL, Challands TJ, Foffa D, Wilkinson M, Clark NDL, et al. Novel track morphotypes from new tracksites indicate increased Middle Jurassic dinosaur diversity on the Isle of Skye, Scotland. PLOS ONE, 2020 DOI: 10.1371/journal.pone.0229640