. Scientific Frontline: Paleontology
Showing posts with label Paleontology. Show all posts
Showing posts with label Paleontology. Show all posts

Thursday, May 18, 2023

Fossil of mosasaur with bizarre “screwdriver teeth” found in Morocco

The strange ridges on the teeth indicate a specialised feeding strategy, however its diet remains a mystery.
Photo Credit: Dr Nick Longrich

Scientists have discovered a new species of mosasaur, a sea-dwelling lizard from the age of the dinosaurs, with strange, ridged teeth unlike those of any known reptile. Along with other recent finds from Africa, it suggests that mosasaurs and other marine reptiles were evolving rapidly up until 66 million years ago, when they were wiped out by an asteroid along with the dinosaurs and around 90% of all species on Earth.

The new species, Stelladens mysterious, comes from the Late Cretaceous of Morocco and was around twice the size of a dolphin.

It had a unique tooth arrangement with blade-like ridges running down the teeth, arranged in a star-shaped pattern, reminiscent of a cross-head screwdriver.

Most mosasaurs had two bladelike, serrated ridges on the front and back of the tooth to help cut prey, however Stelladens had anywhere from four to six of these blades running down the tooth.

“It’s a surprise,” said Dr Nick Longrich from the Milner Centre for Evolution at the University of Bath, who led the study. “It’s not like any mosasaur, or any reptile, even any vertebrate we’ve seen before.”

Wednesday, May 10, 2023

Giants of the Jurassic seas were twice the size of a killer whale

An artist’s impression of the pliosaur
Illustration Credit: Megan Jacobs, University of Portsmouth

Over 20 years ago, the BBC’s "Walking with Dinosaurs" TV documentary series showed a 25-meter long Liopleurodon. This sparked heated debates over the size of this pliosaur as it was thought to have been wildly overestimated and more likely to have only reached an adult size of just over six meters long.

The speculation was set to continue, but now a chance discovery in an Oxfordshire museum has led to University of Portsmouth paleontologists publishing a paper on a similar species potentially reaching a whopping 14.4 meters - twice the size of a killer whale. 

Professor David Martill from the University of Portsmouth’s School of the Environment, Geography and Geosciences, said: “I was a consultant for the BBC’s pilot program ‘Cruel Sea’ and I hold my hands up - I got the size of Liopleurodon horrendously wrong. I based my calculations on some fragmentary material which suggested a Liopleurodon could grow to a length of 25 meters, but the evidence was scant and it caused a lot of controversy at the time.

“The size estimate on the BBC back in 1999 was overdone, but now we have some evidence that is much more reliable after a serendipitous discovery of four enormous vertebrate.”

Tuesday, May 9, 2023

Earth’s first animals had particular taste in real estate

Obamus coronatus.
Photo Credit: Mary Droser/University of California, Riverside

Even without body parts that allowed for movement, new research shows — for the first time — that some of Earth’s earliest animals managed to be picky about where they lived.

These creatures from the Ediacaran Period, roughly 550 million years ago, are strangely shaped soft-bodied animals that lived in the sea. Researchers have long considered them enigmatic. 

“It’s not like studying dinosaurs, which are related to birds that we can observe today,” said Phillip C. Boan, UC Riverside paleontology graduate student and lead author of the new study. “With these animals, because they have no modern descendants, we’re still working out basic questions about how they lived, such as how they reproduced and what they ate.”

For this particular research project, the researchers focused on understanding where in the sea the animals spent their lives. 

The ancient sea was also a largely foreign place compared to today’s marine environments. It was dominated by a mat on the sea floor composed of bacteria and layers of other organic materials. In addition, predatory creatures were uncommon.

Tuesday, May 2, 2023

Fossil find in California shakes up the natural history of cycad plants

Three-dimensional reconstruction of the whole cone and different views of the same cone scale. Scale bar: cone = 400 microns; cone scales = 200 microns.
Image Credit: Andres Elgorriaga, Brian Atkinson

Cycads, a group of gymnosperms which can resemble miniature palm trees (like the popular sago palm houseplant) were long thought to be “living fossils,” a group that had evolved minimally since the time of the dinosaurs. Now, a well-preserved 80-million-year-old pollen cone discovered in California has rewritten scientific understanding of the plants.

The findings are detailed in a paper by two University of Kansas paleobotanists just published in the journal New Phytologist.

“Cycads aren’t well-known but make up a significant part of plant diversity, accounting for around 25% of all gymnosperms,” said lead author Andres Elgorriaga, postdoctoral researcher with the KU Department of Ecology & Evolutionary Biology and KU Biodiversity Institute and Natural History Museum3. “Cycads are plants that have thick stems and short stature, with thick, palm-like leaves on top. They produce cones like pine cones and are related to other seed-bearing plants that also don’t produce flowers, like Ginkgo and the monkey puzzle tree. But they’re also highly endangered, with the highest level of endangerment among all plant groups. Trafficking of cycads also is a significant issue.”

Tuesday, April 18, 2023

Swimming secrets of prehistoric reptiles unlocked by new study

Paleobiologist Dr Susana Gutarra taking measurements from a very complete specimen of Liopleurodon, a plesiosaur from the Middle-Late Jurassic of Germany (Museum of Paleontology in Tübingen).
Photo Credit: Dr Susana Gutarra

Some of the most extraordinary body transformations in evolution have occurred in animals that adapted to life in water from land-living ancestors, such as modern whales, turtles and seals. During the Mesozoic, from 252 to 66 million years ago, while the dinosaurs stomped about on land, many groups of reptiles took to the seas, such as the iconic ichthyosaurs, plesiosaurs, crocodiles and mosasaurs.

In a new paper, published in the journal Palaeontology, a Bristol team of paleobiologists used state-of-the-art statistical methods to perform a large-scale quantitative study, the first of its kind, on the locomotion of Mesozoic marine reptiles.

The researchers collected measurements from 125 fossilized skeletons, and used these to explore changes in swimming styles within lineages and through time, discovering that there was no explosive radiation at the beginning of the Mesozoic, but a gradual diversification of locomotory modes, which peaked in the Cretaceous period.

Monday, April 17, 2023

New details of Tully monster revealed

The Tully monster.
Discovered in the 1950s and first described in a paper in 1966, the Tully monster, with its stalked eyes and long proboscis, is difficult to compare to all other known animal groups. Unique to Illinois in the U.S., it became its state fossil in 1989.
Image Credit: © 2023 Takahiro Sakono

For more than half a century, the Tully monster (Tullimonstrum gregarium), an enigmatic animal that lived about 300 million years ago, has confounded paleontologists, with its strange anatomy making it difficult to classify. Recently, a group of researchers proposed a hypothesis that Tullimonstrum was a vertebrate similar to cyclostomes (jawless fish like lamprey and hagfish). If it was, then the Tully monster would potentially fill a gap in the evolutionary history of early vertebrates. Studies so far have both supported and rejected this hypothesis. Now, using 3D imaging technology, a team in Japan believes it has found the answer after uncovering detailed characteristics of the Tully monster which strongly suggest that it was not a vertebrate. However, its exact classification and what type of invertebrate it was is still to be decided.

In the 1950s, Francis Tully was enjoying his hobby fossil hunting in a site known as Mazon Creek Lagerstätte in the U.S. state of Illinois, when he discovered what would later become known as the Tully monster. This 15-centimeter (on average), 300-million-year-old marine “monster” turned out to be an enigma, as ever since its discovery researchers have debated where it fits in the classification of living things (its taxonomic position). Unlike dinosaur bones and hard-shelled creatures that are often found as fossils, the Tully monster was soft-bodied. The Mazon Creek Lagerstätte is one of the few places in the world where the conditions were just right for imprints of these marine animals to be captured in detail in the underwater mud, before they could decay. In 2016, a group of scientists in the US proposed a hypothesis that the Tully monster was a vertebrate. If this was the case, then it could be a missing piece of the puzzle on how vertebrates evolved.

Thursday, April 13, 2023

Apes may have evolved upright stature for leaves, not fruit, in open woodland habitats

Artistic rendering of the open woodland habitat reconstruction at Moroto II with Morotopithecus bishopi vertically climbing with infant on back and juvenile below. Active volcano (Mount Moroto) is in background. Fossil relative of an elephant (Prodeinotherium) is foraging in center back.
Illustration Credit: Corbin Rainbolt

Anthropologists have long thought that our ape ancestors evolved an upright torso in order to pick fruit in forests, but new research from the University of Michigan suggests a life in open woodlands and a diet that included leaves drove apes’ upright stature.

The findings shed light on ape origins and push back the origin of grassy woodlands from between 7 million and 10 million years ago to 21 million years ago in equatorial Africa, during the Early Miocene.

Fruit grows on the spindly peripheries of trees. To reach it, large apes need to distribute their weight on branches stemming from the trunk, then reach out with their hands toward their prize. This is much easier if an ape is upright because it can more easily grab onto different branches with its hands and feet. If its back is horizontal, then its hands and feet are generally underneath the body, making it much harder to move outward to the smaller branches of a tree—especially if the ape is large bodied.

Wednesday, April 12, 2023

Small and simple key to evolution success of mammals

Artistic reconstruction of early mammal ancestors (species: Hadrocodium wui) shown hunting insect prey, illustrating how the adoption of an insectivorous diet and miniaturization played an important role in mammal evolution.
Illustration Credit: Dr Stephan Lautenschlager, University of Birmingham

Ancestors of modern mammals evolved into one of the most successful animal lineages by starting out small and simple, researchers have found.

A new study, published today in Communications Biology, shows that skull bones were successively reduced in early mammals around 150 to 100 million years ago.  

The research further demonstrated that alongside the reduction of skull bones, early mammals also became a lot smaller, some of which had a skull length of only 10-12 mm. This miniaturization considerably restricted the available food sources and early mammals adapted to feeding mostly on insects, allowing them to thrive in the shadows of dinosaurs.

In many vertebrate groups (animals with a back bone), such as fishes and reptiles, the skull and lower jaw are composed of numerous bones. This was also the case in the earliest ancestors of modern mammals over 300 million years ago.

95-million-year-old sauropod dinosaur skull first of its kind in Australia

Diamantinasaurus matildae head.
Illustration Credit: Elena Marian/ Australian Age of Dinosaurs Musuem of Natural History

A Curtin University-led research team has analyzed Australia’s first nearly complete sauropod dinosaur skull found in Queensland, Australia, gaining a better understanding of the animal’s anatomy, relationships to other sauropods, and feeding habits.

The research, published in Royal Society Open Science and completed in collaboration with the Australian Age of Dinosaurs Museum of Natural History, found that the skull – belonging to a dinosaur nicknamed ‘Ann’ – was from the species Diamantinasaurus matildae. Diamantinasaurus is a member of the dinosaur group Sauropoda, known for having small heads, long necks and tails, barrel-like bodies, and four columnar legs.

Lead researcher and paleontologist Dr Stephen Poropat, from Curtin’s School of Earth and Planetary Sciences, said ‘Ann’ is the first sauropod dinosaur found in Australia to include most of the skull, and also the first Diamantinasaurus specimen to preserve a back foot.

“I was lucky enough to be involved in this Australian-first discovery. Being able to lead the research on these fossils was a huge privilege. This skull gives us a rare glimpse into the anatomy of this enormous sauropod that lived in northeast Australia almost 100 million years ago,” Dr Poropat said.

Thursday, March 30, 2023

Predatory dinosaurs such as T. rex sported lizard-like lips

A juvenile Edmontosaurus disappears into the enormous, lipped mouth of Tyrannosaurus.
Illustration Credit Dr Mark Witton

A new study suggests that predatory dinosaurs, such as Tyrannosaurus rex, did not have permanently exposed teeth as depicted in films such as Jurassic Park, but instead had scaly, lizard-like lips covering and sealing their mouths.

Researchers and artists have debated whether theropod dinosaurs, the group of two-legged dinosaurs that includes carnivores and top predators like T. rex and Velociraptor, as well as birds, had lipless mouths where perpetually visible upper teeth hung over their lower jaws, similar to the mouth of a crocodile.

However, an international team of researchers challenge some of the best-known depictions, and say these dinosaurs had lips similar to those of lizards and their relative, the tuatara - a rare reptile found only in New Zealand, which are the last survivors of an order of reptiles that thrived in the age of the dinosaurs.

In the most detailed study of this issue yet, the researchers examined the tooth structure, wear patterns and jaw morphology of lipped and lipless reptile groups and found that theropod mouth anatomy and functionality resembles that of lizards more than crocodiles. This implies lizard-like oral tissues, including scaly lips covering their teeth.

“Exquisite” sabertooth skull offers clues about Ice Age predator

Dave Easterla, left, Distinguished University Professor Emeritus of Biology at Northwest Missouri State University and Matthew Hill, associate professor of anthropology at Iowa State, with a fossilized complete skull from a sabertooth cat from southwest Iowa.
Photo Credit: Christopher Gannon/Iowa State University.

The recent discovery of a sabertooth cat skull in southwest Iowa is the first evidence the prehistoric predator once inhabited the state.

The chance of finding any fossilized remains from a sabertooth cat is slim, said Matthew Hill, an associate professor of archaeology at Iowa State and expert on animal bones. The remarkably well-preserved skull found in Page County is even rarer, and its discovery offers clues about the iconic Ice Age species before its extinction roughly 12-13,000 years ago.

“The skull is a really big deal,” said Hill. “Finds of this animal are widely scattered and usually represented by an isolated tooth or bone. This skull from the East Nishnabotna River is in near perfect condition. It’s exquisite.”

Hill analyzed the specimen in collaboration with David Easterla, Distinguished University Professor Emeritus of Biology at Northwest Missouri State University. Their findings are newly published in Quaternary Science Reviews.

Wednesday, March 29, 2023

Extinction of steam locomotives derails assumptions about biological evolution

The Union Pacific Big Boy Steam Engine (one of the largest steam engines ever built and still functioning) visited Lawrence on Sept. 2, 2021.
Photo Credit: Bruce Lieberman

When the Kinks’ Ray Davies penned the tune “Last of the Steam-Powered Trains,” the vanishing locomotives stood as nostalgic symbols of a simpler English life. But for a paleontologist at the University of Kansas, the replacement of steam-powered trains with diesel and electric engines, as well as cars and trucks, might be a model of how some species in the fossil record died out.

Bruce Lieberman, professor of ecology & evolutionary biology and senior curator of invertebrate paleontology at the KU Biodiversity Institute & Natural History Museum, sought to use steam-engine history to test the merits of “competitive exclusion,” a long-held idea in paleontology that species can drive other species to extinction through competition.

Working with former KU postdoctoral researcher Luke Strotz, now of Northwest University in Xi’an, China, Lieberman found the fossil record largely lacks the detailed data verifying competitive exclusion found in the history of steam engines: “It's really hard to actually see any evidence that competition does play a big role in evolution,” Lieberman said.

Their findings have just been published in the paper “The end of the line: competitive exclusion and the extinction of historical entities2” in the peer-reviewed journal Royal Society Open Science.

Monday, March 27, 2023

Beaver Fossil Named After Buc-ee’s

Matthew Brown (left) and Steve May with beaver skulls new and old in the vertebrate paleontology collections at the Jackson School of Geosciences. Brown, the director of the collections, holds a skull from a modern North American Beaver. May, a research associate, holds a skull from Anchitheriomys buceei, a new species of ancient beaver that he discovered in the collections and named.
Photo Credit: UT Jackson School of Geosciences.

A new species of ancient beaver that was rediscovered by researchers in The University of Texas Austin’s fossil collections has been named after Buc-ee’s, a Texas-based chain of popular travel centers known for its cartoon beaver mascot.

The beaver is called Anchitheriomys buceei, or “A. buceei” for short.

Steve May, a research associate at the UT Jackson School of Geosciences, said that the beaver’s Texas connection and a chance encounter with a Buc-ee’s billboard are what inspired the name.

May is the lead author of the paper that describes A. buceei, along with another, much smaller, species of fossil beaver. Published in the journal Palaeontologia Electronica, the paper provides an overview of beaver occurrences along the Texas Gulf Coast from 15 million to 22 million years ago based on bones and archival records in the UT collections.

While driving down a highway in 2020, May spotted a Buc-ee’s billboard that said “This is Beaver Country.” The phrase brought to mind the Texas beaver fossils he had been studying at UT’s Texas Vertebrate Paleontology Collections.

Wednesday, March 15, 2023

New Fossil Analysis Reveals Dinosaur with Record-Holding 15-Meter-Long Neck

 A rendering of the sauropod known as Mamenchisaurus sinocanadorum, which had a 15-meter-long neck, about 10 feet longer than a typical school bus.
Illustration Credit: Júlia d'Oliveira

With their long necks and formidable bodies, sauropod dinosaurs have captured people’s imaginations since the first relatively complete sauropod fossils were discovered in the United States in the late 1800s. Now an international team led by Stony Brook University paleontologist Andrew J. Moore, PhD, has revealed that a Late Jurassic Chinese sauropod known as Mamenchisaurus sinocanadorum sported a 15-meter-long neck. A new analysis of this dinosaur, published in the Journal of Systematic Paleontology, provides fresh insights on the evolution of the iconic sauropod body.

For sauropods, the long neck was the anatomical key to achieving a large body size. To power such a large body, sauropods had to be efficient at gathering foodstuffs, and that's what a long neck was built for. A sauropod could plant itself in one spot and hoover up surrounding vegetation, conserving energy while taking in tons of food. Having a long neck probably also allowed enormous sauropods to shed excess body heat by increasing their surface area, much like the ears of elephants. This way of life – long neck-fueled, quadrupedal gigantism – is not one that is available to mammals or any other form of life today. The sauropod lifestyle was exceptionally successful: their lineage appeared early in dinosaur evolutionary history and persisted until the final days of the Mesozoic, when an asteroid wiped out all dinosaurs (except birds).

Sunday, March 12, 2023

Why are mammals more likely to go extinct on islands than on the mainland?

Illustration of Sardinian Dwarf Mammoth, Sardinian Giant Otter, Deer, Sardinian Dhole and Giant Pica
 Illustration Credit: Peter Schouten

Islands are "laboratories of evolution" and home to animal species with many unique features, including dwarfs that evolved to very small sizes compared to their mainland relatives, and giants that evolved to large sizes. A team of researchers from the German Centre of Integrative Biodiversity Research (iDiv) and Martin Luther University Halle-Wittenberg (MLU) has now found that species that evolved to more extreme body sizes compared to their mainland relatives have a higher risk of extinction than those that evolved to less extreme sizes. Their study, which was published in Science, also shows that extinction rates of mammals on islands worldwide increased significantly after the arrival of modern humans.

Islands are hotspots for biodiversity - they cover less than 7% of the Earth’s land area, but account for up to 20% of all terrestrial species on the planet. However, islands are also hotspots for species extinction as 50% of today’s IUCN threatened species are native to islands. 

Monday, February 27, 2023

Dinosaur claws used for digging and display

Therizinosaurs claw hooking and pulling trees
Image Credit: Shuyang Zhou for the 3D modelling and functional scenario restoration

Dinosaur claws had many functions, but now a team from the University of Bristol and the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) in Beijing has shown some predatory dinosaurs used their claws for digging or even for display.

The study focused on two groups of theropod dinosaurs, the alvarezsaurs and therizinosaurs, that had weird claws whose function had been a mystery up to now. It turns out that alvarezsaurs used their rock-pick-like claws for digging, but their close relatives, the giant therizinosaurs, used their overdeveloped, meter-long, sickle-like claws for display.

The new work is led by Zichuan Qin, a PhD student at the University of Bristol and the IVPP. He developed a new, computational approach in biomechanics to identify functions based on detailed comparison with living animals. First, the claws were modelled in three dimensions from CT scans, then modelled for stress and strain using engineering methods, and finally matched to functions of pulling, piercing and digging by comparison with modern animals whose claw functions are known.

“Alvarezsaurs and therizinosaurs are definitely the strangest cousins among dinosaurs,” said Professor Michael Benton, one of Zichuan’s supervisors. “Alvarezsaurs were the tiniest dinosaurs ever, the size of chickens, with stubby forelimbs and robust single claws, but their closest relative, the therizinosaurs, evolved in the exact opposite path.”

Monday, February 13, 2023

Researchers solve a 150-year-old mystery

A reconstruction - of the aetosaur assemblage in its habitat.
Illustration Credits: © J. Kowalski (drawing) and P. Janecki (coloring)

The Aetosaurs had a small head and a crocodile-like body. The land dwellers were up to six meters long and widely distributed geographically. They died out about 204 million years ago, at the end of the Triassic. In Kaltental near Stuttgart, Germany, an assemblage of 24 Aetosaurus ferratus individuals, only between 20 and 82 centimeters long, was discovered in 1877. Since then, scientists have been puzzling over whether they were juveniles or small adults. A team led by Elżbieta M. Teschner from the University of Bonn has now solved the mystery: Bone examination of two specimens shows that they are juveniles. The results have now been published in the Journal of Vertebrate Paleontology.

Reptiles of the genus Aetosaurus ferratus were discovered in a quarry near Kaltental, now a district of Stuttgart, and were first described nearly 150 years ago. The assemblage of about 24 individuals was dated to be about 215 million years old. "What was striking was that the total body length was only between 20 and 82 centimeters," says Elżbieta M. Teschner, who is pursuing a doctorate in paleontology at the University of Bonn while also conducting research at the University of Opole (Poland). "Interestingly, they were also the only fossils found in the area," she adds.

Wednesday, February 1, 2023

319-million-year-old fish preserves the earliest fossilized brain of a backboned animal


Video Credit: University of Michigan

The CT-scanned skull of a 319-million-year-old fossilized fish, pulled from a coal mine in England more than a century ago, has revealed the oldest example of a well-preserved vertebrate brain.

The brain and its cranial nerves are roughly an inch long and belong to an extinct bluegill-size fish. The discovery opens a window into the neural anatomy and early evolution of the major group of fishes alive today, the ray-finned fishes, according to the authors of a University of Michigan-led study scheduled for publication Feb. 1 in Nature.

The serendipitous find also provides insights into the preservation of soft parts in fossils of backboned animals. Most of the animal fossils in museum collections were formed from hard body parts such as bones, teeth and shells.

The CT-scanned brain analyzed for the new study belongs to Coccocephalus wildi, an early ray-finned fish that swam in an estuary and likely dined on small crustaceans, aquatic insects and cephalopods, a group that today includes squid, octopuses and cuttlefish. Ray-finned fishes have backbones and fins supported by bony rods called rays.

Thursday, January 26, 2023

Fossils of Arctic primate relatives tell climate-adaptation story

Artist's reconstruction of Ignacius dawsonae surviving six months of winter darkness in the extinct warm temperate ecosystem of Ellesmere Island, Arctic Canada.
Illustration Credit: Kristen Miller, Biodiversity Institute, University of Kansas.

Two sister species of near-primate, called “primatomorphans,” dating back about 52 million years have been identified by researchers at the University of Kansas as the oldest to have dwelled north of the Arctic Circle. The findings was published in the peer-reviewed journal PLOS ONE.

According to lead author Kristen Miller, doctoral student with KU’s Biodiversity Institute and Natural History Museum, both species — Ignacius mckennai and I. dawsonae — descended from a common northbound ancestor who possessed a spirit “to boldly go where no primate has gone before.”

The specimens were discovered on Ellesmere Island, Nunavut, Canada, in layers of sediment linked with the early Eocene, an epoch of warmer temperatures that could foretell how ecosystems will fare in coming years due to human-driven climate change.

“No primate relative has ever been found at such extreme latitudes,” Miller said. “They’re more usually found around the equator in tropical regions. I was able to do a phylogenetic analysis, which helped me understand how the fossils from Ellesmere Island are related to species found in midlatitudes of North America — places like New Mexico, Colorado, Wyoming and Montana. Even down in Texas we have some fossils that belong to this family as well.”

Tuesday, January 17, 2023

Ancient chimaeras were suction feeders, not shell crushers, new research shows

Iniopera reconstruction
Resized Image using AI by SFLORG
Photo Credit: Richard Dearden / University of BIrmingham

A rare three-dimensional fossil of an ancient chimaera has revealed new clues about the diversity of these creatures in the Carboniferous period, some 300 million years ago.

Research led by the Muséum national d'histoire naturelle (MNHN) and the University of Birmingham has shown that an ancient relative of chimaeras – jawed vertebrates that are related to sharks and rays – fed by sucking in prey animals underwater.

The fossil, from a genus called Iniopera, is the only suction feeder to be identified among chimaeras, and quite different from living chimaeras, which feed by crushing mollusks and other hard-shelled prey between their teeth. The research is published in the journal PNAS.

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