Bear teeth break free – Researchers discover the origin of unusual bear dentition

Lower jaw of a polar bear
The polar bear has a second molar that is only slightly larger than the first. Although the polar bear is a carnivore, it is descended from the omnivorous brown bear. 
Photo Credit: © Katja Henßel, SNSB

Mammalian teeth show an astonishing diversity that has developed over 225 million years. One approach to describing the development of mammalian teeth is the so-called “Inhibitory Cascade Model”, short ICM. The ICM describes the growth pattern of molars in the lower jaw. According to the model, the following applies to many mammals: The front molars in the lower jaw influence the growth of all the teeth behind them. 

Certain molecules inhibit or activate tooth growth in the animal's dentition according to the same pattern. Which molars become small or large depends on the size of the first molar, which depends on the animal's diet. In carnivorous mammals, the first molar is usually larger than the third. In herbivores, it is the other way around: the first molar is small, while the third is large. 

Australopithecus deyiremeda, an ancestor of the human species discovered in Ethiopia, was bipedal and climbed trees

Professor Lluís Gibert, from the University of Barcelona, is the only expert from a European institution participating in an international study based on the analysis of the bones of a fossilized foot and teeth that has revealed how Australopithecus deyiremeda, a human ancestor that coexisted more than three million years ago with Australopithecus afarensis — the famous Lucy — on the plains of East Africa, moved and fed.
Photo Credit: Courtesy of University of Barcelona

In 2009, scientists found eight bones from the foot of a human ancestor in layers of ancient sediment at the Woranso-Mille site in the central Afar region of Ethiopia. The fossil remains, known as the Burtele Foot, were discovered by a team led by paleoanthropologist Yohannes Haile-Selassie, from Arizona State University (United States), but were not assigned to any fossil species of a human ancestor from the African continent.

A study now published in the journal Nature and led by Haile-Selassie solves the mystery and reveals that Burtele Foot belongs to the species Australopithecus deyiremeda, a new hominid fossil discovered years ago by the researcher’s team at the Woranso-Mille site (Nature, 2015). Thus, the study of this fossil foot — dated to about 3.4 million years ago — reveals that A. deyiremeda was an Australopithecus that walked on two limbs (bipedalism) and also lived in trees, as indicated by the presence of a prehensile big toe like that of chimpanzees. 

The international team of experts includes Professor Lluís Gibert, from the Faculty of Earth Sciences of the University of Barcelona, who is the only researcher from a European institution to sign the study. Geological analyses were decisive for dating and linking this foot to the remains of A. deyiremeda. 

Looping long-necked dinosaur site reveals its secrets

An aerial view of the loop section of the West Gold Hill Dinosaur Tracksite in Colorado.
Photo Credit: Dr. Paul Murphey

An analysis of a unique looping trail of ancient footprints in the United States reveals the dinosaur which made it may have been limping. 

The site near Ouray in Colorado is one of the most continuous and tightly turning sauropod trackways ever documented. 

Dr. Anthony Romilio from The University of Queensland’s Dinosaur Lab analyzed more than 130 footprints along the 95.5-metre track made 150 million years ago. 

“This was left in the Late Jurassic when long-necked dinosaurs such as Diplodocus and Camarasaurus roamed North America,” Dr Romilio said. 

The world’s oldest RNA extracted from woolly mammoth

“Such studies could fundamentally reshape our understanding of extinct megafauna as well as other species, revealing the many hidden layers of biology that have remained frozen in time until now”, says postdoc at the University of Caopenhagen, Emilio Mármol.
Image Credit: Scientific Frontline / stock image

Scientists have taken an important step closer to understanding the mythical mammoths that roamed the Earth thousands of years ago. 

For the first time ever, a research team has succeeded in isolating and sequencing RNA molecules from woolly mammoths dating back to the Ice Age. These RNA sequences are the oldest ever recovered and come from mammoth tissue preserved in the Siberian permafrost for nearly 40,000 years. The study, published in the journal Cell, shows that not only DNA and proteins, but also RNA, can be preserved for very long periods of time, and provide new insights into the biology of species that have long since become extinct. 

Ancient mammoth tooth offers clues about Ice Age life in northeastern Canada

Image Credit: Scientific Frontline / AI generated

The re-examination of a 19th-century fossil indicates that woolly mammoths once roamed much farther east than previously believed, proof that an old specimen can still have secrets to reveal

A worn-down mammoth tooth discovered nearly 150 years ago on an island in Nunavut offers new insights into where and how the Ice Age giants lived and died.

A McGill-led study has reclassified the 1878 find, originally thought to be a Columbian mammoth, as an older, cold-adapted woolly mammoth (Mammuthus primigenius), making it the most northeasterly woolly mammoth find ever in North America. The tooth, unearthed on Long Island, Nunavut near the junction of Hudson and James bays, was first described in 1898 by Geological Survey of Canada director Robert Bell.

Scientists Confirmed That a "Terrible" Hyena Lived in the Territory of the Modern Caucasus

The scientists used morphometric and morphological analysis of teeth.
Photo Credit: Daniyar Khantemirov

Ural scientists with colleagues from China and Azerbaijan have established that "terrible" hyenas (Dinocrocuta gigantea) lived in the territory of the modern Caucasus 10-9 million years ago. This fact was confirmed by studying jaw fragments that were found in the Upper Miocene site of Eldari, Azerbaijan. The researchers published a description and photographs of the fragments in the journal Palaeoworld.

"In our work, the Dinocrocute hyenas from the Caucasus are described for the first time. Other finds of this species are described from Southern Europe or Northern China. In other words, our finding fills a gap in understanding the distribution of dinocrocutes, which were one of the key predators in the faunas of the Miocene, a geological epoch from 23 to 5 million years before our time," explains Daniyar Khantemirov, co-author of the work, laboratory researcher at the UrFU Laboratory of Natural Science Methods in Humanitarian Research.

Did Lead Limit Brain and Language Development in Neanderthals and Other Extinct Hominids?

UC San Diego researchers have found high levels of lead in the teeth of both Neanderthals (left) and modern humans (right). However, a gene mutation may have protected modern human brains, allowing language to flourish.
Photo Credit: Kyle Dykes/UC San Diego Health Sciences

Ancient human relatives were exposed to lead up to two million years ago, according to a new study. However, a gene mutation may have protected modern human brains, allowing language to flourish.

What set the modern human brain apart from our now extinct relatives like Neanderthals? A new study by University of California San Diego School of Medicine and an international team of researchers reveals that ancient hominids — including early humans and great apes — were exposed to lead earlier than previously thought, up to two million years before modern humans began mining the metal. This exposure may have shaped the evolution of hominid brains, limiting language and social development in all but modern humans due to a protective genetic variant that only we carry. The study was published in Science Advances.

The researchers analyzed fossilized teeth from 51 hominids across Africa, Asia and Europe, including modern and archaic humans such as Neanderthals, ancient human ancestors like Australopithecus africanus, and extinct great apes such as Gigantopithecus blacki.

Fossilized feces help bring prehistoric worlds to life — in molecular detail

Image Credit: Courtesy of Curtin University

An international research team led by Curtin University has used prehistoric feces to better understand how molecular fossilization works, offering a new window into what ancient animals ate, the world they lived in and what happened after they died.

Published in the journal Geobiology and funded by the ARC Laureate Fellowship program, the study examined 300-million-year-old fossilized droppings, or ‘coprolites’, mostly from the Mazon Creek fossil site in the United States.

The coprolites were already known to contain cholesterol derivatives, which is strong evidence of a meat-based diet, but the new research explored how those delicate molecular traces were preserved and survived the ravages of time.

Usually, soft tissues are fossilized due to phosphate minerals, but the study found molecules were preserved thanks to tiny grains of iron carbonate scattered throughout the fossil, acting like microscopic time capsules.

A Paleontologist Has Discovered a Tooth of an Extinct Carnivorous Whale in the Sverdlovsk Region

The unique find belonged to a giant aquatic mammal that lived 37 million years ago
Photo Credit: Maxim Sinitsa

In the Sverdlovsk region, paleontologists have found the tooth of an ancient carnivorous whale that lived during the Eocene period (approximately 37 million years ago). This is the first such find, indicating that this animal lived in the Urals in ancient times. The unique find was discovered by Maxim Sinitsa, Associate professor of the UrFU Department of Biodiversity and Bioecology, during a joint expedition of the Ural-Siberian Society of Fossil Lovers public organization.

"We have been collecting fossils on the banks of the Tura River. The expedition included both volunteers and professional paleontologists from Ekaterinburg and Tyumen. We traveled to a well-known location, where Eocene deposits, about 37 million years old, are exposed for many kilometers. This time, hundreds of teeth and skeletal fragments of cartilaginous (rays, gray, otodus and sand tiger sharks of the genera striatolamia, yekelotodus, mennerotodus, physogaleus), bony fish (whiting, cod and tuna fish), as well as part of the shell of a turtle were found. But the main find is a well-preserved fragment of an ancient whale tooth from the extinct Basilosaurid family," says Maxim Sinitsa.

Women of Science: A Legacy of Achievement

Future generations to pursue their passions and break down barriers in the pursuit of knowledge.
Image Credit: Scientific Frontline stock image

Throughout history, women have made groundbreaking contributions to science, despite facing significant societal barriers and a lack of recognition. Their relentless pursuit of knowledge and innovation has shaped our understanding of the world and paved the way for future generations of scientists. This article celebrates the achievements of some of these remarkable women, highlighting their struggles and the impact of their work.

The women featured in this article, along with countless others throughout history, have made invaluable contributions to the advancement of science. Their achievements, often accomplished in the face of adversity and societal barriers, have shaped our understanding of the world and paved the way for future generations of scientists. These women demonstrate the power of perseverance, the importance of challenging established norms, and the profound impact that individual dedication can have on scientific progress. By recognizing and celebrating their legacies, we not only honor their contributions but also inspire future generations to pursue their passions and break down barriers in the pursuit of knowledge.

Apex predators in prehistoric Colombian oceans would have snacked on killer whales today

. Illustration of some of the apex predators in the Paja Formation biota with a human for scale.
Illustration Credit: Guillermo Torres, Hace Tiempo, Instituto von Humboldt.

Predators at the top of a marine food chain 130 million years ago ruled with more power than any modern species, McGill research into a marine ecosystem from the Cretaceous period revealed. 

The study, published in the Zoological Journal of the Linnean Society, reconstructs the ecosystem of Colombia’s Paja Formation, and finds it was teeming with marine reptiles reaching over 10 meters in length that inhabited a seventh trophic level.  

Trophic levels are the layers or ranks within a food chain that describe the roles organisms play in an ecosystem based on their source of energy and nutrients. Essentially, they help define who eats whom in an ecosystem. Today’s marine trophic levels cap at six, with creatures like killer whales and great white sharks. 

The discovery of giant marine reptile apex predators occupying a seventh trophic level underscores the Paja ecosystem’s unmatched diversity and complexity, offering a rare view into an evolutionary arms race among predators and prey. 

In the evolution of walking, the hip bone connected to the rib bones

New reconstruction of the skeleton of Tiktaalik roseae, a 375-million-year-old fossil fish. In a new study, researchers used micro-CT imaging to reveal vertebrae and ribs of the fish that were previously hidden beneath rock. The new reconstruction shows that the fish’s ribs likely attached to its pelvis, an innovation thought to be crucial to supporting the body and for the eventual evolution of walking.
Photo Credit: Thomas Stewart / Pennsylvania State University
(CC BY-NC-ND 4.0 DEED)

Before the evolution of legs from fins, the axial skeleton — including the bones of the head, neck, back and ribs — was already going through changes that would eventually help our ancestors support their bodies to walk on land. A research team including a Penn State biologist completed a new reconstruction of the skeleton of Tiktaalik, the 375-million-year-old fossil fish that is one of the closest relatives to limbed vertebrates. The new reconstruction shows that the fish’s ribs were likely attached to its pelvis, an innovation thought to be crucial to supporting the body and for the eventual evolution of walking.

A paper describing the new reconstruction, which used microcomputed tomography (micro-CT) to scan the fossil and reveal vertebrae and ribs of the fish that were previously hidden beneath rock, appeared in the journal Proceedings of the National Academy of Sciences.

“Tiktaalik was discovered in 2004, but key parts of its skeleton were unknown,” said Tom Stewart, assistant professor of biology in the Eberly College of Science at Penn State and one of the leaders of the research team. “These new high-resolution micro-CT scans show us the vertebrae and ribs of Tiktaalik and allow us to make a full reconstruction of its skeleton, which is vital to understanding how it moved through the world.”

Persian plateau unveiled as crucial hub for early human migration out of Africa

Pebdeh Cave located in the southern Zagros Mountains. Pebdeh was occupied by hunter-gatherers as early as 42,000 years ago.
Photo Credit: Mohammad Javad Shoaee

A new study combining genetic, palaeoecological, and archaeological evidence has unveiled the Persian plateau as a pivotal geographic location serving as a hub for Homo sapiens during the early stages of their migration out of Africa.  

This study sheds new light on the complex journey of human populations, challenging previous understandings of our species’ expansion into Eurasia. 

The study, published in Nature Communications, highlights a period between 70,000 to 45,000 years ago when human populations did not uniformly spread across Eurasia, leaving a gap in our understanding of their whereabouts during this time frame. 

Research uncovers a rare resin fossil find: A spider that aspires to be an ant

Ant-mimicking spider in fossilized resin
Photo Credit: George Poinar Jr / Oregon State University

Arachnophobia can make humans flee at the sight of a brown recluse, black widow or even a daddy long legs, but animal predators of spiders know no such fear.

That’s why paleobiologist George Poinar Jr. explains, some spider species have developed the defense of deception. They masquerade as a much less desirable prey – ants – and Poinar’s recent paper in Historical Biology presents an early record of an ant-mimicking spider in fossilized resin.

“Ants are particularly good creatures for spiders to pretend to be – many animals find ants distasteful or dangerous to eat,” said Poinar, who has a courtesy appointment in the Oregon State University College of Science. “Ants are aggressive in their own defense – they have a strong bite as well as stinging venom, and they can call in dozens of nestmates as allies. Spiders, meanwhile, have no chemical defenses and are loners, which makes them vulnerable to being hunted by larger spiders, wasps and birds – predators that would rather avoid ants. So, if a spider can be like an ant, it’s more likely to be unbothered.”

Spiders that disguise themselves as ants live in many locations around the globe but until now most had been able to avoid detection from fossil researchers as well as predators. The specimen that Poinar describes, which he named Myrmarachne colombiana, was entombed in a type of fossilized resin known as copal.

Rays were more diverse 150 million years ago than previously thought

Aellopobatis bavarica: The newly discovered species, complete fossils are only known from Germany. This species is also the largest species of all and can grow up to 170 cm in size.
Photo Credit: Türtscher et al.

New fossil ray species discovered in Bavarica, Germany: Aellopobatis bavarica from the Late Jurassic

In a new study recently published in the journal Papers in Paleontology, an international team of scientists led by paleobiologist Julia Türtscher from the University of Vienna has explored the puzzling world of rays that lived 150 million years ago and discovered a previously hidden diversity – including a new ray species. This study significantly expands the understanding of these ancient cartilaginous fish and provides further insights into a past marine ecosystem.

In her new study, paleobiologist Julia Türtscher from the Institute of Paleontology at the University of Vienna examined 52 fossil rays from the Late Jurassic period. These rays are 150 million years old, from a time when Europe was largely covered by the sea, except for a few islands, comparable to today's Caribbean. The Late Jurassic specimens are particularly valuable to scientists because they are among the oldest known fully preserved ray specimens. As only the teeth of fossilized rays are usually preserved, such rare skeletal finds provide exciting insights into the early evolution of this group. Although the exceptionally well-preserved fossils (from Germany, France, and the UK) have been known for some time, they have been largely unexplored. Türtscher's study is the first comprehensive analysis of the variation in body shape in these rays.

Killer instinct drove evolution of mammals’ predatory ancestors

Inostrancevia, a more advanced predatory synapsid and one of the first sabertoothed carnivores, from the late Permian (~259-252 Million years ago). (Display at the Royal Ontario Museum, Canada).
Photo Credit: Suresh A. Singh

The evolutionary success of the first large predators on land was driven by their need to improve as killers, researchers at the University of Bristol and the Open University suggest.

The forerunners of mammals ruled the Earth for about 60 million years, long before the origin of the first dinosaurs. They diversified as the top predators on land between 315–251 million years ago.

Researchers studied the jaw anatomy and body size of carnivorous synapsids, using these traits to reconstruct the likely feeding habits of these ancient predators and chart their ecological evolution through time. They found a major shift in synapsid jaw function roughly 270 million years ago linked to a significant shift in predatory behavior that has important implications for the evolution of our earliest ancestors. 

As herbivores grew larger and faster, carnivores adapted to become bigger and better predators to survive.

“Earlier synapsid predators such as the famous sail backed Dimetrodon, had fairly long jaws with lots of teeth to ensure that once they ensnared their prey, it wouldn’t escape,” explained lead author Dr Suresh Singh based in Bristol’s School of Earth Sciences. “However, we saw a shift in jaw function toward shorter jaws with greater muscle efficiency and fewer teeth that were concentrated at the front of the jaw - these were jaws adapted to deliver deep, powerful bites.

Ancient air-breathing fish comes to surface

Life reconstruction of Harajicadectes zhumini, a 40 cm long lobe-finned fish that is not too distantly related to the fishes that gave rise to the earliest limbed tetrapods.
Illustration Credit: Brian Choo, Flinders University

Alice Spring’s Finke River (Larapinta), often cited as one of the oldest rivers in the world, once hosted waters teeming with bizarre animals – including a sleek predatory lobe-finned fish with large fangs and bony scales.

The newly described fossil fish has been named Harajicadectes zhumini by an international team of researchers led by Flinders University paleontologist Dr Brian Choo.

The fossil was named for the Harajica Sandstone Member where the fossils were found in Australia’s ‘Red Centre’ and the ancient Greek dēktēs (“biter”). It also pays homage to Professor Min Zhu, currently at the Chinese Academy of Sciences, Beijing, who has made some major contributions to the research of early vertebrates.

Insects already had a variety of defense strategies in the Cretaceous

Larva of a wedge-shaped beetle in amber, which could have lived inside other insects like its modern counterparts. 
Image Credit: © Carolin Haug

Analyses of amber show that insect larvae were already using a wide variety of tactics to protect themselves from predators 100 million years ago.

Early life stages of insects fulfill important functions in our ecosystems. They decompose dead bodies and wood, forming soil and returning various elements into material cycles. Not least, they are a major food source for many larger animals such as birds and mammals. This has led to many insect larvae developing structures and strategies for reducing the danger of being eaten. These include features like spines and hairs, but also camouflage and concealment. Over millions of years, a wide variety of such adaptation strategies have developed.

Researchers at LMU and the universities of Greifswald and Rostock have studied particularly well-preserved fossils from Burmese amber and have been able to demonstrate that such anti-predator mechanisms had already evolved very diverse forms in insect larvae during the Cretaceous period 100 million years ago. This includes well-known strategies such as that employed by lacewing larvae, which carry various plant and animal materials on their back to give them camouflage, or the ploy of mimicking the appearance of certain plant parts.

Deadly chicken disease: ancient DNA reveals evolution of virulence

With the increase in poultry farming, Marek's disease virus evolved
Photo Credit: Heidi-Ann Fourkiller

Using genetic analyses, an international team led by LMU paleogeneticist Laurent Frantz has revealed the evolutionary history of the pathogen of a fatal disease in chickens.

A notifiable animal disease in Germany, Marek’s disease is caused by the globally distributed Marek’s disease virus (MDV). Over the past century, the virus, which causes tumors in chickens and has a high mortality rate, has become increasingly aggressive. Combating the disease costs the poultry industry over a billion dollars every year. With the help of ancient DNA, an international team of scientists led by LMU paleogenomicist Professor Laurent Frantz and Professor Greger Larson and Professor Adrian Smith from the University of Oxford has now decoded the evolution of MDV and shed light on what is behind the growing virulence.

The international team from the fields of paleogenetics, archeology, and biology isolated viral genomes from chicken bones up to 1,000 years old from 140 archeological sites in Europe and the Near East. “Our data shows that the virus was already widely distributed at least 1,000 years before the first description of the disease in 1907,” says Frantz. When the disease was first described, it was said to produce only mild symptoms in older chickens. With the dramatic increase in poultry farming in the 1950s and 1960s, the virus evolved and has become increasingly virulent despite the development of several vaccines.

This Japanese ‘dragon’ terrorized ancient seas

UC Associate Professor Takuya Konishi is an expert on ancient marine reptiles such as mosasaurs.
 Photo Credit: Joseph Fuqua II/UC

Researchers have described a Japanese mosasaur the size of a great white shark that terrorized Pacific seas 72 million years ago.

Extra-long rear flippers might have aided propulsion in concert with its long-finned tail. And unlike other mosasaurs, or large extinct marine reptiles, it had a dorsal fin like a shark’s that would have helped it turn quickly and with precision in the water.

University of Cincinnati Associate Professor Takuya Konishi and his international co-authors described the mosasaur and placed it in a taxonomic context in the Journal of Systematic Palaeontology.

The mosasaur was named for the place where it was found, Wakayama Prefecture. Researchers call it the Wakayama Soryu, which means blue dragon. Dragons are creatures of legend in Japanese folklore, Konishi said.

“In China, dragons make thunder and live in the sky. They became aquatic in Japanese mythology,” he said.