Tag Archives: fossils

Ancient Fossils of Land-Dwelling Animals Found in Australia Dating Back 380 Million Years

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Paleontologist at Flinders University brian chu and his colleagues described a new genus and species of Devonian tetrapod fish based on several nearly complete skulls and postcranial skeletons.

rebuilding the life of Harajikadectes zumini. Image credit: Brian Choo, Flinders University.

“Tetrapodomorpha “It consists of tetrapods and their closest fish relatives, the oldest records of which are from the Pragians of China,” said Dr Chu and co-authors.

“This group diversified greatly in both marine and freshwater habitats during the Middle to Late Devonian, giving rise to several distinct lineages, including the earliest quadrupeds.”

“Tetrapods flourished after the Devonian limbless fish tetrapods experienced a marked decline in diversity during the Carboniferous, but only survived into the early Permian before disappearing from the fossil record. There were only a handful of representative animals.”

This new species of tetrapod lived about 380 million years ago and was up to 45 to 50 centimeters long.

with scientific name Harajikadectes zuminithis fish is particularly distinctive for its large opening at the top of its skull.

“These spire-like structures are thought to facilitate air breathing at the surface, and modern African bichir fish have similar structures for taking in air at the surface,” said Dr Chew. Ta.

“This feature appears in multiple tetrapomodorf lineages at about the same time during the middle to late Devonian period.”

“In addition to Harajikadectes zumini Large spiracles also appeared from central Australia. gogonathus El Pisto Stegarian from Western Australia Tiktaalik — are the closest relatives of four-limbed quadrupeds. ”

“And it shows up in unrelated places.” Pickeringius Western Australian stingray fin fish first described in 2018. ”

with Dr. Chu Harajikadectes zumini fossil. Image credit: Flinders University.

Professor John Long from Flinders University said: “This synchronous emergence of air-breathing adaptations may have coincided with a period of reduced atmospheric oxygen during the mid-Devonian.”

“The ability to supplement gill breathing with oxygen from the air may have provided an adaptive advantage.”

“We discovered this new form of lobe-finned fish in one of the most remote fossil sites in all of Australia, the Harajika Sandstone Formation in the Northern Territory, about 200km west of Alice Springs. It dates from the mid-Devonian period. Late period, approximately 380 years ago.'' 1 million years old. ”

“It's difficult to pinpoint the location. Harajikadectes zumini sit in this group of fishes because they appear to have convergently acquired a mosaic of specialized features characteristic of widely separate branches of the tetrapod radiation. ”

of findings will appear in Journal of Vertebrate Paleontology.

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brian chu other. A new species of pedunculated tetrapod fish that lived in the middle to late Devonian period of central Australia. Journal of Vertebrate Paleontology, published online on February 5, 2024. Doi: 10.1080/02724634.2023.2285000

Source: www.sci.news

Fossils dating back 1.75 billion years shed new light on the evolution of photosynthesis

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Microscopic image of a modern cyanobacterium called Oscillatoria

Shutterstock / Ekki Ilham

Researchers have identified photosynthetic structures inside a 1.75 billion-year-old cyanobacteria fossil. This discovery is the oldest evidence yet of these structures and provides clues to how photosynthesis evolved.

Emmanuel Javeau Researchers from the University of Liège in Belgium analyzed fossils collected from rocks at three locations. The oldest site is the approximately 1.75 billion-year-old McDermott Formation in Australia, the other two are the billion-year-old Grassy Bay Formation in Canada and the Bllc6 Formation in the Democratic Republic of Congo. was.

From these rocks, the researchers extracted fossilized cyanobacteria that produce energy through photosynthesis. “They're so small, less than a millimeter, that you can't see them with the eye,” Java says. She and her colleagues placed the fossils in resin, sliced ​​them into sections 60 to 70 nanometers thick using a diamond-bladed knife, and analyzed their internal structures using an electron microscope.

They discovered that cyanobacteria in Australia and Canada contain thylakoids, membrane-enclosed sacs in which photosynthesis occurs. “These are the oldest fossilized thylakoids that we know of today,” Java says. Previously, the oldest thylakoid fossils were around 550 million years old. “So we delayed the fossil record by 1.2 billion years,” she says.

This is important because not all cyanobacteria have thylakoids and it is unclear when these structures, which make photosynthesis more efficient, first evolved, they said. Kevin Boyce at Stanford University in California. The origins of this diversification can now be traced back at least 1.75 billion years, he says. The oldest fossils of cyanobacteria are about 2 billion years old, but other evidence, such as geochemical signatures, indicate that photosynthesis has been around even longer than that.

It is widely believed that cyanobacteria helped build up oxygen in Earth's atmosphere 2.4 billion years ago. “The idea is that perhaps during this time they invented thylakoids, which increased the amount of oxygen on Earth,” Java says. “Now that we have discovered very old thylakoids and found them preserved in very old rocks, we think we might be able to test this hypothesis even further back in time,” she says. .

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Source: www.newscientist.com

Uncovering the Astonishing Facts about Ancient Bead-Like Fossils

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Paleontologists have determined that a mysterious fruit first discovered in the 1970s is the oldest known frankincense fossil. Scale bar = 2 mm.
Credit: Stephen Manchester

Mysterious fossils discovered in India in the 1970s have been identified as part of the Frankincense family, suggesting a Southern Hemisphere origin and reshaping our understanding of plant evolution. In the early 1970s, paleontologists working on the outskirts of an Indian village discovered tiny bead-like fossils embedded in the gray chert that dotted the surrounding fields. The site was notorious for the discovery of hard-to-identify plant fossils, including the fruits of extinct creatures. The fossils have been named “Enigmocarpon”.

The new fossils proved to be similarly frustratingly unwieldy. More plants were discovered in India in subsequent decades, but scientists were unable to determine which type of plant they belonged to.

A breakthrough in fossil identification: Now, researchers say they have solved the mystery. Stephen Manchester, curator of paleobotany at the Florida Museum of Natural History, used CT scanning technology to create his 3D reconstructions of the original fossil specimens and other specimens collected since then. He showed this to his colleagues and noticed something strange about his five triangular seeds inside.

Before the widespread use of CT scans in paleontology, these small fossils, less than 10 mm in diameter, were particularly difficult to study and identify. “When I showed him the 3-D images, he said, ‘Those aren’t seeds. They’re pyrenes,'” Manchester said with Walter Judd, curator of botany at the Florida Museum. I remembered the conversation. Pyrene is a woody dispersal pod that provides an additional layer of protection to the seeds. Distinguishing between seeds and pyrenes requires close scrutiny, especially when they are the size of a snowflake.

“If we had a specimen that broke in just the right plane, we would have been able to identify it, but we couldn’t identify it with the material we had,” Manchester said. Although they may look like seeds, these woody structures are actually pyrenes, similar to the stones found in peaches and date palms.

Frankincense family connection: Only a few plant groups produce pyrene, and even fewer have fruits containing five seeds arranged in a pentagram. Through a process of elimination, Manchester and Judd determined that the fossils belonged to the frankincense family, an extinct member of the Kansas family. Fossilized trees, leaves, fruits, and flowers of this family have been found elsewhere in India, often sandwiched between thick basalt slabs created by the largest volcanic eruptions in Earth’s history.

Geological background and importance: At that time, India was an island off the southeast coast of Africa. India’s continental plate slowly moved toward Europe and Asia, breaking the seal of a thin layer of Earth’s crust as it passed through Madagascar. The fossils were preserved during a quiet period between eruptions, which makes it the oldest fossil of the Kansidae family ever discovered, and has important implications for the origin of the family. Scientists have a good idea of ​​when this group of plants first evolved, but it’s still unclear where they came from.

Source: scitechdaily.com

Newly Discovered Fossils Shed Light on Enigmatic Human Lineage in the Levant

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Orthographic view of the static skull, mandible, and parietal bones.Credit: Tel Aviv University

Nesher Ramla homoan ancient hominin group discovered in Israel reveals a complex admixture of Eurasian and African hominins 140,000 years ago, changing perceptions of the origins of Neanderthals.

Researchers have discovered a previously unknown archaic hominin group they named Nesha Ramla. homo” at a recently excavated site in Israel. This group, dating from about 140,000 to 120,000 years ago, is thought to be the last survivor of the Middle Pleistocene. homo. They exhibit a unique blend of Neanderthal and ancient human characteristics and technology.

Neanderthals are thought to have originated and flourished in continental Europe long before modern humans arrived. However, recent evidence suggests a genetic contribution from as yet unknown non-European populations and points to a long and dynamic history of interactions between Eurasian and African hominin populations.

Human interaction in Eurasia and Africa

Here, Israel Hershkovitz, Yossi Zeidner and colleagues present fossil, artifact, and radiometric evidence from the Levantine region of the Middle East that illustrates this complexity. According to Hershkovitz et al., the newly discovered Nesher Ramla homo They exhibit anatomical features that are older than their contemporaneous Eurasian Neanderthals and modern humans, who also lived in the Levant. This discovery indicates that this archaic lineage may represent one of the last surviving populations of the Middle Pleistocene. homo in southwest Asia, Africa, and Europe.

Archaeological context and cultural interaction

In joint research, Zaidner other. We provide archaeological context for the new fossils and report on their associated radiometric dates, artifact assemblages, and the behavioral and environmental insights they provide. Researchers found that Nesher Ramla homo Familiar with technology that was previously known only to a select few homo sapiens And Neanderthals. Taken together, these findings provide archaeological support for close cultural interactions and genetic admixture between different human lineages before 120,000 years ago. This may help explain the different expressions of teeth and skeletal features in later Levantine fossils.

“Interpretation of Nesher Ramla fossils and stone tools will have mixed reactions among paleoanthropologists. Nevertheless, the age of Nesher Ramla materials, the discordant morphological and archaeological similarities , and the site’s location at the crossroads of Africa and Eurasia make this a major discovery,” writes Marta Lahr in an accompanying Perspective.

For more information about this research, see Types of prehistoric humans previously unknown to science.

References:

“Middle Pleistocene Homo from Nesher Ramla, Israel” Israel Hershkovitz, Hilla May, Rachel Salig, Ariel Pokhodzhaev, Dominique Grimaud Hervé, Emiliano Bruner, Cinzia Fornai, Rolf Quam, Juan. Written by Luis Arzuaga, Victoria A. Crenn, and Maria Martinon Torres, José María Bermudez de Castro, Laura Martin Frances, Vivian Soulon, Lou Albesado Ball, Amelie Viale, and Tim Schuler , Giorgio Manzi, Antonio Profico, Fabio Di Vincenzo, Gerhard W. Weber, Yossi Seidner, June 25, 2021, science.
DOI: 10.1126/science.abh3169

“Behavior and culture of Homo during the Middle Pleistocene, 140,000 to 120,000 years ago, and interaction with Homo sapiens” Yossi Seidner, Laura Senty, Marion Prevost, Norbert Mercier, Christophe Farguerre, Gilles Guerin, Hélène Valadas, Mairis Richard, Asmodee Ghaly, Christophe Pécherin, Olivier Tombre, Edwidge Pons-Branch, Naomi Porat, Ruth Shahak Gross, David E. Friesem, Reuven Yeshurun, Zohar Turdjman Yaffe, Amos Frumkin, Gadi Herzlinger, Ravid Eckstein, Maayan Shemar, Oz Valoner, Rachel Salig, Hila May, Israel Hershkovitz, June 25, 2021, science.
DOI: 10.1126/science.abh3020

Source: scitechdaily.com