PhD student Tharika Liyanage is on a quest to solve a molecule mystery that dates back billions of years, writes Lauren Pay.

Everyone has a different soul-burning question.

It might be ‘what is the meaning of life?’ or ‘will I ever find love?’

Such questions sit heavy on the heart, and could, in some cases, remain forever unanswered.

Most of us must learn to live with the idea of never knowing. But not Tharika Liyanage. The ANU PhD researcher has decided that instead of waiting around, she will answer her soul-burning question: who makes cheilanthanes?

A cheilan-what now?

Exactly.

They may be almost invisible, but cheilanthanes are a big deal. These fossilised biological molecules dating back billions of years are found in almost every rock and oil on Earth. There’s probably more than 500 billion tonnes of the stuff. That’s more mass than if we combined all the plants, animals, insect, people and fungi alive today.

The problem is we don’t know who made cheilanthanes. Liyanage is on a quest to find out where they come from.

“The whole mystery was so intriguing,” Liyanage says.

“Previous research on this topic had stalled because they were looking in the past, but I’m searching for the source in the present.”

One is easily caught up in the drama of this mystery, even before knowing what a cheilanthane is, or why they are so important.

But important they are. This stealthy molecule is likely to play a crucial role in challenging our ideas of how life evolved on our planet.

In essence, a cheilanthane is a hydrocarbon. It can also be classified as a biomarker, which are fossilised markers of certain molecules preserved in the rock record.

“With their presence, we can start to make deductions about past ecosystems,” Liyanage explains.

“Cheilanthanes are so interesting because they are found in the rock record as far back as 1.64 billion years ago, and all through the geological record to more recently.”

Previous research has indicated the source of these cheilanthanes is extinct, but Liyanage has discovered that might not be the case.

Her quest for answers took her around the globe. Using a technique she invented for this purpose, she found evidence of cheilanthanes in the European Alps, and even as far as Antarctica.

“When we first realised that there was evidence suggesting cheilanthane producing organisms still existed I was dumbfounded,” Liyanage says.

“We spent such a long time looking so I was nervous we were never going to find them. It really was one of those Eureka moments.”

This important finding has allowed her to link the biomarker with a biological source.

“We can now work to piece together past ecosystems in Earth’s history,” Liyanage explains.

This discovery is the topic of Liyanage’s entry to the Three Minute Thesis (3MT) competition. Having won the ANU round and then gone head-to-head with 54 other presenters in the semi-finals, Liyanage then placed second at the Asia-Pacific final.

It’s an incredible feat for an incredible young researcher on an incredible quest.

However, Liyanage doesn’t intend for the story of cheilanthanes to end here.

“There are still lots of unanswered questions about why they are made, and how this might be used to our benefit,” she says.

She now has many more soul-burning questions about this amazing molecule, and will continue her research to answer as many as she can.

Watch Tharika Liyanage’s Three Minute Thesis presentation here.

Featured image: PhD researcher Tharika Liyanage is on the hunt for a mysterious molecule that may rewrite the books on evolution . Photo : ANU

Provided by ANU

Three dinosaurs from Northwest China represent two new species and are some of the first vertebrates uncovered in the region, according to a study published in Scientific Reports. The findings shed light on sauropods in China.   

Dr. Xiaolin Wang and colleagues analysed fossil fragments (spinal vertebrae and rib cage) previously discovered in the Turpan-Hami Basin (Xinjiang, China) and dated to the Early Cretaceous (around 130 to 120 million years ago). They compared specific features of the remains (vertebrae and rib structure) to other sauropod dinosaurs from China and other localities. 

The authors identified the first specimen as a new species and named it Silutitan sinensis. The authors found that some characteristics of the neck vertebrae indicate that it belonged to a family of sauropods known as Euhelopodidae, which so far have been found only in East Asia. They compared the specimen with what they believe was a closely related group of dinosaurs, or genus, (Euhelopus) and estimated that the specimen was originally over 20 metres long.   

The authors named the second specimen, which they also identify as a new species, Hamititan xinjiangensis. The specimen consists of seven vertebrae from the tail, which the authors believe are the fourth to tenth in the spine. The authors conclude the shape and ridges along vertebrae suggest that it belonged to a family of sauropods known as Titanosaurs, abundant in both Asia and South America. They estimate the full specimen was 17 meters long by comparing it to what they believe to be closely related genera (Rapetosaurus and Opisthocoelicaudia).

The third specimen was limited to four vertebrae and rib fragments. The authors’ analysis suggests it may be a somphospondylan sauropod, a group of dinosaurs who lived from the late Jurassic, 160.3 million years ago to the late Cretaceous, 66 million years ago.

These samples are some of the first dinosaurs reported in the Turpan-Hami Basin, increasing the known diversity of the Mesozoic reptiles found in the area. The findings also shed light on which sauropods were present in China. 

Featured image: Map showing the fossil site where the new sauropod dinosaur specimens were collected (A,B), and the relative positions of these three specimens (C). Credit: Nature Publishing Group

Reference: Wang, X. et al, The first dinosaurs from the Early Cretaceous Hami Pterosaur Fauna, China, Sci Rep (2021). DOI: 10.1038/s41598-021-94273-7

Provided by Nature Publishing Group

The diet of animals is an important part of understanding how they behave and what roles they play in the world. This is more difficult to know in fossil animals because they rarely preserve all of the information we would need. Reconstructing the diet of fossil birds has been especially hard as they have small, fragile bodies that are challenging to preserve. Our current knowledge of fossil bird diet heavily relies on rare instances where food was preserved inside their fossilised bodies. Of the over 150 species of birds currently known from the Mesozoic Era, the period of Earth’s history when dinosaurs ruled the Earth, only 7 species have any sort of food preserved in their stomachs (Fig. 1).

HKU PhD student Case Vincent MILLER and his supervisor Research Assistant Professor & Assistant Dean (e-learning) Dr Michael PITTMAN (Vertebrate Palaeontology Laboratory, Research Division for Earth and Planetary Science & Department of Earth Sciences) want to change this. The duo reviewed more than 1,000 publications on animal diet, with a special focus on birds and non-avian dinosaurs, while also incorporating innovations from other fields including medicine and materials science. In the end, they produced a framework of seven techniques to combine for determining fossil bird diet (Fig. 2). Dr Pittman notes, “As a scientist, it is risky to rely on only a single line of evidence. It’s when you find several that agree that you can better support your conclusions.”

Very little quantitative work has been done on fossil bird diet, the team reports, but in the review they identified some fossil birds with previously-unrecognised agreement on their diet. The first is Shenqiornis, an Early Cretaceous enantiornithine “opposite bird” from northern China. The shape of its claws and the mechanics of its jaws (Fig. 3) point to it being a carnivore. The second is Confuciusornis (Fig. 4), one of the first beaked fossil birds, which is known from hundreds of specimens from the Early Cretaceous of northern China. Two different mechanical metrics of its jaw, including one Miller and Pittman studied last year (see note 1), found it suited for eating plants. The duo note that the diet of the earliest undisputed bird, Archaeopteryx, is still uncertain despite several quantitative studies looking at it. The studies contradict one another, which may mean that different individuals of Archaeopteryx ate different things.

The team’s next goal is to apply their framework to groups of fossil birds whose diets remain unstudied. “When I started my PhD, I planned on studying the diet of obscure bird groups that scientists still hadn’t figured out,” Miller said. “But to my surprise, scientists hadn’t figured out the diet of most fossil birds! I’ve identified several families of Mesozoic birds with interesting dietary hypotheses to test during my PhD. Preliminary application of our framework to one of those families managed to narrow their diet possibilities from five down to two, and increase the number of known fossil bird diets by almost 20%. To anyone interested in the ecology of Mesozoic birds and the origins of today’s bird diversity, I would say the future looks very bright.”

The paper is published in Biological Reviews and can be accessed here .

Featured image: Reconstruction of the early fossil beaked bird Confuciusornis. The beak of Confuciusornis was previously studied by this team and found to have strength similar to birds eating plants or insects. Image credit: Gabriel Ugueto.

Reference: Miller, C.V. and Pittman, M. (2021), The diet of early birds based on modern and fossil evidence and a new framework for its reconstruction. Biol Rev. https://doi.org/10.1111/brv.12743

Provided by HKU

Paleontologists have identified a new genus and species of small-sized mesoeucrocodylian from the fossilized remains found in the Patagonian mountains of southern Chile.

A 150-million-year-old fossilized skeleton discovered in the mountains of southern Chile was determined to be the ancestor of the modern crocodile, the Argentine Museum of Natural Sciences announced on Friday.

The species, named Burkesuchus mallingrandensis, was found in 2014 in an Andean fossil deposit near the Patagonian town of Mallin Grande by Argentine and Chilean researchers. Since then it has been analyzed at the Argentine Museum of Natural Sciences (MACN) in Buenos Aires.

The specimen is a “grandfather” of current crocodiles and should allow scientists to understand how they evolved, the museum said.

Scientists believe the fossil will help them understand how these reptiles went from being terrestrial to aquatic. Along with other fossils, the discovery supports the idea that South America was the cradle of evolution for crocodiles.

About 200 million years ago “crocodiles were smaller, and did not live in water. Paleontologists always wanted to know what that transition was like,” Federico Agnolin, who found the specimen, told Reuters.

“What Burkesuchus shows is a series of unique traits, which no other crocodile has because they were the first that began to get into the water, into fresh water,” Agnolin said.

According to the MACN, crocodiles appeared at the beginning of the Jurassic period, around the time of the first dinosaurs. In a few million years they got into the water, thanks to the existence of warm and shallow seas. South America is known for its richness in marine crocodile fossils.

A paper on the findings was published in the journal Scientific Reports.

Featured image: Paleontologist Fernando Novas holds the fossil skull of the Burkesuchus mallingrandensis, which could shed light on the origin of modern crocodiles, in Buenos Aires, Argentina March 9, 2021. Laboratorio de Anatomia Comparada – Museo de Ciencias Naturales “Bernardino Rivadavia”/Handout via REUTERS

Reference: F.E. Novas et al. 2021. New transitional fossil from late Jurassic of Chile sheds light on the origin of modern crocodiles. Sci Rep 11, 14960; doi: 10.1038/s41598-021-93994-z

Provided by REUTERS

Whole-genome sequencing efforts around the world have offered important insights into human diversity, historical migrations, and the relationships between people of different regions—but scientists still don’t have a complete picture because some regions and people remain understudied. A new study reported in the journal Cell on August 4 helps to fill one of these big gaps by generating more than 100 high-coverage genome sequences from eight Middle Eastern populations using linked-read sequencing.

“The Middle East is an important region to understand human history, migrations, and evolution: it is where modern humans first expanded out of Africa, where hunter-gatherers first settled and transitioned into farmers, where the first writing systems developed, and where the first major known civilizations emerged,” says Mohamed Almarri of the Wellcome Sanger Institute, UK. “However, despite this importance, the region has been historically understudied in genomic studies.”

In the new study*, Almarri, Marc Haber (@MarcHaber, University of Birmingham, UK), and their colleagues sequenced 137 whole genomes from eight Middle Eastern populations.

By generating the most comprehensive resource of human genetic variation in the Middle East using a new sequencing technology called linked-read sequencing, the researchers were able to reconstruct the genomic history of the region with unprecedented resolution. The researchers say that some of the events recorded in the Middle Eastern genomes could be linked with what’s known from archeology or linguistics, such as the invention of agriculture and the spread of Semitic languages. But other events can only be elucidated by studying the DNA of ancient and modern people who lived in the region.

Some of their most notable findings include the following:

• The identification of 4.8 million new gene variants that are specific to Middle Eastern populations that could now provide the basis for future research.
• Genetic variants that show evidence of selection—in other words, mutations that spread unusually quickly—potentially due to adaptation to the changing environment and lifestyle.
• In the Levant, where agriculture was first developed, populations experienced a massive growth around the transition to agriculture that wasn’t paralleled in Arabia.
• Arabian populations suffered a severe population decrease around 6,000 years ago, which coincides with the change in climate in Arabia turning it from a green, wet region into the largest sand desert in the world today.
• Middle Easterners descend from the same population that expanded out of Africa 50,000 to 60,000 years ago.
• Arabian groups have significantly lower Neanderthal ancestry than other Eurasians, potentially caused by excess basal Eurasian and African ancestry in Arabians that depletes their Neanderthal ancestry
• The movement of populations during the Bronze Age potentially spread the Semitic languages from the Levant to Arabia and East Africa.
• An increase in the frequency of variants associated with type 2 diabetes in some populations in the past 2,000 years, suggesting that variants that were beneficial in the past are today associated with diseases.

“We found 4.8 million variants that were not previously discovered in other populations,” Haber says. “Hundreds of thousands of these are common in the region, and any of them could hold medical relevance.”

“Our study fills a major gap in international genomic projects by cataloguing genetic variation in the Middle East,” says Chris Tyler-Smith of the Wellcome Sanger Institute, UK. “The millions of new variants we found in our study will improve future medical association studies in the region. Our results explain how the genetics of Middle Easterners formed over time, providing new insights, which complement knowledge from archeology, anthropology, and linguistics.”

The researchers say they will now follow up on variants that show evidence of selection. Through these continued studies, they hope to further understand the biological effects of those newly found variants while further refining the genetic history of the region.

Cover Image: Top Left: Genome sequencing has been key to understanding much about the human past. Image Kennethr, Pixabay

Reference: Almarri et al.: “The Genomic History of the Middle East”, Cell, 2021. https://www.cell.com/cell/fulltext/S0092-8674(21)00839-4 

Provided by Cell Press

The bones of an ancient man who lived in our area until about 130,000 years ago were discovered in excavations at the prehistoric site “Nesher Ramla”

Researchers from Tel Aviv University and the Hebrew University have identified a new type of ancient man at the Nesher Ramla site, who lived in Israel until 130,000 years ago. According to the researchers, the morphology of the human type “Eagle Ramla” is a general morphology, and it shares features both with the Neanderthals (mainly in the teeth and jaw) and with older humans such as Homo erectus (mainly in the skull). At the same time, it is very different from modern man – the structure of the skull is completely different, it has no chin and the teeth are very large. Following the findings of the study, the researchers believe that the ancient human group “Nesher Ramla” is the origin population from which most human populations in the Middle Pleistocene evolved, including the Neanderthals from Europe, and they mated with Homo sapiens who arrived in the area 200,000 years ago. .

Behind the exciting discovery, published in the prestigious journal Science, are two research teams: an anthropological team led by Prof. Israel Hershkovitz, Dr. Hila May and Dr. Rachel Sarig of the Sackler Faculty of Medicine , Dan David Center for Human History Research and the Shmonis Institute of Anthropology, Sitting at the Steinhardt Museum of Nature at Tel Aviv University, and an archeological team led by Dr. Yossi Zeidner of the Institute of Archeology at the Hebrew University of Jerusalem. The excavations at the site were conducted by the Zinman Institute of Archeology, University of Haifa.

The “new” ancient man

“The scientific importance of finding a new type of human allows us to put the fossil world in order, put together another piece in the puzzle of ancient human evolution and understand the journeys he went through around the old world,” says Prof. Hershkovitz. “The” Nesher Ramla “human type is the bridge between the Asian and European populations in the Middle Pleistocene and shows that some of the fossils of the time classified into different species are in fact local geographical orientations of the same group – the Nesher Ramla group.”   

The human fossil was discovered by Dr. Zeidner of the Hebrew University in rescue excavations conducted at the prehistoric site “Nesher Ramla”. This site is located in the mining area of ​​the Nesher cement plant (owned by Len Belvatnik) near the city of Ramla. Many animals such as horses, donkeys and wild bulls, stone tools as well as human bones. Among the bones were also the bones of the “new” ancient man. Was known to science.This is the first type of person defined in the country, and as is customary, the new person was named based on the place of his discovery – “person type Nesher Ramla”.

Dr. Zeidner further noted that “the discovery is extraordinary, we did not imagine that alongside the ancient Homo sapiens, another group of people roamed here who survived to such a late stage in human history. If so far there have not been enough findings regarding this type of person, now a window is opened for us to know more about his lifestyle and culture that were very close to those of Homo spines. “Findings regarding his lifestyle, culture and cultural connections between” Adam Nesher Ramla ” They too are today in the scientific journal Science in a parallel article.

Prof. Hershkovitz adds that the discovery of the ancient man “Nesher Ramla” challenges the accepted view that Neanderthal man originated in Europe. “Until the new findings were revealed, most researchers believed that the Neanderthals were a ‘European story’, with small groups of them having to migrate south with the spread of glaciers in Europe and even arriving in Israel about 70,000 years ago. The man from Nesher Ramla challenges this theory. “Neanderthals in Europe lived in Israel about 400,000 years ago, and from here they migrated (in repeated migrations) west to Europe and east to Asia. The famous Neanderthals of Western Europe are nothing but the remnants of a much larger population living here in the Levant – and not the other way around.”

According to Dr. May, although unfortunately no DNA has been preserved in the Ramla fossil fossil, the findings could offer a solution to a very big question in human history: how Homo sapiens genes entered the Neanderthal population living in Europe long before Homo sapiens arrived there. In previous studies geneticists studying the DNA of Neanderthals in Europe assumed the existence of a Neanderthal-like population, which they called the “missing population” or “X population”, which mated with the Homo sapiens population at least 100,000 years ago, and its descendants migrated to Europe. -Science, the researchers claim that the person from “Nesher Ramla” represents the same population that is missing in the human fossil evidence. Moreover, the researchers claim that the person from “Nesher Ramla” is not a single find in our area, Like the human fossils from the Tabun Cave that are about 160,000 years old,

The Land of Israel as a melting pot in the old world

“People think in paradigms,” explains Dr. Sarig, “so to this day attempts have been made to associate these fossils with known human groups such as Homo sapiens, Homo erectus, Homo heidelbergensis or Neanderthals, and now we come and say: No – they are a group in themselves with characteristics And special markers. At a later stage small groups of the Nesher Ramle human type also migrated to Europe (in interglacial periods) – where they are known as pre-Neanderthals, and evolved, over time, to become the ‘classic Neanderthals’ we know. Similarly, the archaic Asian populations that carry Neanderthal characteristics (and were considered an evolution from the local Homo erectus) are probably the descendants of populations that migrated from our region (human type Nesher Ramla) eastward towards Asia. Being a crossroads between Africa, Europe and Asia, the Land of Israel was a melting pot in which the various human populations mingled with each other and spread throughout the Old World.

Dr. Sarig believes that this discovery of a new type of man with primordial (archaic) and Neanderthal features, with similarities to fossils from both Europe and East Asia, will lead to the history of Neanderthals being studied differently. More, European-Asian, where the Levant is the starting point or connection point between the two continents.

“The discovery from the Nesher Ramla site writes a new and fascinating chapter in the story of human evolution,” says Dr. Sarig. “A common perception among anthropologists,” says Prof. Hershkovitz, is that “the past changes (according to the findings), only the future is certain.”

Provided by Tel Aviv University

Researchers from the University of Bristol and University College London have used cutting-edge techniques to digitally reconstruct the skull of one of the earliest limbed animals.

Tetrapods include mammals, reptiles and amphibians – everything from salamanders to humans. Their origin represents a crucial time in animal evolution, from the development of limbs with digits and the shift from water on to land. The study, which was recently published in the Journal of Vertebrate Paleontology, depicts the reconstructed skull of a prehistoric amphibian, the 340-million year old Whatcheeria deltae, to reveal what this animal looked like and how it may have fed.

First discovered in Iowa in 1995, the fossils of Whatcheeria were originally squashed flat after being buried by mud at the bottom of an ancient swamp, but palaeontologists were able to use computational methods to restore the bones to their original arrangement. The fossils were put through a CT scanner to create exact digital copies, and software was used to separate each bone from the surrounding rock. These digital bones were then repaired and reassembled to produce a 3D model of the skull as it would have appeared while the animal was alive.

The authors found that Whatcheeria possessed a tall and narrow skull quite unlike many other early tetrapods that were alive at the time. Lead author James Rawson, who worked on this project alongside his undergraduate degree in palaeontology and evolution, said: “Most early tetrapods had very flat heads which might hint that Whatcheeria was feeding in a slightly different way to its relatives, so we decided to look at the way the skull bones were connected to investigate further.”

By tracing the connecting edges of the skull bones, known as sutures, the authors were able to figure out how this animal tackled its prey. Professor Emily Rayfield, of the University of Bristol’s School of Earth Sciences, who also worked on the study, said: “We found that the skull of Whatcheeria would have made it well-adapted to delivering powerful bites using its large fangs.”

Co-author Dr Laura Porro said: “There are a few types of sutures that connect skull bones together and they all respond differently to various types of force. Some are better at dealing with compression, some can handle more tension, twisting and so on. By mapping these suture types across the skull, we can predict what forces were acting on it and what type of feeding may have caused those forces.”

The authors found that the snout had lots of overlapping sutures to resist twisting forces from struggling prey, while the back of the skull was more solidly connected to resist compression during biting.

Mr Rawson added: “Although this animal was still probably doing most of its hunting in the water, a bit like a modern crocodilian, we’re starting to see the sorts of adaptations that enabled later tetrapods to feed more efficiently on land.”

Paper:

‘Osteology and digital reconstruction of the skull of the early tetrapod Whatcheeria deltae’ in Journal of Vertebrate Paleontology by James Rawson, Dr Laura Porro, Dr Elizabeth Martin-Silverstone and Professor Emily Rayfield.

Featured image: Skull fossils of amphibian. Credit: Field Museum of Natural History, Chicago

Provided by University of Bristol