more Quotes
Connect with us

Entertainment news

Shaking the dinosaur family tree: How did ‘bird-hipped’ dinosaurs evolve? – EurekAlert

Dinosaurs of the early Jurassic

image: Top left: Lesothosaurus
Top right: Heterodontosaurus
Foreground: Scutellosaurus

view more 

Credit: John Sibbick

Researchers have conducted a new analysis of the origins of ‘bird-hipped’ dinosaurs – the group which includes iconic species such as Triceratops – and found that they likely evolved from a group of animals known as silesaurs, which were first identified two decades ago.

The researchers, from the University of Cambridge and the Universidade Federal de Santa Maria in Brazil, were attempting to solve a long-standing mystery in palaeontology: where the ‘bird-hipped’ dinosaurs, or ornithischians, came from.

Currently, there is a gap of more than 25 million years in the fossil record, making it difficult to find the branch of the dinosaur family tree where ornithischians belong.

The researchers conducted an extensive analysis of early dinosaurs as well as silesaurs, a group named after Silesaurus, first described in 2003. The researchers suggest that silesaurs progressively modified their anatomy during the Late Triassic Period, so that they came to resemble ornithischians by the Early Jurassic Period.

However, these ornithischian ancestors have the hip structure of the ‘lizard-hipped’ dinosaurs, or saurischians, suggesting that the earliest bird-hipped dinosaurs were in fact lizard-hipped. The results are reported in the Zoological Journal of the Linnean Society.

Dinosaurs originated in the Late Triassic period, about 225 million years ago, and dominated life on Earth until a mass extinction event 66 million years ago. Dinosaurs have fascinated us since they were first named as such by Richard Owen in 1842.

The earliest discovered dinosaur remains were scrappy: odd-looking teeth and a few bones. By the latter half of the 19th century however, enough dinosaur remains had been found that a classification system was needed. Harry Seeley, who had been trained in Cambridge by Adam Sedgwick, developed such a classification of dinosaurs based primarily upon the shape of their hip bones: they were either saurischians (lizard-hipped) or ornithischians (bird-hipped). This classification, first published in 1888, proved reliable: all dinosaur discoveries seemed to slot neatly into one or other of these groupings.

However, in a 2017 paper, Professor David Norman from Cambridge’s Department of Earth Sciences and his former PhD students Matthew Baron and Paul Barrett argued that these dinosaur family groupings need to be rearranged, re-defined and re-named. In a study published in Nature, the researchers suggested that bird-hipped dinosaurs and lizard-hipped dinosaurs such as Tyrannosaurus evolved from a common ancestor, potentially overturning more than a century of theory about the evolutionary history of dinosaurs.

Controversy aside, it has long been recognised that the bird-hipped dinosaurs are clearly anatomically distinct from all other types of dinosaurs, even though they have nothing to do with birds. But how they came to be, has remained a long-standing problem.

“It seemed to be that they originated with all other dinosaurs in the Late Triassic but exhibited a unique set of features that could not be fitted into an evolutionary succession from their dinosaur cousins,” said Norman, who is a Fellow of Christ’s College. “It was as if they just suddenly appeared out of nowhere.”

Recent work has begun to indicate a more varied and puzzling picture of ornithischian origins. From a phylogenetic perspective – how the dinosaur family tree branches over time – it is predicted that ornithischian remains should first appear in the fossil record about 225 million years ago.

“However, the more we’ve looked in rocks of that age, the less we’ve found,” said Norman. “The first unarguable ornithischian remains date from less than 200 million years ago, meaning there is a 25+ million-year ornithischian gap. So far, all attempts to fill that gap have failed.”

One solution to this conundrum can be traced back to a discovery in the early years of this century, when the skeleton of an unusual Late Triassic dinosaur-like animal was discovered in Poland. It was described by Jerzy Dzik and named Silesaurus (the ‘Silesian lizard’).

Silesaurus has long slender legs that gave it an upright dinosaur-like posture – and its hip bones are arranged like a saurischian – but it seemed to have a toothless, beak-like region at the front of its lower jaw. This was not unlike the toothless beak-like structure known as a predentary that is found in all ornithischian dinosaur skulls, although the uniquely ornithischian predentary bone was not present.

Its teeth were also constricted at the top of the roots, and the crowns of the teeth were leaf-shaped in profile: a type of tooth shape seen in many early ornithischians. Dzik speculated about the possible ornithischian similarities of Silesaurus, but the suggestion was dismissed or ignored by most researchers.

In the years that followed, more Silesaurus-like creatures were discovered, mostly in South America. Many of these specimens were fragments, but the toothless tip of the lower jaw and the leaf-shaped teeth were common.

The accumulation of these specimens attracted the attention of several researchers. Their analyses suggested that silesaurs were close relatives of true dinosaurs. Either they were placed on a branch just before the origin of true dinosaurs or, in some instances, they appeared as a sister group to Ornithischia. In 2020, Mauricio Garcia and Rodrigo Müller from the Universidade Federal de Santa Maria in Brazil proposed that silesaur-like creatures could sit on the branch of Dinosauria that led to Ornithischia.

“This work attracted our attention in Cambridge,” said Norman. “A few years ago, I devised a research project aimed directly at the problem of how the Ornithischia came to be, and Matt was the research student on the project.”

Norman and Barron began to collaborate with Rodrigo and Mauricio, enlarging the original analysis to include a range of ornithischian dinosaurs, as well as dinosaur ancestors. The outcome of their collaboration is a family tree that depicts silesaurs as a succession of animals on the stem of the branch leading to Ornithischia.

“Silesaurians progressively modified their anatomy during the Late Triassic, so that they come to resemble ornithischians,” said Norman. “We have been able to trace this transition through the development of the toothless beak, the development of leaf-shaped coarse-edged teeth typical of those seen in the herbivorous ornithischians, modifications to the shoulder bones, changes in the proportions of the pelvic bones, and finally a restructuring of the muscle attachment areas on the hind legs.”

The research suggests that ornithischians did not arise from nowhere. Rather, they first appeared in the Late Triassic in the guise of silesaurs that gradually rearranged their anatomy with the passage of time until recognisable ornithischians had evolved by the beginning of the Jurassic Period.

However, there is another aspect to this explanation, which is that the earliest ornithischians of the Late Triassic had none of the anatomical characteristics of true ornithischians: they lacked a predentary and, most importantly, retained the early saurischian hip construction.

“So, the very earliest ornithischians were, technically, saurischian,” said Norman. “From a taxonomic perspective, classifying silesaurs as early ornithischians seems counterintuitive. But, taking a Darwinian perspective, the unique anatomical characteristics of ornithischians had to evolve from somewhere, and where better than from their nearest relatives: their saurischian cousins!”


Continue Reading

Entertainment news

What keeps plant roots growing toward gravity? Study identifies four genes – hortidaily.com

What happens belowground in a corn field is easy to overlook, but corn root architecture can play an important role in water and nutrient acquisition, affecting drought tolerance, water use efficiency, and sustainability. If breeders could encourage corn roots to grow down at a steeper angle, the crop could potentially access important resources deeper in the soil.

A first step toward that goal is learning the genes involved in gravitropism and root growth in response to gravity. In a new study published in the Proceedings of the National Academy of Sciences, University of Wisconsin scientists, in collaboration with researchers at the University of Illinois, identify four such genes in corn and the model plant Arabidopsis.

When a germinating seed is turned on its side, some roots make a sudden, steep turn towards gravity, while others turn a fraction more slowly. The researchers used machine vision methods to observe subtle differences in root gravitropism in thousands of seedlings and combined that data with genetic information for each seedling. The result mapped the likely positions of gravitropism genes in the genome.

The map got the researchers to the right neighborhood in the genome – regions of a few hundred genes – but they were still a long way from identifying specific genes for gravitropism. Fortunately, they had a tool that could help.

Relevant genetics
“Because we had previously performed the same experiment with the distantly related Arabidopsis plant, we were able to match genes within the relevant regions of the genome in both species. Follow-up tests verified the identity of four genes that modify root gravitropism. The new information could help us understand how gravity shapes root system architectures,” says Edgar Spalding, professor in the Department of Botany at the University of Wisconsin and lead author of the study.

Matt Hudson, professor in the Department of Crop Sciences at the University of Illinois and study co-author, adds, “We looked at an under-researched trait in maize that is important for a number of reasons, especially in the context of climate change. And we did it by making the evolutionary differences between plants work in our favor.”

Corn and Arabidopsis, a small mustard relative, exhaustively described by plant biologists, evolved about 150 million years apart in evolutionary history. Hudson explains that although both species share basic plant functions, the genes controlling them have likely been jumbled within the genome over time. That turns out to be a good thing for narrowing down common genes.

In closely related species, genes tend to line up in approximately the same order in the genome (e.g., ABCDEF). Although the same genes might exist in distantly related species, the order of genes in the region the trait maps to doesn’t match (e.g., UGRBZ). After the researchers identified where to look in each genome, the otherwise mismatched gene sequences made the common genes (in this case, B) pop out.

“I thought it was super cool that we could identify genes we wouldn’t have found otherwise just by comparing genomic intervals in unrelated plant species,” Hudson says. “We were pretty confident they were the right genes when they popped right out of this analysis, but Spalding’s group then spent seven or eight more years getting solid biological data to verify they do, indeed, play a role in gravitropism. Having done that, I think we’ve validated the whole approach so that you could use this method for many different phenotypes in the future.”

Environment
Spalding notes the method was probably particularly successful because precise measurements were made in a common environment.

“Often, maize researchers will measure their traits of interest in a field, whereas Arabidopsis researchers tend to raise their plants in growth chambers,” he says. “We measured the root gravitropism phenotype in a highly controlled way. These seeds were grown on a petri dish, and the assay lasted just hours, as opposed to traits you might measure in the real world that are open to all sorts of variabilities.”

Even when traits can be measured in a common environment, not all traits make good candidates for this method. The researchers emphasize traits in question should be fundamental to basic plant function, ensuring the same ancient genes exist in unrelated species. 

“Gravitropism may be especially amenable to study through this approach because it would have been key to the original specialization of shoots and roots after the successful colonization of land,” Spalding says.

Hudson notes gravitropism will be key to the colonization of a different landscape, as well.

“NASA is interested in growing crops on other planets or in space, and they need to know what you’d have to breed for to do that,” he says. “Plants are pretty discombobulated without gravity.”

For more information:
University of Illinois
www.aces.illinois.edu

Continue Reading

Entertainment news

Brand New Scarlet & Violet Pokémon Revealed, And It’s A Floppy One – Kotaku

Serebii

The sadly low-res video shows the little beasties popping their heads out of the sand on the beach, implying we’ve got at least a Water-type here. Multi-lingual discussion during the video has Pokécologists (everyone start using this term) question whether it’s related to Diglett, but then conclude that no, it’s a whole new species of Pokémon.

Advertisement

Goodness knows what is going on in that video, with the Wingulls seemingly stuck in the air, and the background looking like it’s running on GBA.

This makes it the 16th new Pokémon unique to the Paldean region to be revealed, ahead of November’s release of Pokémon Scarlet and Violet. Most of which have been utterly bonkers.

Advertisement

Generally when The Pokémon Company reveals a new creature, we get a hint dropped like this, and then a nice press release packed with information. So be sure to check back later for an update on this post with all that extra news.

 

Continue Reading

Entertainment news

Russia’s Alrosa discovers 22 new diamond deposits in Zim – Mnangagwa – New Zimbabwe.com


Spread This News

By Bloomberg News


Russian miner Alrosa PSJC has discovered 22 new diamond deposits in Zimbabwe, according to the southern African nation’s president, Emmerson Mnangagwa.

Alrosa will only be allowed to work on two of the diamond deposits, while the rest will be made available to other investors, Zimbabwe’s Information Ministry said, citing comments by Mnangagwa in New York at the weekend. The president attended a business meeting on the sidelines of the United Nations General Assembly.

The Russian company declined an emailed request for comment.

In 2019, Alrosa signed an agreement with the state-owned Zimbabwe Mining Development Corp. to jointly explore for gems in the country. At the time, the company said it would spend $12 million exploring some of the 40 diamond mining rights it holds in the country.

Many in the diamond industry refuse to deal in Russian gems following the invasion of Ukraine and after mining giant Alrosa was hit with US sanctions.

After returning to Zimbabwe on Tuesday, Mnangagwa said there was interest from US-based investors in a number of sectors including mining and agriculture. A group of those investors will come to the country next month to look at opportunities, the state-owned Zimbabwe Broadcasting Corp. reported.

Continue Reading

Trending

Copyright © 2021 ZimFocus.

www.luzroyale.ky/

www.1africafocus.com

www.zimfocus.co.zw

www.classifieds.com/

One Zimbabwe Classifieds | ZimMarket

www.classifiedszim.com

www.1zimbabweclassifieds.co.zw

www.1southafricaclassifieds.com

www.1africaclassifieds.com

www.1usaclassifieds.com

www.computertraining.co.zw/

www.1itonlinetraining.com/

www.bbs-bitsbytesandstem.com/

Zimbabwe Market Classifieds | ZimMarket

1 Zimbabwe Market Classifieds | ZimMarket

www.1zimlegends.com

Linking Buyers To Sellers Is Our Business Tradition