Latest news with #end-Cretaceous
Yahoo
16-04-2025
- Science
- Yahoo
They're not the prettiest, but they survived 2 extinction events
Garbage in, garbage out. High protein, low fat. Cut the carbs and stay hydrated. It turns out it does matter what you eat, especially to crocodylians — crocodiles, alligators and gharials — a species researchers say persisted despite two mass extinction events because they adapted their diet and the places where they found food. 'Lots of groups closely related to crocodylians were more diverse, more abundant, and exhibited different ecologies, yet they all disappeared except these few generalist crocodylians alive today,' said the lead author Keegan Melstrom. 'Extinction and survivorship are two sides of the same coin. Through all mass extinctions, some groups manage to persist and diversify. What can we learn by studying the deeper evolutionary patterns imparted by these events?' Researchers reconstructed their dietary ecololgy by examining the teeth and skulls of 99 extinct crocodylomorph species and 20 living crocodylian species. The research is the first to reconstruct the dietary ecology of crocodylomorphs to identify characteristics that helped some groups persist and thrive through two mass extinctions — the end-Triassic, about 201.4 million years ago, and the end-Cretaceous, about 66 million years ago. Their study was published in the journal Paleontology on Tuesday. 'Despite being stereotyped as 'living fossils', the characteristics that facilitated their survival remain largely unknown, but trends in other clades, such as mammals, suggest that dietary ecology may play a key role in persisting during and after mass extinctions,' an abstract of the study said. Earth has gone through five mass extinctions in its history — and experts would argue we are undergoing a sixth — so the gritty survival of these toothy animals may provide tools on how to better protect vulnerable species today. Take the gharial, with its long, thin jaws it uses to feed on fish. Populations were once distributed across Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan. It currently survives in several severely fragmented populations in India and Nepal and is down to less than 250 in numbers. It thrives in big rivers and with its elongated snout and interlocking teeth, adults can quickly snatch a fish. Juveniles munch on insects, crustaceans and frogs. Males can reach up to 20 feet in length, but you don't have to worry about this gigantic creature chasing after you on land because of its weak leg muscles. When it does move across land, think of belly slides. The species is critically endangered, with India granting full protection in the 1970s. Habitat fragmentation, the damming of rivers and hunting are all factors that have this animal on collision course for extinction. Melstrom, an assistant professor at the University of Oklahoma, teamed up with Randy Irmis, curator of paleontology at the Natural History Museum of Utah and a professor in the University of Utah's Department of Geology & Geophysics, to conduct the research probing the dietary ecology of the species that for now have withstood all the tribulations of time. 'We propose that one reason for the success and longevity of the crocodylomorph clade is their remarkable dietary flexibility, a characteristic that is still observed in living crocodylians,' the study says. A clade is a grouping that includes a common ancestor and all the descendants (living and extinct) of that ancestor. The team studied a fossil dataset that spans six continents and 200 million years of evolutionary history. 'Crocodylomorphs have survived two major mass extinctions and may be on the cusp of a third,' the research said, underscoring the need for better conservation practices and using science to help stave off extinction. As an example, the gharials are a keystone species indicating the health of an entire river-based ecosystem. Wildlife SOS says to save the species, you need to save their home. Controlled repopulation efforts have been successful to a degree. In 2024, 160 gharial eggs hatched across the Gandak River in Nepal after intense monitoring by federal officials, scientists and volunteers. The Gandak is a major left bank tributary of the Ganges in India. But ultimately, the key to ensuring the long-term survival of this ancient species lies in restoring balance to the affected ecosystem and, of course, ensuring they stay on the right diet and adapt.
Yahoo
02-04-2025
- Science
- Yahoo
A Curious Mutation Is Letting Earth's Deep-Sea Creatures Survive the Abyss
Despite everything stacked against them, a variety of life thrives at ocean depths with bone-crushing pressure, low-oxygen, no light, and immensely cold temperatures. A new study analyzes the evolutionary history of 11 deep-sea species from environments stretching from the central Indian Ocean and the western Pacific Ocean and found that all species contained the convergent evolution of the rtf1 gene, which improves transcription efficiency at higher pressures. Although other evolutionary changes also aid in these species' deep-sea survival, this universal adaptation shows that nature uses similar evolutionary solution when faced with overwhelming environmental challenges. Life isn't easy in the hadal zone. The deepest region of the world's oceans—stretching more than 6,000 meters (19,700 feet) below the surface—the zone is home to pressures up to 1,100 times stronger than Earth's atmosphere at sea level. Despite this extreme pressure—not to mention bone-chilling temperatures, low-oxygen levels, and absolute darkness—life thrives in these ultra-deep trenches, fractures, and vents, and a new study published in the journal Cell investigates how nature pulled off this incredible feat. In this new study, scientists from Chinese Academy of Sciences, Northwestern Polytechnical University, and BGI-Qingdao (a gene research institute) explored deep-sea fish habitats from the central Indian Ocean and the western Pacific, including the deepest point on the planet's surface, the Mariana Trench, using a variety of research vessels and piloted submersibles. From these habitats, the researchers reconstructed the evolutionary history of six major animal groups across 11 species, which included snailfish, tripodfish, cusk-eels, and lizardfish. While some species came from the hadal zone, this study also included specimens found all the way up to 1,218 meters (nearly 4,000 feet), which is still considered 'deep sea' by definition. This process identified two main 'pathways' for deep-sea fish evolution that largely supported a century-old hypothesis that attempted to answer how animals evolved to live in these seemingly inhospitable environments. The first pathway, which the researchers call the 'ancient survivors,' relates to species that have called these dark depths home for dozens or maybe even hundreds of millions of years. These organisms specifically navigated these pitch-dark waters before the end-Cretaceous mass extinction event some 66 million years ago. However, the 'new immigrants' are species that are recent arrivals (at least geologically speaking), having arrived in the hadal zone after the extinction of all land-based dinosaurs. However, across these different animal groups, species, and pathways, the researchers noticed that all specimens containing a highly conserved mutation impacted the rtf1 gene if the fish lived below 3,000 meters (nearly 10,000 feet). They found that this gene affects transcription efficiency specifically in high pressure environments and is likely the genetic mechanism for adapting to the crushing pressures found at these depths. This is an example of convergent evolution where separate species develop similar evolutionary changes despite not having a recent common ancestor. They also found that invertebrates were much more likely to survive in deeper ocean depths for two main reasons. 'First, as top predators, vertebrates require specific ecological conditions, including sufficient prey populations,' the authors write. 'Second, vertebrates may face significant challenges from the high pressure and darkness of the deep sea, possibly due to the sensitivity of their complex central nervous system.' The authors note that while they've found convergent evolutionary explanations for the deep-sea survival of these species, it's likely that a variety of other genetic changes additionally aid in these creatures' ability to survive the impossible. The team also detected traces of a anthropogenic pollutants, including polychlorinated biphenyls (PCBs), and believe future studies should analyze how this pollution could impact these incredible animals already surviving against all odds. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
12-03-2025
- Science
- Yahoo
Scientists Found 52-Foot-Tall Underground Ripples From the Asteroid That Killed the Dinosaurs
Some 66 million years after the Chicxulub asteroid impact kickstarted the Cretaceous–Paleogene (K-T) extinction, scientists are still finding stunning evidence of its destruction. In 2021, researchers spotted 'megaripples' nearly one mile below the surface, suggesting that the megatsunami created by the impact left behind geologic formations as the waves collided with the continental shelf. Now, the authors have expanded the search and found evidence of megaripples in a 900-square-mile area throughout the Gulf of Mexico, along with their varying formations along the upper shelf and the deep sea. Of the five mass extinctions that have impacted our planet in the past 500 million years, the Cretaceous–Paleogene (K-T) extinction event certainly delivers on dramatic flair. On a spring day some 66 million years ago, a six-mile-wide asteroid smashed down just north of what is now Mexico's Yucatan Peninsula. This sudden impact created tsunamis stretching one mile tall and racing outward from the asteroid's dino-killing blow. As those waves raced toward present-day Louisiana (which was largely underwater at the time), they achieved most of their gargantuan height as they reached the ramp of the continental shelf. In 2021, using seismic data gathered by the oil and natural gas company Devon Energy, scientists led by Gary Kinsland from the University of Louisiana at Lafayette found evidence of this geologic trauma in the form of 52-foot-tall 'megaripples' located one mile underground—an area of rock associated with the end-Cretaceous period. Initially surveying a 77-mile area, Kinsland and his team determined that these subterranean ripples likely formed as the asteroid-generated megatsunamis disturbed sediment near the shore. Now, a new study from the same team reveals that these 'megaripples'—roughly spaced up to one kilometer apart—can be found both further up the shelf of what is now central Louisiana and further down in deeper waters of the Gulf of Mexico. The scientists behind this new paper found evidence of megaripples in a larger, 900-square-mile area, and explain that these formations vary depending on where the tsunami impacted sediments along the paleo-shelf. The results of the study were published in the journal Marine Geology. 'The megaripples are different on the slope, at the shelf break and further up the shelf,' Kinsland, the lead author of the new study, told Live Science. 'This is important information in modeling of tsunami, in prediction of future tsunami interactions with shelves and in the understanding of the Chicxulub tsunami.' As the study explains, the largest of these megaripples can be seen along the paleo-shelf break—the area where the Gulf's depth dramatically increases down the slope of the continental shelf toward the deep sea. The way that waves interact with the continental shelf is a well-known process known as the 'Van Dorn effect,' which describes how waves surge over a shelf. The study also discovered that megaripples further inland were more weakly asymmetric, suggesting the waves' behavior changed as they entered shallower waters. Conversely, megaripples in the deep sea took on varied shapes, likely as a result of interactions with faults and collapses, according to Live Science. 'From the coverage of the three areas here in Louisiana we infer that the buried northern Gulf of Mexico shelf system, from Texas to Florida, is covered with megaripples from at least the paleo-slope up to the paleo-bathymetry where Gulf storms would have eroded the megaripples after their formation,' the team said in a press statement. While this gives scientists a better understanding of how the Chicxulub impact tsunami affected the region, it also provides a stunningly powerful example of how tsunamis interact with continental shelves. And if our worst fears are ever realized, it may help us prepare for future asteroid encounters during Earth's never-ending journey through the universe. You Might Also Like The Do's and Don'ts of Using Painter's Tape The Best Portable BBQ Grills for Cooking Anywhere Can a Smart Watch Prolong Your Life?
Yahoo
05-02-2025
- Science
- Yahoo
Remarkable Fossil Discovery Hints at Antarctic Origins of All Modern Birds
A near-perfect fossilized skull discovered in Antarctica reveals the bridge between prehistoric and modern birds, a new study has found. The fossil is a specimen of a species called Vegavis iaai, which lived around 69 million years ago – more than 2 million years before the mass extinction that wiped out all non-avian dinosaurs. It has a long pointed beak and a brain shape unlike any other Mesozoic birds, which were markedly different from species that would evolve into the class of feathered creatures we see around us today. Ever since Vegavis was described 20 years ago, some paleontologists suspected the genus might be an early member of modern birds, within the order of waterfowl. Others doubted it since modern birds were extremely rare prior to the asteroid impact that triggered the end-Cretaceous extinction. But they were missing what is arguably the most important piece of Vegavis, at least when it comes to taxonomy: a somewhat-intact skull. "Few birds are as likely to start as many arguments among paleontologists as Vegavis," says lead author Christopher Torres, a paleontologist from Ohio University. "This new fossil is going to help resolve a lot of those arguments. Chief among them: where is Vegavis perched in the bird tree of life?" Bird fossils can be quite delicate, and few from this time are preserved in such good shape as this one. All other Vegavis specimens found to date have been either skeletons sans head, or just bits of the skull. The researchers suspect the species may have survived the mass extinction because of their Antarctic location, which would have offered a temperate climate with lush vegetation at a time when the rest of the world was quite uninhabitable. "Elsewhere globally, the rapid environmental upheaval characterizing the K–Pg boundary is generally marked by similarly rapid replacement of stem birds by crown birds, followed by diversification of the latter early in the Palaeogene," the authors write. That makes V. iaii the best representative we have for the bridge between prehistoric and modern birds. The researchers used X-ray micro-computed tomography to scan the skull and digitally reconstruct it in three dimensions, revealing details of its braincase, palate, rostrum and mandible, as well as its brain shape. The specimen hints at features consistent with modern waterfowl, but unlike the ducks and geese of today, V. iaai also had a slender, pointed beak and powerful jaw muscles for snapping up fish: features that are more similar to those of diving birds of today like grebes and loons. It has a well-developed salt gland in the nasal region of its beak, a feature that removes sodium chloride from the blood of some marine bird species with diets high in seafood and, consequentially, salt. The rest of the fossil skeleton builds on this picture of V. iaai's aquatic lifestyle, with legs that positioned the feet to propel the bird through the water in pursuit of swimming prey. "Those few places with any substantial fossil record of Late Cretaceous birds, like Madagascar and Argentina, reveal an aviary of bizarre, now-extinct species with teeth and long bony tails, only distantly related to modern birds," says paleontologist Patrick O'Connor from Ohio University. "Something very different seems to have been happening in the far reaches of the Southern Hemisphere, specifically in Antarctica." This research was published in Nature. DNA Confirms Orcas Prey Upon One of Australia's Deadliest Marine Predators 'Beyond Doubt': Proteins in Fossil From Actual Dinosaur, Claim Scientists 'Lost City' Deep Under The Ocean Is Unlike Anything We've Ever Seen Before on Earth
