Yale researchers have identified the oldest-known, definitive members of the lizard crown group that includes all living lizards and their closest extinct relatives.
The two new species, Eoscincus ornatus and Microteras borealis, fill important gaps in the fossil record and offer tantalizing clues about the complexity and geographic distribution of lizard evolution. The new lizard "kings" are described in a study published in Nature Communications.
"This helps us time out the ages of the major living lizard and snake groups, as well as when their key anatomical features originated," said Chase Brownstein, first author of the study. Brownstein, a Yale senior, collaborated on the study with Yale paleontologists Jacques Gauthier and Bhart-Anjan S. Bhullar.
Gauthier is a professor of Earth and planetary sciences in Yale's Faculty of Arts and Science and curator at the Yale Peabody Museum of Natural History. Bhullar is an associate professor of Earth and planetary sciences and an associate curator at the Peabody Museum.
A 2-million-year-old Ecosystem in Greenland Uncovered by Environmental DNA
December 7, 2022
Abstract:
(Nature) Late Pliocene and Early Pleistocene epochs 3.6 to 0.8 million years ago1 had climates resembling those forecasted under future warming2. Palaeoclimatic records show strong polar amplification with mean annual temperatures of 11–19 °C above contemporary values. The biological communities inhabiting the Arctic during this time remain poorly known because fossils are rare5. Here we report an ancient environmental DNA (eDNA) record describing the rich plant and animal assemblages of the Kap København Formation in North Greenland, dated to around two million years ago. The record shows an open boreal forest ecosystem with mixed vegetation of poplar, birch and thuja trees, as well as a variety of Arctic and boreal shrubs and herbs, many of which had not previously been detected at the site from macrofossil and pollen records. The DNA record confirms the presence of hare and mitochondrial DNA from animals including mastodons, reindeer, rodents and geese, all ancestral to their present-day and late Pleistocene relatives. The presence of marine species including horseshoe crab and green algae support a warmer climate than today. The reconstructed ecosystem has no modern analogue. The survival of such ancient eDNA probably relates to its binding to mineral surfaces. Our findings open new areas of genetic research, demonstrating that it is possible to track the ecology and evolution of biological communities from two million years ago using ancient eDNA.
Scientists Discovered Something Morbidly Mysterious at the Bottom of the Indian Ocean by Tessa Koumoundouros
December 11, 2022
Introduction:
(Science Alert) After discovering a host of bizarre creatures of the deep near Cocos (Keeling) Islands, Australia's national science agency CSIRO has found something quite surprising in the depths of the watery abyss: a shark graveyard, full of fossilized teeth, some millions of years old.
Initially, researchers thought they'd pulled up a net full of disappointing sediment and manganese nodules. Until they had a closer look.
"It was amazing, it really was," Museums Victoria Research Institute collections officer Dianne Bray tells the Australian Broadcasting Corporation (ABC).
"Not all were fossils, some were relatively recent mako sharks and two species of great white shark relatives."
More than 750 mineralized teeth, representing a range of predatory species, were hauled up from a depth of 5.4 kilometers (3.3 miles).
Researchers Uncover 92 Fossil Nests Belonging to Some of India’s Largest Dinosaurs January 19, 2023
Introduction:
(EurekAlert) The discovery of more than 250 fossilized eggs reveals intimate details about the lives of titanosaurs in the Indian subcontinent, according to a study published January 18, 2022 in the open-access journal PLOS ONE by Harsha Dhiman of the University of Delhi, New Delhi and colleagues.
The Lameta Formation, located in the Narmada Valley of central India, is well-known for fossils of dinosaur skeletons and eggs of the Late Cretaceous Period. Recent work in the area uncovered 92 nesting sites containing a total of 256 fossil eggs belonging to titanosaurs, which were among the largest dinosaurs to have ever lived. Detailed examination of these nests has allowed Dhiman and colleagues to make inferences about the life habits of these dinosaurs.
The authors identified six different egg-species (oospecies), suggesting a higher diversity of titanosaurs than is represented by skeletal remains from this region. Based on the layout of the nests, the team inferred that these dinosaurs buried their eggs in shallow pits like modern-day crocodiles. Certain pathologies found in the eggs, such as a rare case of an “egg-in-egg”, indicate that titanosaur sauropods had a reproductive physiology that parallels that of birds and possibly laid their eggs in a sequential manner as seen in modern birds. The presence of many nests in the same area suggests these dinosaurs exhibited colonial nesting behavior like many modern birds. But the close spacing of the nests left little room for adult dinosaurs, supporting the idea that adults left the hatchlings (newborns) to fend for themselves.
Details of dinosaur reproductive habits can be difficult to determine. These fossil nests provide a wealth of data about some of the largest dinosaurs in history, and they come from a time shortly before the age of dinosaurs came to an end. The insights gleaned from this study contribute significantly to paleontologists’ understanding of how dinosaurs lived and evolved.
Aftermath of the K-T impact, which left a crater measuring 180 km (112 mi) in diameter. This occurred around 66 million years ago in what is now southeast Mexico, and led to the extinction of the dinosaurs.
"Furious volcanism continues weeks after the event, the resulting plume wrapping around Earth. Nearby land areas are largely scoured to the bare rock by mega tsunamis, which washed over the closer secondary craters. Acrylic on illustration board."
Embers of an Ancient Inferno Pinpoint the Worst Extinction in Earth's History by Clare Watson
February 1, 2023
Introduction:
(Science Alert) The link between ancient volcanic eruptions and the most severe extinction event the world has ever seen just got even stronger. A new analysis of mercury isotopes has provided evidence that a quarter of a billion years ago, far-flung places in Earth's Southern Hemisphere were blanketed with debris from volcanic eruptions in Siberia.
The so-called Great Dying, also called the Permian-Triassic mass extinction event, ensued, where most of life was wiped out under ash-filled skies.
While it's clear how things ended – with the loss of more than 90 percent of marine species and over 70 percent of land-dwelling vertebrates – our understanding of how Earth's biggest die-off event unfolded remains a bit cloudy, despite geologists' best efforts.
Through piecing together chemical traces trapped in rocks and ocean sediments, geoscientists are fairly confident that a series of volcanic eruptions unleashed a cascade of dramatic changes in Earth's atmosphere and oceans that eventually suffocated animals.
But an extinction event as big as the Great Dying also needs a pretty solid case before geoscientists can definitively say what caused it, and when it happened. They are squinting back in time some 252 million years, after all.
The CT-scanned skull of a 319-million-year-old fossilized fish, pulled from a coal mine in England more than a century ago, has revealed the oldest example of a well-preserved vertebrate brain.
The brain and its cranial nerves are roughly an inch long and belong to an extinct bluegill-size fish. The discovery opens a window into the neural anatomy and early evolution of the major group of fishes alive today, the ray-finned fishes, according to the authors of a University of Michigan-led study scheduled for publication Feb. 1 in Nature.
The serendipitous find also provides insights into the preservation of soft parts in fossils of backboned animals. Most of the animal fossils in museum collections were formed from hard body parts such as bones, teeth and shells.
The CT-scanned brain analyzed for the new study belongs to Coccocephalus wildi, an early ray-finned fish that swam in an estuary and likely dined on small crustaceans, aquatic insects and cephalopods, a group that today includes squid, octopuses and cuttlefish. Ray-finned fishes have backbones and fins supported by bony rods called rays.
Fossil bones from two newly described penguin species, one of them thought to be the largest penguin to ever live—weighing more than 150 kilograms, more than three times the size of the largest living penguins—have been unearthed in New Zealand.
An international team, including researchers from the University of Cambridge, reported the discovery in the Journal of Paleontology. The paper's senior author, Alan Tennyson from the Museum of New Zealand Te Papa Tongarewa, discovered the fossils in 57 million-year-old beach boulders in North Otago, on New Zealand's South Island, between 2016 and 2017.
The fossils were then exposed from within the boulders by Al Manning. They have been identified as being between 59.5 and 55.5 million years old, marking their existence as roughly five to 10 million years after the end-Cretaceous extinction which led to the extinction of non-avian dinosaurs.
The team used laser scanners to create digital models of the bones and compare them to other fossil species, flying diving birds like auks, and modern penguins. To estimate the size of the new species, the team measured hundreds of modern penguin bones and calculated a regression using flipper bone dimensions to predict weight.
Ancient Proteins Offer New Clues About Origin of Life on Earth February 27, 2023
Introduction:
(EurekAlert) By simulating early Earth conditions in the lab, researchers have found that without specific amino acids, ancient proteins would not have known how to evolve into everything alive on the planet today—including plants, animals, and humans.
The findings, which detail how amino acids shaped the genetic code of ancient microorganisms, shed light on the mystery of how life began on Earth.
“You see the same amino acids in every organism, from humans to bacteria to archaea, and that’s because all things on Earth are connected through this tree of life that has an origin, an organism that was the ancestor to all living things,” said Stephen Fried, a Johns Hopkins chemist who co-led the research with scientists at Charles University in the Czech Republic. “We’re describing the events that shaped why that ancestor got the amino acids that it did.”
The findings are newly published in the Journal of the American Chemical Society.
In the lab, the researchers mimicked primordial protein synthesis of 4 billion years ago by using an alternative set of amino acids that were highly abundant before life arose on Earth.
Scientists Identify Chemical Reaction That May Have Triggered Life on Earth by David Nield
March 14, 2023
Introduction:
(Science Alert) There was a critical point early in Earth's history when chemical reactions among the mix of organic molecules began to be powered from within, forming something we might start to think of as biological.
Just what this first metabolic reaction might have looked like remains an area of speculation. It had to have been simple enough to emerge from the assorted components likely to be present already, yet still efficient enough to serve as a catalyst for changes in its environment.
Now a team of researchers from Rutgers University and The City College of New York in the US have identified a protein that may have played a crucial role in getting life as we know it started – a simple peptide they're calling nickelback.
This isn't a tribute to the well-known Canadian rock band, but rather a reference to the protein's backbone, consisting of a chain of amino acids and two nitrogen atoms bonded to a pair of nickel atoms.
Not only could this discovery shed more light on the way that life began here on Earth, it could also give astronomers another clue in the search for life on other planets where these essential chemical ingredients are just beginning to form.
Earliest Evidence of A Meteorite Hitting Earth May Have Been Found by Dr Alfredo Carpineti, PhD.
March 17, 2023
Introduction:
(IFL Science) Researchers might have uncovered what is believed to be the earliest evidence of a meteorite's impact on Earth. In rocks from 3.48 billion years ago, researchers have discovered structures consistent with a collision from the heavens. These are rock spherules whose structure and chemical composition indicate that the extraterrestrial hypothesis is most likely the correct one.
Finding evidence of ancient impacts is difficult here on Earth. Tectonic plates and erosion have wiped out the evidence of these events that shaped the early history of our planet. The oldest known impact crater is the Yarrabubba crater in Western Australia, which dates from 2.23 billion years ago.
But there are regions on Earth with much older rocks, so researchers have been looking for indirect evidence of these impacts – such as the spherules. But rock spherules are not meteorite impact-exclusive. Geologists are aware of a few ways for them to come into being.
The analysis, led by graduate researcher Michaela Dobson from the University of Auckland, is consistent with the melting of rock following a high-speed impact. Basically, the space bolide struck the ground and melted rocks that flew into the air as tiny splashes, before landing back down and solidifying into these rocky droplets.
The way they are shaped, looking like teardrops and dumbbells, and with bubbles inside them, is a big indication that they formed following an impact. They look like other impact spherules that have been discovered in the same location at the Pilbara Craton in Australia and in the Barberton Greenstone Belt in South Africa, although these are slightly younger, ranging between 3.4 to 3.2 billion years old.
World’s Oldest Preserved Brain Found in a 319 Million-Year-Old Fish Fossil by Madeleine Muzdakis
April 1, 2023
Introduction:
(My Modern Met) Fish are generally not known to be clever critters with tremendous brain power. Goldfish, in particular, are believed by many to have three-second memory spans, but that's not true. Another fish's brain has recently grabbed the spotlight for a different reason. A 319-million-year-old fish fossil sitting in the Manchester Museum has revealed that within its skull are a brain and cranial nerves that are the oldest well-preserved vertebrate brain ever discovered. This rare find has excited researchers around the world and is described in a Nature paper.
Discovered over 100 years ago in a Lancashire, UK, mine, the fossil was encased in soapstone. It has since sat in the museum but was recently examined by researchers. Known as Coccocephalus wildi, it is the only specimen found of its kind. Although just the skull was discovered, the fish likely stretched six to eight inches. While not originally looking for a brain, researchers discovered a strange object in the skull using CT scans. Like vertebrate brains, the object was bilaterally symmetrical, contained hollow spaces, and had multiple filaments (like cranial nerves). The brain folds inward, unlike in today's living ray-finned fishes.
Vertebrate brains decay quickly, so finding fossilized specimens is unusual. Likely the dead critter was quickly enshrouded in sediment with low oxygen levels. Senior author of the paper Sam Giles of the University of Birmingham said in a statement, “This unexpected find of a three-dimensionally preserved vertebrate brain gives us a startling insight into the neural anatomy of ray-finned fish. It tells us a more complicated pattern of brain evolution than suggested by living species alone, allowing us to better define how and when present-day bony fishes evolved.”
“Comparisons to living fishes showed that the brain of Coccocephalus is most similar to the brains of sturgeons and paddlefish, which are often called ‘primitive’ fishes because they diverged from all other living ray-finned fishes more than 300 million years ago,” he noted. The modern world's 30,000 ray-finned fish species are half of all the vertebrate species on this planet.
