Fossilized poop, called coprolites, collected in Nong Yakong village, Chaiyaphum Province, Thailand. Coprolites are an important source for studying ancient parasites. Nonsrirach et al. under CC-BY 4.0
Fossilized feces preserve evidence of ancient parasites that infected an aquatic predator over 200 million years ago, according to a study published August 9, 2023 in the open-access journal PLOS ONE by Thanit Nonsrirach of Mahasarakham University, Thailand and colleagues.
Parasites are a common and important component of ecosystems, but ancient parasites are difficult to study due to a poor fossil record. Parasites often inhabit the soft tissues of their host, which rarely preserve as fossils. There are, however, cases where traces of parasites can be identified within fossilized feces (coprolites). In this study, Nonsrirach and colleagues describe evidence of parasites in a Late Triassic coprolite from the Huai Hin Lat Formation of Thailand, which is over 200 million years old.
The coprolite is cylindrical in shape and over 7cm long. Based on its shape and contents, the researchers suggest it was likely produced by some species of phytosaur, crocodile-like predators which are also known from this fossil locality. Microscopic analysis of thin sections of the coprolite revealed six small, round, organic structures between 50-150 micrometers long. One of these, an oval-shaped structure with a thick shell, is identified as the egg of a parasitic nematode worm, while the others appear to represent additional worm eggs or protozoan cysts of unclear identity.
This is the first record of parasites in a terrestrial vertebrate host from the Late Triassic of Asia, and a rare glimpse into the life of an ancient animal that was apparently infected by multiple parasitic species. This discovery also adds to the few known examples of nematode eggs preserved within the coprolites of Mesozoic animals. These findings are therefore a significant contribution to scientific understanding of the distribution and ecology of parasites of the distant past.
The authors add: “Coprolite is a significant paleontological treasure trove, containing several undiscovered fossils and expanding our understanding of ancient ecosystems and food chains.”
Reference:
Thanit Nonsrirach, Serge Morand, Alexis Ribas, Sita Manitkoon, Komsorn Lauprasert, Julien Claude. First discovery of parasite eggs in a vertebrate coprolite of the Late Triassic in Thailand. PLOS ONE, 2023; 18 (8): e0287891 DOI: 10.1371/journal.pone.0287891
Note: The above post is reprinted from materials provided by PLOS.
A remarkable new fossil from China reveals for the first time that a group of reptiles were already using whale-like filter feeding 250 million years ago.
New research by a team from China and the UK has shown details of the skull of an early marine reptile called Hupehsuchus that indicate it had soft structures such as an expanding throat region to allow it to engulf great masses of water containing shrimp-like prey, and baleen whale-like structures to filter food items as it swam forward.
The team also found that the Hupehsuchus skulls show the same grooves and notches along the edges of its jaws similar to baleen whales, which have keratin strips instead of teeth.
“We were amazed to discover these adaptations in such an early marine reptile,” said Zichen Fang of the Wuhan Center of China Geological Survey, who led the research. “The hupehsuchians were a unique group in China, close relatives of the ichthyosaurs, and known for 50 years, but their mode of life was not fully understood.”
“The hupesuchians lived in the Early Triassic, about 248 million years ago, in China and they were part of a huge and rapid re-population of the oceans,” said Professor Michael Benton, a collaborator at the University of Bristol’s School of Earth Sciences. “This was a time of turmoil, only three million years after the huge end-Permian mass extinction which had wiped out most of life. It’s been amazing to discover how fast these large marine reptiles came on the scene and entirely changed marine ecosystems of the time.”
“We discovered two new hupehsuchian skulls,” said Professor Long Cheng, also of the Wuhan Center of China Geological Survey, who directed the project. “These were more complete than earlier finds and showed that the long snout was composed of unfused, straplike bones, with a long space between them running the length of the snout. This construction is only seen otherwise in modern baleen whales where the loose structure of the snout and lower jaws allows them to support a huge throat region that balloons out enormously as they swim forward, engulfing small prey.”
Li Tian, a collaborator from the University of Geosciences Wuhan, added: “The other clue came in the teeth… or the absence of teeth,” says Li Tian, a collaborator from the University of Geosciences Wuhan. “Modern baleen whales have no teeth, unlike the toothed whales such as dolphins and orcas. Baleen whales have grooves along the jaws to support curtains of baleen, long thin strips of keratin, the protein that makes hair, feathers and fingernails. Hupehsuchus had just the same grooves and notches along the edges of its jaws, and we suggest it had independently evolved into some form of baleen.”
Reference:
Zi-Chen Fang, Jiang-Li Li, Chun-Bo Yan, Ya-Rui Zou, Li Tian, Bi Zhao, Michael J. Benton, Long Cheng, Xu-Long Lai. First filter feeding in the Early Triassic: cranial morphological convergence between Hupehsuchus and baleen whales. BMC Ecology and Evolution, 2023; 23 (1) DOI: 10.1186/s12862-023-02143-9
Researchers have described a new species of armored reptile that lived near the time of the first appearance of dinosaurs. With bony plates on its backbone, this archosaur fossil reveals that armor was a boomerang trait in the story of dinosaur and pterosaur evolution: the group’s ancestors were armored, but this characteristic was lost and then independently re-evolved multiple times later among specialized dinosaurs like ankylosaurs, stegosaurs, and others. The study is published today in the Zoological Journal of the Linnean Society.
“We are just starting to understand that there were many dinosaur-like creatures across the planet well before dinosaurs evolved,” said the study’s lead author Sterling Nesbitt, associate professor of geosciences at Virginia Tech and a research associate in the American Museum of Natural History’s Division of Paleontology. “Dinosaurs were latecomers to the Triassic reptile party. They showed up well after many dinosaur-looking reptiles were established across our planet.”
Archosaurs are reptiles that are divided into two major branches: the bird-line, which includes pterosaurs and dinosaurs, including living dinosaurs (birds); and the crocodilian line, including crocodiles, alligators, caimans, and gharials. The newly described archosaur species, named Mambachiton fiandohana, is the earliest diverging member of the bird line of archosaur evolution. The fossil, which is about 235 million years old, was found in 1997 in Madagascar by a team of researchers led by the Museum’s Frick Curator of Fossil Mammals John Flynn, who worked at the Field Museum at the time, in close collaboration with scientists and students at the University of Antananarivo in Madagascar.
“This discovery documents the importance of the southern hemisphere fossil record in understanding this important period of the Triassic, when dinosaurs were first appearing,” Flynn said. “This time interval is really poorly known elsewhere in the world, showing the tremendous value of our quarter-century-long Madagascar-U.S. research and education partnership to advancing scientific knowledge.”
A four-legged, long-tailed precursor to dinosaurs and pterosaurs, Mambachiton is estimated to have been 4-6 feet (1.5-2 meters) long, weighing between 25-45 pounds (10-20 kilograms). Unexpectedly, the species had an extensive series of bony plates called osteoderms covering its backbone. Although osteoderms are common in crocodilians and their relatives, they are rare in bird-line archosaurs, with the exception of dinosaurs like stegosaurs, ankylosaurs, titanosaur sauropods, and at least one theropod.
Mambachiton shows definitively that the bird-line archosaur group was ancestrally armored. This armor was lost in the evolution of dinosaurs and pterosaurs but then re-appeared later several times, independently, in the dinosaur lineage.
“The loss and re-evolution of armor is an important aspect of the story of dinosaur evolution — freeing them from some of the biomechanical body constraints of the ancestral archosaurs and potentially contributing to some of the locomotor shifts as dinosaurs diversified into a dizzying array of different ecology and body forms,” said co-author Christian Kammerer, a former Gerstner Scholar at the Museum and a research curator in paleontology at the North Carolina Museum of Natural Sciences.
“Mambachiton demonstrates that retention of ancestral features or acquisition of new traits depend on interactions within the ecosystem,” said project co-leader Lovasoa Ranivoharimanana of the University of Antananarivo. “When a character is essential, it is retained, but when it is no longer useful, it disappears.”
Other authors on the study include Emily Patellos from the University of Southern California and Virginia Tech, and André Wyss from the University of California, Santa Barbara.
Funding or other support was provided in part by the National Geographic Society (grant #s 5957-97, 6271-98, and 7052-01); World Wide Fund for Nature/World Wildlife Fund, Madagascar; the Division of Paleontology at the American Museum of Natural History; and the Field Museum of Natural History Meeker Family Fellowship. The joint Madagascar-U.S. paleontological exploration, research, and education program was supported by the Université d’Antananarivo, Ministère de L’Enérgie et des Mines, and ICTE/MICET (Madagascar), and the American Museum of Natural History, Field Museum of Natural History, and University of California-Santa Barbara (U.S.).
Reference:
Sterling J Nesbitt, Emily Patellos, Christian F Kammerer, Lovasoa Ranivoharimanana, Andre´ R Wyss, John J Flynn. The earliest-diverging avemetatarsalian: a new osteoderm-bearing taxon from the Triassic (Earliest Late Triassic) of Madagascar and the composition of avemetatarsalian assemblages prior to the radiation of dinosaurs. Zoological Journal of the Linnean Society, 2023; DOI: 10.1093/zoolinnean/zlad038
Impact craters and their broader structures can be visible in a geologic map, like a bullseye. But what geophysical traces remain at the structure’s outermost edges? Credit: Huber et al. (2023), JGR Planets
Earth’s oldest craters could give scientists critical information about the structure of the early Earth and the composition of bodies in the solar system as well as help to interpret crater records on other planets. But geologists can’t find them, and they might never be able to, according to a new study. The study was published in the Journal of Geophysical Research Planets, AGU’s journal for research on the formation and evolution of the planets, moons and objects of our Solar System and beyond.
Geologists have found evidence of impacts, such as ejecta (material flung far away from the impact), melted rocks, and high-pressure minerals from more than 3.5 billion years ago. But the actual craters from so long ago have remained elusive. The planet’s oldest known impact structures, which is what scientists call these massive craters, are only about 2 billion years old. We’re missing two and a half billion years of mega-craters.
The steady tick of time and the relentless process of erosion are responsible for the gap, according to Matthew S. Huber, a planetary scientist at the University of the Western Cape in South Africa who studies impact structures and led the new study.
“It’s almost a fluke that the old structures we do have are preserved at all,” Huber said. “There are a lot of questions we’d be able to answer if we had those older craters. But that’s the normal story in geology. We have to make a story out of what’s available.”
Geologists can sometimes spot hidden, buried craters using geophysical tools, such as seismic imaging or gravity mapping. Once they’ve identified potential impact structures, they can search for physical remnants of the impact process to confirm its existence, such as ejecta and impact minerals.
The big question for Huber and his team was how much of a crater can be swept away by erosion before the last lingering geophysical traces disappear. Geophysicists have suggested that 10 kilometers (6.2 miles) of vertical erosion would erase even the biggest impact structures, but that threshold had never been tested in the field.
To find out, the researchers dug into one of the planet’s oldest known impact structures: the Vredefort crater in South Africa. The structure is about 300 kilometers (186 miles) across and was formed about 2 billion years ago when an impactor about 20 kilometers (12.4 miles) across slammed into the planet.
The impactor hit with such energy that the crust and mantle rose up where the impact occurred, leaving a long-term dome. Farther from the center, ridges of rock jutted up, minerals transformed and rock melted. And then time took its course, eroding about 10 kilometers (6.2 miles) down from the surface in two billion years.
Today, all that remains at the surface is a semicircle of low hills southwest of Johannesburg, which marks the center of the structure, and some smaller, telltale signs of impact. The bullseye, caused by the uplift of the mantle, appears in gravity maps, but beyond the center, geophysical evidence of the impact is lacking.
“That pattern is one of the last geophysical signatures that is still detectable, and that only happens for the largest-scale impact structures,” Huber said. Because only the deepest layers of the structure remain, the other geophysical traces have disappeared.
But that’s okay, because Huber wanted to know just how reliable those deep layers are for recording ancient impacts from both a mineralogical and geophysical perspective.
“Erosion makes these structures disappear from the top down,” Huber said. “So we went from the bottom up.”
The researchers sampled rock cores across a 22-kilometer (13.7-mile) transect and analyzed their physical properties, searching for differences in density, porosity and mineralogy between impacted and non-impacted rocks. They also modeled the impact event and what its effects on rock and mineral physics would be and compared that to what they saw in their samples.
What they found was not encouraging for the search for Earth’s oldest craters. While some impact melt and minerals remained, the rocks in the outer ridges of the Vredefort structure were essentially indistinguishable from the non-impact rocks around them when viewed through a geophysical lens.
“That was not exactly the result we were expecting,” Huber said. “The difference, where there was any, was incredibly muted. It took us a while to really make sense of the data. Ten kilometers of erosion and all the geophysical evidence of the impact just disappears, even with the largest craters,” confirming what geophysicists had estimated previously.
The researchers caught Vredefort just in time; if much more erosion occurs, the impact structure will be gone. The odds of finding buried impact structures from more than 2 billion years ago are low, Huber said.
“In order to have an Archean impact crater preserved until today, it would have to have experienced really unusual conditions of preservation,” Huber said. “But then, Earth is full of unusual conditions. So maybe there’s something unexpected somewhere, and so we keep looking.”
Reference:
M. S. Huber, E. Kovaleva, A. S. P. Rae, N. Tisato, S. P. S. Gulick. Can Archean Impact Structures Be Discovered? A Case Study From Earth’s Largest, Most Deeply Eroded Impact Structure. Journal of Geophysical Research: Planets, 2023; 128 (8) DOI: 10.1029/2022JE007721
Undersea images of lava from Kama’ehu volcano, contrasting fresh-looking young lavas (top) versus older sediment-covered lavas (bottom). The two images on the bottom are courtesy of JAMSTEC.
Kamaʻehuakanaloa (formerly Lōʻihi Seamount), a submarine Hawaiian volcano located about 20 miles off the south coast of the Big Island of Hawai’i, has erupted at least five times in the last 150 years, according to new research led by Earth scientists at the University of Hawai’i at Mānoa. For the first time, scientists were able to estimate the ages of the most recent eruptions of Kamaʻehu, as well as the ages of eight additional older eruptions at this volcano going back about 2,000 years. Their findings were published recently in Geology.
Hawaiian volcanoes are thought to transition through a series of growth stages. Kamaʻehu is currently in the earliest submarine “pre-shield” stage of growth, whereas the active neighboring volcano Kīlauea is in its main shield-building stage.
“Kamaʻehu is the only active and exposed example of a pre-shield Hawaiian volcano,” said Aaron Pietruszka, lead author of the study and associate professor in the Department of Earth Sciences at the UH Mānoa School of Ocean and Earth Science and Technology (SOEST). “On the other Hawaiian volcanoes, this early part of the volcanic history is covered by the great outpouring of lava that occurs during the shield stage. Thus, there is great interest in learning about the growth and evolution of Kama’ehu.”
Kama’ehu’s history revealed with chemistry and underwater videos
Previously, the only known and confirmed eruption of Kamaʻehu was the one that occurred in 1996, an event that was only discovered because it coincided with a large swarm of earthquakes that were detected remotely by seismometers on the Big Island.
“Seismometers can only be used to detect the ongoing active eruptions of submarine volcanoes because earthquakes are transient,” said Pietruszka. “In order to determine the ages of older eruptions at Kamaʻehu, we took a different approach. We used a mass spectrometer to measure tiny amounts of the isotope radium-226 in pieces of quenched glassy lava that were sampled from the seafloor outcrops of Kamaʻehu using a submersible.”
Magma naturally contains radium-226, which radioactively decays at a predictable rate. So, Pietruzska and co-authors used the amount of radium-226 in each sample to infer the approximate time elapsed since the lava was erupted on the seafloor, that is, the eruption age of the sample.
Pietruszka started this investigation many years ago as a postdoctoral researcher at the Carnegie Institution for Science, just after finishing his doctoral degree in Earth science from SOEST. Once he returned to UH Mānoa in 2019, he got access to submersible dive videos and photos around Kama’ehu and had the information he needed to finish connecting the dots.
“The submersible dive images and videos provided independent confirmation of our estimates of eruption ages,” said Pietruszka. “The lavas with the freshest appearance also had the most radium-226, and vice versa for the lavas with the ‘older’ appearance, that is, fractured and broken, and/or covered with marine sediment. I was surprised to discover that Kama’ehu had erupted five times within the last ~150 years, which implies a frequency of ~30 years between eruptions at this volcano. This is much slower than at Kīlauea, which erupts almost continuously (with infrequent pauses of only a few years).”
Chemical changes in lava over time
The chemistry of the lava erupted from Hawaiian volcanoes changes over time. The new eruption ages for the lavas from Kama’ehu, coupled with measurements of lava chemistry, reveal that the timescale of variation in lava chemistry at this pre-shield volcano is about 1200 years. In contrast, Kīlauea lava chemistry changes over a timescale of only a few years to decades, with a complete cycle over about 200 years.
“We think that the origin of this difference is related to the position of the two volcanoes over the Hawaiian hotspot,” said Pietruszka. “This is an area of Earth’s mantle that is rising toward the surface — a “mantle plume” that ultimately melts to form the magma that supplies Hawaiian volcanoes. Models and other isotope data from thorium-230 suggest that the center of a mantle plume should rise faster than its margin. Our results — specifically, the factor of six longer timescale of variation in lava chemistry at Kama’ehu — provides independent confirmation of this idea.”
The research team hopes to better understand how Hawaiian volcanoes work from their earliest growth stages to their full, and frequently active, maturity to help them understand the deep controls on volcanic eruptions that initiate within the mysterious, upwelling mantle plume under the Hawaiian hotspot.
Reference:
Aaron J. Pietruszka, Michael O. Garcia, Richard W. Carlson, Erik H. Hauri. Slow changes in lava chemistry at Kama‘ehuakanaloa linked to sluggish mantle upwelling on the margin of the Hawaiian plume. Geology, 2023; 51 (8): 713 DOI: 10.1130/G51350.1
Royal Ontario Museum (ROM) announces the oldest swimming jellyfish in the fossil record with the newly named Burgessomedusa phasmiformis. These findings are announced in the journal Proceedings of the Royal Society B.
Jellyfish belong to medusozoans, or animals producing medusae, and include today’s box jellies, hydroids, stalked jellyfish and true jellyfish. Medusozoans are part of one of the oldest groups of animals to have existed, called Cnidaria, a group which also includes corals and sea anemones. Burgessomedusa unambiguously shows that large, swimming jellyfish with a typical saucer or bell-shaped body had already evolved more than 500 million years ago.
Burgessomedusa fossils are exceptionally well preserved at the Burgess Shale considering jellyfish are roughly 95% composed of water. ROM holds close to two hundred specimens from which remarkable details of internal anatomy and tentacles can be observed, with some specimens reaching more than 20 centimetres in length. These details enable classifying Burgessomedusa as amedusozoan. By comparison with modern jellyfish, Burgessomedusa would also have been capable of free-swimming and the presence of tentacles would have enabled capturing sizeable prey.
“Although jellyfish and their relatives are thought to be one of the earliest animal groups to have evolved, they have been remarkably hard to pin down in the Cambrian fossil record. This discovery leaves no doubt they were swimming about at that time,” said co-author Joe Moysiuk, a Ph.D. candidate in Ecology & Evolutionary Biology at the University of Toronto, who is based at ROM.
This study, identifying Burgessomedusa, is based on fossil specimens discovered at the Burgess Shale and mostly found in the late 1980s and 1990s under former ROM Curator of Invertebrate Palaeontology Desmond Collins. They show that the Cambrian food chain was far more complex than previously thought, and that predation was not limited to large swimming arthropods like Anomalocaris (see field image showing Burgessomedusa and Anomalocaris preserved on the same rock surface).
“Finding such incredibly delicate animals preserved in rock layers on top of these mountains is such a wonderous discovery. Burgessomedusa adds to the complexity of Cambrian foodwebs, and like Anomalocaris which lived in the same environment, these jellyfish were efficient swimming predators,” said co-author, Dr. Jean-Bernard Caron, ROM’s Richard Ivey Curator of Invertebrate Palaeontology. “This adds yet another remarkable lineage of animals that the Burgess Shale has preserved chronicling the evolution of life on Earth.”
Cnidarians have complex life cycles with one or two body forms, a vase-shaped body, called a polyp, and in medusozoans, a bell or saucer-shaped body, called a medusa or jellyfish, which can be free-swimming or not. While fossilized polyps are known in ca. 560-million-year-old rocks, the origin of the free-swimming medusa or jellyfish is not well understood. Fossils of any type of jellyfish are extremely rare. As a consequence, their evolutionary history is based on microscopic fossilized larval stages and the results of molecular studies from living species (modelling of divergence times of DNA sequences). Though some fossils of comb-jellies have also been found at the Burgess Shale and in other Cambrian deposits, and may superficially resemble medusozoan jellyfish from the phylum Cnidaria, comb-jellies are actually from a quite separate phylum of animals called Ctenophora. Previous reports of Cambrian swimming jellyfish are reinterpreted as ctenophores.
The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks and are managed by Parks Canada. Parks Canada is proud to work with leading scientific researchers to expand knowledge and understanding of this key period of Earth history and to share these sites with the world through award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Site in 1980 due to its outstanding universal value and is now part of the larger Canadian Rocky Mountain Parks World Heritage Site.
Reference:
Justin Moon, Jean-Bernard Caron, Joseph Moysiuk. A macroscopic free-swimming medusa from the middle Cambrian Burgess Shale. Proceedings of the Royal Society B: Biological Sciences, 2023; 290 (2004) DOI: 10.1098/rspb.2022.2490
Mesozoic mural depicting different ocean species that have evolved through time. [Credit: Smithsonian Institution]Movement in the Earth’s tectonic plates indirectly triggers bursts of biodiversity in 36-million-year cycles by forcing sea levels to rise and fall, new research has shown.
Researchers including geoscientists at the University of Sydney believe these geologically driven cycles of sea level changes have a significant impact on the diversity of marine species, going back at least 250 million years.
As water levels rise and fall, different habitats on the continental shelves and in shallow seas expand and contract, providing opportunities for organisms to thrive or die. By studying the fossil record, the scientists have shown that these shifts trigger bursts of new life to emerge.
The research has been published in the journal Proceedings of the National Academy of Sciences, led by Associate Professor Slah Boulila from Sorbonne University in Paris.
Study co-author Professor Dietmar Müller, from the School of Geosciences at the University of Sydney, said: “In terms of tectonics, the 36-million-year cycle marks alterations between faster and slower seafloor spreading, leading to cyclical depth changes in ocean basins and in the tectonic transfer of water into the deep Earth.
“These in turn have led to fluctuations in the flooding and drying up of continents, with periods of extensive shallow seas fostering biodiversity.
“This work was enabled by the GPlates plate tectonic software, developed by the EarthByte Group at the University of Sydney, supported by Australia’s National Collaborative Research Infrastructure Strategy (NCRIS) via AuScope.”
The team based their findings on the discovery of strikingly similar cycles in sea-level variations, Earth’s interior mechanisms and marine fossil records.
Scientists now have overwhelming evidence that tectonic cycles and global sea level change driven by Earth’s dynamics have played a crucial role in shaping the biodiversity of marine life over millions of years.
“This research challenges previous ideas about why species have changed over long periods,” Professor Müller said.
“The cycles are 36 million years long because of regular patterns in how tectonic plates are recycled into the convecting mantle, the mobile part of the deep Earth, similar to hot, thick soup in a pot, that moves slowly.”
Professor Müller said the Cretaceous Winton Formation in Queensland serves as a prime example of how sea-level changes have shaped ecosystems and influenced biodiversity in Australia.
The formation, renowned for its collection of dinosaur fossils and precious opal, provides a valuable window into a time when much of the Australian continent was flooded.
As sea levels rose and fell, the flooding of the continent created expanding and contracting ecological recesses in shallow seas, providing unique habitats for a wide range of species.
“The Cretaceous Winton Formation stands as a testament to the profound impact of these sea-level changes, capturing a snapshot of a time when Australia’s landscape was transformed and fascinating creatures roamed the land,” Professor Müller said.
Reference:
Slah Boulila, Shanan E. Peters, R. Dietmar Müller, Bilal U. Haq, Nathan Hara. Earth’s interior dynamics drive marine fossil diversity cycles of tens of millions of years. Proceedings of the National Academy of Sciences, 2023; 120 (29) DOI: 10.1073/pnas.2221149120
In this overview map of Utah earthquakes, the dotted line marks the approximate location of the transition zone between the Basin and Range province and the Colorado Plateau and the blue rectangle indicates the study area. Historic seismic events in the study area (1900–1981, 4.5 ≤ M ≤ 6.6) from UUSS and USGS catalogs, and location of basins and ranges mentioned in the text. Horizontal purple dashed lines indicate approximate locations of Blue Ribbon (BRT) and Cove Fort (CVT) Transverse Zones (P. D. Rowley, 1998), thin black lines indicate Quaternary faults. MP: Markagunt Plateau Volcanic Field. The larger map (c) shows seismicity in the study area since 1981, ML ≥ 2.5 (UUSS). PHOTO CREDIT: University of Utah
Most of the earthquakes rumbling under the West’s Great Basin come in surges, clustered together in time and place. Scientists call these seismic groups “swarms,” which are a distinct category from the numerous aftershocks following a big shake, such as the 5.7 magnitude Magna quake of 2020 on the Wasatch Fault.
Rather than getting spread out evenly over time, many of these small, often imperceptible quakes strike a region in a short period of time, say a few days or weeks.
Central Utah has been the stage for dozens of earthquake swarms that have been recorded over the past 40 years by an ever-expanding network of seismic arrays managed by the University of Utah.
Now U seismologists are analyzing decades of seismic data in hopes of discerning the significance of these swarms in a geologically complex region known as a geothermal hotspot and for recent — geologically speaking — volcanism.
“In central Utah, seismic swarms are much more common than any other type of sequence. We looked into all types of sequences, but 80% of the sequences are swarms. That’s remarkable,” said Gesa Petersen, a post-doctoral research fellow. “We also saw that these are very heterogeneous. So one location in central Utah can have a very, very different behavior than other locations just 30, 40, 50 kilometers away.”
With U. geology professor Kristine Pankow, Petersen publish the latest findings July 13 in the journal Geochemistry, Geophysics, Geosystems. Funding came from the state of Utah and the $220 million Department of Energy grant supporting the U’s geothermal research station known as Utah FORGE.
A geothermal hot spot
Located outside Milford, FORGE is within the research area that spans Beaver, Iron, Sevier and Paiute counties. The research area is home to three geothermal power-generating plants and includes the towns of Circleville, Beaver and Richfield.
The researchers suspect the earthquakes are triggered by hot water, powered by geothermal activity, coursing through fissures in Earth’s crust.
During the past 40 years, the U of U Seismograph Stations detected earthquake sequences featuring earthquakes of magnitude 1.5 or greater. But in further examining the data, Peterson and Pankow were able to identify hundreds of additional smaller earthquakes, as small as magnitude 0.5 recorded in 50 distinct sequences.
They concluded 40 qualified as swarms. Much can be learned from these smaller quakes, but they are hard to study, according to Pankow, who is the Seismograph Stations associate director.
(BRT) and Cove Fort (CVT) Transverse Zones (P. D. Rowley, 1998), thin black lines indicate Quaternary faults. MP: Markagunt Plateau Volcanic Field. The larger map (c) shows seismicity in the study area since 1981, ML ? 2.5 (UUSS).
“We’re all worried about the Wasatch Front, but the other thing to know is we have earthquakes all over Utah,” said Pankow. “We recorded a certain level, but in some of these places there’s probably earthquakes happening all the time that we just don’t see. That’s something that’s really important to get an understanding of.”
Thousands of earthquakes
All told the research analyzed 2,300 earthquakes, most of which were between magnitude 1 and 3. The largest was a magnitude 5.1 that hit east of Richfield in 1989. That one was not part of a swarm, but rather was a mainshock followed by numerous aftershocks. The full catalog for the study area contains 20,000 events between 1981 and 2023, according to Petersen.
“However, we cannot exactly say how many of them are part of a sequence because we limit the study for sequences that have at least 20 earthquakes within 10 days. We do not look into smaller sequences because we need some minimum to look at statistical parameters and to compare characteristic patterns of the sequences,” she said. “However, in the 1980s and 1990s, the seismic network of Utah was not as dense as today. There were significantly less stations. Therefore we can only study larger sequences with larger magnitudes from these times. There were likely many more swarms or seismic sequences.”
The study greatly expanded on another recent study that focused exclusively on a swarm of hundreds of small quakes around Milford in the spring of 2021. That area had not experienced much earthquake activity during the entire 40-year window of seismograph data. Meanwhile, earthquakes have been happening as frequently as every few months in the nearby Mineral Mountains to the west during this same time period, Petersen said.
“So it’s a very heterogeneous system there,” she said. “You have a bunch of earthquakes in the same place and you can start learning about the structures that are activated in the place. If you have like only a single earthquake, you can’t learn that much then.”
The Mineral Mountains swarms were first detected a few years ago when new seismometers were installed for the FORGE geothermal research project.
“Before that we didn’t have the resolution, but now we can see there are events always coming, and it’s rapid,” Petersen said. “Within a couple of hours, you suddenly have 30, 40, 50 events and then it’s pausing again. You have this repeatedly, you have lots of activity. You can’t really feel it. It’s too small for that, but we can see it on the seismometers.”
The paper, titled “Small-Magnitude Seismic Swarms in Central Utah (US): Interactions of Regional Tectonics, Local Structures and Hydrothermal Systems,” can be found here.
Reference:
G. M. Petersen, K. L. Pankow. Small‐Magnitude Seismic Swarms in Central Utah (US): Interactions of Regional Tectonics, Local Structures and Hydrothermal Systems. Geochemistry, Geophysics, Geosystems, 2023; 24 (7) DOI: 10.1029/2023GC010867
Note: The above post is reprinted from materials provided by University of Utah. Original written by Brian Maffly.
Today an international team of researchers has chosen the location which best represents the beginnings of what could be a new geological epoch, the Anthropocene.
The Anthropocene Working Group have put forward Crawford Lake, in Canada, as a Global Boundary Stratotype Section and Point (GSSP) for the Anthropocene. A GSSP is an internationally agreed-upon reference point to show the start of a new geological period or epoch in layers of rock that have built up through the ages.
It’s been proposed by some geologists that we are now living in the Anthropocene — a new geological epoch in which human activity has become the dominant influence on the world’s climate and environment.
The concept has significant implications for how we consider our impact on the planet. But there is disagreement in the scientific community about when the Anthropocene began, how it is evidenced and whether human influence has been substantial enough to constitute a new geological age, which usually span millions of years.
To help answer these questions, the International Commission on Stratigraphy (ICS) set up the Anthropocene Working Group.
“The sediments found at the bottom of Crawford Lake provide an exquisite record of recent environmental change over the last millennia,” says Dr Simon Turner, Secretary of the Anthropocene Working Group from UCL. “Seasonal changes in water chemistry and ecology have created annual layers that can be sampled for multiple markers of historical human activity. It is this ability to precisely record and store this information as a geological archive that can be matched to historical global environmental changes which make sites such as Crawford Lake so important. A GSSP is used to correlate similar environmental changes seen in other sites worldwide, so it is critical to have a robust and reproducible record at this type locality.”
The team has gathered core sample sections from a variety of environments around the world, from coral reefs to ice sheets. Samples from a range of these sites were then sent for analysis to the University of Southampton’s GAU-Radioanalytical labs at the National Oceanography Centre in Southampton. Researchers there processed the samples to detect a key marker of human influence on the environment — the presence of plutonium.
Professor Andrew Cundy, Chair in Environmental Radiochemistry at the University of Southampton and member of the Anthropocene Working Group, explains: “The presence of plutonium gives us a stark indicator of when humanity became such a dominant force that it could leave a unique global ‘fingerprint’ on our planet.
“In nature, plutonium is only present in trace amounts. But in the early-1950s, when the first hydrogen bomb tests took place, we see an unprecedented increase and then spike in the levels of plutonium in core samples from around the world. We then see a decline in plutonium from the mid-1960s onwards when the Nuclear Test-Ban Treaty came into effect.”
Other geological indicators of human activity include high levels of ash from coal-fired power stations, high concentrations of heavy metals, such as lead, and the presence of plastic fibres and fragments. These coincide with ‘The Great Acceleration’ — a dramatic surge across a range of human activity, from transportation to energy use, starting in the mid-20th century and continuing today.
From the hundreds of samples analysed, the core from Crawford Lake has been proposed as the GSSP, along with secondary supporting sites that show similar high-resolution records of human impact. Evidence from the sites will now be presented to the ICS, which will decide next year whether to ratify the Anthropocene as a new geological epoch.
The fossil showing the entangled skeletons of the dinosaur (Psittacosaurus) and the mammal (Repenomamus). Scale bar equals 10 cm.
Canadian and Chinese scientists have described an unusual fossil from around 125 million years ago that shows a dramatic moment in time when a carnivorous mammal attacked a larger plant-eating dinosaur.
“The two animals are locked in mortal combat, intimately intertwined, and it’s among the first evidence to show actual predatory behaviour by a mammal on a dinosaur,” explains Dr. Jordan Mallon, palaeobiologist with the Canadian Museum of Nature and co-author on the study published today in the journal Scientific Reports.
The fossil’s presence challenges the view that dinosaurs had few threats from their mammal contemporaries during the Cretaceous, when dinosaurs were the dominant animals. The rare fossil is now in the collections of the Weihai Ziguang Shi Yan School Museum in China’s Shandong Province.
The dinosaur in the well-preserved fossil is identified as a species of Psittacosaurus, which is about the size of a large dog. Plant-eating psittacosaurs are among the earliest known horned dinosaurs and lived in Asia during the Early Cretaceous, from around 125 to 105 million years ago. The mammal in the fossil pair is a badger-like animal, called Repenomamus robustus. Although not large by dinosaur standards, it was among the largest mammals during the Cretaceous, at a time when mammals had not yet come to dominate the Earth.
Prior to this discovery, palaeontologists knew that Repenomamus preyed on dinosaurs including Psittacosaurus because of fossilized baby bones of the herbivore found in the mammal’s stomach.
“The co-existence of these two animals is not new, but what’s new to science through this amazing fossil is the predatory behaviour it shows,” says Mallon.
The fossil was collected in China’s Liaoning Province in 2012, and both skeletons are nearly complete. Their completeness is due to the fact that they come from an area known as the Liujitun fossil beds, which have been dubbed “China’s Dinosaur Pompeii.”
The name refers to the many fossils of dinosaurs, small mammals, lizards and amphibians in the area, animals that were buried suddenly en masse by mudslides and debris following one or more volcanic eruptions. The existence of volcanic material in the rock matrix of the study’s fossil was confirmed following analysis by Canadian Museum of Nature mineralogist Dr. Aaron Lussier.
The Psittacosaurus-Repenomamus fossil was in the care of study co-author Dr. Gang Han in China, who brought it to the attention of Canadian Museum of Nature palaeobiologist Xiao-Chun Wu. Dr. Wu has worked with researchers in China for decades and knew it was special when he saw it.
A close examination of the fossil pair shows that the Psittacosaurus is lying prone, with its hindlimbs folded on either side of its body. The body of the Repenomamus coils to the right and sits atop its prey, with the mammalgripping the jaw of the larger dinosaur. The mammal is also biting into some of the ribs, and the back foot of Repenomamus is gripping onto the dino’s hind leg. “The weight of the evidence suggests that an active attack was underway,” says Dr. Mallon.
Mallon, Wu and colleagues ruled out the possibility that the mammal was simply scavenging a dead dinosaur. The bones of the dinosaur have no tooth marks, for example, suggesting it was not being scavenged, but rather was being preyed upon. And it’s unlikely the two animals would have become so entangled if the dinosaur had been dead before the mammal came upon it. The position of the Repenomamus over top of the Psittacosaurus suggests it was also the aggressor.
Analogies of smaller animals attacking larger prey are known in the modern world. Mallon and Wu note that some lone wolverines are known to hunt larger animals, including caribou and domestic sheep. And on the African savanna, wild dogs, jackals and hyenas will attack prey that are still alive, with the prey collapsing, often in a state of shock.
“This might be the case of what’s depicted in the fossil, with the Repenomamus actually eating the Psittacosaurus while it was still alive — before both were killed in the roily aftermath,” explains Mallon.
The research team speculates in their paper that the volcanically derived deposits from the Lujiatun fossil beds in China will continue to yield new evidence of interactions among species, otherwise unknown from the rest of the fossil record.
Reference:
Gang Han, Jordan C. Mallon, Aaron J. Lussier, Xiao-Chun Wu, Robert Mitchell, Ling-Ji Li. An extraordinary fossil captures the struggle for existence during the Mesozoic. Scientific Reports, 2023; 13 (1) DOI: 10.1038/s41598-023-37545-8
Did the pterosaurs, flying reptiles from the days of the dinosaurs, practice parental care or not? New research by scientists from Ireland (University College Cork), China (Nanjing and Yunnan Universities) and the UK (University of Bristol and Queen Mary University of London) shows that pterosaurs were indeed caring parents — but only the larger species.
This solves a long-standing conundrum. To be able to fly soon after hatching from the egg, a bird or pterosaur must have well-developed wings. Studies of smaller pterosaurs from the Jurassic showed that their babies already had large wings when they hatched and they could have wobbled into flight within a few days of birth.
But did this work for the later pterosaurs which were much larger in size? In the Cretaceous, pterosaurs usually had wingspans of 5 metres, and some even reached 10-15 metres, the size of a small glider.
“This was a difficult project,” says the study leader, Dr Zixiao Yang from University College Cork (UCC). ‘We needed examples of pterosaurs where we had at least one hatchling or very young specimen as well as adults so we could study their growth rates. But baby pterosaurs are really rare.”
Dr Yang collaborated with Professor Baoyu Jiang from Nanjing University, Professor Michael Benton of University of Bristol, Professor Xu Xing of Yunnan University, and Professor Maria McNamara of UCC on the research.
“Luckily, we were able to use some classic specimens from the Jurassic of Europe and the Cretaceous of North America, together with new finds from China. By measuring the skulls, backbones, wings, and hind legs, we were able to test for differences in the relative growth of different parts of the body.”
The research focussed on testing the allometry, or how the creatures’ characteristics changed with size.
“We are all familiar with allometry in human babies, puppies and kittens — their heads, eyes and knees are huge, and the rest of the body grows faster to get to adult proportions. It’s the same with many animals, including dinosaurs and pterosaurs. The babies have cute faces, with short noses, big eyes, and big heads,” Dr Yang said.
“The small, bird-sized, Jurassic pterosaurs were born with large wings and strong arms and legs, evidence that the babies could fly from birth. As they grew from baby to adult, their arms and legs showed negative allometry, meaning they started large and were then growing more slowly than the rest of the body.”
“But it was different for the Cretaceous giants. They also started as small babies, but the key limb bones show positive allometry through growth, suggesting a very different developmental model.”
“This means that the pterosaur giants had sacrificed low-input childcare to the need to grow huge eventually as adults. Minimal childcare makes sense in the early evolutionary history of these ancient reptiles because it saves energy. But to grow huge, the larger pterosaurs had a problem — it basically took much longer to become an adult, and therefore parents needed to protect their young from accidents. The babies of all pterosaurs, large and small, were small because of the limitations of egg size. Investing in childcare by having non-flying babies was offset in evolutionary terms by allowing pterosaurs to evolve truly huge sizes.”
“We see the same thing in birds and mammals today. Some birds fly very young, and of course some mammals like cattle and antelopes are on their feet the day they are born. But this kind of behaviour is risky for the babies because they are often clumsy and are easy targets for predators; it’s costly also for the mother because the babies must have highly developed wings or legs at the point of birth. So, we see the same thing in extinct pterosaurs. They were restricted in maximum body size until the end of the Jurassic, at which point their parental care behaviour changed, and then they could achieve huge sizes.”
Reference:
Zixiao Yang, Baoyu Jiang, Michael J. Benton, Xing Xu, Maria E. McNamara, David W. E. Hone. Allometric wing growth links parental care to pterosaur giantism. Proceedings of the Royal Society B: Biological Sciences, 2023; 290 (2003) DOI: 10.1098/rspb.2023.1102
A new 145-million-year-old pterosaur. Credit: René Lauer
A new 145-million-year-old pterosaur (extinct flying reptiles that lived alongside the dinosaurs) was named today by a team of British, American and German researchers. The animal was nicknamed ‘Elvis’ when the fossil was first unearthed in Bavaria, Germany because of the giant pompadour-like bony crest on its skull.
Now the animal has been given a formal scientific name of Petrodactyle wellnhoferi. The name translates as ‘Wellnhofer’s stone-finger’ honouring legendary German palaeontologist Peter Wellnhofer who spent his career working on German pterosaurs. Petrodactyle is a member of a group of pterosaurs called the ctenochasmatids that were mostly small filter feeders. Petrodactyle is a very complete skeleton with nearly every bone preserved and in remarkable detail.
Many pterosaurs are known with bony crests which they used primarily as sexual signals to other members of the species, but Pterodactyle has by far the largest crest even seen in a ctenochasmatid. Dr David Hone of Queen Mary University of London was the lead author on the study said, “Big though this crest is, we know that these pterosaurs had skin-like extensions attached to it, so in life Petrodactyle would have had an even larger crest.”
The details of the specimen are especially clear under UV light which helps show the difference between the bones and the rock in which they are embedded, which under natural light are a very similar colour. René Lauer of the Lauer Foundation, an author on the study said, “The use of UV Induced Fluorescence digital photography provided the ability to discern fine structures small bones and provided additional information regarding the structures of the bony crest which aided in the interpretations and conclusions of this unique new species.”
Petrodactyle was unusually large too. It has a wingspan of around 2 meters, but it was still an older ‘teenager’ by pterosaur standards and would have been even larger as a fully mature animal. Even so, it is one of the largest pterosaurs known from the Late Jurassic period. Bruce Lauer of the Lauer Foundation, an author on the study said “The specimen was located in a quarry which is producing scientifically important fossils that provide additional insights into Late Jurassic Pterosaurs. This research is a great example of the benefits of cooperation between amateur collectors, commercial fossil dealers, our Foundation and research scientists to advance science.”
Like other ctenochasmatids, Petrodactyle was at home on the shore of shallow seas but might have ventured into estuaries or to lakes. It’s long jaw with many small teeth would have been good for grabbing at small fish, shrimp and other aquatic prey. However, unlike most other ctenochasmatids, it had an expansion at the back of the skull to attach large jaw muscles and give it a stronger bite than many of its contemporaries. Frederik Spindler of the Dinosaurier Museum in Germany, an author on the study said, “It is amazing to document an increasingly wide range of adaptations. Pterosaurs were a fundamental part of the Jurassic ecology.”
Dr Hone concluded “Peter Wellnhofer is long overdue having a species of German pterosaur named after him to honour his lifelong contribution to the study of these amazing animals.”
The Lauer Foundation acquires, curates, and provides access to a collection of scientifically important Palaeontological specimens. The collection is available to the scientific community for research, publication, exhibition and educational outreach.
Reference:
David W.E. Hone, René Lauer, Bruce Lauer, Frederik Spindler. Petrodactyle wellnhoferi gen. et sp. nov.: A new and large ctenochasmatid pterosaur from the Late Jurassic of Germany. Palaeontologia Electronica, 2023; DOI: 10.26879/1251
Left: Feathers from a baby bird that lived 99 million years ago, preserved in amber. Photo by Shundong Bi. Right: Illustration of what a newly hatched Enantiornithine bird may have looked like.
Every bird you’ve ever seen — every robin, every pigeon, every penguin at the zoo — is a living dinosaur. Birds are the only group of dinosaurs that survived the asteroid-induced mass extinction 66 million years ago. But not all the birds alive at the time made it. Why the ancestors of modern birds lived while so many of their relatives died has been a mystery that paleontologists have been trying to solve for decades. Two new studies point to one possible factor: the differences between how modern birds and their ancient cousins molt their feathers.
Feathers are one of the key traits that all birds share. They’re made of a protein called keratin, the same material as our fingernails and hair, and birds rely on them to fly, swim, camouflage, attract mates, stay warm, and protect against the sun’s rays. But feathers are complex structures that can’t be repaired, so as a means of keeping them in good shape, birds shed their feathers and grow replacements in a process called molting. Baby birds molt in order to lose their baby feathers and grow adult ones; mature birds continue to molt about once a year.
“Molt is something that I don’t think a lot of people think about, but it is fundamentally such an important process to birds, because feathers are involved in so many different functions,” says Jingmai O’Connor, associate curator of fossil reptiles at Chicago’s Field Museum. “We want to know, how did this process evolve? How did it differ across groups of birds? And how has that shaped bird evolution, shaped the survivability of all these different clades?” Two of O’Connor’s recent papers examine the molting process in prehistoric birds.
A paper in the journal Cretaceous Research published in May 2023 detailed the discovery of a cluster of feathers preserved in amber from a baby bird that lived 99 million years ago.
Today, baby birds are on a spectrum in terms of how developed they are when they’re born and how much help they need from their parents. Altricial birds hatch naked and helpless; their lack of feathers means that their parents can more efficiently transmit body heat directly to the babies’ skin. Precocial species, on the other hand, are born with feathers and are fairly self-sufficient.
All baby birds go through successive molts — periods when they lose the feathers they have and grow in a new set of feathers, before eventually reaching their adult plumage. Molting takes a lot of energy, and losing a lot of feathers at once can make it hard for a bird to keep itself warm. As a result, precocial chicks tend to molt slowly, so that they keep a steady supply of feathers, while altricial chicks that can rely on their parents for food and warmth undergo a “simultaneous molt,” losing all their feathers at roughly the same time.
The amber-preserved feathers in this study are the first definitive fossil evidence of juvenile molting, and they reveal a baby bird whose life history doesn’t match any birds alive today. “This specimen shows a totally bizarre combination of precocial and altricial characteristics,” says O’Connor, who was the first author of the paper alongside senior author Shundong Bi of the Indiana University of Pennsylvania. “All the body feathers are basically at the exact same stage in development, so this means that all the feathers started growing simultaneously, or near simultaneously.” However, this bird was almost certainly part of a now-extinct group called the Enantiornithines, which O’Connor’s previous work has shown were highly precocial.
O’Connor hypothesizes that the pressures of being a precocial baby bird that had to keep itself warm, while undergoing a rapid molt, might have been a factor in the ultimate doom of the Enantiornithines. “Enantiornithines were the most diverse group of birds in the Cretaceous, but they went extinct along with all the other non-avian dinosaurs,” says O’Connor. “When the asteroid hit, global temperatures would have plummeted and resources would have become scarce, so not only would these birds have even higher energy demands to stay warm, but they didn’t have the resources to meet them.”
Meanwhile, an additional study published July 3 in Communications Biology by O’Connor and Field Museum postdoctoral researcher Yosef Kiat examines molting patterns in modern birds to better understand how the process first evolved.
In modern adult birds, molting usually happens once a year in a sequential process, in which they replace just a few of their feathers at a time over the course of a few weeks. That way, they’re still able to fly throughout the molting process. Simultaneous molts in adult birds, in which all the flight feathers fall out at the same time and regrow within a couple weeks, are rarer and tend to show up in aquatic birds like ducks that don’t absolutely need to fly in order to find food and avoid predators.
It’s very rare to find evidence of molting in fossil birds and other feathered dinosaurs, and O’Connor and Kiat wanted to know why. “We had this hypothesis that birds with simultaneous molts, which occur in a shorter duration of time, will be less represented in the fossil record,” says O’Connor — less time spent molting means fewer opportunities to die during your molt and become a fossil showing signs of molting. To test their hypothesis, the researchers delved into the Field Museum’s collection of modern birds.
“We tested more than 600 skins of modern birds stored in the ornithology collection of the Field Museum to look for evidence of active molting,” says Kiat, the first author of the study. “Among the sequentially molting birds, we found dozens of specimens in an active molt, but among the simultaneous molters, we found hardly any.”
While these are modern birds, not fossils, they provide a useful proxy. “In paleontology, we have to get creative, since we don’t have complete data sets. Here, we used statistical analysis of a random sample to infer what the absence of something is actually telling us,” says O’Connor. In this case, the absence of molting fossil birds, despite active molting being so prevalent in the sample of modern bird specimens, suggests that fossil birds simply weren’t molting as often as most modern birds. They may have undergone a simultaneous molt, or they may not have molted on a yearly basis the way most birds today do.
Both the amber specimen and the study of molting in modern birds point to a common theme: prehistoric birds and feathered dinosaurs, especially ones from groups that didn’t survive the mass extinction, molted differently from today’s birds.
“All the differences that you can find between crown birds and stem birds, essentially, become hypotheses about why one group survived and the rest didn’t,” said O’Connor. “I don’t think there’s any one particular reason why the crown birds, the group that includes modern birds, survived. I think it’s a combination of characteristics. But I think it’s becoming clear that molt may have been a significant factor in which dinosaurs were able to survive.”
Reference:
Yosef Kiat, Jingmai Kathleen O’Connor. Rarity of molt evidence in early pennaraptoran dinosaurs suggests annual molt evolved later among Neornithes. Communications Biology, 2023; 6 (1) DOI: 10.1038/s42003-023-05048-x
A new armoured dinosaur, known as an ankylosaur, has been described and named for Prof Paul Barrett of the Natural History Museum.
Vectipelta barretti was discovered in the Wessex formation on the Isle of Wight and represents the first armoured dinosaur from the dinosaur Isle to be described in 142 years.
Lead author Stuart Pond explained the importance of this find, ‘This is an important specimen because it sheds light on ankylosaur diversity within the Wessex formation and Early Cretaceous England.
‘For virtually 142 years, all ankylosaur remains from the Isle of Wight have been assigned to Polacanthus foxii, a famous dinosaur from the island, now all of those finds need to be revisited because we’ve described this new species.’
The new species differs from Polacanthus foxii, previously the only known ankylosaur from the Isle of Wight, in several key characteristics. The fossilized remains show differences in the neck and back vertebrae, a very different structure to the pelvis and more blade-like spiked armour.
The researchers used phylogenetic analysis to work out the relationships between different ankylosaurs and discovered that they are not actually very closely related. In fact, Vectipelta was found to be most closely related to some Chinese ankylosaurs, suggesting dinosaurs moved freely from Asia to Europe in the Early Cretaceous.
Vectipelta barretti would have been roaming the earth during the Early Cretaceous, a time for which fossil remains are rare worldwide. This has led some to suggest that a mass extinction occurred at the end of the Jurassic, which makes the understanding of dinosaur diversity at this time crucial to understanding if such an event occurred and how life recovered. With rocks from this time mostly absent in North America, the Wessex Formation and the Isle of Wight are hugely important areas in answering these questions.
At the time the Isle of Wight would have had a climate similar to that of the Mediterranean and was a flood plain covered by a large meandering river system. Floods would have washed organic material such as plants, logs and even dinosaur bodies together and, as waters receded, this organic matter would have been isolated in ponds on the floodplain that eventually dried out and were buried in the clay soil, preserving this organic material as the fossils we find today.
On naming the new dinosaur for Prof Paul Barrett of the Natural History Museum, senior author Dr Susannah Maidment said, ‘Myself and some of the other authors on this study have been mentored or supervised by Paul for most of our careers, and it was notable to us that Paul hadn’t had a dinosaur named after him yet. He’s hugely influential in in vertebrate palaeontology, and he’s a world-leading authority on dinosaurs.
‘We really wanted to thank him for his support and mentorship, so we decided to name a, slow-moving, spikey organism after him.’
Prof Paul Barrett has worked at the Natural History Museum, London for 20 years and in that time has published an impressive 220 scientific papers. He has also supervised 31 PhD students and mentored many others, encouraging a whole new generation of palaeontologists.
Of the honour Prof Barrett said, ‘I’m flattered and absolutely delighted to have been recognised in this way, not least as the first paper I ever wrote was also on an armoured dinosaur in the NHM collections. I’m sure that any physical resemblance is purely accidental.’
The team are optimistic that more species will be discovered in the area in the future. Dr Maidment concluded, ‘We have new iguanodontians that we are lining up, to be prepped and to be studied. I think we have at least two new taxa in the collections. With regards to ankylosaurs, they are somewhat rarer, so I think we need to keep our eyes peeled.’
The new dinosaur is part of the internationally important collection held at Dinosaur Isle Museum, operated by the Isle of Wight Council. Parts of the dinosaur will be on display at the museum for the school holidays. The bones have been cleaned from their surrounding matrix by staff and volunteers at the museum which has made the research possible.
Reference:
Stuart Pond, Sarah-Jane Strachan, Thomas J. Raven, Martin I. Simpson, Kirsty Morgan, Susannah C. R. Maidment. Vectipelta barretti, a new ankylosaurian dinosaur from the Lower Cretaceous Wessex Formation of the Isle of Wight, UK. Journal of Systematic Palaeontology, 2023; 21 (1) DOI: 10.1080/14772019.2023.2210577
The fossil was found on a National Trust beach on the Isle of Wight
The first side-necked turtle ever to be found in the UK has been discovered by an amateur fossil collector and palaeontologists at the University of Portsmouth.
The fossil remains are the earliest of a so-called side-necked pan-pleurodiran turtle, named as such because they fold their neck into their shell sideways when threatened. This does mean they can only see out with one eye.
Originally found on a National Trust beach on the Isle of Wight, the turtle fossil is an almost complete shell with cervical, dorsal and caudal vertebrae, scapulae, pelvic girdle and appendicular bones. Sadly, the skull was missing.
Lead author, Megan Jacobs, said: “This is an amazing discovery because it’s the first time this type of turtle has been found in the UK. Even more exciting is that we used a new technique of radiometric dating to determine the age of the fossil beyond any doubt. And to top it off, CT scanning revealed all the tiny bones inside. It’s really incredible for what looks like a rolled beach pebble!”
Megan and colleagues dissected minerals from inside the turtle shell and analysed them for uranium and lead. By measuring the ratio of lead to radioactive uranium, they established the turtle was from the Lower Cretaceous period, around 127 million years ago.
The fossil was originally found on the foreshore at Brook Bay on the southwest coast of the Isle of Wight by fossil collector Steve Burbridge. This part of the coast is well-known for fossil vertebrates that come from the cliff and foreshore exposures of the upper part of the famous Isle of Wight fossil beds of the Wessex Formation.
This is the first time that radiometric dating has been used on a fossil from the Wessex formation.
Megan added: “We’ve nicknamed the turtle ‘Burby’ after Steve who very kindly donated the specimen to the Dinosaur Isle Museum at Sandown on the Isle of Wight.”
The researchers also used cutting-edge micro CT scanning at the University of Portsmouth’s Future Technology Centre to discern various tiny bones. This advanced imaging technique provided invaluable insight into the structure and composition of the turtle’s shell, without damaging it.
Steve said: “It’s beyond my wildest dreams to have one of my finds published. I could never have guessed it was such an incredibly important fossil. It’s so wonderful to see all the tiny bones inside too.”
Geologist, Dr Catherine Mottram, from the University of Portsmouth’s School of the Environment, Geography and Geosciences is one of the paper’s co-authors. She said: “It is exciting that we have been able to use cutting edge radiometric dating techniques to provide absolute constraints for this important sequence for the first time.”
Other co-authors include Adán Pérez-García and Marcos Martín-Jiménez from UNED, Spain, Professor David Martill, Andrew Gale and Charles Wood from the University of Portsmouth, and Oliver Mattsson from Dinosaur Expeditions.
The paper is published in the scientific journal Cretaceous Research.
Reference:
Megan L. Jacobs, Adán Pérez-García, Marcos Martín-Jiménez, Catherine M. Mottram, David M. Martill, Andrew S. Gale, Oliver L. Mattsson, Charles Wood. A well preserved pan-pleurodiran (Dortokidae) turtle from the English Lower Cretaceous and the first radiometric date for the Wessex Formation (Hauterivian–Barremian) of the Isle of Wight, United Kingdom. Cretaceous Research, 2023; 150: 105590 DOI: 10.1016/j.cretres.2023.105590
Ten years ago, Samer Naif made an unexpected discovery in Earth’s mantle: a narrow pocket, proposed to be filled with magma, hidden some 60 kilometers beneath the seafloor of the Cocos Plate.
Mantle melts are buoyant and typically float toward the surface — think underwater volcanoes that erupt to form strings of islands. But Naif’s imaging instead showed a clear slice of semi-molten rock: low-degree partial melts, still sandwiched at the base of the plate some 37 miles beneath the ocean floor.
Then, the observation provided an explanation for how tectonic plates can gradually slide, lubricated by partial melting. The study also “raised several questions about why magma is stored in a thin channel — and where the magma originated from,” says Naif, an assistant professor in the School of Earth and Atmospheric Sciences at Georgia Institute of Technology.
Fellow researchers went on to share competing interpretations for the cause of the channel — including studies that argued against magma being needed to explain the observation.
So Naif went straight to the source.
“I basically went on a multiyear hunt, akin to a Sherlock Holmes detective story, looking for clues of mantle magmas that we first observed in the 2013 Nature study,” he says. “This involved piecing together evidence from several independent sources, including geophysical, geochemical, and geological (direct seafloor sampling) data.”
Now, the results of that search are detailed in a new Science Advances article, “Episodic intraplate magmatism fed by a long-lived melt channel of distal plume origin,” authored by Naif and researchers from the U.S. Geological Survey at Woods Hole Coastal and Marine Science Center, Northern Arizona University, Lamont-Doherty Earth Observatory of Columbia University, the Department of Geology and Geophysics at Woods Hole Oceanographic Institution, and GNS Science of Lower Hutt, New Zealand.
Zeroing in
A relatively young oceanic plate — some 23 million years old — the Cocos Plate traces down the western coast of Central America, veering west to the Pacific Plate, then north to meet the North American Plate off the Pacific coast of Mexico.
Sliding between these two plates caused the devastating 1985 Mexico City earthquake and the 2017 Chiapas earthquake, while similar subduction between the Cocos and Caribbean plates resulted in the 1992 Nicaragua tsunami and earthquake, and the 2001 El Salvador earthquakes.
Scientists study the edges of these oceanic plates to understand the history and formation of volcanic chains — and to help researchers and agencies better prepare for future earthquakes and volcanic activity.
It’s in this active area that Naif and fellow researchers recently set out to document a series of magmatic intrusions just beneath the seafloor, in the same area that the team first detected the channel of magma back in 2013.
Plumbing the depths
For the new study, the team combined geophysical, geochemical, and seafloor drilling results with seismic reflection data, a technique used to image layers of sediments and rocks below the surface. “It helps us to see the geology where we cannot see it with our own eyes,” Naif explains.
First, the researchers observed an abundance of widespread intraplate magmatism. “Volcanism where it is not expected,” Naif says, “basically away from plate boundaries: subduction zones and mid-ocean ridges.”
Think Hawaii, where “a mantle plume of hot, rising material melts during its ascent, and then forms the Hawaii volcanic chain in the middle of the Pacific Ocean,” just as with the Cocos Plate, where the team imaged the volcanism fed by magma at the lithosphere-asthenosphere boundary — the base of the sliding tectonic plates.
“Below it is the convecting mantle,” Naif adds. “The tectonic plates are moving around on Earth’s surface because they are sliding on the asthenosphere below them.”
The researchers also found that this channel below the lithosphere is regionally extensive — over 100,000 square kilometers — and is a “long-lived feature that originated from the Galápagos Plume,” a mantle plume that formed the volcanic Galápagos islands, supplying melt for a series of volcanic events across the past 20 million years, and persisting today.
Importantly, the new study also suggests that these plume-fed melt channels may be widespread and long-lived sources for intraplate magmatism itself — as well as for mantle metasomatism, which happens when Earth’s mantle reacts with fluids to form a suite of minerals from the original rocks.
Connecting the (hot spot) dots
“This confirms that magma was there in the past — and some of it leaked through the mantle and erupted near the seafloor,” Naif says, “in the form of sill intrusions and seamounts: basically volcanoes located on the seafloor.”
The work also provides compelling supporting evidence that magma could still be stored in the channel. “More surprising is that the erupted magma has a chemical fingerprint that links its source to the Galápagos mantle plume.”
“We learned that the magma channel has been around for at least 20 million years, and on occasion some of that magma leaks to the seafloor where it erupts volcanically,” Naif adds.
The team’s identified source of the magma, the Galápagos Plume, “is more than 1,000 kilometers away from where we detected this volcanism. It is not clear how magma can stay around in the mantle for such a long time, only to leak out episodically.”
Plume hunters wanted
The evidence that the team compiled is “really quite subtle and requires a detailed and careful study of a suite of seafloor observations to connect the dots,” Naif says. “Basically, the signs of such volcanism, while they are quite clear here, also require high resolution data and several different types of data to be able to detect such subtle seafloor features.”
So, “if we can see such subtle clues of volcanism here,” Naif explains, “it means a similar, careful analysis of high resolution data in other parts of the seafloor may lead to similar discoveries of volcanism elsewhere, caused by other mantle plumes.”
“There are numerous mantle plumes dotted across the planet. There are also numerous seamounts — at least 100,000 of them! — covering the seafloor, and it is anyone’s guess how many of them formed in the middle of the tectonic plates because of magma sourced from distant mantle plumes that leaked to the surface.”
Naif looks forward to continuing that search, from seafloor to asthenosphere.
Reference:
Samer Naif, Nathaniel C. Miller, Donna J. Shillington, Anne Bécel, Daniel Lizarralde, Dan Bassett, Sidney R. Hemming. Episodic intraplate magmatism fed by a long-lived melt channel of distal plume origin. Science Advances, 2023; 9 (23) DOI: 10.1126/sciadv.add3761
Steve May, a research associate at the Jackson School of Geosciences, holds a fossil from a plesiosaur, an extinct marine reptile. Credit: Jackson School of Geosciences/ The University of Texas at Austin.
A team led by scientists at The University of Texas at Austin has filled a major gap in the state’s fossil record — describing the first known Jurassic vertebrate fossils in Texas.
The weathered bone fragments are from the limbs and backbone of a plesiosaur, an extinct marine reptile that would have swum the shallow sea that covered what is now northeastern Mexico and far western Texas about 150 million years ago.
The bones were discovered in the Malone Mountains of West Texas during two fossil hunting missions led by Steve May, a research associate at UT Austin’s Jackson School of Geosciences Museum of Earth History.
Before the discovery, the only fossils from the Jurassic that had been collected and described from outcrops in Texas were from marine invertebrates, such as ammonites and snails. May said that the new fossil finds serve as solid proof that Jurassic bones are here.
“Folks, there are Jurassic vertebrates out there,” May said. “We found some of them, but there’s more to be discovered that can tell us the story of what this part of Texas was like during the Jurassic.”
A paper describing the bones and other fossils was published in Rocky Mountain Geology on June 23.
The Jurassic was an iconic prehistoric era when giant dinosaurs walked the Earth. The only reason we humans know about them, and other Jurassic life, is because of fossils they left behind.
But to find Jurassic-aged fossils, you need Jurassic-aged rocks. Because of the geological history of Texas, the state hardly has any outcrops from this time in Earth history. The 13 square miles of Jurassic-aged rocks in the Malone Mountains make up most of those rocks in the state.
In 2015, when May learned while researching a book that there were no Jurassic bones in the Texas fossil record, he decided to go to the Malone Mountains to explore.
“You just don’t want to believe that there are no Jurassic bones in Texas,” May said. “Plus, there was a tantalizing clue.”
The clue was a mention of large bone fragments in a 1938 paper on the geology of the Malone Mountains by Claude Albritton, who later became a geology professor at Southern Methodist University (SMU). It was enough of a lead to get May and his collaborators out to West Texas to see for themselves. Large bone fragments are what they found. The plesiosaur fossils are eroded and broken up.
But it’s a start that could lead to more science, said co-author Louis Jacobs, a professor emeritus at SMU.
“Geologists are going to go out there looking for more bones,” Jacobs said. “They’re going to find them, and they’re going to look for the other things that interest them in their own special ways.”
Today, the Malone Mountains rise above the dry desert landscape. During the Jurassic, the sediments were deposited just below sea level probably within miles of the shoreline.
The team found several other specimens that give a look into the ancient shallow marine environment, such as petrified driftwood filled with burrows from marine worms and the shells of clams, snails and ammonites. The researchers found a range of plant fossils, including a pinecone, and wood with possible growth rings.
Globally, Jurassic plant fossils from lower latitudes close to the Earth’s equator are relatively rare, said co-author and paleobotanist Lisa Boucher, the director of the Jackson School’s Non-Vertebrate Paleontology Lab. She said the plant finds should make the Malones a place of interest to other paleobotanists and those interested in paleoenvironmental reconstruction.
Scientists have been conducting research in the Malones for over 100 years. So, why did it take so long to bring back Jurassic bones? May has several ideas — from remoteness of the area and permitting, to the research interests of past scientists. Whatever the reasons, Boucher said that the team’s discovery of a Texas first shows the value of field work — simply traveling to a place to see what’s there.
“It’s frequently part of the scientific process,” Boucher said. “There’re a few lines buried in an old publication, and you think ‘surely somebody has already looked at that,’ but often they haven’t. You need to delve into it.”
The study’s additional co-authors are Kenneth Bader, a laboratory manager at the Jackson School Museum of Earth History; Joshua Lively, the curator of paleontology at Utah State University and a Jackson School alumnus; and Timothy Myers and Michael Polcyn, both researchers at Southern Methodist University.
Reference:
Steven R. May, Kenneth S. Bader, Lisa D. Boucher, Louis L. Jacobs, Joshua R. Lively, Timothy S. Myers, Michael J. Polcyn. A record of Late Jurassic vertebrates from Texas. Rocky Mountain Geology, 2023; 58 (1): 19 DOI: 10.24872/rmgjournal.58.1.19
Powerful volcanic eruptions produce ash plumes that can create their own weather systems, providing the conditions for lightning at higher altitudes than normally seen.
New research published in the journal Geophysical Research Letters showed that the plume emitted by the Hunga Volcano eruption in 2022 created the highest lightning flash rates ever recorded on Earth, more than any storm ever documented.
“The eruption of Hunga Volcano was the largest volcanic explosion since Krakatau in 1883,” said Sonja Behnke, of Los Alamos National Laboratory’s Electromagnetic Sciences and Cognitive Space Applications group and author on the paper.
Powerful volcanic eruptions produce ash plumes that can create their own weather systems, providing the conditions for lightning at higher altitudes than normally seen. When the undersea volcano in Tonga erupted, it created a plume that went more than 25 miles higher than typical thunderstorms. Lightning was observed at stratospheric altitudes (12 to 18 miles), where the air pressure is too low to support thunderstorm-like lightning. This fast-rising volcanic plume may have created locally higher pressures to support the environment necessary for lightning.
After reaching its maximum height, the plume expanded outward as an umbrella cloud, creating fast-moving circular ripples known as gravity waves, similar to a rock dropped in a pond. Donut-shaped rings of lightning expanded with the umbrella cloud and were as large as 174 miles in diameter. Similar “lightning holes” have been observed in thunderstorms, but never on this large of a scale.
The lightning was detected by space-based optical sensors, and global networks of ground-based radio antennas thousands of miles away.
The research team, led by the US Geological Survey Cascades Volcano Observatory, found that the eruption produced 2,615 flashes per minute at its peak intensity, which lasted nearly five minutes. This peak lightning rate is significantly higher than the second most intense lightning event ever detected — 993 flashes per minute — in a thunderstorm over the southern United States in 1999.
Remote detection of lightning helped create a detailed timeline of this historic eruption, and demonstrated the value of using volcanic lightning for monitoring volcanic activity.
“Lightning observations such as these reveal detail about the evolution of an eruption over time, which is particularly valuable when cloud-cover obscures satellite observations of a plume,” said Behnke.
The work was supported by the U.S. Geological Survey Volcano Hazards Program, the Laboratory Directed Research and Development program at Los Alamos National Laboratory and a NASA ROSES-2019 “Earth Science Research from Operational Geostationary Satellite Systems” program award.
Reference:
Alexa R. Van Eaton, Jeff Lapierre, Sonja A. Behnke, Chris Vagasky, Christopher J. Schultz, Michael Pavolonis, Kristopher Bedka, Konstantin Khlopenkov. Lightning Rings and Gravity Waves: Insights Into the Giant Eruption Plume From Tonga’s Hunga Volcano on 15 January 2022. Geophysical Research Letters, 2023; 50 (12) DOI: 10.1029/2022GL102341
At the center the Earth is a solid metal ball, a kind of “planet within a planet,” whose existence makes life on the surface possible, at least as we know it.
How Earth’s inner core formed, grew and evolved over time remains a mystery, one that a team of University of Utah-led researchers is seeking to plumb with the help of seismic waves from naturally occurring earthquakes. While this 2,442-kilometer-diameter sphere comprises less than 1% of the Earth’s total volume, its existence is responsible for the planet’s magnetic field, without which Earth would be a much different place.
But the inner core is not the homogenous mass that was once assumed by scientists, but rather it’s more like a tapestry of different “fabric,” according to Guanning Pang, a former PhD student in the U.’s Department of Geology and Geophysics.
“For the first time we confirmed that this kind of inhomogeneity is everywhere inside the inner core,” Pang said. Now a post-doctoral researcher at Cornell University, Pang is the lead author of a new study, published July 5 in Nature that opens a window into the deepest reaches of Earth. He conducted the study as part of his PhD dissertation at Utah.
The other final frontier
“What our study was about was trying to look inside the inner core,” said U seismologist Keith Koper, who oversaw the study. “It’s like a frontier area. Anytime you want to image the interior of something, you have to strip away the shallow effects. So this is the hardest place to make images, the deepest part, and there’s still things that are unknown about it.”
This research harnessed a special dataset generated by a global network of seismic arrays set up to detect nuclear blasts. In 1996, the United Nations established the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, CTBTO, to ensure compliance with the international treaty that bans such explosions.
Its centerpiece is the International Monitoring System (IMS), featuring four systems for detecting explosions using advanced sensing instruments sited all over the world. While their purpose is to enforce an international ban on nuclear detonations, they have yielded troves of data scientists can use to shed new light on what’s going on in Earth’s interior, oceans and atmosphere.
This data has facilitated research that illuminated meteor blasts, identified a colony of pygmy blue whales, advanced weather prediction, and provided insights into how icebergs form.
While Earth’s surface has been thoroughly mapped and characterized, its interior is much harder to study since it cannot be directly accessed. The best tools for sensing this hidden realm are earthquakes’ seismic waves propagating from the planet’s thin crust and vibrating through its rocky mantle and metallic core.
“The planet formed from asteroids that were sort of accreting [in space]. They’re running into each other and you generate a lot of energy. So the whole planet, when it’s forming up, is melting,” Koper said. “It’s simply that the iron is heavier and you get what we call core formation. The metals sink to the middle, and the liquid rock is outside, and then it essentially freezes over time. The reason all the metals are down there is because they’re heavier than the rocks.”
Planet within a planet
For the past few years, Koper’s lab has been analyzing seismic data senstivite to the inner core. A previous study, led by Pang identified variations between the rotations of Earth and its inner core that may have triggered a shift in the length of the day in 2001 to 2003.
Earth’s core, which measures about 4,300 miles across, is comprised mostly of iron and some nickel, along with a few other elements. The outer core remains liquid, enveloping the solid inner core.
“It’s like a planet within a planet that has its own rotation and it’s decoupled by this big ocean of molten iron,” said Koper, a geology professor who directs the U of U Seismograph Stations, or UUSS.
The protective field of magnetic energy surrounding Earth is created by convection occurring within the liquid outer core, which extends 2,260 kilometers (1,795 miles) above the solid core, he said. The molten metal rises above the solid inner core, cools as it approaches Earth’s rocky mantle and sinks. This circulation generates the bands of electrons enveloping the planet. Without Earth’s solid inner core, this field would be much weaker and the planetary surface would be bombarded with radiation and solar winds that would strip away the atmosphere and render the surface uninhabitable.
For the new study, the U team looked at seismic data recorded by 20 arrays of seismometers placed around the world including two in Antarctica. The closest to Utah is outside Pinedale, Wyo. These instruments are inserted in boreholes drilled up to 10 meters into granite formations and arranged in patterns to concentrate the signals they receive, similar to the way parabolic antennae work.
Pang analyzed seismic waves from 2,455 earthquakes, all exceeding magnitude 5.7, or about the strength of the 2020 quake that rocked Salt Lake City. The way these waves bounced off the inner core help map its internal structure.
Smaller quakes do not generate waves strong enough to be useful for the study.
“This signal that comes back from the inner core is really tiny. The size is about on the order of a nanometer,” Koper said. “What we’re doing is looking for a needle in a haystack. So these baby echoes and reflections are very hard to see.”
The core is changing
Scientists first used seismic waves to determine that the inner core was solid in 1936. Before the discovery by Danish seismologist Inge Lehmann, it was assumed the entire core was liquid since it is exceedingly hot, approaching 10,000 degrees Fahrenheit, about the temperature on the sun’s surface.
At some point in Earth’s history, the inner core started “nucleating,” or solidifying, under the intense pressures existing at the center of the planet. It remains unknown when that process began, but the U team gleaned important clues from the seismic data, which revealed a scattering effect associated with waves that penetrated to the core’s interior.
“Our biggest discovery is the inhomogeneity tends to be stronger when you get deeper. Toward the center of the Earth it tends to be stronger,” Pang said.
“We think that this fabric is related to how fast the inner core was growing. A long time ago the inner core grew really fast. It reached an equilibrium, and then it started to grow much more slowly,” Koper said. “Not all of the iron became solid, so some liquid iron could be trapped inside.”
Participating in the study, which was funded by the National Science Foundation, were researchers from University of Southern California, the Université de Nantes in France, and the Los Alamos National Laboratory.
Reference:
Guanning Pang, Keith D. Koper, Sin-Mei Wu, Wei Wang, Marine Lasbleis, Garrett Euler. Enhanced inner core fine-scale heterogeneity towards Earth’s centre. Nature, 2023; DOI: 10.1038/s41586-023-06213-2
Note: The above post is reprinted from materials provided by University of Utah. Original written by Brian Maffly.
When someone near you turns their head towards something in the environment, you likely can’t help to follow their gaze direction. This reaction is observed in mammals, birds and even reptiles alike. It’s an effective way to gather information about what caught the attention of your fellow, which you might otherwise have missed. However, a far more advanced behavior is to follow someone’s gaze to a location that is initially obstructed from your view. By repositioning yourself to see what the other person is looking at, you demonstrate an understanding that the other has a different perspective. This ability, known as visual perspective taking develops in children between the ages of one-and-a-half to two years and serves as the foundation for later comprehending referential communication and that others have minds that differ from your own.
Visual perspective taking has, to date, only been found in very few species. Mainly in apes and some monkeys, but also in dogs and crow birds. However, there is limited knowledge regarding the evolutionary origins of this crucial social skill. A team of researchers from Lund University aimed to investigate a potential early emergence of visual perspective taking in dinosaurs. Through a comparison of alligators with the most primitive existing birds, known as palaeognaths, they discovered that visual perspective taking originated in the dinosaur lineage likely 60 million years, or more, prior to its appearance in mammals.
Crocodilians are the closest living relatives to birds. Their neuroanatomy has remained largely unchanged for hundreds of millions of years, and is similar to that of the common ancestor of dinosaurs and crocodilians. Palaeognath birds comprise the ostrich birds, such as emus and rheas, but also the flighted tinamous. Their brains are in large parts comparable to their forebearers, the non- avian paravian dinosaurs, which feature such celebrities as the velociraptors. Comparing these two groups of animals creates a bracket around the extinct lineage of dinosaurs leading up to modern birds.
The study revealed that alligators do not demonstrate visual perspective taking, although they do follow gaze to a visible location. In contrast, all tested bird species exhibited visual perspective taking. Additionally, the birds engaged in a behaviour called “checking back,” where the observer looks back into the eyes of the gazer, and re-tracks the gaze, when unable to find anything in the direction of their gaze the first time. This behaviour indicates an expectation that the gaze is referring to a target in the environment. Previously, this has only been observed in humans, apes and monkeys, and ravens.
Palaeognath birds emerged 110 million years ago, predating the two mammal groups endowed with visual perspective taking — primates and dogs — with 60 million years. Considering the neuroanatomical similarities between these birds and their non-avian forebearers, it is plausible that the skill originated even earlier in the dinosaur lineage. However, it is less likely to have been present among the earliest dinosaurs, which had more alligator-like brains. Maybe future research will show the ability to be more widespread among mammals than currently known, but even if that would be the case it will most probably still be predated by the dinosaur origin. Nevertheless, it is not surprising that visual perspective taking emerged earlier in the dinosaurs, which include the birds, given their superior vision compared to most mammals, that historically relied on nocturnal adaptations. It was only with the emergence of the primates and certain carnivores that our visual capabilities improved.
This is yet another finding that calls into question the prevailing view that mammals drove the evolution of complex cognition, and that they are the cognitive yardstick to which other animals should be compared. An increasing number of studies show the remarkable neurocognition of the avian dinosaurs, the birds, which might prompt a rethinking of the natural history of cognition.
Comments from the authors:
Senior author, prof. Mathias Osvath: “Early in my career, crow birds earned the nickname “feathered apes,” due to numerous research findings that showcased their remarkable cognition. However, I’m beginning to question whether it would be more fitting to consider primates as honorary birds.”
First author (then PhD-student), Dr Claudia Zeiträg: “Birds are commonly being overlooked when it comes to their cognitive skills. Our findings show that they do not only have several cognitive skills on par with those of apes, but that their forebearers most likely had these skills long before they evolved in mammals.”
Middle author, Dr Stephan Reber: “Crocodilians are ideal models to study the evolutionary origins of cognitive capacities in birds. What they share most probably existed in the common ancestor of dinosaurs and crocodilians. If crocodilians lack an ability birds possess, it likely evolved in the dinosaur lineage after the split. This approach allows us to study the cognition of extinct species.”
Reference:
Claudia Zeiträg, Stephan A. Reber, Mathias Osvath. Gaze following in Archosauria—Alligators and palaeognath birds suggest dinosaur origin of visual perspective taking. Science Advances, 2023; 9 (20) DOI: 10.1126/sciadv.adf0405
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