Dinosaur species laid eggs like reptiles, brooded like birds, new study finds
The birds we see today are the predecessor of a dinosaur that learned to fly and survived mass extinction 66 million years ago, but little is known about their transition.
While they were the only species to survive the Cretaceous period, there also wasn’t much known about how similar the dinosaurs and modern-day birds could be.
A tiny piece of a dinosaur eggshell, about the size of a fingernail, was central in an international study published Monday in the Proceedings of the National Academy of Sciences journal, helping reconstruct the prehistoric creature’s reproductive system and establish its physiology, metabolism and body temperature.
The Troodon, believed to be a meter-long meat-eating dinosaur, is considered to have given rise to birds, said Francois Therrien, a paleontologist at the Royal Tyrrell Museum in Drumheller, Alta., who is one the authors of the study.
The study, he said, “can give us a lot of information about what occurred during that transformation from a typical meat-eating dinosaur to a bird, (like) answering questions about whether the birds really inherit most of the characteristics from meat-eating dinosaurs.”
Therrien added the transition was a gradual one, something researchers found by looking at similarities the dinosaur had to modern-day reptiles and birds.
The study found that Troodons were warm-blooded animals with a reproductive system similar to today’s reptiles, but they also had the ability to moderate their body temperature similar to birds.
While Troodon eggs resembled a bird’s egg in shape and surface, the female dinosaurshad two ovaries and could lay two eggs at a time, like that of reptiles.
This also means a female Troodon could lay four to six eggs per clutch, said Darla Zelenitsky, a dinosaur paleobiology professor at the University of Calgary.
“We were able to figure out the dinosaur produced its eggs very slowly, which is typical of modern reptiles,” said Zelenitsky, who also is one of the authors of the study.
Female birds have one ovary and can lay an egg every one or two days. Researchers aren’t clear if the evolutionary loss of an ovary happened among non-avian dinosaurs or after the transition into birds.
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The study used a technique called dual clumpedisotope thermometry to measure the heavier varieties of oxygen and carbonin the eggshell fossils to determine the body temperatures of Troodons and to better understand the dinosaur’s reproductive system.
The findings were then matched with eggshells of modern-day reptiles, such as crocodiles, alligators and certain species of a turtle, as well as birds like chickens, sparrows, wrens and ostriches.
The dinosaur nestlings, some found at two sites in southern Alberta, had up to 24 eggs, suggesting female Troodons laid eggs in communal nests, which is seen among birds including ostriches.
“It’s possible that some (Troodon) mothers congregated together to build communal nests and lay all their eggs, and then share duties of guarding and brooding all the eggs in turns,” Therrien said.
The nests also reflected intelligence among the Troodons, Therrien and Zelenitsky said. The dinosaurs buried the eggs in the nest vertically with the pointy down and the blunt side up, which could have improved incubation.
The eggshell fossils, which are stored at the Royal Tyrrell Museum, helped scientists reconstruct the Earth’s surface temperature to understand better the body temperature of the dinosaur and the mineralization processes of the fossils.
The isotope clumping of oxygen and carbon crystallization, which depends on temperature, also revealed the body temperature of the species.
Troodon dinosaurs were believed to lay eggs at between 30 C and 42 C. The species had a resting body temperature of 42 C, which could be lowered to 30 C, depending on their environment, similar to birds.
Scientists are now looking into whether Troodons could have survived in humid areas in different parts of the world, as opposed to the semi-arid regions where the eggs were first discovered.
“Most people think that you need to find complete dinosaur skeletons to be able to say something about its biology and the animals when they were alive,” Therrien said.
“With the study, we truly can go into how an animal functioned by studying the isotopic composition of the eggshell that you can’t obtain from the study of bones alone.”
Researchers are now looking into Troodon eggs from different sites and from periods to see if the patterns found in this study continue to be consistent with other eggs.
ESA – Cheops explores mysterious warm mini-Neptunes – European Space Agency
ESA’s exoplanet mission Cheops confirmed the existence of four warm exoplanets orbiting four stars in our Milky Way. These exoplanets have sizes between Earth and Neptune and orbit their stars closer than Mercury our Sun.
These so-called mini-Neptunes are unlike any planet in our Solar System and provide a ‘missing link’ between Earth-like and Neptune-like planets that is not yet understood. Mini-Neptunes are among the most common types of exoplanets known, and astronomers are starting to find more and more orbiting bright stars.
Mini-Neptunes are mysterious objects. They are smaller, cooler, and more difficult to find than the so-called hot Jupiter exoplanets which have been found in abundance. While hot Jupiters orbit their star in a matter of hours to days and typically have surface temperatures of more than 1000 °C, warm mini-Neptunes take longer to orbit their host stars and have cooler surface temperatures of only around 300 °C.
The first sign of the existence of these four new exoplanets was found by the NASA TESS mission. However, this spacecraft only looked for 27 days at each star. A hint to a transit – the dimming of light as a planet passes in front of its star from our viewpoint – was spotted for each star. During its extended mission, TESS revisited these stars and the same transit was seen again, implying the existence of planets.
Scientists calculated the most likely orbital periods and pointed Cheops at the same stars at the time they expected the planets to transit. During this hit-or-miss procedure Cheops was able to measure a transit for each of the exoplanets, confirming their existence, discovering their true orbital periods and taking the next step in their characterisation.
The four newly discovered planets have orbits between 21 and 53 days around four different stars. Their discovery is essential because it brings our sample of known exoplanets closer to the longer orbits that we find in our own Solar System.
One of the outstanding questions about mini-Neptunes is what they are made of. Astronomers predict that they have an iron-rocky core with thick outer layers of lighter material. Different theories predict different outer layers: Do they have deep oceans of liquid water, a puffy hydrogen and helium atmosphere or an atmosphere of pure water vapour?
Discovering the composition of mini-Neptunes is important to understand the formation history of this type of planet. Water-rich mini-Neptunes probably formed far out in the icy regions of their planetary system before migrating inwards, while combinations of rock and gas would tell us that these planets stayed in the same place as they formed.
The new Cheops measurements helped determine the radius of the four exoplanets, while their mass could be determined using observations from ground-based telescopes. Combining the mass and radius of a planet gives an estimate of its overall density.
The density can only give a first estimate of the mass of the iron-rocky core. While this new information about the density is an important step forward in understanding mini-Neptunes, it does not contain enough information to offer a conclusion for the outer layers.
The four newly confirmed exoplanets orbit bright stars, which make them the perfect candidates for a follow-up visit by the NASA/ESA/CSA James Webb Space Telescope or ESA’s future Ariel mission. These spectroscopic missions could discover what their atmospheres contain and provide a definitive answer to the composition of their outer layers.
A full characterisation is needed to understand how these bodies formed. Knowing the composition of these planets will tell us by what mechanism they formed in early planetary systems. This in turn helps us better understand the origins and evolution of our own Solar System.
The results were published in four papers: ‘Refined parameters of the HD 22946 planetary system and the true orbital period of the planet d’ by Z. Garai et al. is published in Astronomy & Astrophysics. https://www.aanda.org/10.1051/0004-6361/202345943
‘Two Warm Neptunes transiting HIP 9618 revealed by TESS & Cheops’ by H. P. Osborn et al. is published in the Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/stad1319
‘TESS and CHEOPS Discover Two Warm Sub-Neptunes Transiting the Bright K-dwarf HD15906’ by A. Tuson et al. is published in the Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/stad1369
‘TOI-5678 b: a 48-day transiting Neptune-mass planet characterized with CHEOPS and HARPS’ by S. Ulmer-Moll et al. is published in Astronomy & Astrophysics. https://www.aanda.org/10.1051/0004-6361/202245478
Brightest gamma-ray burst ever seen, the largest known explosion since Big Bang, has a unique jet structure unlike any other
Scientists may finally know what made the largest explosion in the universe ever seen by humankind so powerful.
Astronomers have discovered that the brightest gamma-ray burst (GRB) ever seen had a unique jet structure and was dragging an unusually large amount of stellar material along with it.
This might explain the extreme properties of the burst, believed to have been launched when a massive star located around 2.4 billion light-years from Earth in the direction of the constellation Sagitta underwent total gravitational collapse to birth a black hole, as well as why its afterglow persisted for so long.
The GRB officially designated GRB 221009A but nicknamed the BOAT, or the brightest of all time, was spotted on October 9, 2022, and stood out from other GRBs due to its extreme nature. It was seen as an immensely bright flash of high-energy gamma-rays, followed by a low-fading afterglow across many wavelengths of light.
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“GRB 221009A represents a massive step forward in our understanding of gamma-ray bursts and demonstrates that the most extreme explosions do not obey the standard physics assumed for garden variety gamma-ray bursts,” George Washington University researcher and study lead author Brendan O’Connor said in a statement. O’Connor led a team that continued to monitor the BOAT GRB with the Gemini South Telescope in Chile following its initial discovery in Oct 2023.
Northwestern University doctoral candidate Jillian Rastinejad, who was also part of a team that observed the BOAT on Oct. 14 after its initial discovery,told Live Science that GRB 221009A is thought to be brighter than other highly energetic GRBs by a factor of at least 10.
“Photons have been detected from this GRB that has more energy than theLarge Hadron Collider (LHC) produces,” she said.
Even before the BOAT was spotted, GRBs were already considered the most powerful, violent, and energetic explosions in the universe, capable of blasting out as much energy in a matter of seconds as the sun will produce over its entire around ten billion-year lifetime. There are two types of these blasts, long-duration, and short-duration, which might have different launch mechanisms, both resulting in the creation of a black hole.
Further examination of the powerful GRB has revealed that it is unique for its structure as well as its brightness. The GRB was surprisingly wide. So wide, in fact, that astronomers were initially unable to see its edges.
“Our work clearly shows that the GRB had a unique structure, with observations gradually revealing a narrow jet embedded within a wider gas outflow where an isolated jet would normally be expected,” co-author and Department of Physics at the University of Bath scientist Hendrik Van Eerten said in a statement.
Thus, the jet of GRB 221009A appears to possess both wide and narrow “wings” that differentiate it from the jets of other GRBs. This could explain why the afterglow of the BOAT continued to be seen by astronomers in multiple wavelengths for months after its initial discovery.
Van Eerten and the team have a theory as to what gives the jet of the BOAT its unique structure.
“GRB jets need to go through the collapsing star in which they are formed,” he said. “What we think made the difference in this case was the amount of mixing that happened between the stellar material and the jet, such that shock-heated gas kept appearing in our line of sight all the way up to the point that any characteristic jet signature would have been lost in the overall emission from the afterglow.”
Van Eerten also points out the findings could help understand not just the BOAT but also other incredibly bright GRBs.
“GRB 221009A might be the equivalent of the Rosetta stone of long GRBs, forcing us to revise our standard theories of how relativistic outflows are formed in collapsing massive stars,” O’Connor added.
The discovery will potentially lay the foundation for future research into GRBs as scientists attempt to unlock the mysteries still surrounding these powerful bursts of energy. The findings could also help physicists better model the structure of GRB jets.
“For a long time, we have thought about jets as being shaped like ice cream cones,” study co-author and George Washington University associate professor of physics Alexander van der Horst said. “However, some gamma-ray bursts in recent years, and in particular the work presented here, show that we need more complex models and detailed computer simulations of gamma-ray burst jets.”
The team’s research is detailed in a paper published in the journal Science Advances.
Scientists discover first ‘virgin birth’ in a crocodile
Scientists have recorded the first known case of a “virgin birth” in a female crocodile who had no contact with males for around 16 years.
The reptile was able to produce a fully formed foetus that was 99.9% genetically identical to her.
The researchers said this discovery, reported in the journal Biology Letters, provides “tantalising insights”, suggesting its evolutionary ancestors such as the dinosaurs may also have been capable of self-reproduction.
Also known as facultative parthenogenesis, virgin birth has been documented in species of birds, fish lizards and snakes, but never before in crocodiles.
It is the process by which an egg develops into an embryo without fertilisation by sperm.
The American crocodile (Crocodylus acutus) was taken into captivity in 2002 when she was two years old and placed in an enclosure in Costa Rica.
She remained there alone for the next 16 years.
In January 2018, zookeepers discovered a clutch of 14 eggs in the enclosure.
These eggs did not hatch but one contained a fully formed foetus.
Genetic analysis of the tissues from the foetus’s heart and from the mother’s shed skin revealed a 99.9% match – confirming that the offspring had no father.
Facultative parthenogenesis is rare but is thought to occur when a species faces challenging or unfavourable conditions, such as environmental stress or lack of mates.
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