Shoo, Shoo Shuvuuia: Nocturnal Owl-Like Dinosaur with Keen Eyesight and Acute Hearing

            A small  carnivorous dinosaur had superb low-light vision and hearing that was likely as good as an owl's. And like an owl, the tiny dinosaur probably used those exceptional abilities to stalk and catch its desert prey under the cover of darkness.

    The owl-like Shuvuuia (shu-VU-ya) was a theropod, a three-toed and bipedal carnivorous dinosaur. There's only one known species, Shuvuuia deserti, and it was smaller than a domestic cat, measuring 2 feet (0.6 meters) long. Shuvuuia lived about 75 million to 81 million years ago, during the late Cretaceous period in what is now the Gobi Desert in Mongolia.

      Prior analysis of Shuvuuia's fossilized eye bones revealed that it had large eyes that were specialized for seeing in dim light. But at the time, little was known about dinosaur adaptations for nocturnal activity. In a new study presented May 7, 2021 in Science, researchers looked at skulls from dozens of species of extinct theropods and modern birds, the only theropod lineage that survived to the present.

      By comparing dinosaurs' fossilized eye and ear structures with those in living animals that have nocturnal habits, the researchers were able to see if a dinosaur was adapted for day or night activity.

        Soft tissue is rarely preserved in the fossil record, but paleontologists can find clues about dinosaurs' eyes and vision in the bones that form a circle in the eye socket, known as the scleral ring. Scleral rings are found in many vertebrates (including extinct dinosaurs), and the diameter of this ring reveals the maximum width that an animal's pupil can dilate, hinting at their ability to see in low light, said lead study author Dr. Jonah Choiniere, University of the Witwatersrand in Johannesburg.  

     But nighttime hunting doesn't just depend on having good eyesight; specialized hearing is also key. So the researchers examined ear anatomy in 88 bird species and 17 extinct fossil theropods, using computed X-ray tomography (CT) scans to construct digital 3D models of the animals' skulls. They paid close attention to the cochlea, the part of the inner ear canal that holds sensory receptors for picking up sound waves. Decades of previous research had shown that the length of this canal is closely linked to how well animals can hear, and the length of Shuvuuia's ear canal suggested that its hearing would have been "off the charts," Dr. Choiniere said.

      "Shuvuuia had proportionally longer cochlear ducts than even the bird with the best hearing, the barn owl," Dr. Choiniere continued. What's more, the size of Shuvuuia's scleral rings showed that it also possessed "incredible night vision — better than any living bird we measured," he added. 

      The combination of light-sensitive eyes and superior hearing suggested that Shuvuuia would have been highly effective at detecting and ambushing prey at night, as owls do. By comparison, the theropod Velociraptor, which lived in the Gobi Desert alongside Shuvuuia, had an intermediate eye shape, "and was probably more twilight-active," said study co-author Dr. Lars Schmitz, W.M. Keck Science Department at Scripps College, CA. This is the first time that such extreme specializations for hearing and vision have been documented in an extinct dinosaur; in combining vision with hearing, the study also provides the best evidence for nocturnal behavior in dinosaurs, Dr. Schmitz said. 

     With a "hodgepodge body" Shuvuuia was an odd-looking dinosaur, and though it's related to fearsome meat-eating theropods such as Velociraptor and Tyrannosaurus rex, "it's totally unlike them," Dr. Choiniere said. "It's got a lightly built jaw, and its teeth look like tiny grains of basmati rice. It's got this massive eye, but the beak is very small," he said. Shuvuuia's forelimbs were powerful and bulky, tipped with a huge claw like an aardvark's. Capping off this hodgepodge of features was a pair of long, slender hind legs that were built for running. Shuvuuia deserti may have preyed on nocturnal desert insects. Shuvuuia deserti may have preyed on nocturnal desert insects. 

      However strange its body may have looked, these traits may have made Shuvuuia a better nighttime hunter. Some modern mammals that live in arid desert environments, as Shuvuuia did, combine lengthy hind limbs with digging forelimbs, "and they often have really good night vision and hearing," which helps them track and catch hard-to-find prey, Dr. Choiniere said. Burrowing desert prey would also be an easy meal for Shuvuuia to dig up with its powerful forearms. "This observation that Shuvuuia could have operated at night makes a lot of sense in light of the rest of the adaptations," he said. "It puts those into perspective and allows us to think it would have fit into a desert ecosystem today really well." 

      Animals that live together in the same geographical location often require the same resources in order to survive, but they can share them by being either night owls or early birds. Dinosaurs likely did this as well, and this study is just the beginning of paleontologists' discoveries of nocturnal and daytime preferences in these extinct animals and how those preferences might have affected their habits and behavior, Dr. Schmitz said. "That's something that we really don't understand well yet in the fossil record, but we know from looking at living species," he said. "I think there are some exciting discoveries waiting to be made."

         I wonder why we usually use birds to define early morning or late night behaviors. Which are you?

Beginning of Plate Tectonics Was More Recent and More Gradual Than Expected Based on Northwest Australian Rocks

      

      Researchers from Cologne University present important new constraints showing that plate tectonics started relatively slowly, although the early earth's interior was much hotter.

       For this research, reported in the January 12, 2021 Proceedings of National Academy of Sciences, geologists and geophysicists led by Dr. Jonas Tusch  investigated up to 3.5 billion year old igneous rocks from northwest Australia that cover 800 million years of earth's early history.

 

      The analysis of these rock successions reveals that the oldest samples exhibit small anomalies in the isotope abundances of the element tungsten (W) that progressively diminish with time. 

     The origin of these anomalies, namely the relative abundance of 182W, relates to ancient heterogeneities in the terrestrial mantle that must have formed immediately after formation of the earth more than 4.5 billion years ago. The novel tool of high-precision 182W isotope measurements to rocks from the Pilbara Craton in Australia, that span an age range from 3.5 billion years to 2.7 billion years, was used in this study.

      The preservation of these 182W anomalies in the igneous rocks from northwest Australia demonstrate that pristine mantle reservoirs from the beginning of our planet were conserved over timescales exceeding more than one billion years during the Hadean time period.

      This finding is very surprising, because higher mantle temperatures in the early earth suggest that mantle convection was more extensive and much faster than today. Interestingly, the observed 182W anomalies start to diminish at around 3 billion years ago, within a geological era that is assumed to mark the beginning of modern plate tectonics. 

     The onset of modern plate tectonics, involving subduction processes and mountain uplift, has been shown to be a key event triggering the emergence of large continental masses and an oxygen-rich atmosphere, all of which set the stage for the origin of more complex life. This artist conception of earth during the Hadean time period (which predates "modern" plate tectonics).

Here's to our oxygen-rich atmosphere of 2021. Breathe deep and sense those plates moving!

Steph [aka WW (Tungsten Tungsten;-))]

Introducing Bruno!

      This is a good day to introduce Bruno, a Denver Dumb Friends League pup, rescued from the same place as Maizie, the night before election day.

     Bruno joined foster pup, Millie, and the two were hysterical romping, spooning, and whispering to each other. It made election night lots more fun. They had a blast together until Millie went to her furever home with a veteran and his parrot the day before Thanksgiving.

     Bruno is 4 years old and was surrendered with his 7 year old mom. He needed someone to pal around with for awhile. And in return, Bruno taught Millie, also 4, the art of house training. A win-win for everyone!

     I did consider adopting both of them but when this vet held Millie, close to tears of joy in his eyes, I knew Millie needed to be with him. He lost his dog at the same time that Maizie died. We are planning playdates so they will be together again.

      

       We are already looking forward to a Christmastime visit to the Great Sand Dunes to roam the dunes and let some of Maizie's ashes blow in that beautiful wind. I sure miss Maizie but Bruno's curious, slightly shy, and funny nature is helping me with grief.

         We'll get back to science topics next month, after the last 3 weeks of school. In the meantime, I would love to hear your dog tales, cat tales, gerbil tales, parrot tales...

With dogged determination,

Steph and Bruno

The Amazing Maizie 14 years, PEOTS 7 years

      On this 7-year anniversary of Partial Ellipsis of the Sun and 14th-year anniversary of Maizie’s birth (in October), I am writing about Maizie, canine extraordinaire.

     Maizie May was my beloved, fun, and happy companion for 12.5 years. I went to the Denver Dumb Friends League with my friend, Mike, on April 2, 2008. "Pucker" was released from the lost animals hold for exactly 1 minute when we found each other. I ran down the hall to the Adoption Desk saying "She's the one! She's the one!" And so the newly-named Maizie came home the next day to live with my daughter, Zoë, and me. Here she is on that day.

      This girl loved a good road trip. We took more than a dozen  trips to the Great Sand Dunes, one of her two favorite places. Kunming Park was the other favorite. 

      We trekked to Arches National Park, the Paint Mines in Calhoun, to Crystal Bridges Art Museum in Arkansas, to Minnesota for Zoe’s drop-off and graduation from college. We took so many trips to Silver Plume, Palisade, and all over the Colorado, Utah, and Wyoming mountains.

          She liked to rest on my left knee as I drove, soaking up the sunshine and scanning the scenery for elk, deer, and other furry friends. She slept on my left shoulder at night.

            Maizie died in my arms September 21, 2020 at 4:40 p.m. She was bathed in heliotrope-magenta light as she crossed over the Rainbow Bridge. I held her body for over an hour and felt her comforting me.

      During the ten months she fought lymphoma with chemotherapy and her oncologist’s help, we had some awesome adventures, including a trip to San Luis Park and the Great Sand Dunes in April, just before they closed the gates:

https://youtu.be/bhnOENk2QDk

Maizie was spunky, calm, sweet, and adventurous and up for new treks up until the day she died. The growths on her neck returned and even large doses of lomustine could not stop them. She was still so Maizie right up to the end when breathing was difficult. 

           I miss her every minute and talk to her all the time. She brought me such joy. Grief is so non-linear. I find sad tears, happy smiles, weird firsts (moving her water bowls) commingle. 

      I saw her in the full moon Thursday night. She was smiling broadly, telling me she is always in my heart and how much she loved our adventures. 

       

     Here’s to Maizie, the most faithful, loving, sweet dog ever.

     Thanks for coming on this mountain and park ride with me.

Happy trails, Maizie,

Steph

            

Rudists, Nudists, and Buddhists

     Although we have already discussed rudist (not rudest) clams here at PEOTS, new research about these reef builders of the Cretaceous was just published in February, 2020, warranting another look. Plus, I like the "Rudists, Nudists, and Buddhists" title. Rudists colonizing in zen-like seas? Count us in. 

        The earth turned faster at the end of the Cretaceous than it does today, rotating 372 times a year, compared to the current 365 1/4, according to a new study of fossil rudist shells. The research also shows a day lasted only 23.5 hours, according to the new study in American Geophysical Union's journal Paleoceanography and Paleoclimatology.

     The ancient mollusk, from an extinct and quite diverse group known as rudist clams, grew fast, laying down daily growth rings. The new study used lasers to sample minute slices of shell and count the growth rings with great accuracy. The growth rings allowed the researchers to determine the number of days in a year and more accurately calculate the length of a day 70 million years ago. The new measurement informs models of how the Moon formed and how close to Earth it has been over the 4.5-billion-year history of the Earth-Moon gravitational dance.

     The high resolution obtained in the new study combined with the fast growth rate of the ancient bivalves revealed unprecedented detail about how the animal lived and the water conditions it grew in, down to a fraction of a day.

     "We have about four to five datapoints per day, and this is something that you almost never get in geological history. We can basically look at a day 70 million years ago. It's pretty amazing," said Dr.  Niels de Winter, an analytical geochemist at Vrije Universiteit Brussel and the lead author of the new study.

     Climate reconstructions of the deep past typically describe long term changes that occur on the scale of tens of thousands of years. Studies like this one give a glimpse of change on the timescale of living things and have the potential to bridge the gap between climate and weather models.

     Chemical analysis of the shell indicates ocean temperatures were warmer in the Late Cretaceous than previously appreciated, reaching 40 degrees Celsius (104 degrees Fahrenheit) in summer and exceeding 30 degrees Celsius (86 degrees Fahrenheit) in winter. The summer high temperatures likely approached the physiological limits for mollusks, de Winter said.

     "The high fidelity of this data-set has allowed the authors to draw two particularly interesting inferences that help to sharpen our understanding of both Cretaceous astrochronology and rudist palaeobiology," said Dr. Peter Skelton, a retired paleobiologist at the Open University and a rudist expert unaffiliated with the new study.

    The new study analyzed a single individual that lived for over nine years in a shallow seabed in the tropics -- a location which is now, 70-million-years later, dry land in the mountains of Oman.

     "Torreites sanchezi mollusks look like tall pint glasses with lids shaped like bear claw pastries. The ancient mollusks had two shells, or valves, that met in a hinge, like asymmetrical clams, and grew in dense reefs, like modern oysters. They thrived in water several degrees warmer worldwide than modern oceans."

     In the late Cretaceous, rudists like T. sanchezi dominated the reef-building niche in tropical waters around the world, filling the role held by corals today. They disappeared in the same event that killed the non-avian dinosaurs 66 million years ago.

     "Rudists are quite special bivalves. There's nothing like them living today," de Winter said. "In the late Cretaceous especially, most of the reef builders are these bivalves. So they really took on the ecosystem building role that the corals have today."

     The new method focused a laser on small bits of shell, making holes 10 micrometers in diameter, or about as wide as a red blood cell. Trace elements in these tiny samples reveal information about the temperature and chemistry of the water at the time the shell formed. The analysis provided accurate measurements of the width and number of daily growth rings as well as seasonal patterns. The researchers used seasonal variations in the fossilized shell to identify years.

     The new study found the composition of the shell changed more over the course of a day than over seasons, or with the cycles of ocean tides. The fine-scale resolution of the daily layers shows the shell grew much faster during the day than at night.

     "This bivalve had a very strong dependence on this daily cycle, which suggests that it had photosymbionts," de Winter said. "You have the day-night rhythm of the light being recorded in the shell."

     This result suggests daylight was more important to the lifestyle of the ancient mollusk than might be expected if it fed itself primarily by filtering food from the water, like modern day clams and oysters, according to the authors. De Winter said the mollusks likely had a relationship with an indwelling symbiotic species that fed on sunlight, similar to living giant clams, which harbor symbiotic algae.

     "Until now, all published arguments for photosymbiosis in rudists have been essentially speculative, based on merely suggestive morphological traits, and in some cases were demonstrably erroneous. This paper is the first to provide convincing evidence in favor of the hypothesis," Skelton said, but cautioned that the new study's conclusion was specific to Torreites and could not be generalized to other rudists.

     De Winter's careful count of the number of daily layers found 372 for each yearly interval. This was not a surprise, because scientists know days were shorter in the past. The result is, however, the most accurate now available for the late Cretaceous, and has a surprising application to modeling the evolution of the earth-moon system.

     The length of a year has been constant over earth's history, because earth's orbit around the sun does not change. But the number of days within a year has been shortening over time because days have been growing longer. The length of a day has been growing steadily longer as friction from ocean tides, caused by the moon's gravity, slows earth's rotation.

    The pull of the tides accelerates the moon a little in its orbit, so as earth spin slows, the moon moves farther away. The moon is pulling away from earth at 3.82 centimeters (1.5 inches) per year. Precise laser measurements of distance to the moon from earth have demonstrated this increasing distance since the Apollo space program left helpful reflectors on the moon's surface.

     But scientists conclude the moon could not have been receding at this rate throughout its history, because projecting its progress linearly back in time would put the moon inside the earth only 1.4 billion years ago. Scientists know from other evidence that the Moon has been with us much longer, most likely coalescing in the wake of a massive collision early in Earth's history, over 4.5 billion years ago. So the Moon's rate of retreat has changed over time, and information from the past, like a year in the life of an ancient clam, helps researchers reconstruct that history and model of the formation of the moon.

       Rudists' growth patterns and rates provide great data for models from the Cretaceous.

Have you encountered any rudists in your fossil meanderings around the earth?
Steph

Diatoms and Diatomaceous Earth: Beer Filtration for What Ales You

      Diatomite is a generally light-colored sedimentary rock that is  composed mostly of the siliceous skeletons of diatoms. It is an extremely porous rock with a fine particle size and a low specific gravity. These properties make it useful as a filter media, especially for beer and wine. It is also used as an absorbent, and as a lightweight filler for paint and plastics. When diatomite is crushed into a very fine powder, it is called diatomaceous earth.

      Diatoms are members of a large, diverse group of algae that drift in the waters of both oceans and lakes. A few types of diatoms live on the bottom of these water bodies and in soils. Most diatoms are microscopic, although a few species are up to two (2) mm in length. As a group, diatoms are unique because they are single-celled organisms that produce an external cell wall composed of silica, called a frustule. These frustules are very thin and have a delicate structure.

      Most diatoms are photosynthetic and live in water less than thirty (30) feet deep, where sunlight can penetrate. Diatoms are prolific and are responsible for producing nearly half of the organic mass in the world’s oceans. Their abundance and tiny size places them at the base of the marine food chain. We have discussed the strength and Fibonacci ordering of diatoms before here at PEOTS.

     After diatoms die ("die, atoms, die!"-- sorry, I couldn't resist) their siliceous frustules sink. In some areas, the frustules are not incorporated into the bottom sediment because they dissolve as they sink or dissolve while on the sediment surface. If the sediment is composed of over 30% diatom frustules by weight, it is called diatomaceous ooze or siliceous ooze.

      Of course, all this ooze discussion leads to a talk of diatomaceous ooze filtering your booze. Freshwater ooze or earth must be used unless you like your booze salty (yuck for me!).    Diatomite from saltwater sources can contain salts that can produce objectionable or toxic effects. Although some beer crafters are, indeed, using salt in the brewing process. Enjoy the beer, skip the pretzels? Have a little diatomaceous ooze with your booze? Woe is mead?

 

     The four main uses of diatomite in the United States during 2019 were filtration (50%), light aggregate (30%), fillers (15%), and absorbents (5%).

      Diatomaceous earth is used as a lightweight, inert filler in some manufactured products. It is added to paint as a whitening agent and extender. Diatomite is added to plastics as a lightweight filler. 

     If dry diatomaceous earth is placed on a liquid spill, it can absorb and hold an amount of liquid equivalent to its own weight. This absorption facilitates containment, cleanup, and removal. Capillary action of liquids into diatomaceous earth is enhanced by its small particle size, high surface area, and its high porosity.

       These same properties make diatomaceous earth able to absorb skin oils when used in cosmetics and facial masks. Diatomaceous earth is an absorbent ingredient of some kitty litters. It is also used as a soil treatment to absorb and hold water.

     Diatomaceous earth is used as a mild abrasive in some toothpastes, facial scrubs, and metal polishes. Its silica particles are small, friable, have a high surface area, and are angular in shape. These are properties that help it perform well as a mild abrasive.

     Diatomaceous earth is used as a growing medium in hydroponic gardens. It is inert, holds water, and has a porosity that allows the soil to breathe. To help grain and other seeds from sticking together and remain dry, they are dusted with diatomaceous earth.

     The cost of diatomite depends on its quality, how it will be used, and the preparation effort that has been invested by the supplier. The cost of diatomite straight from the mine without processing for use in concrete starts at about $7/ton. Diatomite from high-grade deposits that has been crushed, sized, and sieved for use in cosmetics, art supplies, & DNA extraction markets can cost more than $400/ton.

     The extraordinary intricacy of diatoms in Scanning Electron Micrographs shown throughout this post is astounding. Do you have a favorite?

Hoping you are all well in this weirdest of times,

Steph

P.S. Begone, M a r c h, oh longest of months this year.