Tag: dinosaurs

Tyrannosaurus Lips and Other Wonders of Science

personby Deborah J. Ross
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Once my science classes progressed beyond “the parts of the cell,” I loved them. So much so that my college degree is in Biology, which entailed many classes in Physics and General and Organic Chemistry. Fast forward many decades, I had the joy to attend Launch Pad Astronomy Workshop, about which I have previously blogged. But I’ve never given up my love of Things Prehistoric. Here are two wonderful new stories:

T. rex had thin lips and a gummy smile, controversial study suggests

 

Theropod dinosaurs — a group of bipedal, mostly meat-eating dinosaurs that included T. rex, Velociraptor and Spinosaurus — may instead have concealed their deadly chompers behind thin lips that kept their teeth hydrated and tough enough to crush bones. 

Paleontologists had already suggested that T. rex may have had lips, and there has been debate whether carnivorous dinosaurs looked more like present-day crocodiles, which don’t have lips and have protruding teeth, or if they more likely resembled monitor lizards, whose large teeth are covered by scaly lips.

Rhino-like ‘thunder beasts’ grew massive in the evolutionary blink of an eye after dinos died off

 

In the aftermath of the dinosaur-killing asteroid impact, a second explosion rocked the animal kingdom. 

This time, it was the mammals that blew up. Rhino-like horse relatives that had lived in the shadow of the dinosaurs became gigantic “thunder beasts” as suddenly as an evolutionary lightning strike,  new research, published Thursday (May 11) in the journal Science(opens in new tab), shows.

“Even though other mammalian groups attained large sizes before [they did], brontotheres were the first animals to consistently reach large sizes,” study first author Oscar Sanisidro(opens in new tab), a researcher with the Global Change Ecology and Evolution Research Group at the University of Alcalá in Spain. “Not only that, they reached maximum weights of 4-5 tons [3.6 to 4.5 metric tons] in just 16 million years, a short period of time from a geological perspective.”

Last year, weird “bramble snout” fossils were documented at the site called “Castle Bank,” but new research published May 1 in the journal Nature Ecology and Evolution(opens in new tab) describes the whole fossil deposit.

Hosting a myriad of soft-bodied marine creatures nd their organs, which are scarcely preserved in the fossil record, the site resembles the world-renowned Cambrian deposits of Burgess Shale in Canada and Qingjiang biota in China. The rocks of Castle Bank, however, are 50 million years younger and give researchers a unique window into how soft-bodied life diversified in the Ordovician Period (485.4 million to 443.8 million years ago), according to a statement released by Amgueddfa Cymru – Museum Wales.

Researchers believe they’ve recovered more than 170 species from the site, most of which are new to science. These include what appear to be late examples of Cambrian groups, including the weirdest wonders of evolution, the nozzle-nosed opabiniids, and early examples of animals that evolved later, including barnacles, shrimp and an unidentified six-legged insect-like creature. The rocks are also home to the fossilized digestive systems of trilobites and the eyes and brain of an unidentified arthropod, as well as preserved worms and sponges.

Romancing the Prehistoric

personby Deborah J. Ross
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I was – note the past tense – going to write a post about re-entry after Covid-19 vaccination and how awesome it was to give my younger daughter a hug after over a year, but then I saw this story from Science magazine and could not resist.

Did you ever wish you could see a living dinosaur? I sure did! (I still do…but from a safe distance.) As a child I loved movies with stop-action animation of dinosaurs, like the original King Kong or the Ray Harryhausen movie, The Valley of Gwangi. In high school I wrote a short novel about two teenagers and their horses who discover a hidden valley where dinosaurs still roam. Jurassic Park and its sequels blew me away, the movies even more so than the novels. The novels were longer on explanation, the movies far more powerful in vividness. The moment when Alan Grant, upon learning that Professor Hammond has created a T. rex and almost faints,  that’s how I would have felt. Great acting and directing aside, these books and films spoke to a universal or near-universal human longing to see amazing charismatic animals from the distant past.

The earlier stories, at least the ones I read and watched, made no effort at a scientific basis for the present-day existence of prehistoric animals. It was all “Land That Time Forgot” hand-waving. Crichton took a different tack: dinosaurs did not persist in some undiscovered corner of or beneath the Earth: humans re-created them using DNA preserved in amber. We’ve been able to recover DNA from Pleistocene mammals, but never anything as old as 65 million years. Many scientists doubt that DNA could survive that long, no matter how preserved. When an animal dies, its DNA begins to decay. A 2012 study on moa bones showed that genetic material deteriorates at such a rate that it halves itself every 521 years. This speed would mean paleontologists can only hope to recover recognizable DNA sequences the past 6.8 million years. In 2020, Chinese Academy of Sciences paleontologist Alida Bailleul and her colleagues proposed they had found a chemical signature suggestive of DNA in a 70 million year old baby hadrosaur fossil. If confirmed, this material would be so degraded into components, not sequences. It’s also possible the chemical signature was that of bacteria, not the dinosaur itself.

The Siberian permafrost that has yielded mammoth DNA is about 2.6 million years old, but freezing turns out to be a pretty good preservative of DNA. Scientists have now been able to sequence DNA from extinct mammoths 1.2 million years ago. That’s a world record. The previous record, in 2013, was from a 750,000-year-old horse. The new study includes DNA from three species of mammoth from three time periods (1.2 million, 1 million, and 700,000 years ago) and there are all kinds of reasons to be excited about it, not just the age but the evolutionary relationships and a previously unknown type.

Which brings us to the question we’re all asking: Once we’ve sequenced this DNA, whether from mammoths, saber-toothed cats, ground sloths, or whatever – what do we do with it? What we can do now is better understand the evolution and relationships of these amazing animals. What popular media want, however, is to use the material to create living extinct species. The process of de-extinction can proceed either by cloning – taking material from a recently extinct species and replicating it – or by using ancient, fragmentary DNA. We’ve got a long way to go with either technique. Many extinct species lack contemporary surrogates to carry the artificially created embryos to term. For others, suitable habitat no longer exists (really? Where would you turn a giant ground sloth loose? A saber-toothed cat? Or would these animals exist only in the unnatural environment of zoos?) Back in 2009, Spanish scientists cloned a newly extinct Pyrenean ibex, although the clone died within a few hours of birth.

There are, however, a few good candidates for which possibly viable DNA sources exist. Species like the passenger pigeon and Carolina parakeet might fare well, given the human responsibility for their disappearance, although they might turn out to be temporally invasive species. Continue reading “Romancing the Prehistoric”…