Pterodactyls No Longer Birds of a Feather?
For a couple of decades now, feathered dinosaurs have been all the rage. This interest follows on discoveries of spectacularly preserved ancient birds and bird-like dinos in Liaoning Province, China.The sediments there preserved bones and soft features like impressions, internal organs, and feathers.
Paleontologists studying non-dinosaurian flying reptiles (the Pterosaurs) soon jumped on the bandwagon. They began noting what appeared to be a fuzzy covering like gosling down on what was previously considered to be leathery, bat-like wings. Suddenly, books picturing Mesozoic dinosaurs and reptiles became filled with shaggy, fuzz-covered pterodactyl. But hold on!
A recent study indicates that what folks took to be a coating of down may have been fibers from the wing membrane’s internal structure. Such fibers appear to have peeled away like thin filaments after death and before the preservation process. It appears, we may well be back to wings like leather. It would seem that, like Fuzzy Wuzzy the bear in the popular nursery rhyme, Terry the pterodactyl wasn’t really fuzzy.Was he?
ALL DIAMONDS ARE NOT CREATED EQUALLY
An article in a recent issue of the journal Nature points to two sources of carbon in creating diamonds. Most diamonds seem to have been formed from carbon that originated within Earth’s crust and surface on plates that then became subducted into the upper mantled own to depths as far as 150 miles and more below ground. Enormous heat and pressure squeezed the carbon into diamonds that eventually made their way back to the surface. Most of these diamonds are small and are considered of limited commercial value.
Then there are so-called mantle diamonds, which reportedly formed as far below the surface as 435 miles before being delivered to the surface by deep-source volcanic eruptions. Those eruptions resulted in what are called lamproite or kimberlite pipes.And those pipes draw commercial diamond mining operations because they have produced spectacular finds.The Hope Diamond is believed to be just such a deep-source diamond.
Now earth scientists say chemical analysis reveals that the carbon forming those shallow-sourced diamonds is markedly different from the carbon forming deep-source diamonds. Previously, it was thought that all the carbon might have come from the surface via subduction. But the new study suggests subducted carbon usually gets transported no further than 310 to 370 miles below
ground before it rises back to the surface in magma.
So, there must be a different carbon source for diamonds that formed as much as 400 to 435 miles below ground. Scientists speculate the source was “primordial carbon” from the days of Earth’s formation that had remained sequestered down in the lower mantle—except for those rare moments when deep-source volcanic eruptions brought marvels like the Hope Diamond to light.
FOR HALF A BILLION YEARS, THE EYES HAVE IT!
Trilobites, like non-avian dinosaurs, are long extinct. In fact, the last trilobite to glide beneath the ocean blue died out some 250 million years ago. This event was even before the first dinosaur appeared on land.But the legacy of the trilobite persists!
While studying the eyes of a trilobite, paleontologists from the University of Cologne, and the University of Edinburgh, discovered that the ancient eye lens was remarkably similar. The eye of the trilobite, AULACOPLEURA koninekii, appears to even be much simpler than compared to the lens of the compound eyes of modern crustaceans and insects.The trilobite eye held some 200 light-sensing units known as ommatidia. This number compared to thousands of such structures in modern insects.
Still, if there were much fewer units back in the day, per the journal Scientific Reports, this study reveals “a vision system that has persisted, nearly unchanged, for at the last half a billion years.”
Editor’s Note: Be sure to check out the Rock & Gem website (www.rockngem.com) each week to enjoy the Trilobite of the Week post, courtesy of Joseph “Paleo Joe” Kchodl.