Ben Garrod*1 “Titanosaurs: the largest animals ever to walk the Earth” http://www.theguardian.com/science/2016/jan/17/dinosaur-titanosaur-largest-animal-ever-walk-earth-argentina
Since its discovery, an international team of biologists, Hollywood model makers, a BBC film crew and palaeontologists, led by Dr Diego Pol and his colleagues from the Museum of Paleontology Egidio Feruglio in Argentina, has worked tirelessly and after 40,000 hours’ work, the results are astounding. The team discovered that not only was this giant herbivore a new species but it was the largest dinosaur ever, dwarfing its closest competitors. What’s more, the team found that seven of these animals actually died in the exact same spot, across at least three different occasions, approximately 101.6 million years ago.
さて、この”the fires of scientific debate”とは例えば、
(…) From the seven individuals, 223 bones have been recovered to date, allowing Pol and his team to use multiple methods to develop a reliable size estimate. Their results show that this dinosaur was 37m in length and weighed 70 metric tons, making it the largest animal ever to walk the face of the planet.
These dinosaurs had to sustain this incredible weight on four specially adapted column-like legs. They were so big they probably used the heavy musculature running from their thighs to halfway down their tails to gain momentum for walking. What’s more, in order to survive the stresses and fractures that could easily result from such extreme weights, these animals not only evolved to reduce the toes in their forelimbs, forcing them to walk on horseshoe-shaped stumps of reduced metacarpal bones, they walked on tiptoes, with huge fleshy pads cushioning the impact as they moved.
Weighing as much as up to 15 African elephants, this new species of dinosaur hasn’t even been named yet and although we still can’t fully explain why seven animals were found together, the 80 or so giant serrated carnivore teeth from an unknown killer found alongside the bones hint at a murderous end for these gentle giants. However, as a lifesize replica skeleton is unveiled at New York’s American Museum of Natural History*3, this super-size discovery is set not only to inspire a new generation of dinosaur fans but will stoke the fires of scientific debate for years to come.
How do you eat a skip full of food every day without ever chewing? How do you walk on tiptoes when you’re the length of four London buses? How do you have sex when you weigh 70 tons? While the answers to these three questions is probably “with great difficulty”, scientists are tackling such improbable questions after uncovering what is undoubtedly the biggest dinosaur excavation of all time.
こいつが発見されるまで世界最大の恐竜の座にいたArgentinosaurusも（その名のとおり）アルヘンティナ出身（北パタゴニア）*4。 さらに、やはりパタゴニアで2014年９月に発見されたDreadnoughtus schraniも「かつて地球を歩いた最大の生き物」と称されていたのだった*5。
ところで、「恐竜」について昨年読んだ記事で面白かったのは、Alexa Lim “What killed the dinosaurs? Dark matter may have played a role.”*6。恐竜の絶滅の原因は小惑星の激突であるというのはほぼ定説になっているが、小惑星の激突を惹き起こしたのは「暗黒物質」だったという、ハーヴァード大学物理学教授 Lisa Randall*7の説。
*2:See eg. https://en.wikipedia.org/wiki/Sauropoda https://ja.wikipedia.org/wiki/%E7%AB%9C%E8%84%9A%E4%B8%8B%E7%9B%AE “How sauropods swept with their necks” http://www.bbc.com/news/science-environment-24659005
*3:See http://www.amnh.org/exhibitions/the-titanosaur See also Carolyn Kormann “Remember the Titanosaur” http://www.newyorker.com/tech/elements/remember-the-titanosaur
*4:See Press Association “Dinosaur experts bring Argentinosaurus strolling back to life” http://www.theguardian.com/science/2013/oct/30/dinosaur-skeleton-simulation
*5:Greg Botelho “Meet Dreadnoughtus, perhaps the biggest creature to ever walk the planet” http://edition.cnn.com/2014/09/04/world/americas/dreadnoughtus-huge-dinosaur/ See also Ian Sample “Battleship beast: colossal dinosaur skeleton found in southern Patagonia” http://www.theguardian.com/science/2014/sep/04/battleship-beast-colossal-dinosaur-skeleton-found-patagonia-argentina-dreadnoughtus-schrani
*7:See eg. http://physics.harvard.edu/people/facpages/randall.html https://en.wikipedia.org/wiki/Lisa_Randall https://ja.wikipedia.org/wiki/%E3%83%AA%E3%82%B5%E3%83%BB%E3%83%A9%E3%83%B3%E3%83%89%E3%83%BC%E3%83%AB