Launch limit for pterosaur flight

first_imgBERLIN—The ancient flying reptiles called pterosaurs include the largest flying animals ever discovered, with estimated wingspans as wide as 11 meters, the width of a doubles tennis court. Exactly how such gargantuan creatures could have taken off, stayed aloft, and landed safely has long puzzled biomechanics experts. New calculations presented here last week at the Society of Vertebrate Paleontology’s annual meeting suggest that flying and landing weren’t problems even for the biggest specimens, but takeoff probably limited how large the animals could grow.Pterosaurs existed from the late Triassic until the end of the Cretaceous period—about 200 million to 66 million years ago. Although they lived at the same time, pterosaurs are not dinosaurs; they form a distinct branch of the evolutionary tree. The most famous member of the group is the first named species, Pterodactylus antiquus, commonly known as a pterodactyl. They were some of the smaller pterosaurs, with an estimated adult wingspan of about a meter, about the size a peregrine falcon. The largest known pterosaurs, Hatzegopteryx, unearthed in Romania, and Quetzalcoatlus, found in Texas, are thought to have had wingspans of 10 or 11 meters—more than three times the wingspans of today’s largest birds.Some researchers have argued that those giants were simply too large to fly. But given their large wings—a skin-and-muscle membrane that extended between an extended fourth finger and the animals’ hind legs—most researchers think they did spend time in the air. Many previous models and estimates were based on scaling up the physiology of birds, but pterosaurs had such different body plans that those models are potentially misleading, says Colin Palmer of the University of Bristol in the United Kingdom. He and Michael Habib of the University of Southern California in Los Angeles attempted to devise a more accurate model of the forces on the animals as they launched, flew, and landed. They used computed tomography scans of pterosaur fossils and wind tunnel tests of model pterosaur wings to develop a computer model of a pterosaur with a 6-meter wingspan. They then scaled up their model to have 9-meter and 12-meter wingspans and calculated the forces on the animals’ bones, wings, and muscles as they took off, flew, and landed.Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)Staying airborne was no problem for their model pterosaurs, Palmer told the meeting. Even animals with wingspans of 15 meters would have had enough muscle power to counteract the drag that exists when the animal is in the air. Landing is a more complicated process, he says, and those modeling experiments were less definitive. The calculations didn’t place a clear limit on the ability of bone to absorb the stress of landing, but even up to 12 meters, Palmer says, their model animals could land safely.Taking off was the biggest challenge for the model pterosaurs. The animals probably launched using all four limbs (scientists think they walked on all fours) and so had more muscle power available than today’s birds do. Model animals with wingspans of 9 or 10 meters had no problem taking off. But according to the model, animals with wingspans greater than 11 meters had trouble jumping high enough to start flapping their wings fully before they fell back to the ground. Thus, the larger pterosaurs couldn’t launch very effectively. In theory, animals even bigger than that could get airborne under ideal conditions, with a hard surface under them and no headwind. “But without ideal conditions, you get eaten,” Palmer says. Habib agrees. An animal with a 12-meter wingspan “could leap in a computer,” he says, “but the real world had Tyrannosaurus in it.”All such computer models have limitations, says Alexander Kellner of the Brazilian National Museum at the Federal University of Rio de Janeiro. But the new calculations do help researchers better understand the physiological limits of the flying giants. “They were very different from anything living today,” he says, so basing models on fossil data is important. Additional fossil scans could help refine the models even further, he says.last_img read more

The 5 Takeaways from the Coyotes introduction of

The 5 Takeaways from the Coyotes introduction of

first_img The 5: Takeaways from the Coyotes’ introduction of Alex Meruelo TEMPE, Ariz. — The Arizona Cardinals used their first three picks in the 2016 NFL Draft on players who hail from the SEC.Known as the country’s premier college football conference, it makes sense to pluck talent from schools like Ole Miss, Texas A&M and Missouri.However, with the first of their fifth-round picks (No. 167 overall), they turned to a lesser-known player and college, tabbing safety Marqui Christian from Midwestern State. Derrick Hall satisfied with D-backs’ buying and selling What Christian becomes is anyone’s guess, but for now, what exactly do the Cardinals have in the small-school prospect?“A tough player, instinctive, fast, strong, quick, a leader, smart, dependable, great character, consistent; just an all-around great guy, full speed and intense,” he said. “I only know one speed and that’s full speed. Also, a hard worker. A guy that’s ready to come in and learn and help the team get to the championship next year.” – / 23 Source: Facebook Comments   Share   Last season, Christian won the Cliff Harris Award as the nation’s top small-college defensive player as he racked up 95 total tackles, forced three fumbles, recovered two fumbles and broke up three passes.If that style of safety reminds you of someone, say the Cardinals’ Deone Bucannon, then you’re smart to make the comparison. Christian said that’s how the team sees him, too.“They kind of talked as a hybrid-type guy; a safety playing down in the box, just using my different talents — blitzing off the edge, man-to-man in the slot, zone, interchangeable at safety, maybe playing deep,” he said of his expected role. “Basically, a hybrid role, an interchangeable safety role, playing down in the box and then sometimes playing high and patrolling the middle some.”The ability to do all that would make Christian quite valuable, and no doubt the Cardinals are hopeful he will develop into that kind of an impact player. Like many NFL players who come from smaller schools, the biggest knock against him was the competition he faced and not his own skill set.“He is a guy that really came onto the scene late for us,” Cardinals GM Steve Keim said before praising the team’s area scouts who discovered Christian. “But the closure that came in late in the process was a guy named Adrian Wilson, who went to the NFLPA game and came back with his jaw dropping.” Wilson, of course, is a former Cardinals safety who did his best work in the box and is now a scout for the team. If Bucannon is the one who Christian is supposed to model his game after, it could be argued Bucannon’s game was first seen in Wilson.Keim said the 5-foot-10, 196-pound Christian has all the physical tools the Cardinals look for in a safety, and a 4.46 40-yard dash at his Pro Day as well as solid times in the shuttle and 3-cone drills are evidence he has the speed and quickness the team covets.Which is why, while Christian expects to see a lot of time in the box, Cardinals coach Bruce Arians believes he can play all over the field.“He can do everything,” he said. “He can cover a lot of ground. He’s a 4.4-guy, can play man-to-man, can be interchangeable — which we like to do with our safeties — and he will strike you.”Christian said he has plenty of experience blitzing from his time in college, and once he learned of the Cardinals’ interest in him, he studied their scheme. He saw how Arizona prefers to play man coverage and go after the quarterback, which seems to fit his style.Christian said he needs to improve by learning how to shed blockers and add enough weight to take on NFL players. Top Stories Grace expects Greinke trade to have emotional impact Former Cardinals kicker Phil Dawson retireslast_img read more