first_img Email Click to view the privacy policy. Required fields are indicated by an asterisk (*) Sign up for our daily newsletter Get more great content like this delivered right to you! Country Birds were born about 150 million years ago, when a group of small meat-eating dinosaurs spread their feathered wings and took to the skies. They soon split into two distinct groups: the lineage that led to modern birds, called the ornithuromorphs, and the so-called opposite birds, or enantiornithines, whose shoulder ball-and-socket joints connected in an inverse way from those of living birds. Relatively poor fliers, the opposite birds also typically had teeth and clawed wings. They thrived for millions of years, but vanished along with their dinosaur relatives in the mass extinction at the end of the Cretaceous.Meanwhile, the lineage of modern birds evolved “huge chest muscles and wings comprised of many different types of feathers layered over each other”—features essential to high-powered flight, Brusatte explains. Their bone structure also suggests that they grew much faster than the opposite birds. But researchers did not know when those features emerged. Although they had found some excellent specimens of the earliest birds, such as Germany’s famed 150-million-year-old Archaeopteryx, as well as stunning later fossils from northeastern China, a 20-million-year gap remained between Archaeopteryx and other fossils, most of which were opposite birds, Chiappe says.The new fossils fill the gap in time and also in anatomy. Writing in Nature Communications, the Beijing team describes two skeletons of a species they call Archaeornithura meemannae. (Archaeornithura means “ancient ornithuromorph,” and meemannae is in honor of Chinese paleontologist Meemann Chang.) Each exquisitely preserved specimen has the telltale traits of a modern bird: fan-shaped tail feathers, highly fused bones at the ends of the wings, and the U-shaped wishbone familiar to anyone who has carved a roast chicken. The fossils even have a small projection on the front edge of their wings—known to boost maneuverability during flight—that is remarkably similar to that of today’s birds.Furthermore, Archaeornithura had long legs and feet apparently adapted to wading in water, similar to those of today’s plovers, suggesting that modern birds arose in aquatic habitats. Finding such a modern bird, already specialized for wading, suggests that millions of years of aquatic evolution took place even before A. meemannae came on the scene, Zhou explains. He suggests that while the opposite birds found safety in the trees, life in more open, aquatic spaces may have given the ornithuromorphs “more choices of high protein food” and favored their evolution into swift fliers so they could avoid the danger of predators. All this evolution must have happened after Archaeopteryx but before 130 million years ago.The fossils reveal the origins of the features that, tens of millions of years later, may have allowed modern birds to survive the Cretaceous extinction when other birds did not, Zhou and Wang say. No one is sure just what conditions prevailed in the postasteroid apocalypse, but Wang speculates that the fast growth rates of modern birds, which let them reach adulthood faster and spend less time dependent on their parents, may have given them an advantage; likewise skilled flight may have been a boon.  But this idea is “too simplistic,” counters Sankar Chatterjee, a paleontologist at Texas Tech University in Lubbock, because many ornithuromorphs vanished during the extinction, too. Nevertheless, Brusatte argues, “from the ashes of that extinction, a few groups of more sophisticated birds, with better flight abilities and perhaps faster growth rates, were able to survive.” Those key traits, the new fossils show, arose near the dawn of bird evolution.*Correction, 5 May, 3:57 p.m.: An earlier version of this story stated that mosasaurs were living 130 million years ago at the time of the earliest relatives of modern birds. Mosasaurs did not arrive until much later, but plesiosaurs were thriving at that time.center_img Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe Put yourself on the planet 130 million years ago. Most of the animals, from horned dinosaurs to swimming, predatory plesiosaurs, would be deeply alien, not to say terrifying. But rising from the wetlands and winging across the sky were birds startlingly like today’s. That’s the message from two bird skeletons—spectacularly preserved with feathers and all—reported this week.The 130-million-year-old fossils of wading birds, found in northeast China by a team led by paleontologists Min Wang and Zhonghe Zhou of the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, push back the lineage that led to today’s birds by at least 5 million years and make it almost certain that the origin of the lineage was much older still. The fossils’ specialized anatomy suggests that key factors in birds’ long-term success, such as expert flying ability and rapid growth rates, arose surprisingly early in avian evolution.“New bird fossils seem to come out every week now, and they are revolutionizing our understanding of bird evolution. But of all the new specimens, this is one of the most important found over the last decade,” says paleontologist Stephen Brusatte of the University of Edinburgh in the United Kingdom. Not only does the bird look nearly modern, but it was apparently a water dweller, showing that “ancient birds became specialized in their respective habits” very early, says paleontologist Luis Chiappe of the Natural History Museum of Los Angeles County in California.last_img

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