Bird Evolution
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Flying Dromaeosaurs
A winged, but flightless, Deinonychus by Stephen A. Czerkas FLYING DROMAEOSAURS Stephen A. Czerkas, Dianshuang Zhang, Jinglu Li and Yinxian Li The Dinosaur Museum, 754 South 200 West, Blanding, Utah 84511, USA; Liaoning Provincial Bureau of Land Resources Management, Liaoning Fossil Administration Office, and Liaoning Museum of Paleontology, Left of Nanshan Park, Beipiao, Liaoning Province 122100, People’s Republic of China. The Dinosaur Museum © 2002 Abstract Dromaeosaurs have been regarded as theropod dinosaurs that were among the closest avian ancestors which were strictly terrestrial having not yet evolved the ability to fly. Consequently, phylogenetic analyses have resulted in the claims of birds having evolved from “the ground up” within a dinosaurian ancestry. Though widely accepted, the relationship between birds and dinosaurs has remained highly controversial and disputed by advocates of birds as having been derived from an arboreal, non-dinosaurian type of archosaur. The cladistical interpretation of the dinosaur/bird relationship hinges upon the presumption of the dromaeosaurs inability to fly. Recent discoveries of dromaeosaurs have revealed impressions of feathers and avian characters in the skeleton that nearly equal and even surpass that of Archaeopteryx. Yet despite this, the ability to fly has been discounted due to the shorter length of the forelimbs. Described below are two such dromaeosaurs, but preserved with impressions of primary flight feathers extending from the manus which demonstrate an undeniable correlation towards the ability to fly. This compelling evidence refutes the popular interpretation of birds evolving from dinosaurs by revealing that dromaeosaurs were already birds and not the non-avian theropod dinosaurs as previously believed. -
The Phylogenetic Position of Ambiortus: Comparison with Other Mesozoic Birds from Asia1 J
ISSN 00310301, Paleontological Journal, 2013, Vol. 47, No. 11, pp. 1270–1281. © Pleiades Publishing, Ltd., 2013. The Phylogenetic Position of Ambiortus: Comparison with Other Mesozoic Birds from Asia1 J. K. O’Connora and N. V. Zelenkovb aKey Laboratory of Evolution and Systematics, Institute of Vertebrate Paleontology and Paleoanthropology, 142 Xizhimenwai Dajie, Beijing China 10044 bBorissiak Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya ul. 123, Moscow, 117997 Russia email: [email protected], [email protected] Received August 6, 2012 Abstract—Since the last description of the ornithurine bird Ambiortus dementjevi from Mongolia, a wealth of Early Cretaceous birds have been discovered in China. Here we provide a detailed comparison of the anatomy of Ambiortus relative to other known Early Cretaceous ornithuromorphs from the Chinese Jehol Group and Xiagou Formation. We include new information on Ambiortus from a previously undescribed slab preserving part of the sternum. Ambiortus is superficially similar to Gansus yumenensis from the Aptian Xiagou Forma tion but shares more morphological features with Yixianornis grabaui (Ornithuromorpha: Songlingorni thidae) from the Jiufotang Formation of the Jehol Group. In general, the mosaic pattern of character distri bution among early ornithuromorph taxa does not reveal obvious relationships between taxa. Ambiortus was placed in a large phylogenetic analysis of Mesozoic birds, which confirms morphological observations and places Ambiortus in a polytomy with Yixianornis and Gansus. Keywords: Ornithuromorpha, Ambiortus, osteology, phylogeny, Early Cretaceous, Mongolia DOI: 10.1134/S0031030113110063 1 INTRODUCTION and articulated partial skeleton, preserving several cervi cal and thoracic vertebrae, and parts of the left thoracic Ambiortus dementjevi Kurochkin, 1982 was one of girdle and wing (specimen PIN, nos. -
A Chinese Archaeopterygian, Protarchaeopteryx Gen. Nov
A Chinese archaeopterygian, Protarchaeopteryx gen. nov. by Qiang Ji and Shu’an Ji Geological Science and Technology (Di Zhi Ke Ji) Volume 238 1997 pp. 38-41 Translated By Will Downs Bilby Research Center Northern Arizona University January, 2001 Introduction* The discoveries of Confuciusornis (Hou and Zhou, 1995; Hou et al, 1995) and Sinornis (Ji and Ji, 1996) have profoundly stimulated ornithologists’ interest globally in the Beipiao region of western Liaoning Province. They have also regenerated optimism toward solving questions of avian origins. In December 1996, the Chinese Geological Museum collected a primitive bird specimen at Beipiao that is comparable to Archaeopteryx (Wellnhofer, 1992). The specimen was excavated from a marl 5.5 m above the sediments that produce Sinornithosaurus and 8-9 m below the sediments that produce Confuciusornis. This is the first documentation of an archaeopterygian outside Germany. As a result, this discovery not only establishes western Liaoning Province as a center of avian origins and evolution, it provides conclusive evidence for the theory that avian evolution occurred in four phases. Specimen description Class Aves Linnaeus, 1758 Subclass Sauriurae Haeckel, 1866 Order Archaeopterygiformes Furbringer, 1888 Family Archaeopterygidae Huxley, 1872 Genus Protarchaeopteryx gen. nov. Genus etymology: Acknowledges that the specimen possesses characters more primitive than those of Archaeopteryx. Diagnosis: A primitive archaeopterygian with claviform and unserrated dentition. Sternum is thin and flat, tail is long, and forelimb resembles Archaeopteryx in morphology with three talons, the second of which is enlarged. Ilium is large and elongated, pubes are robust and distally fused, hind limb is long and robust with digit I reduced and dorsally migrated to lie in opposition to digit III and forming a grasping apparatus. -
LETTER Doi:10.1038/Nature14423
LETTER doi:10.1038/nature14423 A bizarre Jurassic maniraptoran theropod with preserved evidence of membranous wings Xing Xu1,2*, Xiaoting Zheng1,3*, Corwin Sullivan2, Xiaoli Wang1, Lida Xing4, Yan Wang1, Xiaomei Zhang3, Jingmai K. O’Connor2, Fucheng Zhang2 & Yanhong Pan5 The wings of birds and their closest theropod relatives share a ratios are 1.16 and 1.08, respectively, compared to 0.96 and 0.78 in uniform fundamental architecture, with pinnate flight feathers Epidendrosaurus and 0.79 and 0.66 in Epidexipteryx), an extremely as the key component1–3. Here we report a new scansoriopterygid short humeral deltopectoral crest, and a long rod-like bone articu- theropod, Yi qi gen. et sp. nov., based on a new specimen from the lating with the wrist. Middle–Upper Jurassic period Tiaojishan Formation of Hebei Key osteological features are as follows. STM 31-2 (Fig. 1) is inferred Province, China4. Yi is nested phylogenetically among winged ther- to be an adult on the basis of the closed neurocentral sutures of the opods but has large stiff filamentous feathers of an unusual type on visible vertebrae, although this is not a universal criterion for maturity both the forelimb and hindlimb. However, the filamentous feath- across archosaurian taxa12. Its body mass is estimated to be approxi- ers of Yi resemble pinnate feathers in bearing morphologically mately 380 g, using an empirical equation13. diverse melanosomes5. Most surprisingly, Yi has a long rod-like The skull and mandible are similar to those of other scansoriopter- bone extending from each wrist, and patches of membranous tissue ygids, and to a lesser degree to those of oviraptorosaurs and some basal preserved between the rod-like bones and the manual digits. -
Tiny Fossil Sheds Light on Miniaturization of Birds
Retraction Tiny fossil sheds light on miniaturization of birds Roger B. J. Benson Nature 579, 199–200 (2020) In view of the fact that the authors of ‘Hummingbird-sized dinosaur from the Cretaceous period of Myanmar‘ (L. Xing et al. Nature 579, 245–249; 2020) are retracting their report, I wish to retract this News & Views article, which dealt with this study and was based on the accuracy and reproducibility of their data. Nature | 22 July 2020 ©2020 Spri nger Nature Li mited. All rights reserved. drives the assembly of DNA-PK and stimulates regulation of protein synthesis. And, although 3. Dragon, F. et al. Nature 417, 967–970 (2002). its catalytic activity in vitro, although does so further studies are required, we might have 4. Adelmant, G. et al. Mol. Cell. Proteom. 11, 411–421 (2012). much less efficiently than can DNA. taken a step closer to deciphering the 5. Britton, S., Coates, J. & Jackson, S. P. J. Cell Biol. 202, Taken together, these observations suggest mysterious ribosomopathies. 579–595 (2013). a model in which KU recruits DNA-PKcs to the 6. Barandun, J. et al. Nature Struct. Mol. Biol. 24, 944–953 (2017). small-subunit processome. In the case of Alan J. Warren is at the Cambridge Institute 7. Ma, Y. et al. Cell 108, 781–794 (2002). kinase-defective DNA-PK, the mutant enzyme’s for Medical Research, Hills Road, Cambridge 8. Yin, X. et al. Cell Res. 27, 1341–1350 (2017). inability to regulate its own activity gives the CB2 OXY, UK. 9. Sharif, H. et al. -
A Second Cretaceous Ornithuromorph Bird from the Changma Basin, Gansu Province, Northwestern China Author(S): Hai-Lu You , Jessie Atterholt , Jingmai K
A Second Cretaceous Ornithuromorph Bird from the Changma Basin, Gansu Province, Northwestern China Author(s): Hai-Lu You , Jessie Atterholt , Jingmai K. O'Connor , Jerald D. Harris , Matthew C. Lamanna and Da-Qing Li Source: Acta Palaeontologica Polonica, 55(4):617-625. 2010. Published By: Institute of Paleobiology, Polish Academy of Sciences DOI: http://dx.doi.org/10.4202/app.2009.0095 URL: http://www.bioone.org/doi/full/10.4202/app.2009.0095 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. A second Cretaceous ornithuromorph bird from the Changma Basin, Gansu Province, northwestern China HAI−LU YOU, JESSIE ATTERHOLT, JINGMAI K. O’CONNOR, JERALD D. HARRIS, MATTHEW C. LAMANNA, and DA−QING LI You, H.−L., Atterholt, J., O’Connor, J.K., Harris, J.D., Lamanna, M.C., and Li, D.−Q. 2010. A second Cretaceous ornithuromorph bird from the Changma Basin, Gansu Province, northwestern China. -
Fuzzy Simplicial Networks: a Topology-Inspired Model to Improve Task Generalization in Few-Shot Learning
Fuzzy Simplicial Networks: A Topology-Inspired Model to Improve Task Generalization in Few-shot Learning Henry Kvinge∗, Zachary New∗, Nico Courts∗y, Jung H. Lee∗, Lauren A. Phillipsz, Courtney D. Corleyz, Aaron Tuor∗, Andrew Avilaz, Nathan O. Hodasz September 24, 2020 Abstract Deep learning has shown great success in settings with massive amounts of data but has struggled when data is limited. Few-shot learning algorithms, which seek to address this limitation, are designed to generalize well to new tasks with limited data. Typically, models are evaluated on unseen classes and datasets that are defined by the same fundamental task as they are trained for (e.g. category membership). One can also ask how well a model can generalize to fundamentally different tasks within a fixed dataset (for example: moving from category membership to tasks that involve detecting object orientation or quantity). To formalize this kind of shift we define a notion of independence of tasks and identify three new sets of labels for established computer vision datasets that test a model's ability to generalize to tasks which draw on orthogonal attributes in the data. We use these datasets to investigate the failure modes of metric-based few-shot models. Based on our findings, we introduce a new few-shot model called Fuzzy Simplicial Networks (FSN) which leverages a construction from topology to more flexibly represent each class from limited data. In particular, FSN models can not only form multiple representations for a given class but can also begin to capture the low-dimensional structure which characterizes class manifolds in the encoded space of deep networks. -
A New Raptorial Dinosaur with Exceptionally Long Feathering Provides Insights Into Dromaeosaurid flight Performance
ARTICLE Received 11 Apr 2014 | Accepted 11 Jun 2014 | Published 15 Jul 2014 DOI: 10.1038/ncomms5382 A new raptorial dinosaur with exceptionally long feathering provides insights into dromaeosaurid flight performance Gang Han1, Luis M. Chiappe2, Shu-An Ji1,3, Michael Habib4, Alan H. Turner5, Anusuya Chinsamy6, Xueling Liu1 & Lizhuo Han1 Microraptorines are a group of predatory dromaeosaurid theropod dinosaurs with aero- dynamic capacity. These close relatives of birds are essential for testing hypotheses explaining the origin and early evolution of avian flight. Here we describe a new ‘four-winged’ microraptorine, Changyuraptor yangi, from the Early Cretaceous Jehol Biota of China. With tail feathers that are nearly 30 cm long, roughly 30% the length of the skeleton, the new fossil possesses the longest known feathers for any non-avian dinosaur. Furthermore, it is the largest theropod with long, pennaceous feathers attached to the lower hind limbs (that is, ‘hindwings’). The lengthy feathered tail of the new fossil provides insight into the flight performance of microraptorines and how they may have maintained aerial competency at larger body sizes. We demonstrate how the low-aspect-ratio tail of the new fossil would have acted as a pitch control structure reducing descent speed and thus playing a key role in landing. 1 Paleontological Center, Bohai University, 19 Keji Road, New Shongshan District, Jinzhou, Liaoning Province 121013, China. 2 Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, USA. 3 Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing 100037, China. 4 University of Southern California, Health Sciences Campus, BMT 403, Mail Code 9112, Los Angeles, California 90089, USA. -
Winter Bird Feeding
BirdNotes 1 Winter Bird Feeding birds at feeders in winter If you feed birds, you’re in good company. Birding is one of North America’s favorite pastimes. A 2006 report from the U.S. Fish and Wildlife Service estimates that about 55.5 mil- lion Americans provide food for wild birds. Chickadees Titmice Cardinals Sparrows Wood- Orioles Pigeons Nuthatches Finches Grosbeaks Blackbirds Jays peckers Tanagers Doves Sunflower ◆ ◆ ◆ ◆ ◆ ◆ ◆ Safflower ◆ ◆ ◆ Corn ◆ ◆ ◆ Millet ◆ ◆ ◆ Milo ◆ ◆ Nyjer ◆ Suet ◆ ◆ ◆ ◆ ◆ Preferred ◆ Readily Eaten Wintertime—and the Living’s counting birds at their feeders during selecting the best foods daunting. To Not Easy this winterlong survey. Great Back- attract a diversity of birds, provide a yard Bird Count participants provide variety of food types. But that doesn’t n much of North America, winter valuable data with a much shorter mean you need to purchase one of ev- Iis a difficult time for birds. Days time commitment—as little as fifteen erything on the shelf. are often windy and cold; nights are minutes in mid-February! long and even colder. Lush vegeta- Which Seed Types tion has withered or been consumed, Types of Bird Food Should I Provide? and most insects have died or become uring spring and summer, most dormant. Finding food can be espe- lack-oil sunflower seeds attract songbirds eat insects and spi- cially challenging for birds after a D Bthe greatest number of species. ders, which are highly nutritious, heavy snowfall. These seeds have a high meat-to- abundant, and for the most part, eas- shell ratio, they are nutritious and Setting up a backyard feeder makes ily captured. -
The Mesozoic Era Alvarez, W.(1997)
Alles Introductory Biology: Illustrated Lecture Presentations Instructor David L. Alles Western Washington University ----------------------- Part Three: The Integration of Biological Knowledge Vertebrate Evolution in the Late Paleozoic and Mesozoic Eras ----------------------- Vertebrate Evolution in the Late Paleozoic and Mesozoic • Amphibians to Reptiles Internal Fertilization, the Amniotic Egg, and a Water-Tight Skin • The Adaptive Radiation of Reptiles from Scales to Hair and Feathers • Therapsids to Mammals • Dinosaurs to Birds Ectothermy to Endothermy The Evolution of Reptiles The Phanerozoic Eon 444 365 251 Paleozoic Era 542 m.y.a. 488 416 360 299 Camb. Ordov. Sil. Devo. Carbon. Perm. Cambrian Pikaia Fish Fish First First Explosion w/o jaws w/ jaws Amphibians Reptiles 210 65 Mesozoic Era 251 200 180 150 145 Triassic Jurassic Cretaceous First First First T. rex Dinosaurs Mammals Birds Cenozoic Era Last Ice Age 65 56 34 23 5 1.8 0.01 Paleo. Eocene Oligo. Miocene Plio. Ple. Present Early Primate First New First First Modern Cantius World Monkeys Apes Hominins Humans A modern Amphibian—the toad A modern day Reptile—a skink, note the finely outlined scales. A Comparison of Amphibian and Reptile Reproduction The oldest known reptile is Hylonomus lyelli dating to ~ 320 m.y.a.. The earliest or stem reptiles radiated into therapsids leading to mammals, and archosaurs leading to all the other reptile groups including the thecodontians, ancestors of the dinosaurs. Dimetrodon, a Mammal-like Reptile of the Early Permian Dicynodonts were a group of therapsids of the late Permian. Web Reference http://www.museums.org.za/sam/resource/palaeo/cluver/index.html Therapsids experienced an adaptive radiation during the Permian, but suffered heavy extinctions during the end Permian mass extinction. -
Alan Feduccia's Riddle of the Feathered Dragons: What Reptiles
Leigh Evolution: Education and Outreach 2014, 7:9 http://www.evolution-outreach.com/content/7/1/9 BOOK REVIEW Open Access Alan Feduccia’s Riddle of the Feathered Dragons: what reptiles gave rise to birds? Egbert Giles Leigh Jr Riddle of the Feathered Dragons: Hidden Birds of China, properly. This is a great pity, for his story is wonderful: by Alan Feduccia. New Haven, CT: Yale University Press, his birds would have made a far better focus for this 2012. Pp. x + 358. H/b $55.00 book than the dispute. This book’s author is at home in the paleontology, So, what is this dispute that spoiled the book? The anatomy, physiology, and behavior of birds. Who could scientific argument is easily summarized. It started be more qualified to write on their origin and evolution? when a paleontologist from Yale University, John Ostrom, This book is unusually, indeed wonderfully, well and unearthed a 75-kg bipedal theropod dinosaur, Deinonychus, clearly illustrated: its producers cannot be praised too buried 110 million years ago in Montana. Deinonychus highly. It is well worth the while of anyone interested in stood a meter tall, and its tail was 1.5 m long. It was active: bird evolution to read it. Although it offers no answers Ostrom thought that both it and Archaeopteryx,which to ‘where birds came from’, it has God’s plenty of fascin- lived 40 million years earlier, were warm-blooded. Deinony- ating, revealing detail, knit together in powerful criticism chus bore many skeletal resemblances to Archaeopteryx, of prevailing views of bird evolution. -
ORIGIN and EVOLUTION of BIRDS Dr. Ramesh Pathak B.Sc. (Hons.) –II
ORIGIN AND EVOLUTION OF BIRDS Dr. Ramesh Pathak B.Sc. (hons.) –II Prof. Parker has shown a number of peculiarities between birds and repiles,so,he said “birds are transformed and glorified reptiles”. Huxley has established a very close relationship by saying birds are “feathered reptiles”. THEORIES OF ORIGIN OF BIRDS A. Cursorial theory : This theory was championed by Baron Nopsa who maintained that the birds evolved from cursorial bipedal dinosaurs. In attempt to move faster during running to pull themselves a bit faster they moved and beat their arms. In such condition, due to continuous use of arms as propellers brought constant increase in the length and breadth of scales present on them. As the scales lengthened ,the pressure against the air caused their edges frayed leading to scales changing into feathers. But this theory was rejected because scales and feathers are fundamentally different structures arising from different layers of skin. B.Tetrapteryx theory :It was proposed by Beebe and Gregorg. According to this theory the ancestors of birds were arboreal reptiles who used to jump from branch to branch and in doing so the scales were transformed into feathers by fraying of the edges. After developing feathers on all the four limbs (Tetrapteryx stage), they used only the anterior wings and the unused posterior wings were lost. This theory was also discarded because there is no evidence that birds had ever four wings. C. Gliding thery : It is based on the idea of Beebe and Georg.It was proposed by Heilmann but does not recognize the tetrapteryx stage.