The Evolutionary Continuum of Limb Function from Early Theropods to Birds
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Fused and Vaulted Nasals of Tyrannosaurid Dinosaurs: Implications for Cranial Strength and Feeding Mechanics
Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics ERIC SNIVELY, DONALD M. HENDERSON, and DOUG S. PHILLIPS Snively, E., Henderson, D.M., and Phillips, D.S. 2006. Fused and vaulted nasals of tyrannosaurid dinosaurs: Implications for cranial strength and feeding mechanics. Acta Palaeontologica Polonica 51 (3): 435–454. Tyrannosaurid theropods display several unusual adaptations of the skulls and teeth. Their nasals are fused and vaulted, suggesting that these elements braced the cranium against high feeding forces. Exceptionally high strengths of maxillary teeth in Tyrannosaurus rex indicate that it could exert relatively greater feeding forces than other tyrannosaurids. Areas and second moments of area of the nasals, calculated from CT cross−sections, show higher nasal strengths for large tyrannosaurids than for Allosaurus fragilis. Cross−sectional geometry of theropod crania reveals high second moments of area in tyrannosaurids, with resulting high strengths in bending and torsion, when compared with the crania of similarly sized theropods. In tyrannosaurids trends of strength increase are positively allomeric and have similar allometric expo− nents, indicating correlated progression towards unusually high strengths of the feeding apparatus. Fused, arched nasals and broad crania of tyrannosaurids are consistent with deep bites that impacted bone and powerful lateral movements of the head for dismembering prey. Key words: Theropoda, Carnosauria, Tyrannosauridae, biomechanics, feeding mechanics, computer modeling, com− puted tomography. Eric Snively [[email protected]], Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada; Donald M. Henderson [[email protected]], Royal Tyrrell Museum of Palaeontology, Box 7500, Drumheller, Alberta T0J 0Y0, Canada; Doug S. -
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 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. -
The Origin and Early Evolution of Dinosaurs
Biol. Rev. (2010), 85, pp. 55–110. 55 doi:10.1111/j.1469-185X.2009.00094.x The origin and early evolution of dinosaurs Max C. Langer1∗,MartinD.Ezcurra2, Jonathas S. Bittencourt1 and Fernando E. Novas2,3 1Departamento de Biologia, FFCLRP, Universidade de S˜ao Paulo; Av. Bandeirantes 3900, Ribeir˜ao Preto-SP, Brazil 2Laboratorio de Anatomia Comparada y Evoluci´on de los Vertebrados, Museo Argentino de Ciencias Naturales ‘‘Bernardino Rivadavia’’, Avda. Angel Gallardo 470, Cdad. de Buenos Aires, Argentina 3CONICET (Consejo Nacional de Investigaciones Cient´ıficas y T´ecnicas); Avda. Rivadavia 1917 - Cdad. de Buenos Aires, Argentina (Received 28 November 2008; revised 09 July 2009; accepted 14 July 2009) ABSTRACT The oldest unequivocal records of Dinosauria were unearthed from Late Triassic rocks (approximately 230 Ma) accumulated over extensional rift basins in southwestern Pangea. The better known of these are Herrerasaurus ischigualastensis, Pisanosaurus mertii, Eoraptor lunensis,andPanphagia protos from the Ischigualasto Formation, Argentina, and Staurikosaurus pricei and Saturnalia tupiniquim from the Santa Maria Formation, Brazil. No uncontroversial dinosaur body fossils are known from older strata, but the Middle Triassic origin of the lineage may be inferred from both the footprint record and its sister-group relation to Ladinian basal dinosauromorphs. These include the typical Marasuchus lilloensis, more basal forms such as Lagerpeton and Dromomeron, as well as silesaurids: a possibly monophyletic group composed of Mid-Late Triassic forms that may represent immediate sister taxa to dinosaurs. The first phylogenetic definition to fit the current understanding of Dinosauria as a node-based taxon solely composed of mutually exclusive Saurischia and Ornithischia was given as ‘‘all descendants of the most recent common ancestor of birds and Triceratops’’. -
Mini Revision 20160403.Compressed
Xing, L., Lockley, M. G., Yang, G., Cao, J., Benton, M. J., Xu, X., Zhang, J., Klein, H., Persons IV, W. S., Kim, J. Y., Peng, G., Ye, Y., & Ran, H. (2016). A new Minisauripus site from the Lower Cretaceous of China: Tracks of small adults or juveniles? Palaeogeography, Palaeoclimatology, Palaeoecology, 452, 28-39. https://doi.org/10.1016/j.palaeo.2016.04.006 Peer reviewed version License (if available): CC BY-NC-ND Link to published version (if available): 10.1016/j.palaeo.2016.04.006 Link to publication record in Explore Bristol Research PDF-document This is the author accepted manuscript (AAM). The final published version (version of record) is available online via Elsevier at http://www.sciencedirect.com/science/article/pii/S0031018216300608. Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ 1 1 A new Minisauripus site from the Lower Cretaceous of China: tracks of small adults or juveniles? 2 3 Lida Xing a, Martin G. Lockley b, Geng Yang c, Jun Cao c, Michael Benton d, Xing Xu e, Jianping Zhang a, 4 Hendrik Klein f, W. Scott Persons IV g, Jeong Yul Kim h, Guangzhao Peng i, Yong Ye i, Hao Ran j 5 6 a School of the Earth Sciences and Resources, China University of Geosciences, Beijing, China, 7 b Dinosaur Trackers Research -
Tetrapod Track Assemblages from Lower Cretaceous Desert Facies In
Palaeogeography, Palaeoclimatology, Palaeoecology 507 (2018) 1–14 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Tetrapod track assemblages from Lower Cretaceous desert facies in the Ordos Basin, Shaanxi Province, China, and their implications for Mesozoic T paleoecology ⁎ Lida Xinga,b,c, Martin G. Lockleyd, , Yongzhong Tange, Anthony Romiliof, Tao Xue, Xingwen Lie, Yu Tange, Yizhao Lie a State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China b School of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China c State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, China d Dinosaur Trackers Research Group, CB 172, University of Colorado at Denver, PO Box 173364, Denver, CO 80217-3364, USA e Shaanxi Geological Survey, Xi'an 710054, Shaanxi, China f School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia ARTICLE INFO ABSTRACT Keywords: Tetrapod ichnofaunas are reported from desert, playa lake facies in the Lower Cretaceous Luohe Formation at Ichnofacies Baodaoshili, Shaanxi Province, China, which represent the first Asian example of an ichnnofauna typical of the Brasilichnium Chelichnus Ichnofacies (Brasilichnium sub-ichnofacies) characteristic of desert habitats. The mammaliomorph Sarmientichnus tracks, assigned to Brasilichnium, -
A New Crested Theropod Dinosaur from the Early Jurassic of Yunnan
第55卷 第2期 古 脊 椎 动 物 学 报 pp. 177-186 2017年4月 VERTEBRATA PALASIATICA figs. 1-3 A new crested theropod dinosaur from the Early Jurassic of Yunnan Province, China WANG Guo-Fu1,2 YOU Hai-Lu3,4* PAN Shi-Gang5 WANG Tao5 (1 Fossil Research Center of Chuxiong Prefecture, Yunnan Province Chuxiong, Yunnan 675000) (2 Chuxiong Prefectural Museum Chuxiong, Yunnan 675000) (3 Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences Beijing 100044 * Corresponding author: [email protected]) (4 College of Earth Sciences, University of Chinese Academy of Sciences Beijing 100049) (5 Bureau of Land and Resources of Lufeng County Lufeng, Yunnan 650031) Abstract A new crested theropod, Shuangbaisaurus anlongbaoensis gen. et sp. nov., is reported. The new taxon is recovered from the Lower Jurassic Fengjiahe Formation of Shuangbai County, Chuxiong Yi Autonomous Prefecture, Yunnan Province, and is represented by a partial cranium. Shuangbaisaurus is unique in possessing parasagittal crests along the orbital dorsal rims. It is also distinguishable from the other two lager-bodied parasagittal crested Early Jurassic theropods (Dilophosaurus and Sinosaurus) by a unique combination of features, such as higher than long premaxillary body, elevated ventral edge of the premaxilla, and small upper temporal fenestra. Comparative morphological study indicates that “Dilophosaurus” sinensis could potentially be assigned to Sinosaurus, but probably not to the type species. The discovery of Shuangbaisaurus will help elucidate the evolution of basal theropods, especially the role of various bony cranial ornamentations had played in the differentiation of early theropods. -
Xjiiie'icanj/Useum
XJiiie'ican1ox4tatreJ/useum PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK 24, N.Y. NUMBER 2I8I JUNE 4, I964 Relationships of the Saurischian Dinosaurs BY EDWIN H. COLBERT1 INTRODUCTION The word "Dinosauria" was coined by Sir Richard Owen in 1842 as a designation for various genera and species of extinct reptiles, the fossil bones of which were then being discovered and described in Europe. For many years this term persisted as the name for one order of reptiles and thus became well intrenched within the literature of paleontology. In- deed, since this name was associated with fossil remains that are frequently of large dimensions and spectacular shape and therefore of considerable interest to the general public, it in time became Anglicized, to take its proper place as a common noun in the English language. Almost every- body in the world is today more or less familiar with dinosaurs. As long ago as 1888, H. G. Seeley recognized the fact that the dino- saurs are not contained within a single reptilian order, but rather are quite clearly members of two distinct orders, each of which can be de- fined on the basis of many osteological characters. The structure of the pelvis is particularly useful in the separation of the two dinosaurian orders, and consequently Seeley named these two major taxonomic categories the Saurischia and the Ornithischia. This astute observation by Seeley was not readily accepted, so that for many years following the publication of his original paper proposing the basic dichotomy of the dinosaurs the 1 Chairman and Curator, Department ofVertebrate Paleontology, the American Museum of Natural History. -
Upper Cretaceous), Brazil
Rev. Mus. Argentino Cienc. Nat., n.s. 7(1): 31-36, 2005 Buenos Aires, ISSN 1514-5158 Maniraptoran theropod ungual from the Marília Formation (Upper Cretaceous), Brazil Fernando E. NOVAS1, Luiz Carlos BORGES RIBEIRO2,3 & Ismar de SOUZA CARVALHO4 1CONICET - Museo Argentino de Ciencias Naturales «Bernardino Rivadavia», Av. Angel Gallardo 470, Buenos Aires (1405), Argentina, E-mail: [email protected]. 2Fundação Municipal de Ensino Superior de Uberaba- FUMESU/Centro de Pesquisas Paleontológicas L. I. Price. Av. Randolfo Borges Jr., n° 1.250. Universidade, 38.066-005, Uberaba- MG, Brazil, E-mail: [email protected]. 3Universidade de Uberaba-UNIUBE/Instituto de Formação de Educadores-Departamento de Biologia, Av. Nenê Sabino, n° 1.801. Universitário, Uberaba-MG, 38.055-500, Brazil, E-mail: [email protected]. 4Universidade Federal do Rio de Janeiro, Departamento de Geologia, CCMN/IGEO. 21.949-900 Cidade Universitária-Ilha do Fundão, Rio de Janeiro-RJ, Brazil, E-mail: [email protected] Abstract: A new theropod record from the Marília Formation (Late Cretaceous, Minas Gerais, Brazil) is here described. It consists of an isolated manual ungual which exhibits derived maniraptoran features (e.g., presence of proximodorsal lip). The ungual distinguishes by a set of unique features (e.g., dorsoventrally low and proximodistally elongate profile in side view; block-like flexor tuberosity; proximal articular surface more dorsally oriented than in other theropods; cutting «keel» located distally on ventral surface) suggesting that the animal that produced it was a member of an unknown group of derived maniraptoran theropods, other than alvarezsaurids, deinonychosaurians and oviraptorosaurians already recorded in South America. -
The Fauna from the Tyrannosaurus Rex Excavation, Frenchman Formation (Late Maastrichtian), Saskatchewan
The Fauna from the Tyrannosaurus rex Excavation, Frenchman Formation (Late Maastrichtian), Saskatchewan Tim T. Tokaryk 1 and Harold N. Bryant 2 Tokaryk, T.T. and Bryant, H.N. (2004): The fauna from the Tyrannosaurus rex excavation, Frenchman Formation (Late Maastrichtian), Saskatchewan; in Summary of Investigations 2004, Volume 1, Saskatchewan Geological Survey, Sask. Industry Resources, Misc. Rep. 2004-4.1, CD-ROM, Paper A-18, 12p. Abstract The quarry that contained the partial skeleton of the Tyrannosaurus rex, familiarly known as “Scotty,” has yielded a diverse faunal and floral assemblage. The site is located in the Frenchman River valley in southwestern Saskatchewan and dates from approximately 65 million years, at the end of the Cretaceous Period. The faunal assemblage from the quarry is reviewed and the floral assemblage is summarized. Together, these assemblages provide some insight into the biological community that lived in southwestern Saskatchewan during the latest Cretaceous. Keywords: Frenchman Formation, Maastrichtian, Late Cretaceous, southwestern Saskatchewan, Tyrannosaurus rex. 1. Introduction a) Geological Setting The Frenchman Formation, of latest Maastrichtian age, is extensively exposed in southwestern Saskatchewan (Figure 1; Fraser et al., 1935; Furnival, 1950). The lithostratigraphic units in the formation consist largely of fluvial sandstones and greenish grey to green claystones. Outcrops of the Frenchman Formation are widely distributed in the Frenchman River valley, southeast of Eastend. Chambery Coulee, on the north side of the valley, includes Royal Saskatchewan Museum (RSM) locality 72F07-0022 (precise locality data on file with the RSM), the site that contained the disarticulated skeleton of a Tyrannosaurus rex. McIver (2002) subdivided the stratigraphic sequence at this locality into “lower” and “upper” beds. -
Preliminary Description of Coelophysoids (Dinosauria:Theropoda) from the Upper Triassic (Revuletian:Early-Mid Norian) Snyder Quarry, North-Central New Mexico
Lucas, S.G., and Heckert. A.B., eds., 2000, Dinosaurs of New Mexico. New Mexico Museum of Natural History and Science Bulletin No. 17. 27 PRELIMINARY DESCRIPTION OF COELOPHYSOIDS (DINOSAURIA:THEROPODA) FROM THE UPPER TRIASSIC (REVULETIAN:EARLY-MID NORIAN) SNYDER QUARRY, NORTH-CENTRAL NEW MEXICO ANDREW B. HECKERT!, KATE E. ZEIGLER!, SPENCER G. LUCAS2, LARRY F. RINEHARP, and JERALD D. HARRIS2 'Deparbnent of parth & Planetary Sciences, University of New Mexico, Albuquerque, NM 87131-1116; 'New Mexico Museum of Natural History and Science, 1801 Mountain Road NW, Albuquerque, NM 87104 Abstract-The Upper Triassic Snyder quarry is the second-most productive theropod locality in the Chinle Group. Skull and postcranialelements, particularly tibiae, collected from the Snyder quarry during the last three field seasons demonstrate the presence of at least four individuals of two taxa. The smaller theropod strongly resembles, but is distinct from, the holotype of Eucoelophysis baldwini Sullivan and Lucas and represents either a sexual dimorph or, more likely, a new species of Eucoelophysis. The larger theropod is represented by a single, incomplete fused tibia-fibula-astragalus-calcaneum. Most striking about this taxon is the proximal fusion of the tibia and fibula. These theropods are a small fraction of a rich and diverse assemblage of Upper Triassic vertebrates and invertebrates from the most productive Chinle Group vertebrate fossil assemblage discovered in the last 50 years. INTRODUCTION In 1998, Mark Snyder of Del Mar, California, discovered a spectacular assemblage of fossil vertebrates in the badlands of the Upper Triassic Petrified Forest Formation near Ghost Ranch, north-central New Mexico (Fig. 1).