DOCSLIB.ORG

29.11Briefcomms Mx

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
29.11Briefcomms Mx brief communications Entomology the result of monitoring cues from worker bees, as in the density-dependent prophy- Control Challenge 13 s.e.) Immune defence in s.e.) 1,200 laxis observed in other insects . ± ± 12 Yannick Moret, Paul Schmid-Hempel 11 max 1,000 bumble-bee offspring V 10 Eidgenössische Technische Hochschule Zürich, Ecology and Evolution, ETH-Zentrum NW, mmune-challenged vertebrate females 9 800 transfer specific antibodies to their off- 8092 Zürich, Switzerland 8 600 spring1–3, but this gratuitous immunity e-mail: [email protected] I 7 4 cannot operate in invertebrates . Here we 400 6 1. Hanson, L. A. Ann. Allergy Asthma Immunol. 81, 523–537 show that constitutive immune defence is (1998). 5 200 enhanced in sexual offspring of the bumble- Workers Males Workers Males 2. Coste, A., Sirard, J. C., Johansen, K., Cohen, J. & Kraehenbuhl, J. P. J. Virol. 74, 8966–8971 (2000). Phenol oxidase activity ( bee Bombus terrestris L. when the parental Zone inhibition diameter (mm Antibacterial Enzyme activity activity 3. Rollier, C., Charollois, C., Jamard, C., Trepo, C. & Cova, L. colony is immune-challenged. Our findings Vaccine 18, 3091–3096 (2000). indicate that invertebrates may use a differ- Figure 1 Antibacterial and phenol oxidase activities in the 4. Hoffmann, J. A., Reichhart, J. M. & Hetru, C. Curr. Opin. ent component of the immune system to haemolymph of workers and males from control (orange bars) Immunol. 8, 8–13 (1996). generate a facultative trans-generational and challenged (blue bars) groups from 11 bumble-bee colonies. 5. Söderhäll, K. & Cerenius, L. Curr. Opin. Immunol. 10, 23–28 (1998). increase in the immune response. In workers, antibacterial activity was higher in challenged 6. Nappi, A. J. & Vass, E. Pigment Cell Res. 6, 117–126 (1993). Insect immunity is characterized by the groups than in controls (Wilcoxon’s paired signed-rank test: 7. Thörnqvist, P.-O. & Söderhäll, K. in Diseases in Asian Aquaculture vol. 3 (eds Flegel, T. W. & MacRae, I. H.) inducible expression of a large array of T&46, n411, P*0.02), but phenol oxidase activity was lower 203–218 (Fish Health Section, Asian Fisheries Soc., Manila, (T 43, n411, P40.005). In males, antibacterial activity was antimicrobial peptides and by the constitu- 1 Philippines, 1996). tive melanization–encapsulation response, the same (T&431, n411, NS) but phenol oxidase activity was 8. Nigam, Y., Maudlin, I., Welburn, S. & Rattcliffe, N. A. which is based on a cascade involving an higher (T&46, n411, P*0.02) in the challenged side than in J. Invertebr. Pathol. 69, 279–281 (1997). inactive precursor of the enzyme phenol oxi- controls. Further experiments showed that increased activity in 9. Schmid-Hempel, P. Parasites in Social Insects (Princeton Univ. 4,5 Press, Princeton, New Jersey, 1998). dase . Antibacterial activity can be induced, males correlates with an increased encapsulation response 10.Schmid-Hempel, R. & Schmid-Hempel, P. Funct. Ecol. 12, 4 4 for example, by lipopolysaccharide (LPS) against an invader (F1, 23 5.25, P 0.031). Vmax is measured as 22–30 (1998). extracted from bacterial surfaces. The opera- the maximum change in optical density21013 per minute. 11.Kato, Y. et al. Insect Biochem. Mol. Biol. 24, 539–545 (1994). tion of the cascade is indicated by the phenol 12.Moret, Y. & Schmid-Hempel, P. Science 290, 1166–1168 (2000). 6,7 12 13 13.Barnes, A. I. & Siva-Jothy, M. T. Proc. R. Soc. Lond. B 267, oxidase activity in the insect haemolymph antibacterial and phenol oxidase activity 177–182 (2000). and can be monitored by measuring the rate (1/20 dilution). of conversion of a phenol substrate into As expected, workers in the challenged quinone, which then polymerizes to form groups showed more antibacterial activity melanin. Because both quinone and melanin than controls (Fig. 1). Their phenol oxidase Nanotechnology are toxic to microorganisms5, hosts with high activity, however, was lower (Fig. 1), phenol oxidase activity are less susceptible to indicating that there could be a possible Synthesis of carbon microbial infection8. trade-off between these two immune ‘onions’ in water Social insects cooperate in brood care responses in challenged workers. Haemo- and make a considerable investment in cyte counts were similar between the he fabrication of carbon nanomateri- their offspring. In annual species such as two groups (Wilcoxon’s paired signed-rank als usually calls for expensive vacuum 4 4 1,2 bumble-bees, reproduction occurs at the test, T- 29, n 11, NS). Immune- Tsystems to generate plasmas and end of the colony cycle, when sexuals challenged groups had lower reproductive yields are disappointingly low. Here we (daughter queens and males) emerge — output (repeated measures-MANOVA for describe a simple method for producing here the term ‘trans-generational’ distin- log-transformed number of males and high-quality spherical carbon nano- 4 4 guishes the queen and workers from sexual queens: Hotelling’s T 1.297, F2,9 5.839, ‘onions’ in large quantities without the use offspring. Unlike daughter queens, males P40.024), notably producing fewer queens of vacuum equipment. The nanoparticles, 4 4 do not hibernate, so their reproductive suc- (F1,10 12.082, P 0.006), indicating a pos- which have C60 cores surrounded by onion- cess depends on post-emergence survival sible trade-off between reproductive output like nested particles, are generated by an arc after they leave the parental colony and are and immune response. Male offspring from discharge between two graphite electrodes exposed to parasites in the same habitat9. challenged groups showed higher phenol submerged in water. This technique is eco- Assuming facultative adjustment of off- oxidase activity than controls, but anti- nomical and environmentally benign, and spring immunity, we investigated whether bacterial activity (Fig. 1) and haemocyte produces uncontaminated nanoparticles parasite-challenged parental colonies could counts were comparable between the two which may be useful in many applications. 4 4 enhance their males’ immunocompetence. groups (T- 29, n 11, NS). Nanoparticles have previously been pre- We used a split-colony design10 with As insects do not produce antibodies, pared using a range of vacuum and non- 11 colonies, each equally split into treat- they cannot transfer specific immunity as vacuum methods3–5. Ours is a non-vacuum ment and control groups. In the immune- mammals do1. Male bumble-bees from method in which the carbon arc is sus- challenged group, 70–80% of workers were immune-challenged groups have increased tained in deionized water. The apparatus injected weekly with LPS (Sigma L-2755, constitutive immunity relative to controls, consists of two submerged graphite elec- 0.5 mg ml11 in Ringer’s solution (5 ml)), which both enhances encapsulation (Fig. 1) trodes, and the arc discharge is initiated by which activates the immune system for long and protects against microorganisms5,8. As contacting a pure grounded graphite anode periods11. Control workers were treated in the phenol oxidase enzyme cascade pro- (tip diameter, 5 mm) with the carbon cath- the same way, but with the omission of LPS. vides a broader immunity than the costly ode (tip diameter, 12 mm) of similar puri- Colonies completed their life cycle in the antibacterial immune response12, males ty; the discharge voltage and current were laboratory under standard conditions may benefit by enhancing their most gener- 16–17 V and 30 A, respectively. The nano- (24 7C, 60% relative humidity). We counted al means of prophylaxis. Although the phys- onions are mostly found floating on the the number of sexuals and haemocytes iological mechanism by which this water surface, with the rest falling to the (Neubauer haemocytometer, 1/6 dilution) trans-generational transfer is achieved is bottom of the beaker through natural and used standard protocols to measure unknown, the enhanced immunity could be segregation, giving material of high purity. 506 © 2001 Macmillan Magazines Ltd NATURE | VOL 414 | 29 NOVEMBER 2001 | www.nature.com brief communications ab Cretaceous Gansus (possibly a shore- dwelling bird), from Gansu Province in c the continental interior of China, and Liaononingornis, perhaps the oldest known Onions ornithurine bird from the famous Early Cretaceous Confuciusornis locality2. As hesperornithiform birds (highly derived ornithurines) were already well adapted for foot-propelled diving by the Aptian epoch (the latter part of the Early Figure 1 Carbon nano-‘onions’ created by arc discharge in water. a, Image of a carbon arc discharge in water. Scale bar, 12 mm. b, c, Low- Cretaceous), their divergence must have been and high-magnification electron micrographs of carbon nano-onions floating on the water surface after their production. Scale bars, 10 nm. from even earlier ornithurine birds. By the Late Cretaceous, numerous taxa of hesper- A digital image of the arc discharge in water 3. Cabioch, T., Riviere, J. P. & Delafond, J. J. Mater. Res. 30, ornithiform birds, together with the volant is shown in Fig. 1a. 4787–4792 (1995). ornithurines Ichthyornis and Apatornis, are We investigated the unpurified material 4. Ishigami, M., Cumings, J., Zettl, A. & Chen, S. Chem. Phys. Lett. known from many marine localities in both 319, 457–459 (2000). from the water surface using a JEOL 5. Hsu, W. K. et al. Nature 377, 687 (1995). the Northern and Southern Hemispheres. 4000EX transmission electron microscope. 6. Hsin, Y. L. et al. Adv. Mater. 13, 830–833 (2001). What correlation is there between the dis- A typical high-resolution micrograph of the 7. Tenne, R., Homyonfer, M. & Feldman, Y. Chem. Mater. 10, tributions of shore birds (waders; Charadri- material is shown in Fig. 1b — several 3225–3238 (1998). iformes) and the marine, shoreline habitats spherical carbon nano-onions are evident, of the continental margins? These birds are as well as polyhedral, nested onion-like par- quite cosmopolitan, occurring in shallow ticles.
Load more

Recommended publications
  • 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.
    [Show full text]
  • Appendix A. Supplementary Material
    Appendix A. Supplementary material Comprehensive taxon sampling and vetted fossils help clarify the time tree of shorebirds (Aves, Charadriiformes) David Cernˇ y´ 1,* & Rossy Natale2 1Department of the Geophysical Sciences, University of Chicago, Chicago 60637, USA 2Department of Organismal Biology & Anatomy, University of Chicago, Chicago 60637, USA *Corresponding Author. Email: [email protected] Contents 1 Fossil Calibrations 2 1.1 Calibrations used . .2 1.2 Rejected calibrations . 22 2 Outgroup sequences 30 2.1 Neornithine outgroups . 33 2.2 Non-neornithine outgroups . 39 3 Supplementary Methods 72 4 Supplementary Figures and Tables 74 5 Image Credits 91 References 99 1 1 Fossil Calibrations 1.1 Calibrations used Calibration 1 Node calibrated. MRCA of Uria aalge and Uria lomvia. Fossil taxon. Uria lomvia (Linnaeus, 1758). Specimen. CASG 71892 (referred specimen; Olson, 2013), California Academy of Sciences, San Francisco, CA, USA. Lower bound. 2.58 Ma. Phylogenetic justification. As in Smith (2015). Age justification. The status of CASG 71892 as the oldest known record of either of the two spp. of Uria was recently confirmed by the review of Watanabe et al. (2016). The younger of the two marine transgressions at the Tolstoi Point corresponds to the Bigbendian transgression (Olson, 2013), which contains the Gauss-Matuyama magnetostratigraphic boundary (Kaufman and Brigham-Grette, 1993). Attempts to date this reversal have been recently reviewed by Ohno et al. (2012); Singer (2014), and Head (2019). In particular, Deino et al. (2006) were able to tightly bracket the age of the reversal using high-precision 40Ar/39Ar dating of two tuffs in normally and reversely magnetized lacustrine sediments from Kenya, obtaining a value of 2.589 ± 0.003 Ma.
    [Show full text]
  • The Oldest Record of Ornithuromorpha from the Early Cretaceous of China
    ARTICLE Received 6 Jan 2015 | Accepted 20 Mar 2015 | Published 5 May 2015 DOI: 10.1038/ncomms7987 OPEN The oldest record of ornithuromorpha from the early cretaceous of China Min Wang1, Xiaoting Zheng2,3, Jingmai K. O’Connor1, Graeme T. Lloyd4, Xiaoli Wang2,3, Yan Wang2,3, Xiaomei Zhang2,3 & Zhonghe Zhou1 Ornithuromorpha is the most inclusive clade containing extant birds but not the Mesozoic Enantiornithes. The early evolutionary history of this avian clade has been advanced with recent discoveries from Cretaceous deposits, indicating that Ornithuromorpha and Enantiornithes are the two major avian groups in Mesozoic. Here we report on a new ornithuromorph bird, Archaeornithura meemannae gen. et sp. nov., from the second oldest avian-bearing deposits (130.7 Ma) in the world. The new taxon is referable to the Hongshanornithidae and constitutes the oldest record of the Ornithuromorpha. However, A. meemannae shows few primitive features relative to younger hongshanornithids and is deeply nested within the Hongshanornithidae, suggesting that this clade is already well established. The new discovery extends the record of Ornithuromorpha by five to six million years, which in turn pushes back the divergence times of early avian lingeages into the Early Cretaceous. 1 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, China. 2 Institue of Geology and Paleontology, Linyi University, Linyi, Shandong 276000, China. 3 Tianyu Natural History Museum of Shandong, Pingyi, Shandong 273300, China. 4 Department of Biological Sciences, Faculty of Science, Macquarie University, Sydney, New South Wales 2019, Australia.
    [Show full text]
  • Supplemental Figs S1-S6
    Bayesian tip dating reveals heterogeneous morphological clocks in Mesozoic birds Chi Zhang1,2,* and Min Wang1,2 1Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China 2Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Beijing 100044, China ∗Corresponding author: E-mail: [email protected] Supplementary Information Figures Dromaeosauridae Archaeopteryx Jeholornis Chongmingia Sapeornis Confuciusornis_sanctus Changchengornis Confuciusornis_dui Yangavis Eoconfuciusornis Pengornis Eopengornis Protopteryx 15.5 Boluochia Longipteryx Longirostravis Rapaxavis Shanweiniao Concornis Elsornis Gobipteryx Neuquenornis Eoalulavis Cathayornis Eocathayornis Eoenantiornis Linyiornis mean relative rate Fortunguavis Sulcavis Bohaiornis 0.3 Parabohaiornis Longusunguis Zhouornis Shenqiornis Vescornis Dunhuangia 1.0 Piscivorenantiornis Pterygornis Qiliania Cruralispennia Monoenantiornis Archaeorhynchus Jianchangornis Schizooura Bellulornis Vorona Patagopteryx Songlingornis Iteravis Yanornis clade probability Yixianornis Piscivoravis Longicrusavis 0.5 Hongshanornis Parahongshanornis Archaeornithura Tianyuornis Apsaravis Gansus Ichthyornis Vegavis Anas Hesperornis Gallus Parahesperornis Baptornis_varneri Baptornis_advenus Enaliornis -175 -150 -125 -100 - 7 5 - 5 0 - 2 5 0 Figure S1. Dated phylogeny (time tree) of the Mesozoic birds under the partitioned analysis. The color of the branch represents the mean relative
    [Show full text]
  • Phylogenetic Position of Ornithomimosauria in Coelurosauria with Comments on the Relationship of Ornithomimosaurs and Alvarezsaurids
    ｖｅｒ／化石研究会会誌 ＰＤＦ化／０８０８００７９ 化石研究会誌４１巻１号／本文／５ ２５‐３２ 欧文 2008.09.24 09. 化石研究会会誌 Journal of Fossil Research, Vol.４１（１）,２５-３２（２００８） ［Original report］ Phylogenetic position of Ornithomimosauria in Coelurosauria with comments on the relationship of ornithomimosaurs and alvarezsaurids KOBAYASHI, Yoshitsugu* Abstract The phylogenetic position of Ornithomimosauria within Coerulosauria is discussed. Most of previous phylogenetic analyses suggested that Ornithomimosauria is basal coelurosaur dinosaurs (Tyrannosauridae is the most basal taxon). One study suggested that ornithomimosaurs and alvarezsaurids form a monophyly. This study argues an ornithomimosaurs-alvarezsaurids relationship and supports the idea that they are probably not closely related. Additional information from this study are that two characters for the ornithomimosaur-alvarezsaurid monophyly from the previous study (metacarpals I-III extent of shaft-to-shaft contact 60-70% of shafts and metacarpal I length at least 60% that of metacarapal II) are not supported (roughly 20% contact between metacarpals II and III, less than 50% shaft-to shaft contact in metacarpals I and II in some taxa, and metacarpal I in Harpymimus rougly 50% of metacarpal II). A phylogenetic analysis in this study suggests that the features, supporting a close relationship between ornithomimsoaurs and alvarezsaurids in the previous study are from derived ornithomimids, not primitive forms. Key words： Dinosauria, Coelurosauria, Ornithomimosauria, Alvarezsauridae, phylogeny Introduction ornithomimosaur genera were placed in the Ornithomimosauria are a group of theropod families Harpymimidae (includes Harpymimus) dinosaurs, each of which resembles modern ground and Garudimimidae (includes Garudimimus) (Barsbold, birds in having a beak-like jaw and lightly built body 1981 ; Barsbold and Perle, 1984) from Mongolia with long, slender limbs (Fig.
    [Show full text]
  • Unenlagiid Theropods: Are They Members of the Dromaeosauridae (Theropoda, Maniraptora)?
    “main” — 2011/2/10 — 14:01 — page 117 — #1 Anais da Academia Brasileira de Ciências (2011) 83(1): 117-162 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 www.scielo.br/aabc Unenlagiid theropods: are they members of the Dromaeosauridae (Theropoda, Maniraptora)? , FEDERICO L. AGNOLIN1 2 and FERNANDO E. NOVAS1 1Laboratorio de Anatomía Comparada y Evolución de los Vertebrados Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” Ángel Gallardo, 470 (1405BDB), Buenos Aires, Argentina 2Fundación de Historia Natural “Félix de Azara”, Departamento de Ciencias Naturales y Antropología CEBBAD, Universidad Maimónides, Valentín Virasoro 732 (1405BDB), Buenos Aires, Argentina Manuscript received on November 9, 2009; accepted for publication on June 21, 2010 ABSTRACT In the present paper we analyze the phylogenetic position of the derived Gondwanan theropod clade Unen- lagiidae. Although this group has been frequently considered as deeply nested within Deinonychosauria and Dromaeosauridae, most of the features supporting this interpretation are conflictive, at least. Modification of integrative databases, such as that recently published by Hu et al. (2009), produces significant changes in the topological distribution of taxa within Deinonychosauria, depicting unenlagiids outside this clade. Our analysis retrieves, in contrast, a monophyletic Avialae formed by Unenlagiidae plus Aves. Key words: Gondwana, Deinonychosauria, Dromaeosauridae, Unenlagiidae, Avialae. INTRODUCTION Until recently, the deinonychosaurian fossil record has been geographically restricted to the Northern Hemisphere (Norell and Makovicky 2004), but recent discoveries demonstrated that they were also present and highly diversified in the Southern landmasses, suggesting that an important adaptive radiation took place in Gondwana during the Cretaceous. Gondwanan dromaeosaurids have been documented from Turonian through Maastrichtian beds of Argentina (Makovicky et al.
    [Show full text]
  • A Second Cretaceous Ornithuromorph Bird from the Changma Basin, Gansu Province, Northwestern China Hai-Lu You,Jessie Atterholt
    1 http://app.pan.pl/acta55/app55-You_etal_SOM.pdf SUPPLEMENTARY ONLINE MATERIAL FOR 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 Published in Acta Palaeontologica Polonica 2010 55 (4): 617-625. doi: 10.4202/app.2009.0095 SOM_1 Hypothesized phylogenetic position of Ornithuromorpha gen. et sp. indet. (FRDC-05-CM-021 [05-CM-021, indicated by sternum]) from the Early Cretaceous of the Changma Basin, northwestern Gansu Province, China. Two most parsimonious trees (A, B) of 592 steps (CI = 47; RCI = 47; RI = 67) recovered by cladistic analysis. Other specimen numbers correspond to undescribed enantiornithine fossils in the FRDC collection. http://app.pan.pl/SOM/app55-You_etal_SOM/SOM_1.bmp SOM_2 Apomorphies supporting nodes (with absolute/relative [0-100] Bremer support values in parentheses) from one of the two most parsimonious trees recovered by the present phylogenetic analysis (depicted in SOM_1:A). Confuciusornithidae (3/45): char 62: 0 --> 2 char 128: 1 --> 2 char 172: 0 --> 1 char 173: 0 --> 1 char 231: 0 --> 2 2 Zhongornis + Confuciusornithidae (1/4): char 35: 0 --> 1 char 103: 1 --> 0 char 143: 1 --> 0 char 175: 1 --> 0 Shanweiniao + Longirostravis (2/8): char 171: 0 --> 1 char 209: 0 --> 1 Longipterygidae (2/38): char 5: 0 --> 1 char 79: 0 --> 1 char 196: 0 --> 1 Eoalulavis + Liaoningornis (1/8): char 117: 2 --> 3 Gobipteryx + Vescornis (1/8): char 77: 1 --> 0 char 238: 0 -->
    [Show full text]
  • Birdlike Growth and Mixed-Age Flocks in Avimimids (Theropoda
    www.nature.com/scientificreports OPEN Birdlike growth and mixed-age focks in avimimids (Theropoda, Oviraptorosauria) G. F. Funston1*, P. J. Currie 1, M. J. Ryan2 & Z.-M. Dong3 Avimimids were unusual, birdlike oviraptorosaurs from the Late Cretaceous of Asia. Initially enigmatic, new information has ameliorated the understanding of their anatomy, phylogenetic position, and behaviour. A monodominant bonebed from the Nemegt Formation of Mongolia showed that some avimimids were gregarious, but the site is unusual in the apparent absence of juveniles. Here, a second monodominant avimimid bonebed is described from the Iren Dabasu Formation of northern China. Elements recovered include numerous vertebrae and portions of the forelimbs and hindlimbs, representing a minimum of six individuals. Histological sampling of two tibiotarsi from the bonebed reveals rapid growth early in ontogeny followed by unexpectedly early onset of fusion and limited subsequent growth. This indicates that avimimids grew rapidly to adult size, like most extant birds but contrasting other small theropod dinosaurs. The combination of adults and juveniles in the Iren Dabasu bonebed assemblage provides evidence of mixed-age focking in avimimids and the onset of fusion in young individuals suggests that some of the individuals in the Nemegt Formation bonebed may have been juveniles. Regardless, these individuals were likely functionally analogous to adults, and this probably facilitated mixed-age focking by reducing ontogenetic niche shift in avimimids. Avimimidae was an enigmatic, monogeneric family of oviraptorosaurs from China and Mongolia (Fig. 1). Avimimus was frst described by Kurzanov1 and its bird-like morphology immediately confused palaeontologists. Although regarded as a non-avian theropod by Kurzanov1, other workers interpreted its mosaic of features as similar to those of a fightless avian2, a sauropod3, and even an ornithopod dinosaur3.
    [Show full text]
  • Redalyc.Unenlagiid Theropods: Are They Members of the Dromaeosauridae (Theropoda, Maniraptora)?
    Anais da Academia Brasileira de Ciências ISSN: 0001-3765 [email protected] Academia Brasileira de Ciências Brasil AGNOLIN, FEDERICO L.; NOVAS, FERNANDO E. Unenlagiid theropods: are they members of the Dromaeosauridae (Theropoda, Maniraptora)? Anais da Academia Brasileira de Ciências, vol. 83, núm. 1, marzo, 2011, pp. 117-162 Academia Brasileira de Ciências Rio de Janeiro, Brasil Available in: http://www.redalyc.org/articulo.oa?id=32717681007 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative “main” — 2011/2/10 — 14:01 — page 117 — #1 Anais da Academia Brasileira de Ciências (2011) 83(1): 117-162 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 www.scielo.br/aabc Unenlagiid theropods: are they members of the Dromaeosauridae (Theropoda, Maniraptora)? , FEDERICO L. AGNOLIN1 2 and FERNANDO E. NOVAS1 1Laboratorio de Anatomía Comparada y Evolución de los Vertebrados Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” Ángel Gallardo, 470 (1405BDB), Buenos Aires, Argentina 2Fundación de Historia Natural “Félix de Azara”, Departamento de Ciencias Naturales y Antropología CEBBAD, Universidad Maimónides, Valentín Virasoro 732 (1405BDB), Buenos Aires, Argentina Manuscript received on November 9, 2009; accepted for publication on June 21, 2010 ABSTRACT In the present paper we analyze the phylogenetic position of the derived Gondwanan theropod clade Unen- lagiidae. Although this group has been frequently considered as deeply nested within Deinonychosauria and Dromaeosauridae, most of the features supporting this interpretation are conflictive, at least.
    [Show full text]
  • Chapter 4 the Biogeography of Coelurosaurian Theropods and Its Impact on Their Evolutionary History
    Chapter 4 The Biogeography of Coelurosaurian Theropods and Its Impact on Their Evolutionary History ANYANG DING,1 MICHAEL PITTMAN,1 PAUL UPCHURCH,2 JINGMAI O’CONNOR,3 DANIEL J. FIELD,4 AND XING XU3 ABSTRACT The Coelurosauria are a group of mostly feathered theropods that gave rise to birds, the only dinosaurians that survived the Cretaceous-Paleogene extinction event and are still found today. Between their first appearance in the Middle Jurassic up to the end Cretaceous, coelurosaurians were party to dramatic geographic changes on the Earth’s surface, including the breakup of the supercon- tinent Pangaea, and the formation of the Atlantic Ocean. These plate tectonic events are thought to have caused vicariance or dispersal of coelurosaurian faunas, influencing their evolution. Unfortu- nately, few coelurosaurian biogeographic hypotheses have been supported by quantitative evidence. Here, we report the first, broadly sampled quantitative analysis of coelurosaurian biogeography using the likelihood-based package BioGeoBEARS. Mesozoic geographic configurations and changes are reconstructed and employed as constraints in this analysis, including their associated uncertainties. We use a comprehensive time-calibrated coelurosaurian evolutionary tree produced from the The- ropod Working Group phylogenetic data matrix. Six biogeographic models in the BioGeoBEARS package with different assumptions about the evolution of spatial distributions are tested against geographic constraints. Our results statistically favor the DIVALIKE+J and DEC+J models, which allow vicariance and founder events, supporting continental vicariance as an important factor in coelurosaurian evolution. Ancestral range estimation indicates frequent dispersal events via the Apu- lian route (connecting Europe and Africa during the Early Cretaceous) and the Bering land bridge (connecting North America and Asia during the Late Cretaceous).
    [Show full text]
  • A New Paravian Dinosaur from the Late Jurassic of North America Supports a Late Acquisition of Avian flight
    A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight Scott Hartman1, Mickey Mortimer2, William R. Wahl3, Dean R. Lomax4, Jessica Lippincott3 and David M. Lovelace5 1 Department of Geoscience, University of Wisconsin-Madison, Madison, WI, USA 2 Independent, Maple Valley, WA, USA 3 Wyoming Dinosaur Center, Thermopolis, WY, USA 4 School of Earth and Environmental Sciences, The University of Manchester, Manchester, UK 5 University of Wisconsin Geology Museum, University of Wisconsin-Madison, Madison, WI, USA ABSTRACT The last two decades have seen a remarkable increase in the known diversity of basal avialans and their paravian relatives. The lack of resolution in the relationships of these groups combined with attributing the behavior of specialized taxa to the base of Paraves has clouded interpretations of the origin of avialan flight. Here, we describe Hesperornithoides miessleri gen. et sp. nov., a new paravian theropod from the Morrison Formation (Late Jurassic) of Wyoming, USA, represented by a single adult or subadult specimen comprising a partial, well-preserved skull and postcranial skeleton. Limb proportions firmly establish Hesperornithoides as occupying a terrestrial, non-volant lifestyle. Our phylogenetic analysis emphasizes extensive taxonomic sampling and robust character construction, recovering the new taxon most parsimoniously as a troodontid close to Daliansaurus, Xixiasaurus, and Sinusonasus. Multiple alternative paravian topologies have similar degrees of support, but proposals of basal paravian archaeopterygids, avialan microraptorians, and Rahonavis being closer to Pygostylia than archaeopterygids or unenlagiines are strongly rejected. All parsimonious results support the hypothesis that each early paravian clade was plesiomorphically flightless, raising the possibility that avian Submitted 10 September 2018 flight originated as late as the Late Jurassic or Early Cretaceous.
    [Show full text]
  • Chapter 2 the Fossil Record of Mesozoic and Paleocene Pennaraptorans
    Chapter 2 The Fossil Record of Mesozoic and Paleocene Pennaraptorans MICHAEL PITTMAN,1 JINGMAI O’CONNOR,2 EDISON TSE,1 PETER MAKOVICKY,3 DANIEL J. FIELD,4 WAISUM MA,5 ALAN H. TURNER,6 MARK A. NORELL,7 RUI PEI,2 AND XING XU2 ABSTRACT An unabated surge of new and important discoveries continues to transform knowledge of pen- naraptoran biology and evolution amassed over the last 150+ years. This chapter summarizes prog- ress made thus far in sampling the pennaraptoran fossil record of the Mesozoic and Paleocene and proposes priority areas of attention moving forward. Oviraptorosaurians are bizarre, nonparavian pennaraptorans first discovered in North America and Mongolia within Late Cretaceous rocks in the early 20th century. We now know that oviraptorosaurians also occupied the Early Cretaceous and their unquestionable fossil record is currently limited to Laurasia. Early Cretaceous material from China preserves feathers and other soft tissues and ingested remains including gastroliths and other stomach contents, while brooding specimens and age-structured, single- species accumulations from China and Mongolia provide spectacular behavioral insights. Less specialized early oviraptorosaurians like Incisivosaurus and Microvenator remain rare, and ancestral forms expected in the Late Jurassic are yet to be discovered, although some authors have suggested Epidexipteryx and possibly other scansoriopterygids may represent early-diverging oviraptorosaurians. Long-armed scansoriopterygids from the Middle-Late Jurassic of Laurasia are either early-diverg- ing oviraptorosaurians or paravians, and some have considered them to be early-diverging avialans. Known from five (or possibly six) feathered specimens from China, only two mature individuals exist, representing these taxa. These taxa,Yi and Ambopteryx, preserve stylopod-supported wing membranes that are the only known alternative to the feathered, muscular wings that had been exclusively associated with dinosaurian flight.
    [Show full text]