uu.seUppsala University Publications
Change search
Refine search result
4567 301 - 348 of 348
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 301.
    Zigaite, Zivile
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Vilnius University.
    A new thelodont from Lower Silurian of Tuva and north-west Mongolia2004In: Acta Universitatis Latviensis - Earth and Environmental Sciences, ISSN 1407-2157, p. 158-165Article in journal (Refereed)
  • 302.
    Zigaite, Zivile
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Endemic thelodonts (Vertebrata: Thelodonti) from the Lower Silurian of central Asia and southern Siberia2013In: Earth and environmental science transactions of the Royal Society of Edinburgh, ISSN 1755-6910, E-ISSN 1755-6929, Vol. 104, no 2, p. 123-143Article in journal (Refereed)
    Abstract [en]

    New fossil vertebrate microremains from the Lower Silurian of NW Mongolia, Tuva and S Siberia have been discovered, and previous collections of thelodonts (Vertebrata: Thelodonti) from this region re-studied, figured and described, following recent advances in morphology and systematics of thelodont scales. As a result, six thelodont species are described here and attributed to two families and three genera. An emended diagnosis is given for each species. Morpohological scale varieties of each species are revised, and the squamation types are introduced to the species descriptions, resulting in newly grouped morphological sets of scales. The previously monotypic genus Talimaalepis Zigaite, 2004, is proposed to contain two different species; therefore, two new combinations of morphological scale sets of two species are described for the first time. Both of them show transitional scale structure between the genera Loganellia (family Loganellidae) and Helenolepis (family Phlebolepididae). Two of the thelodont genera, Angaralepis and Talimaalepis, as well as all the six species, are endemic and not known anywhere else in the world. They are accompanied by a variety of other peculiar early vertebrates, such as mongolepids, two endemic genera of acanthodians, and putative galeaspids. This work enhances our knowledge of early Silurian vertebrate diversity, and provides evidence of regional palaeoenvironmental conditions and palaeogeographical relationships of the Siberia and Tuva terranes.

  • 303.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blieck, Alain
    University Lille 1, France.
    Palaeobiogeography of Early Palaeozoic vertebrates2013In: Early Palaeozoic Biogeography and Palaeogeography / [ed] Harper, DAT; Servais, T, London, 2013, Vol. 38, p. 449-460Conference paper (Refereed)
    Abstract [en]

    The oldest known Palaeozoic vertebrate record currently is Early Cambrian in age. The first taxa with mineralized exoskeletons are at least Ordovician in age, followed by a sporadic fossil record with Talimaa’s Gap of c. 3 myr in the Rhuddanian (earliest Silurian). Ordovician and Silurian vertebrate faunas are dominated by ‘agnathans’. Early Palaeozoic vertebrates occupied a wide range of environments: nearshore marine to restricted marine in the Ordovician, and on the marine epicontinental shelves of the Silurian. Silurian vertebrates are useful biostratigraphical indicators, as well as good markers of palaeocontinental margins. Two main palaeobiogeographical units are renamed for the Ordovician: a Gondwana Realm and a Laurentia–Siberia–Baltica Realm. Vertebrate fossil localities are more numerous in the Silurian; therefore a series of palaeobiogeographical provinces and realms are defined on Laurentia, Baltica, Avalonia, Siberia, South China and East Gondwana. More discoveries of Silurian vertebrate-bearing localities should certainly help to define additional provinces, in particular along the northern margins of Gondwana and in SE Asia.

  • 304.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blieck, Alain
    University of Lille-1.
    Palaeobiogeography of Early Palaeozoic vertebrates2013In: Geological Society Memoir, ISSN 0435-4052, E-ISSN 2041-4722, Vol. 38, no 1, p. 449-460Article in journal (Refereed)
    Abstract [en]

    The oldest known Palaeozoic vertebrate record currently is Early Cambrian in age. The first taxa with mineralized exoskeletons are at least Ordovician in age, followed by a sporadic fossil record with Talimaa's Gap of c. 3 myr in the Rhuddanian (earliest Silurian). Ordovician and Silurian vertebrate faunas are dominated by 'agnathans'. Early Palaeozoic vertebrates occupied a wide range of environments: nearshore marine to restricted marine in the Ordovician, and on the marine epicontinental shelves of the Silurian. Silurian vertebrates are useful biostratigraphical indicators, as well as good markers of palaeocontinental margins. Two main palaeobiogeographical units are renamed for the Ordovician: a Gondwana Realm and a Laurentia-Siberia-Baltica Realm. Vertebrate fossil localities are more numerous in the Silurian; therefore a series of palaeobiogeographical provinces and realms are defined on Laurentia, Baltica, Avalonia, Siberia, South China and East Gondwana. More discoveries of Silurian vertebrate-bearing localities should certainly help to define additional provinces, in particular along the northern margins of Gondwana and in SE Asia.© The Geological Society of London 2013.

  • 305.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Goujet, Daniel
    Thelodont biostratigraphy indicates the extension of the Lower-Middle Devonian palaeobasin in Svalbard, Norvegian Arctics2012In: Geophysical Research Abstracts, 2012, p. EGU2012-10028-Conference paper (Other academic)
  • 306.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Perez-Huerta, Alberto
    University of Alabama.
    Goujet, Daniel
    Museum nationale d'histoire naturelle Paris.
    Vertebrate microfossils as tool in stratigraphy: a study of the Lower Devonian Andree Land Group, Spitsbergen2014In: STRATI 2013: First International Congress on Stratigraphy At the Cutting Edge of Stratigraphy, Cham: Springer International Publishing , 2014, p. 1167-1171Conference paper (Refereed)
  • 307.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Pérez-Huerta, Alberto
    University of Alabama.
    Goujet, Daniel
    Muséum national d'histoire naturelle.
    Vertebrate Microfossils as Tools in Stratigraphy: A Study of the LowerDevonian Andrée Land Group Spitsbergen2014In: Springer Geology, p. 1167-1171Article in journal (Refereed)
    Abstract [en]

    We have studied vertebrate microremains from the Lower to Middle Devonian of the Andrée Land Group, comprising the Wood Bay and Grey Hoek formations. We have defined two new thelodont assemblages, which represent different depositional phases during the late Early to early Middle Devonian formation of the Andrée Land Group. The definition of these two new thelodont assemblages allows us to precisely establish the relative ages of the Lower–Middle Devonian strata. Rare earth element (REE) abundances were measured in a number of thelodont and chondrichthyan microfossil dental tissue biominerals, using laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS). The evaluation of fossil preservation level was performed using semiquantitative spot-geochemistry analyses on finely polished thelodont scale thin-sections using Energy Dispersive X-ray Spectroscopy (EDS), and Electron Backscattering Diffractometry (EBSD) was applied to detect recrystallization. Stable oxygen isotope measurements (δ18O) of bulk biominerals were conducted in parallel, and showed lower heavy oxygen values in the fossil tissues with stronger visible alteration, such as those from the Grey Hoek Formation. Our results suggest that certain lithostratigraphic units of the Andrée Land Group must be regarded as contemporaneous lithofacies subjected to different sedimentary environments, rather than as separate stratigraphic members.

  • 308.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Fadel, Alexander
    University of Lille-1.
    Qvarnström, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama.
    Jeffries, Teresa
    London Natural History Museum.
    Early vertebrate microremains as proxies to palaeoenvironment: rare earth elements in dermal scale biominerals from the Silurian and Lower Devonian2016In: Thansactions of the Society of Micropalaeontology, 2016Conference paper (Other academic)
  • 309.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Fadel, Alexander
    University of Lille-1.
    Qvarnström, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Pérez-Huerta, Alberto
    University of Alabama.
    Jeffries, Teresa
    London Natural History Museum.
    Early vertebrate microremains as proxies to palaeornvironment :: rare earth elements ind ermal scale biominerals from the Silurian and Lower Devonian2018In: Résumés de la 26-eme RST 2018, 2018, Vol. 3, p. 301-301Conference paper (Refereed)
  • 310.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Fadel, Alexandre
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Perez-Huerta, Alberto
    Jeffries, Teresa
    Maerss, Tiiu
    Ahlberg, Per Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Rare earth elements (REEs) in vertebrate microremains from the upper Pridoli Ohesaare beds of Saaremaa Island, Estonia: geochemical clues to palaeoenvironment2015In: Estonian journal of earth sciences, ISSN 1736-4728, E-ISSN 1736-7557, Vol. 64, no 1, p. 115-120Article in journal (Refereed)
    Abstract [en]

    Rare earth element (REE) compositions of Nostolepis sp. scales, spines, plates and tesserae from Ohesaare bone beds were measured by in situ microsampling using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The obtained REE concentrations, normalized to Post-Archean Australian Shale concentrations, were evaluated using basic geochemical calculations and quantifications. The REE compositions were nearly identical across all the morphotypes and histologies of Nostolepis microremains, showing flat REE patterns with slight depletion in heavy REEs. There was no visible enrichment in middle REEs, indicating good geochemical preservation of bioapatite and absence of any pronounced fractionated REE incorporation during later stages of diagenesis. The shale-normalized (La/Yb)(SN) and (La/Sm)(SN) REE ratio compilations indicated adsorption as the dominating REE uptake mechanism across all datapoints. The absence of well-defmed Ce anomaly suggested oxic palaeoseawater conditions, which agrees with the existing interpretations of the Ohesaare sequence as high-energy shoal and regressive open ocean sedimentary environments.

  • 311.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Fadel, Alexandre
    Universite Lille-1.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Perez-Huerta, Alberto
    University of Alabama.
    Jeffries, Teressa
    Natural History Museum London.
    Ahlberg, Per Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Rare earth and trace elements in fossil vertebrate biomineral as indicators of palaeoecology and palaeoenvironment2014In: 4th Annual Meeting of IGCP 591 The Early to Middle Paleozoic Revolution Estonia, 10-19 June 2014Abstracts & Field Guide, 2014, p. 105-105Conference paper (Refereed)
  • 312.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Fadel, Alexandre
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Univ Lille 1, CNRS UMR8217, Lab Geosyst, F-59655 Villeneuve Dascq, France.
    Perez-Huerta, Alberto
    Univ Alabama, Dept Geol Sci, 2018 Bevill Bldg, Tuscaloosa, AL 35487 USA.
    Jeffries, Teresa
    Dept Earth Sci, Nat Hist Museum, Cromwell Rd, London SW7 5BD, England.
    Goujet, Daniel
    Museum Natl Hist Nat, Dept Hist Terre, Lab Paleontol, UMR CNRS 7207, 57 Rue Cuvier, F-75231 Paris 5, France.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Palaeoenvironments revealed by rare-earth element systematics in vertebrate bioapatite from the Lower Devonian of Svalbard2016In: Canadian journal of earth sciences (Print), ISSN 0008-4077, E-ISSN 1480-3313, Vol. 53, no 8, p. 788-794Article in journal (Refereed)
    Abstract [en]

    In situ rare-earth element (REE) compositions have been measured in early vertebrate microremains from the Lower Devonian basin of Andree Land (Svalbard), with the aim of obtaining information about their early depositional environment and potential reworking. Vertebrate microremains with different histology were used for the analyses, sourced from two different localities of marginal marine to freshwater sediments from geographically distant parts of the Grey Hoek Formation (Skamdalen and Tavlefjellet members). We selected thelodont and undescribed ? chondrichthyan scales, which allowed us to define potential taxonomic, histological, and taphonomic variables of the REE uptake. Results showed REE concentrations to be relatively uniform within the scales of each taxon, but apparent discrepancies were visible between the studied localities and separate taxa. The compilation of REE abundance patterns as well as REE ratios have revealed that thelodont and ? chondrichthyan originating from the same locality must have had different burial and early diagenetic histories. The shapes of the REE profiles, together with the presence and absence of the Eu and Ce anomalies, equally suggested different depositional and diagenetic environments for these two sympatric taxa resulting from either stratigraphical or long-distance reworking. The REE concentrations appear to have visible differences between separate dental tissues, particularly between enameloid and dentine of thelodonts, emphasizing the importance of in situ measurements in microfossil biomineral geochemistry.

  • 313.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Goujet, Daniel
    Museum National Histoire Naturelle.
    New observations on the squamation patterns of articulated specimens of Loganellia scotica (Traquair, 1898) (Vertebrata: Thelodonti) from the Lower Silurian of Scotland2012In: Geodiversitas, ISSN 1280-9659, E-ISSN 1638-9395, Vol. 34, no 2, p. 253-270Article in journal (Refereed)
    Abstract [en]

    Articulated squamations of Loganellia scotica (Traquair, 1898) from the Lower Silurian Lesmahagow inliers of southern Scotland have been studied. They include seven articulated specimens, three of them representing complete thelodont fossils, and four partially preserved postpectoral, precaudal and caudal parrs of the exoskeleton. All the five main types of thelodont scales that is rostral, cephalo-pectoral, postpectoral, precaudal and pinnal sacles, as well as respective squamation patterns have been observed on articulated specimens. The specific orbital, branchial, and bucco-pharyngeal scales, characteristic of L. scotica, have not been found due to the poor or non-preservation of these particular areas within the specimens studied. Tail morphology and squamation pattern of the caudal fin have been studied with particular attention, and the constitution of the caudal fin rays has been analyzed. The rostral squamation pattern is argued to be characteristic to L. scotico.

  • 314.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jeffries, Teresa
    London Natural History Museum.
    Qvarnström, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama.
    Distribution histologique des terres rares (REE) dans des microrestes de vertébrés du Paléozoique Inférieur2016Conference paper (Refereed)
  • 315.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Karatajute-Talimaa, Valentina
    Vilnius University.
    Aspidin or galeaspidin: new early vertebrate histology from the Lower Silurian of Southern Siberia2011In: Program and Abstracts: 71st Annual Meeting Society of Vertebrate Paleontology, 2011, p. Sec1: 221-Conference paper (Refereed)
  • 316.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Karatajute-Talimaa, Valentina
    Vilnius University.
    Goujet, Daniel
    Museum national d'histoire naturelle.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Thelodont scales from the Lower and Middle Devonian Andree Land Group, Spitsbergen2013In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 135, no 1, p. 57-73Article in journal (Refereed)
    Abstract [en]

    Scales of six thelodont taxa are described from the Devonian of Spitsbergen. Numerous samples from localities widely dispersed on Spitsbergen yield several assemblages considered to represent different depositional phases of the late Lower lower Middle Devonian of the Andrée Land Group, but also support the view that certain lithostratigraphic units of the Andrée Land Group should be regarded as contemporaneous lithofacies subjected to different sedimentary environments, rather than as separate stratigraphic members. The description of Woodfjordia collisa gen. et sp. nov., Talivalia svalbardia sp. nov., Canonia cf. C. grossi, Amaltheolepis montiwatsonia sp. nov., Amaltheolepis winsnesi and Amaltheolepis austfjordia sp. nov. also allows for a comparison with similar faunas from other regions of the Northern Hemisphere and motivates further elaboration of Early-Middle Devonian thelodont biostratigraphy.

  • 317.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Karatajute-Talimaa, Valentina
    Vilnius University.
    Joachimski, Michael M.
    University of Erlangen Nuremberg.
    Jeffries, Teresa
    London Natural History Museum.
    Silurian vertebrates from northern Mongolia:: diversity, ecology and environment2014Conference paper (Refereed)
  • 318.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Kear, Ben
    Pérez-Huerta, P
    Jeffries, T, T
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    REE compositions in fossil vertebrate dental tissues indicate biomineral preservation2012In: Geophysical Research Abstracts, 2012, p. EGU2012-9873-Conference paper (Other academic)
  • 319.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Kear, Benjamin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Joachimski, Michael M.
    University of Erlangen-Nuremberg.
    Tutken, Thomas
    University of Bonn.
    Whitehouse, Martin
    Naturhistoriska Riksmuseet.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Geochemistry of dental bioapatite, the key to palaeoclimate2013In: Proceedings of the 3rd IGCP 591 Annual Meeting, Lund, Sweden, 9-19 June 2013 / [ed] Anders Lindskog and Kristina Mehlqvist, Lund: Department of Geology, Lund University , 2013, p. 361-362Conference paper (Refereed)
  • 320.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Kear, Benjamin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Perez-Huerta, Alberto
    University of Alabama.
    Jeffries, Teresa
    Natural History Museum.
    Do fossil vertebrate biominerals hold the key to Palaeozoic climate?2012Conference paper (Refereed)
    Abstract [en]

    Fossil vertebrate hard tissues - teeth and dermoskeleton - are considered among the most geochemically stable biominerals, and therefore are widely used for palaeoenvironmental and palaeoclimatic reconstructions. Elemental and isotopic compositions of fossil dental tissues may provide unique palaeoenvironmental information, ranging from the diet and trophic positions on a food chain, to the palaeosalinity and water temperatures of ancient seas. However, before starting any geochemical interpretations, the preservation potential of fossil tissues must be studied carefully, considering possible alteration of the primary geochemical composition. Evaluation of fossil hard tissue preservation can be made by semiquantitative spot geochemistry analyses on fine polished teeth and scale thin sections using Energy Dispersive X-ray Spectroscopy (EDS), and help to roughly preview the chemical composition. The Electron Backscatter Diffractometry (EBSD) is useful to examine the cristallinity and possible structural alterations. In addition, rare earth element (REE) abundances can be measured in situ within the fine fossil tissues (such as enamel vs. dentine) using Laser Ablation Inductively Coupled Plasma Mass-spectrometry (LA-ICP-MS), and give us information about the selective geochemical resilience between separate vertebrate hard tissues. To conclude, in order to decipher the geochemical signal of fossil biominerals correctly, the evaluation of preservation should be the starting point to any further geochemical studies.

  • 321.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Kear, Benjamin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Tütken, Thomas
    University of Mainz.
    Whitehouse, Martin
    Naturhistoriska Riksmuseet Stockholm.
    Joachimski, Michael M
    University of Erlangen-Nuremberg.
    Jeffries, Teresa
    London Natural History Museum.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Oxygen isotope records in fossil bioapatite reveal sothern high-latitude low-temperature environment during the Early Cretaceous2014In: Résumés dela 24e Réunion des Sciences de la Terre Abstracts, 2014, p. 257-257Conference paper (Refereed)
  • 322.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Perez-Huerta, Alberto
    University of Alabama.
    Jeffries, Teresa
    Natural History Museum.
    Kear, Benjamin P
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Geochemistry of fossilised dental remains - key to palaeobiology and palaeoenvironment.2013In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 135, no 1, p. 25-Article in journal (Refereed)
  • 323.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama.
    Fadel, Alexander
    University of Lille-1.
    Jeffries, Teresa
    London Natural History Museum.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Goujet, Daniel
    Muséum national d'histoire naturelle.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Andrée Land of Spitsbergen:: Devonian vertebrate diversity and palaeoenvironments2018Conference paper (Refereed)
  • 324.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama.
    Jeffries, Teresa
    London Matural History Museum.
    Joachimski, Michael M.
    University of Erlangen Nuremberg.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Märss, Tiiu
    Tallinn University of Technology.
    Ahlberg, Per E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Palaeoenvironmental signatures revealed from the Silurian dental apatite :: rare earth element and stable isotope record2015Conference paper (Refereed)
  • 325.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Richter, Martha
    Natural History Museum.
    Karatajute-Talimaa, Valentina
    Vilnius University.
    Meredith Smith, Moya
    King's College London, Dental Institute.
    Tissue diversity and evolutionary trends of the dermal skeleton of Silurian thelodonts2013In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 25, no 2, p. 143-154Article in journal (Refereed)
    Abstract [en]

    Previously described scale morphotypes of Silurian thelodonts, constrained by their representation as isolated dermaldenticles are reassessed to provide a more robust character basis for their inclusion in future phylogenetic studies. Asrelatively common microfossils, thelodonts are important biostratigraphical markers, but their interrelationships withgeologically younger species known by complete skeletons are still unresolved. We examined scales of 21 knownmorphotypes from north-eastern Europe, Siberia and central Asia and described their distinct tissue arrangementsconsidering (1) thickness and direction of dentine tubules, (2) presence or absence of a pulp canal, (3) number and positionof pulp canals, (4) the presence or absence of a distinct outer crown layer and (5) the extent of Sharpey’s fibres penetratingthe scale base. We correlated the traditional thelodont scale type morphologies with these distinct scale histologies, as foundin Silurian thelodonts. In addition, a new histological type for thelodont scales, the Talimaalepis type, is described torepresent a new taxon, from the Early-Mid Silurian. Our study suggests that, through time, there is a general trend ofincreasing complexity in thelodont dermal tissue structures. Three types of dentine and internal scale organisations weredistinguished in Silurian species studied, namely (1) irregular, thin tubular dentine; (2) irregular, thick tubular dentine, withtwo subtypes as a function of pulp canal development and (3) regular, tubular dentine (orthodentine).

  • 326.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Sansom, Ivan
    University of Birmingham.
    Whitehouse, Martin
    Naturhistoriska riksmuseet.
    Boomer, Ian
    University of Birmingham.
    Stable oxygen isotope compositions in shark enameloid as a proxy to seawater chemistry2013In: Proceedings of the 3rd IGCP 591 Annual Meeting, Lund, Sweden, 9-19 June 2013 / [ed] Anders Lindskog and Kristina Mehlqvist, Lund: Department of Geology, Lund University , 2013, p. 363-364Conference paper (Refereed)
  • 327.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Sansom, Ivan
    Whitehouse, Martin
    Naturhistoriska riksmuseet Stockholm.
    Joachimski, Michael M.
    University of Erlangen-Nuremberg.
    Stable isotope compositions in shark dental tissues as a proxy to seawater chemistry2013In: The Palaeontological Association Newsletter ISSN 0954-9900 / [ed] Christian Klug, 2013Conference paper (Other academic)
  • 328.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Whitehouse, Martin
    Stable oxygen isotopes of dental biomineral: differentiation at the intra- and inter-tissue level of modern shark teeth2014In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 136, no 1, p. 337-340Article in journal (Refereed)
    Abstract [en]

    In situ oxygen isotopic composition of the sandbar shark (Carcharhinus plumbeus) teeth grown at a constant water temperature and salinity were analysed by high precision and high spatialresolution secondary ion mass spectrometry, targeting dental biomineral within the parallel-bundled enameloid (PBE), the tangle-bundled enameloid (TBE) and the dentine. Measured O-18 values had comparable inter-tissue variability in each tooth analysed. The PBE enameloid had the smallest scatter of oxygen isotope ratios, while the TBE enameloid had slightly higher intra-tissue variation of O-18, but similar average values. The dentine had largest variability and lower average O-18. The enameloid of shark teeth is therefore recommended as a target biomineral and a preferential biogeochemical reference for environmental and palaeoenvironmental studies.

  • 329.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Whitehouse, Martin
    Naturhistoriska Riksmuseet Stockholm.
    Joachimski, Michael M.
    University of Erlangen Nuremberg.
    Sansom, Ivan
    University of Birmingham.
    δ18O as Seawater and Palaeoclimate Proxy: Results of in-situ SIMS in Modern Shark and ray Dental Apatite2017Conference paper (Refereed)
  • 330.
    Zigaite, Zivile
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Whitehouse, Martin
    Naturhistoriska Riksmuseet Stockholm.
    Joachimski, Michael M.
    University of Erlangen Nuremberg.
    Sansom, Ivan
    University of Birmingham.
    Ahlberg, Per Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Oxygen isotopes in modern and fossil ecosystems: model and case study overview2016Conference paper (Other academic)
  • 331. Zyla, Dagmara
    et al.
    Wegierek, Piotr
    Owocki, Krzysztof
    Niedzwiedzki, Grzegorz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Insects and crustaceans from the latest Early-early Middle Triassic of Poland2013In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 371, p. 136-144Article in journal (Refereed)
    Abstract [en]

    Two stratigraphical horizons in the Palegi clay-pit, a new Triassic paleontological site within Buntsandstein deposits (latest Olenekian-early Anisian in age) in the Holy Cross Mountains (Poland), have yielded arthropod faunas comprising ca. 400 fossil specimens assigned to two subphyla: Crustacea (class Branchiopoda and Maxillopoda) and Hexapoda (class Insecta). The Palegi arthropod assemblage is similar to that described from the Middle Triassic of France and Germany but is dominated by remains of conchostracans and cockroaches. This new fauna expands our knowledge of the latest Early-early Middle Triassic diversity of insects and freshwater arthropods in the Germanic Basin. The newly discovered fauna represents one of the oldest Mesozoic records of insects described from the Buntsandstein fades of Europe, and provides important information to better appreciate the process of ecosystem recovery after the Permian-Triassic extinction.

  • 332.
    Ödeen, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Animal Ecology.
    Pruett-Jones, Stephen
    Driskell, Amy C.
    Armenta, Jessica K.
    Håstad, Olle
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Multiple shifts between violet and ultraviolet vision in a family of passerine birds with associated changes in plumage coloration2012In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 279, no 1732, p. 1269-1276Article in journal (Refereed)
    Abstract [en]

    Colour vision in diurnal birds falls into two discrete classes, signified by the spectral sensitivity of the violet- (VS) or ultraviolet-sensitive (UVS) short wavelength-sensitive type 1 (SWS1) single cone. Shifts between sensitivity classes are rare; three or four are believed to have happened in the course of avian evolution, one forming UVS higher passerines. Such shifts probably affect the expression of shortwave-dominated plumage signals. We have used genomic DNA sequencing to determine VS or UVS affinity in fairy-wrens and allies, Maluridae, a large passerine family basal to the known UVS taxa. We have also spectrophotometrically analysed male plumage coloration as perceived by the VS and UVS vision systems. Contrary to any other investigated avian genus, Malurus (fairy-wrens) contains species with amino acid residues typical of either VS or UVS cone opsins. Three bowerbird species (Ptilonorhynchidae) sequenced for outgroup comparison carry VS opsin genes. Phylogenetic reconstructions render one UVS gain followed by one or more losses as the most plausible evolutionary scenario. The evolution of avian ultraviolet sensitivity is hence more complex, as a single shift no longer explains its distribution in Passeriformes. Character correlation analysis proposes that UVS vision is associated with shortwave-reflecting plumage, which is widespread in Maluridae.

  • 333.
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Edwardsiella carnea (Gosse, 1856) (Cnidaria, Actiniaria, Edwardsiidae), the presumed adult sea anemone to the parasitic planula of the comb jelly Mnemiopsis leidyi (Ctenophora)2014Conference paper (Refereed)
    Abstract [en]

    The American comb jelly Mnemiopsis leidyi occurred for the first time at the Swedish West Coast, 2006.  Thereafter huge numbers of Mnemiopsis invaded the water around Bohuslän, Sweden. In September 2009 Mnemiopsis appeared in the Gullmar Fjord with up to 500 individuals per liter water, juveniles included. M. leidyi reduced the copepod population in the Gullmar Fjord drastically with more than 90 %. Inside the bells of some M. leidyi a planula was attached nearby the host stomodeum. The planula is a parasite and feed directly from the contents of the stomodeum of M. leidyi. Supposedly the planula belongs to an Edwardsiid anemone from Skagerrak, presumably Edwardsiella carnea (Gosse, 1856.

    M. leidyi was not found in the waters around the Swedish West Coast during the years 2011 and 2012. Since the parasitic planula could not be collected these years, its morphology and cnidom is thus not record in this article. When M. leidyi, infected with the parasitic planula, again invades our waters, hopefully, we might be able to correlate the cnidom of the planula with the cnidom of its adult anemone, the presumed Edwardsiella carnea (Gosse, 1856) from Skagerrak.

    The aim of this study is to describe the morphology and cnidom of the adult Edwardsiid anemone, the presumed Ella. carnea collected from Skagerrak, and to determine its taxonomy down to species level. Its morphology and cnidom correspond to the descriptions of Milne-Edwardsia carnea (Goose, 1856) Carlgren, 1892 (Carlgren 1921) and of Favesia (Milne-Edwardsia) carnea (Goose, 1856) (Carlgren, 1940). The anemone has eight mesenterial compartments (macrocoels) and belongs the family Edwardsiidae Andres, 1881, and to the genus Edwardsiella Andres, 1883 due to lack nemathybomes (nematocyst-filled pockets along the mesenteries).  Ella. carnea appeared in 2 color morphs, one reddish and one lighter colored, partly translucent. Disturbed  Ella. carnea will quickly and completely retract into its surrounding tube. The elongate column is differentiated into: oral disc with tentacle crown, mouth and hypostome; capitulum, the introvert, basally with a ring of yellow blotches, one blotch on each mesenterial compartment; scapus, partly hidden in the tube; and physa, the broader rounded aboral region completely inside the tube. The tentacle crown has 17 or 18 delicate, filiform tentacles arranged in 2-3 cycles. Tentacles of the inner cycle are slightly longer than those of the outer cycle. The cnidom includes broad microbasic b-mastigophores; narrow microbasic b-mastigophores; microbasic p-mastigophores; thin, long basitrichs; and spirocysts. Medium b-mastigophores are the dominating nematocysts.

    The nematocyst descriptions together with the morphology made by Carlgren (1921, 1940) of Milne-Edwardsia carnea (Gosse) and of Favesia (Milne-Edwardsia) carnea (Gosse 1856) have convinced us that our Edwardsiid from Skagerrak is Edwardsiella carnea (Gosse, 1856). We are now eager to study the cnidom of the parasitic planula in Mnemiopsis leidyi, when it again appears on the Swedish west coast to see if the planula belongs to Ella. carnea.

  • 334.
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Nematocysts comparisons within some Hydrozoans, Scyphozoans and Anthozoans2015Conference paper (Refereed)
    Abstract [en]

    The largest nematocyst diversity occurs within Hydrozoa and the smallest diversity in Anthozoa. Isorhizas, present in Hydrozoa, Scyphozoa and Anthozoa, are the most diverse nematocyst group.  The functions of the isorhizas, their capsule shape and size, and their spine pattern can be similar or different within the three major taxonomic groups. As a rule, the more toxic nematocysts are larger than the less toxic ones. Generally, cnidarians feeding on large prey have larger, more toxic penetrating nematocysts with coarser and more pointed spines than animals feeding on small prey. The potent penetrating isorhizas with spherical capsules and hook-shaped spines along the tubule are larger in Physalia pelagica and Uvaria spp (Siphonophora, Hydrozoa) and in Cyanea capillata (Scyphozoa) compared to the smaller spherical isorhizas in the less toxic Aurelia aurita (Scyphozoa) and Tubularia spp (Hydrozoa). Cothylorhiza tuberculata and Casiopea xamancha (Scyphozoa) have still smaller spherical nematocysts. In addition to feeding on small zooplankton these two jellyfishes also get nutrition from symbiotic zooxanthellae. Spherical penetrating isorhiza are not present in Anthozoa. Penetrating isorhizas, specific for Anthozoa, have broad oval to narrow elongate capsules. Many penetrating isorhizas in Hydrozoa have also oval to elongated capsule but they differ in capsule shape and tubule pattern from those of Anthozoa. The largest isorhizas within C. capillata are not penetrators. These isorhizas entangle the prey with their long distal tubules armed with weak spines. Oval and elongated isorhizas, present in the cold water coral Lophelia pertusa and in the anemone Edwardsiella carnea (Anthozoa), might be used as primary attachment at settling for their larvae.  Entangling desmonemes, present in Tubularia spp, Halocordyle disticha and Hydractinia echinata, are specific for Hydrozoa. Other nematocysts, specific only in one of the three major taxonomic groups are the penetrating birophaloids in Siphonophores and stenoteles in Tubularia spp (Hydrozoa), and the penetrating b- and p-mastigophores and p-amastigophores in Anthozoa. The penetrating euryteles in H. echinata (Hydrozoa) are also present in Cyanea spp and A. aurita (Scyphozoa). 

  • 335.
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Larsson, Ann
    The cnidome and ultrastructural morphology of late planulae in Lophelia pertusa (Linnaeus, 1758) - with implications for settling competency2019In: Acta Zoologica (Stockholm), ISSN 0001-7272, E-ISSN 1463-6395, Vol. 00, p. 1-20Article in journal (Refereed)
  • 336.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Borg, Fredrik
    Roat, Carsten
    Kultima, Jens Roat
    Wong, Sau Yu Grace
    Cnidae in the sea anemone Sagartiogeton viduatus (Muller, 1776) (Cnidaria, Anthozoa); A comparison to cnidae in the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria, Anthozoa)2013In: Acta Zoologica (Stockholm), ISSN 0001-7272, E-ISSN 1463-6395, Vol. 94, no 4, p. 392-409Article in journal (Refereed)
    Abstract [en]

    The cnidom of the sea anemone Sagartiogeton viduatus (Muller, 1776) is described from interference-contrast light micrographs (LMs) and scanning electron micrographs (SEMs). Special attention is given to nematocyst maturation, including the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Comparisons are made with Metridium senile (Linnaeus, 1761), whose cnidom, with a few exceptions, is closely similar to that of S.viduatus. The two anemones possess b- and p-mastigophores, p-amastigophores, isorhizas and spirocysts. Although the majority of cnidae in S.viduatus is smaller than corresponding ones in M.senile, they are grouped into the same size classes as those of M.senile, namely small, medium and large. The main differences from M.senile cnidae are the followings: (1) Large acontia p-amastigophores are the largest nematocysts in S.viduatus. (2) They are noticeably larger than the large acontia b-mastigophores, and (3) they are separated from the p-amastigophores of M.senile by the sinusoid pattern of their U-shaped capsular matrix. (4) The large acontia b-mastigophores are microbasic and not mesobasic as in M.Senile, and (5) they do not produce darts. (6) Another difference from M.senile is the absence of catch-tentacle isorhizas.

  • 337.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Friis Moller, Lene
    Sven Loven Marina Centrum, Göteborgs Universitet.
    Edwardsiella carnea (Gosse,1856) (Cnidaria, Actiniaria), the presumed adult seaanemone to the parasitic planula of the comb jelly Mnemiopsis leidy (Cnenophora)2013Conference paper (Other academic)
  • 338.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Govindarajan, Annette
    Källström, Björn
    Selander, Erik
    Dahlgren, Thomas
    The highly toxic and cryptogenic clinging jellyfish Gonionemus sp. (Hydrozoa, Limnomedusae) on the Swedish west coast2019In: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, p. 1-18Article in journal (Refereed)
  • 339.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Gustavsson, Frida
    Sea anemone nematocysts stored and transported in cnidosacs and cnidophage cells in nudibranchs2014In: A variety of interactions in marine environment: abstracts volume from 49th European Marine Biology Symposium, 2014, p. 100-101Conference paper (Other academic)
    Abstract [en]

    Abstract

    The nudibranchs Aeolidia papillosa (Linnaeus, 1759) and Aeolidiella glauca (Alder and Hancock, 1845) were fed with the sea anemones Metridium senile (Linnaeus, 1759) and the small anemone Sagartiogeton viduatus (Muller, 1776). Aeolid nudibranchs are known for storing nematocysts for self-defence from cnidarian preys in their numerous dorsal papillae or cerata. The nudibranchs possess a specific sorting mechanism to sequester these nematocysts. In each cerata tip a divertriculum of the gut opens into a cnidosac. Unfired nematocysts are stored in cnidophage cells inside the cnidosacs. One, two, three or more anemone nematocysts, of the same or of different types, could be present inside one cnidophage. Cnidophages, filled with nematocysts, were pressed out through the cnidosac pore. A. glauca and A. papillosa seemed to have a certain preference to store the most potent, large penetrating nematocysts; the large and medium p-amastigophores. They were relatively more numerous in some cnidosacs than in the anemones. Large p-amastigophores were often more abundant than large b-mastigophores, the most common acontia nematocysts.  Small nematocysts were more abundant in the nudibranch faeces compared to in the cnidosacs. The adhesive spirocysts, which are not useful for self-defence for the nudibranchs, were not found in the cnidosacs or in the cnidophages. Spirocysts were ejected with the faeces. Stored nematocysts might partly mirror which anemone structure the nudibranch had eaten. The larger nematocysts, from the acontia of the anemones, dominated in many cnidophage cells. Expect for in the acontia, medium b-mastigophores were the most common sea anemone nematocysts. In some cnidosacs medium b-mastigophores were the most abundant nematocysts. A. glauca cnidophages had the structure of an elongate bag, with an opening apically, through which nematocysts were ejected. The cnidophages were parallel oriented, with their apical end towards the longitudinal centre of the cnidosacs.  In its broad base a large nucleus and cytoplasm were present. The cnidophage narrowed from its broad base towards its apical end.  Inside the cnidophages the elongate, mostly closely packed anemone nematocysts were parallel oriented.  Their openings pointed all towards the apical cnidophage end with the opening. A. glauca cnidophages were slightly longer than the longest nematocysts of the favorite prey of the nudibranch, the S. viduatus anemone.  Large M. senile nematocysts, too long to fit inside the cnidophages of A. glauca, were ejected with the nudibranch faeces.  In light squash preparations of A. papillosa cerata, narrow strings of undamaged cnidophages could be pressed out of the cnidosac. A. papillosa cnidophages varied in size and shape, and the number of their stored nematocysts varied from 1- 5 up to 15-20.  No opening was visible in the apical cnidophage cell. Basally, the large nucleus and some cytoplasm were visible.  Inside the larger, most common cnidophages, nematocysts were closely packed, and their number was not possible to count, as long as the cnidophage was intact. Nematocysts too long to fit inside the smaller cnidophages had only their apical capsule ends inside the apical cnidophage. Their basal capsule ends, outside the cnidophage, were sometimes spread apart in the squash preparations.  However, the undischarged nematocyst capsules were still kept together by the apical cnidophage. The smallest cnidophages were of the size of the smallest A. papillosa nematocysts. Often they contained one single or 2-4 small nematocysts. The somewhat larger cnidophages contained 2-4, or more nematocysts of different sizes, the largest capsules with their basal end outside the cnidophage.  Empty cnidophage cells, presumably representing different developing stages, were of different sizes and irregular shapes. Some cnidophages were connected to each other. A big nucleus was visible in the cytoplasm. The cytoplasm surrounded the inner cell wall, leaving an inner canal free of substance. In mucus strings, excreted from the nudibranch anus, cnidophage cells filled with nematocysts, small packages of free nematocysts fitting in size into the cnidophages, and strings of closely packed, abundant, free nematocysts were present. Nematocysts in the packages and in the strings were parallel oriented, with their apical capsule end pointing in the same direction. In both A. glauca and A. papillosa cnidae, less useful in self-defence for the nudibranchs, were rejected with the nudibranch faeces. In some faeces discharged or undischarged spirocysts were by far the most abundant cnidae. Small nematocysts were more common in the faeces than larger nematocysts, except for the largest M. senile b-mastigophores in the faeces of A.glauca. Large p-amastigophores were rare or missing. Additional observations and conclusions: Immature nematocysts, early in development, were not found in the cnidosacs. Only a few elongate p-mastigophores, late in development, with the same capsule structure as mature ones were indentified here. Obviously most nematocysts did not complete their maturation in the cnidosacs as proposed by Grennwood and Mariscal (1984). The shape and size of the cnidophages seemed to have an important role in the transportation of nematocysts. No hydrozoan and scyphozoan nematocysts have been found in the cnidosacs. The rounded to oval size of these nematocysts might inhibit their storage in the cnidophages and cnidosacs. Hydrozoan and scyphozoan nematocysts were found in the nudibranch faeces. The sorting and rejecting mechanisms and the transportation of the nematocysts in the nudibranchs are still unknown but must be regarded as a masterpiece

    Sven Loven Marine centre, Fiskebäckskil, Sweden is acknowledged for laboratory facilities, prof. Per Ahlberg, for economic support, and Dr. Daniel Snitting for his criticism of the abstract, both from EBC, Uppsala, University Sweden.

     

  • 340.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Kultima, Jens Roat
    Roat, Carsten
    Tentacle cnidae of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria Anthozoa)2010In: Scientia Marina, ISSN 0214-8358, E-ISSN 1886-8134, Vol. 74, no 3, p. 511-521Article in journal (Refereed)
    Abstract [en]

    Tentacle cnidae of Metridium senile (Linnaeus, 1761) were examined by light microscopy. In addition to spirocysts, feeding-tentacles had 3 nematocyst categories grouped into medium and small size-classes, including 5 types. Spirocysts dominated, especially distally, followed by medium b-mastigophores. The density of cnidae decreased towards the tentacle base. Early cnidoblasts were numerous on the tentacle tip. Late cnicloblasts appeared in a moderate number on the mid-tentacle. Catch-tentacles, found in two Metridium specimens, had a maturity gradient of isorhizas and gland cells along their length. Their tip had two distinct types of mature isorhizas in great numbers and large gland cells, but lacked spirocysts. Mature isorhizas and gland cells decreased in number towards the tentacle base. On the mid-tentacle differentiating ages of isorhizas were numerous. Ordinary feeding-tentacle cnidae, abundant at the tentacle base, decreased in number distally along the tentacle.

  • 341.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Kultima, Jens Roat
    Uppsala University.
    Roat, Carsten
    Rundblom, Karl
    Uppsala University.
    Acontia and mesentery nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria Anthozoa)2010In: Scientia Marina, ISSN 0214-8358, E-ISSN 1886-8134, Vol. 74, no 3, p. 483-497Article in journal (Refereed)
    Abstract [en]

    Acontia and mesentery nematocysts of Metridium senile (Linnaeus, 1761) are described from interference-contrast light micrographs (LMs) and scanning electron micrographs (SEMs). The acontia have 2 nematocyst categories grouped into small, medium and large size-classes, including 5 types: of these, large b-mastigophores and large p-amastigophores are the largest and most abundant. Mesenterial tissues, characterised by small p-mastigophores and medium p-amastigophores, have 3 nematocyst categories grouped as small and medium, including 6 types. Attention is given to nematocyst maturation, especially to the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Groups of differentiating nematoblasts occur along acontia, and near the junction between acontia and mesenterial filaments. Nematoblasts are sparsely found throughout mesenterial tissues.

  • 342.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Kultima, Jens Roat
    Wong, Sau Yu Grace
    Dart formation in nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria Anthozoa)2010In: Scientia Marina, ISSN 0214-8358, E-ISSN 1886-8134, Vol. 74, no 3, p. 499-510Article in journal (Refereed)
    Abstract [en]

    In examining large acontia b-mastigophore and p-amastigophore nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) darts were observed by interference-contrast light microscopy (LM) and scanning electron microscopy (SEM). The darts consist of closely packed spines detached from the shafts, still in three helical rows. Their spines form a hollow cylinder with a sharp tip and indented base, its width similar to that of an undischarged shaft but varying in length. b-mastigophore darts were more common than those of p-mastigophores and many were longer.

  • 343.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Strömberg, Susanna M
    The cnidome and internal morphology of Lophelia pertusa (Linnaeus, 1758) (Cnidaria, Anthozoa)2017In: Acta Zoologica (Stockholm), ISSN 0001-7272, E-ISSN 1463-6395, Vol. 98, p. 191-213Article in journal (Refereed)
    Abstract [en]

    The cnidome of the scleractinian cold-water coral Lophelia pertusa (Linnaeus, 1758, syn. Lophohelia prolifera) was described by Carlgren in 1940. Due to a renewed interest in the cnidae of L. pertusa, specifically comparisons of adult and larval cnidae and their functions, we now redescribe the cnidome from material collected at the Tisler reef in Norway, close to Carlgren's collection site at Saekken (Sweden). Cnidae from column, tentacles, actinopharynx, mesenterial filaments and acontia were investigated. Fresh tissue preparations were compared to histological preparations of decalcified polyps to verify the presence of cnidocysts and secretory cells, and their composition and organization within tissues. The cnidome included microbasic b-mastigophores, microbasic and mesobasic p-mastigophores, holotrichous isorhizas and spirocysts. The nematocyst type cnidae (b-, p-mastigophores, isorhizas) appeared in different size classes with different distributions within the tissue. Spirocysts were highly variable in shape and size, without distinct size classes. In addition, developing stages of cnidae were documented, with new observations on the succession of p-mastigophore shaft development. The present observations were in general congruent with the cnidocyst descriptions from L. prolifera made by Carlgren; however, a tiny cnida, possibly of isorhiza type, has been added. Finally, the use of the term acontia is discussed.

  • 344.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Goujet, Daniel
    National Museum of Natural History, France.
    Karatajute-Talimaa, Valentina
    Vilnius University.
    New vertebrate assemblages from the Andrée Land Group, Spitsbergen, and their biostratigraphic significance2010In: Programme and Abstracts: The Palaeontological Association: 54th Annual Meeting 17th–20th December 2010: Ghent University, 2010, p. 80-81Conference paper (Other academic)
    Abstract [en]

    The Lower and Middle Devonian successions of Spitsbergen provide excellent examples of vertebrate biostratigraphy applied to sedimentary basin analysis. A number of previous works on the Red Bay Group (Lochkovian, Lower Devonian) made a notable study of the earliest Devonian vertebrate record, and their use in biostratigraphy. Our current study concerns the Lower to Middle Devonian of the Andrée Land Group, which comprises the Wood Bay Formation, spanning from Pragian to Emsian in age, and the Grey Hoek Formation, representing the Eifelian. It consists of thick layers of terrigenous sediments, the stratigraphy is largely based on the lithofacies.

    Two new thelodont assemblages are considered to represent different depostional phases of the late Lower - early Middle Devonian of the Andrée Land Group. The first, older assemblage comprises turiinid, talivaliid, and furcacaudid thelodonts, and identifies the lower Wood Bay Formation. The second, younger assemblage is prevailed by the talivaliid thelodont <i>Amaltheolepis winsnesi</i>, and is characteristic for the upper Wood Bay Fm., as well as the lower Grey Hoek Fm. The recognition of these two new thelodont assemblages allows us to precise the relative age of the Lower – Middle Devonian strata.

  • 345.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Karatajūtė-Talimaa, Valentina
    Blieck, Alain
    Vertebrate microremains from the Lower Silurian of Siberia and Central Asia: palaeobiodiversity and palaeobiogeography2011In: Journal of Micropalaeontology, ISSN 0262-821X, E-ISSN 2041-4978, Vol. 30, p. 97-106Article in journal (Refereed)
    Abstract [en]

    The biostratigraphic and palaeogeographical distributions of early vertebrate microfossils from a number of Lower Silurian localities in northwestern Mongolia, Tuva and southern Siberia were reviewed. Vertebrate microremains showed high taxonomic diversity, comprising acanthodians, chondrichthyans, putative galeaspids, heterostracans, mongolepids, tesakoviaspids, thelodonts and possible eriptychiids. The majority of taxa have lower stratigraphic levels of occurrence compared to other Silurian palaeobiogeographical provinces, such as the European-Russian or Canadian Arctic. Vertebrate microremains are numerous within the samples, which may indicate warm-water low-latitude palaeobasins with rich shelf faunas. This disagrees with the recent interpretations of the territory as a northern high-latitude Siberian palaeocontinent. The palaeobiogeographical distribution of vertebrate taxa indicates an endemic palaeobiogeographical province of connected epeiric palaeoseas with external isolation during the early Silurian. In previous works separation between Tuvan and Siberian palaeobiogeographical provinces has been suggested. After careful revision of the vertebrate microfossil record of the region, we find that differences in a few vertebrate taxa do not provide not strong enough evidence to reliably distinguish these provinces. We therefore dispute the hypothesis of two biogeographical provinces in the early Silurian of the Siberian palaeocontinent, and propose a single unified Siberian-Tuvan palaeobiogeographical province.

  • 346.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama, USA.
    Jeffries, Teresa
    Natural History Museum, London, UK.
    Kear, Benjamin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    REE compositions in fossil vertebrate dental tissues – key to biomineral preservation2011In: The Palaeontological Association Newsletter, 2011Conference paper (Other academic)
    Abstract [en]

    Rare earth element (REE) abundances have been measured in a number of Palaeozoic and Mesozoic vertebrate hard tissues (teeth and dermoskeleton) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Fossil vertebrate analysed comprise scales and tesserae of Silurian and Devonian thelodonts, chondrichthyans, galeaspids, mongolepids, spines of acanthodians, as well as teeth of Cretaceous lungfish and marine reptiles.

    Pre-evaluation of fossil preservation level has been made by semi-quantitative spot geochemistry analyses on fine polished teeth and scale thin sections, using energy dispersive X-ray spectroscopy (EDS). Silicification of bioapatite, together with elevated heavy element concentrations corresponded to fossil tissue structure and colour alteration. Stable oxygen isotope measurements (δ<sup>18</sup>O) of bulk biomineral have been conducted in parallel, generally yielding lower heavy oxygen values in stronger alterated teeth and scales. Clear distinction in REE concentrations was observed between dentine and enamel of Cretaceous plesiosaurs, suggesting enamel to be more geochemically resistant to diagenetic overprint.

  • 347.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    Department of Geological Sciences, University of Alabama.
    Jeffries, Teresa
    Mineralogy Department, Natural History Museum, London.
    Kear, Benjamin P
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Geochemistry of fossilised dental remains: a key to palaeobiology and palaeoenvironment2011In: Abstracts: The 2nd Wiman meeting : Carl Wiman's Legacy: 100 years of Swedish Palaeontology : Uppsala 17–18 November 2011 / [ed] Benjamin P. Kear, Michael Streng, 2011, p. 24-25Conference paper (Other academic)
  • 348.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama, USA.
    Joachimski, Michael M.
    University of Erlangen-Nürnberg.
    Lehnert, Oliver
    University of Erlangen-Nürnberg.
    The 18O/16O ratio in vertebrate biogenic apatite as a proxy to Palaeozoic seawater temperatures2011In: Geophysical Research Abstracts: Vol. 13, EGU2011-11965, Göttingen: Copernicus , 2011Conference paper (Other academic)
4567 301 - 348 of 348
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf