Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Refine search result
1234567 1 - 50 of 454
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.
  • 1.
    Abadi, Mehrdad Sardar
    et al.
    Leibniz Inst Appl Geophys, LIAG, Rock Phys & Borehole Geophys, Hannover, Germany..
    Voeten, Dennis F. A. E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Kulagina, Elena, I
    Russian Acad Sci, Ufa Fed Res Ctr, Inst Geol, Ufa, Russia..
    Boulvain, Frederic
    Univ Liege, Dept Geol, Lab Petrol Sedimentaire, Bat B20, Liege, Belgium..
    Da Silva, Anne-Christine
    Univ Liege, Dept Geol, Lab Petrol Sedimentaire, Bat B20, Liege, Belgium..
    A comment on overlooked storm sensitivity of the carbonate factory recorded in the Mississippian Mobarak Formation (Alborz Mountains, Iran)2022In: Geological Journal, ISSN 0072-1050, E-ISSN 1099-1034, Vol. 57, no 10, p. 4388-4392Article in journal (Other academic)
    Abstract [en]

    New interpretations of depositional palaeoenvironments in the Mississippian (Lower Carboniferous) Mobarak Formation (Alborz Mountains, Iran) suggest a significant and persistent influence of storms. This deviates from previous conclusions that these deposits recorded mounds, patch reefs, and extensive lagoons deposited under stagnant environmental conditions. We here clarify and discuss the origin and nature of this misconception by explaining "unexpected" observations that are informed by outdated interpretations of the depositional environment of the Mobarak Formation. This evaluation offers the context required for appropriately interpreting and correlating Mississippian depositional records across the Alborz Basin.

  • 2.
    Abbassi, Nasrollah
    et al.
    Univ Zanjan, Dept Geol, Fac Sci, Zanjan, Iran..
    Kundrat, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ataabadi, Majid Mirzaie
    Univ Zanjan, Dept Geol, Fac Sci, Zanjan, Iran..
    Ahlberg, Per E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala Univ, Sub Dept Evolut & Dev, Evolutionary Biol Ctr, Dept Organismal Biol, Uppsala, Sweden..
    Avian ichnia and other vertebrate trace fossils from the Neogene Red Beds of Tarom valley in north-western Iran2016In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 28, no 8, p. 1075-1089Article in journal (Refereed)
    Abstract [en]

    The Neogene Red Beds of the Tarom valley (north-western Iran) include conglomerate, sandstone, marl and gypsum. Avian and mammal footprints were discovered in one of the sandstone layers at the base of a third Miocene stratigraphical unit in the Gilankesheh area located in the east Tarom valley. The avian ichnia include Aviadactyla vialovi, Avipeda filiportatis, Charadriipeda disjuncta, Charadriipeda isp. A and B and cf. Ornithotarnocia lambrechti. Bird feeding traces are preserved as bilobate, loop-shaped, sinusoidal and ring-like traces. We have also identified a reticulate texture of sole scale imprints in some of the avian ichnia. Two mammal footprints of camelid-like artiodactyls are also present with the avian ichno-assemblage.

  • 3.
    Agnolin, Federico L.
    et al.
    Museo Argentino Ciencias Nat Bernardino Rivadavia, Lab Anat Comparada & Evoluc Vertebrados, Buenos Aires, DF, Argentina.; Univ Maimonides, CEBBAD, Dept Ciencias Nat & Antropol, Fundac Hist Nat Felix de Azara, Buenos Aires, DF, Argentina.
    Powell, Jaime E.
    Inst Miguel Lillo, RA-4000 San Miguel De Tucuman, Tucuman, Argentina.; Consejo Nacl Invest Cient & Tecn, RA-1033 Buenos Aires, DF, Argentina.
    Novas, Fernando E.
    Museo Argentino Ciencias Nat Bernardino Rivadavia, Lab Anat Comparada & Evoluc Vertebrados, Buenos Aires, DF, Argentina.; Consejo Nacl Invest Cient & Tecn, RA-1033 Buenos Aires, DF, Argentina.
    Kundrát, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    New alvarezsaurid (Dinosauria, Theropoda) from Latest Cretaceous of North-western Patagonia with associated eggs2012In: Cretaceous research (Print), ISSN 0195-6671, E-ISSN 1095-998X, Vol. 35, p. 33-56Article in journal (Refereed)
    Abstract [en]

    The Alvarezsauridae represents a branch of peculiar basal coelurosaurs with an increasing representationof their Cretaceous radiation distributed worldwide. Here we describe a new member of the group, Bonapartenykus ultimus gen. et sp. nov. from Campanian-Maastrichtian strata of Northern Patagonia, Argentina. Bonapartenykus is represented by a single, incomplete postcranial skeleton. The morphologyof the known skeletal elements suggests close affinities with the previously described taxon from Patagonia, Patagonykus, and both conform to a new clade, here termed Patagonykinae nov. Two incomplete eggs have been discovered in association with the skeletal remains of Bonapartenykus, andseveral clusters of broken eggshells of the same identity were also found in a close proximity. These belong to the new ooparataxon Arriagadoolithus patagoniensis of the new oofamily Arriagadoolithidae, which provides first insights into unique shell microstructure and fungal contamination of eggs laid by alvarezsaurid theropods. The detailed study of the eggs sheds new light on the phylogenetic position of alvarezsaurids within the Theropoda, and the evolution of eggs among Coelurosauria. We suggest thatplesiomorphic alvarezsaurids survived in Patagonia until the latest Cretaceous, whereas these basal forms became extinct elsewhere.

  • 4.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    A comparative genomic framework for the fish-tetrapod transition2021In: Science China Life Sciences, ISSN 1674-7305, E-ISSN 1869-1889, Vol. 64, no 4, p. 664-666Article in journal (Other academic)
  • 5.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Follow the footprints and mind the gaps: a new look at the origin of tetrapods2019In: Earth and environmental science transactions of the Royal Society of Edinburgh, ISSN 1755-6910, E-ISSN 1755-6929, Vol. 109, no 1-2, p. 115-137Article in journal (Refereed)
    Abstract [en]

    The hypothesis that tetrapods evolved from elpistostegids during the Frasnian, in a predominantly aquatic context, has been challenged by the discovery of Middle Devonian tetrapod trackways predating the earliest body fossils of both elpistostegids and tetrapods. Here I present a new hypothesis based on an overview of the trace fossil and body fossil evidence. The trace fossils demonstrate that tetrapods were capable of performing subaerial lateral sequence walks before the end of the Middle Devonian. The derived morphological characters of elpistostegids and Devonian tetrapods are related to substrate locomotion, weight support and aerial vision, and thus to terrestrial competence, but the retention of lateral-line canals, gills and fin rays shows that they remained closely tied to the water. Elpistostegids and tetrapods both evolved no later than the beginning of the Middle Devonian. The earliest tetrapod records come from inland river basins, sabkha plains and ephemeral coastal lakes that preserve few, if any, body fossils; contemporary elpistostegids occur in deltas and the lower reaches of permanent rivers where body fossils are preserved. During the Frasnian, elpistostegids disappear and these riverine-deltaic environments are colonised by tetrapods. This replacement has, in the past, been misinterpreted as the origin of tetrapods.

    Download full text (pdf)
    FULLTEXT01
  • 6.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jennifer Clack (1947–2020): Palaeontologist who described how vertebrates moved from water to land2020In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 580, no 7805, p. 587-587Article in journal (Other (popular science, discussion, etc.))
  • 7.
    Ahlberg, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Beznosov, P. A.
    Russian Acad Sci, Inst Geol, FRC Komi Sci Ctr, Ural Branch, Syktyvkar 167982, Russia..
    The Significance of the Devonian Tetrapods of Timan2022In: Paleontological journal, ISSN 0031-0301, E-ISSN 1555-6174, Vol. 56, p. 1029-1031Article in journal (Refereed)
    Abstract [en]

    Brief information on the recently described Parmastega and newly discovered unpublished tetrapod material from the Devonian sequence of Timan is given. The significance of these discoveries is discussed.

  • 8.
    Ahlberg, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Beznosov, Pavel
    Luksevics, Ervins
    Clack, Jennifer
    A very primitive tetrapod from the earliest Famennian of South Timan, Russia2011In: Program and Abstracts: 71st Annual Meeting Society of Vertebrate Paleontology, Paris Las Vegas, Las Vegas, Nevada USA, November 2—5, 2011, Philadelphia: Society of Vertebrate Paleontology , 2011, p. 60-60Conference paper (Other academic)
  • 9.
    Ahlberg, Per E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Clack, Jennifer A.
    Univ Museum Zool Cambridge, Downing St, Cambridge CB2 3EJ, England..
    The smallest known Devonian tetrapod shows unexpectedly derived features2020In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 7, no 4, article id 192117Article in journal (Refereed)
    Abstract [en]

    A new genus and species of Devonian tetrapod, Brittagnathus minutus gen. et sp. nov., is described from a single complete right lower jaw ramus recovered from the Acanthostega mass-death deposit in the upper part of the Britta Dal Formation (upper Famennian) of Stensio Bjerg, Gauss Peninsula, East Greenland. Visualization by propagation phase contrast synchrotron microtomography allows a complete digital dissection of the specimen. With a total jaw ramus length of 44.8 mm, Brittagnathus is by far the smallest Devonian tetrapod described to date. It differs from all previously known Devonian tetrapods in having only a fang pair without a tooth row on the anterior coronoid and a large posterior process on the posterior coronoid. The presence of an incipient surangular crest and a concave prearticular margin to the adductor fossa together cause the fossa to face somewhat mesially, reminiscent of the condition in Carboniferous tetrapods. A phylogenetic analysis places Brittagnathus crownward to other Devonian tetrapods, adjacent to the Tournaisian genus Pederpes. Together with other recent discoveries, it suggests that diversification of 'Carboniferous-grade' tetrapods had already begun before the end of the Devonian and that the group was not greatly affected by the end-Devonian mass extinction.

    Download full text (pdf)
    FULLTEXT01
  • 10.
    Ahlberg, Per Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Humeral homology and the origin of the tetrapod elbow: a reinterpretation of the enigmatic specimens ANSP 21350 and GSM 1045362011In: Studies on fossil tetrapods / [ed] P. M. Barrett, A. R. Milner, London: The Palaeontological Association , 2011, p. 17-29Chapter in book (Refereed)
    Abstract [en]

    Two putative tetrapod humeri of Devonian age, ANSP 21350 from the late Famennian of Pennsylvania and GSM 104536 from the late Frasnian of Scat Craig, Scotland, are reinterpreted in the light of more recent discoveries. The morphology of ANSP 21350 can be more fully homologized with those of elpistostegids and early tetrapods than previously recognized. Unique features include distally displaced dorsal muscle attachments and a ventrally rotated distal face of the bone. This suggests that a weight-bearing ventrally directed forearm was created, not by means of a flexed elbow as in other tetrapods, but by distorting the humerus. The olecranon process on the ulna was probably poorly developed or absent. Primitive characters that are absent in other tetrapods add support to the contention that ANSP 21350 is the least crownward of known tetrapod humeri. Contrary to previous claims, Acanthostega has a characteristic tetrapod ulnar morphology with an olecranon process; it does not resemble an elpistostegid ulna and is not uniquely primitive for tetrapods. This suggests that the flexed tetrapod elbow with ulnar extensor muscles attached to the olecranon evolved simultaneously with the large rectangular entepicondyle typical for early tetrapods, probably as part of a single functional complex. GSM 104536 is denfinitely not a primitive tetrapod humerus, nor a sarcopterygian branchial bone, but cannot be positively identified at present.    

  • 11.
    Ahlberg, Per
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Haitina, Tatjana
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Chapter 8 Neural Crest in Fossil Vertebrates:: What, If Anything, Can We Know?2020In: Evolving Neural Crest Cells / [ed] Brian Frank Eames, Daniel Meulemans Medeiros, Igor Adameyko, Taylor & Francis Group, 2020, 1, p. 1-294Chapter in book (Refereed)
  • 12.
    Allen, Marie
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Medicinsk genetik och genomik. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Bjerke, Mia
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab. Karolinska Inst, Dept Lab Med, SE-14186 Stockholm, Sweden..
    Edlund, Hanna
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology. Uppsala University, Science for Life Laboratory, SciLifeLab. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Nelander, Sven
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Neuro-Oncology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Westermark, Bengt
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Immunology, Genetics and Pathology, Neuro-Oncology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Origin of the U87MG glioma cell line: Good news and bad news2016In: Science Translational Medicine, ISSN 1946-6234, E-ISSN 1946-6242, Vol. 8, no 354, article id 354re3Article in journal (Refereed)
    Abstract [en]

    Human tumor-derived cell lines are indispensable tools for basic and translational oncology. They have an infinite life span and are easy to handle and scalable, and results can be obtained with high reproducibility. However, a tumor-derived cell line may not be authentic to the tumor of origin. Two major questions emerge: Have the identity of the donor and the actual tumor origin of the cell line been accurately determined? To what extent does the cell line reflect the phenotype of the tumor type of origin? The importance of these questions is greatest in translational research. We have examined these questions using genetic profiling and transcriptome analysis in human glioma cell lines. We find that the DNA profile of the widely used glioma cell line U87MG is different from that of the original cells and that it is likely to be a bona fide human glioblastoma cell line of unknown origin.

  • 13.
    Aresh, Bejan
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Developmental Genetics.
    Peuckert, Christiane
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Dissection and Culture of Mouse Embryonic Kidney2017In: Journal of Visualized Experiments, E-ISSN 1940-087X, no 123, article id e55715Article in journal (Refereed)
    Abstract [en]

    The goal of this protocol is to describe a method for the dissection, isolation, and culture of mouse metanephric rudiments. During mammalian kidney development, the two progenitor tissues, the ureteric bud and the metanephric mesenchyme, communicate and reciprocally induce cellular mechanisms to eventually form the collecting system and the nephrons of the kidney. As mammalian embryos grow intrauterine and therefore are inaccessible to the observer, an organ culture has been developed. With this method, it is possible to study epithelial-mesenchymal interactions and cellular behavior during kidney organogenesis. Furthermore, the origin of congenital kidney and urogenital tract malformations can be investigated. After careful dissection, the metanephric rudiments are transferred onto a filter that floats on culture medium and can be kept in a cell culture incubator for several days. However, one must be aware that the conditions are artificial and could influence the metabolism in the tissue. Also, the penetration of test substances could be limited due to the extracellular matrix and basal membrane present in the explant. One main advantage of organ culture is that the experimenter can gain direct access to the organ. This technology is cheap, simple, and allows a large number of modifications, such as the addition of biologically active substances, the study of genetic variants, and the application of advanced imaging techniques.

  • 14. Astin, T. R.
    et al.
    Marshall, J.E.A
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Berry, C.M.
    The sedimentary environment of the Late Devonian EastGreenland tetrapods2010In: Geological Society Special Publication, ISSN 0305-8719, E-ISSN 2041-4927, Vol. 339, p. 93-109Article in journal (Refereed)
  • 15.
    Aydin, Ebru
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Kloos, Dick-Paul
    Gay, Emmanuel
    Jonker, Willem
    Hu, Lijuan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Bullwinkel, Joern
    Brown, Jeremy P.
    Manukyan, Maria
    Giera, Martin
    Singh, Prim B.
    Fundele, Reinald
    A hypomorphic Cbx3 allele causes prenatal growth restriction and perinatal energy homeostasis defects2015In: Journal of Biosciences, ISSN 0250-5991, E-ISSN 0973-7138, Vol. 40, no 2, p. 325-338Article in journal (Refereed)
    Abstract [en]

    Mammals have three HP1 protein isotypes HP1 beta (CBX1), HPl gamma (CBX3) and HP1 alpha (CBX5) that are encoded by the corresponding genes Cbx1, Cbx3 and Cbx5. Recent work has shown that reduction of CBX3 protein in homozygotes for a hypomorphic allele (Cbx3(hypo)) causes a severe postnatal mortality with around 99% of the homozygotes dying before weaning. It is not known what the causes of the postnatal mortality are. Here we show that Cbx3(hypo/hypo) conceptuses are significantly reduced in size and the placentas exhibit a haplo-insufficiency. Late gestation Cbx3(hypo/hypo) placentas have reduced mRNA transcripts for genes involved in growth regulation, amino acid and glucose transport. Blood vessels within the Cbx3(hypo/hypo) placental labyrinth are narrower than wild-type. Newborn Cbx3(hypo/hypo) pups are hypoglycemic, the livers are depleted of glycogen reserves and there is almost complete loss of stored lipid in brown adipose tissue (BAT). There is a 10-fold reduction in expression of the BAT-specific Ucp1 gene, whose product is responsible for non-shivering themogenesis. We suggest that it is the small size of the ChX3(hypo/hypo) neonates, a likely consequence of placental growth and transport defects, combined with a possible inability to thermoregulate that causes the severe postnatal mortality.

  • 16.
    Bajdek, Piotr
    et al.
    Aleja Najswietszej Maryi Panny 20-20A, PL-42200 Czestochowa, Poland..
    Owocki, Krzysztof
    Polish Acad Sci, Inst Paleobiol, Twarda 51-55, PL-00818 Warsaw, Poland..
    Sennikov, Andrey G.
    Russian Acad Sci, Borissiak Paleontol Inst, Profsoyuznaya 123, Moscow 117997, Russia.;Kazan Fed Univ, Kremlyovskaya 18, Kazan 420008, Russia..
    Golubev, Valeriy K.
    Russian Acad Sci, Borissiak Paleontol Inst, Profsoyuznaya 123, Moscow 117997, Russia.;Kazan Fed Univ, Kremlyovskaya 18, Kazan 420008, Russia..
    Niedzwiedzki, Grzegorz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Residues from the Upper Permian carnivore coprolites from Vyazniki in Russia - key questions in reconstruction of feeding habits2017In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 482, p. 70-82Article in journal (Refereed)
    Abstract [en]

    Residues of twenty-five coprolite fragments collected from the Upper Permian of Vyazniki (European Russia) were studied in detail. The phosphatic composition, general shape and size, and bone inclusions of these specimens indicate that medium to large-sized carnivores, such as therocephalian therapsids or early archosauriforms, were the most likely coprolite producers. The contents of the examined fossils (i.e. Scale, bone and tooth fragments, mineral grains, and microbial structures) do not differ significantly among the samples, implying fairly comparable feeding habits of their producers. Fragments of large tooth crowns in two of the analyzed samples imply that either (1) the coprolite producer swallowed the cranial elements of its prey or (2) the coprolite producer broke and swallowed its own tooth while feeding (such tooth damage is known in archosaurs that have tooth replacement, e.g. crocodiles and dinosaurs). Indeed, the most complete tooth fragment in these fossils is serrated, most likely belonging to an early archosauriform known from skeletal records from the Late Permian of Vyaznilci. Another coprolite fragment contains the etched tooth of a lungfish, while putative actinopterygian fish remains (scales and small fragments of bones) are abundant in some samples. Mineral particles (mostly quartz grains, feldspars and mica) may have been swallowed accidentally. The preserved microbial colonies (mineralized fossil fungi and bacteria or their pseudomorphs), manifested in the coprolites as Fe-rich mineral structures, seem to have developed on the expelled feces rather than on the items before they were swallowed.

  • 17.
    Bajdek, Piotr
    et al.
    Aleja Najswieztszej Maryi Panny 20-20A, PL-42200 Czestochowa, Poland..
    Qvarnström, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Owocki, Krzysztof
    Polish Acad Sci, Inst Paleobiol, Twarda 51-55, PL-00818 Warsaw, Poland..
    Sulej, Tomasz
    Polish Acad Sci, Inst Paleobiol, Twarda 51-55, PL-00818 Warsaw, Poland..
    Sennikov, Andrey G.
    Russian Acad Sci, Borissiak Paleontol Inst, Profsoyuznaya 123, Moscow 117997, Russia.;Kazan Fed Univ, Kremlyovskaya 18, Kazan 420008, Russia..
    Golubev, Valeriy K.
    Russian Acad Sci, Borissiak Paleontol Inst, Profsoyuznaya 123, Moscow 117997, Russia.;Kazan Fed Univ, Kremlyovskaya 18, Kazan 420008, Russia..
    Niedzwiedzki, Grzegorz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Microbiota and food residues including possible evidence of pre-mammalian hair in Upper Permian coprolites from Russia2016In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 49, no 4, p. 455-477Article in journal (Refereed)
    Abstract [en]

    Coprolites (fossil faeces) provide direct evidence on the diet of its producer and unique insights on ancient food webs and ecosystems. We describe the contents of seven coprolites, collected from the Late Permian Vyazniki site of the European part of Russia. Two coprolite morphotypes (A, B) contain remains of putative bacteria, cyanobacteria, fungi, protists, invertebrate eggs, arthropod elements, undigested bone and tooth fragments, fish scales and elongated hair-like structures with hollow interiors. Content, size and shape of the coprolites together with the associated body fossil record suggest that the most probable scat-producers were carnivorous tetrapods; the bone-rich morphotype A reveals short food retention time and a fast metabolism and is therefore assigned to therapsid carnivores whereas morphotype B with rarer and degraded bones are assigned to archosauromorphs or other non-therapsid carnivores. The general coprolite matrix contains abundant micron-sized spheres and thin-walled vesicles which are interpreted as oxide and phosphatic pseudomorphs after microbial cells. From analyses of the undigested bones, we infer that they represent remains of actinopterygian fish, a therapsid and unrecognizable parts of amphibians and/or reptiles. Additionally, hair-like structures found in one coprolite specimen occur as diagenetically altered (oxide-replaced) structures and moulds (or partly as pseudomorphs) in a microcrystalline carbonate-fluoride-bearing calcium phosphate. This suggests that the latest Permian therapsids probably were equipped with hair-like integument or hairsuit. If true, this is by far the oldest evidence of this mammalian character in the stem group of mammals.

  • 18.
    Ballesteros, Ainara
    et al.
    Inst Marine Sci ICM CSIC, Dept Marine Biol & Oceanog, Barcelona, Spain..
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Santin, Andreu
    Inst Marine Sci ICM CSIC, Dept Marine Biol & Oceanog, Barcelona, Spain..
    Marambio, Macarena
    Inst Marine Sci ICM CSIC, Dept Marine Biol & Oceanog, Barcelona, Spain..
    Narda, Mridvika
    ISDIN, Innovat & Dev, Barcelona, Spain..
    Gili, Josep-Maria
    Inst Marine Sci ICM CSIC, Dept Marine Biol & Oceanog, Barcelona, Spain..
    Cnidome and Morphological Features of Pelagia noctiluca (Cnidaria: Scyphozoa) Throughout the Different Life Cycle Stages2021In: Frontiers in Marine Science, E-ISSN 2296-7745, Vol. 8, article id 714503Article in journal (Refereed)
    Abstract [en]

    Pelagia noctiluca is considered the most important jellyfish in the Mediterranean Sea, due to its abundance and the severity of its stings. Despite its importance in marine ecosystems and the health problems caused by its massive arrival in coastal areas, little is known about its early life stages and its cnidome has never been described. This study of the morphological and anatomical features throughout the life cycle identifies four early stages: two ephyra and two metaephyra stages. Ephyra stage 1, newly developed from a planula, has no velar canals, gastric filaments or nematocyst batteries. Ephyra stage 2, has velar canals, a cruciform-shaped manubrium and gastric filaments. Metaephyra stage 3 has eight tentacle buds and nematocyst clusters for the first time. Lastly, in metaephyra stage 4, the eight primary tentacles grow nearly simultaneously, with no secondary tentacles. Complete nematocyst battery patterns gradually develop throughout the later life stages. Four nematocyst types are identified: a-isorhiza, A-isorhiza, O-isorhiza and eurytele. Of these, a-isorhiza and eurytele are the most important throughout the entire life cycle, while A-isorhiza and O-isorhiza have a more important role in advanced stages. All nematocysts show a positive correlation between increasing capsule volumes and increasing body diameter of the ephyrae, metaephyrae, young medusae and adult medusae. In the early stages, the volumes of euryteles in the gastric filaments are larger than those in the exumbrella, indicating that the capsule volume is critical in the absence of marginal tentacles, specialized for feeding. This study provides updated information, the most extensive description to date, including high-resolution photographs and schematic drawings of all the developmental stages in the life cycle of P. noctiluca. Additionally, the first cnidome characterization is provided for each stage to facilitate accurate identification of this species when collected in the water column, and to raise awareness of the potential for human envenomation.

    Download full text (pdf)
    FULLTEXT01
  • 19.
    Banote, Rakesh Kumar
    et al.
    Univ Gothenburg, Sahlgrenska Acad, Dept Psychiat & Neurochem, Inst Neurosci & Physiol, S-41345 Gothenburg, Sweden.;Cellectricon AB, Neongatan 4B, SE-43153 Molndal, Sweden..
    Chebli, Jasmine
    Univ Gothenburg, Sahlgrenska Acad, Dept Psychiat & Neurochem, Inst Neurosci & Physiol, S-41345 Gothenburg, Sweden..
    Satir, Tugce Munise
    Univ Gothenburg, Sahlgrenska Acad, Dept Psychiat & Neurochem, Inst Neurosci & Physiol, S-41345 Gothenburg, Sweden..
    Varshney, Gaurav K.
    NHGRI, Translat & Funct Genom Branch, NIH, Bethesda, MD 20892 USA.;Oklahoma Med Res Fdn, Genes & Human Dis Program, 825 NE 13th St, Oklahoma City, OK 73104 USA..
    Camacho, Rafael
    Univ Gothenburg, Sahlgrenska Acad, Ctr Cellular Imaging, Core Facil, Gothenburg, Sweden..
    Ledin, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. NHGRI, Translat & Funct Genom Branch, NIH, Bethesda, MD 20892 USA.
    Burgess, Shawn M.
    NHGRI, Translat & Funct Genom Branch, NIH, Bethesda, MD 20892 USA..
    Abramsson, Alexandra
    Univ Gothenburg, Sahlgrenska Acad, Dept Psychiat & Neurochem, Inst Neurosci & Physiol, S-41345 Gothenburg, Sweden..
    Zetterberg, Henrik
    Univ Gothenburg, Sahlgrenska Acad, Dept Psychiat & Neurochem, Inst Neurosci & Physiol, S-41345 Gothenburg, Sweden.;Sahlgrens Univ Hosp, Clin Neurochem Lab, Molndal, Sweden.;UCL Inst Neurol, Dept Neurodegenerat Dis, Queen Sq, London WC1N 3BG, England.;UK Dementia Res Inst, London WC1N 3BG, England..
    Amyloid precursor protein-b facilitates cell adhesion during early development in zebrafish2020In: Scientific Reports, E-ISSN 2045-2322, Vol. 10, no 1Article in journal (Refereed)
    Abstract [en]

    Understanding the biological function of amyloid beta (A beta) precursor protein (APP) beyond its role in Alzheimer's disease is emerging. Yet, its function during embryonic development is poorly understood. The zebrafish APP orthologue, Appb, is strongly expressed during early development but thus far has only been studied via morpholino-mediated knockdown. Zebrafish enables analysis of cellular processes in an ontogenic context, which is limited in many other vertebrates. We characterized zebrafish carrying a homozygous mutation that introduces a premature stop in exon 2 of the appb gene. We report that appb mutants are significantly smaller until 2 dpf and display perturbed enveloping layer (EVL) integrity and cell protrusions at the blastula stage. Moreover, appb mutants surviving beyond 48 hpf exhibited no behavioral defects at 6 dpf and developed into healthy and fertile adults. The expression of the app family member, appa, was also found to be altered in appb mutants. Taken together, we show that appb is involved in the initial development of zebrafish by supporting the integrity of the EVL, likely by mediating cell adhesion properties. The loss of Appb might then be compensated for by other app family members to maintain normal development.

    Download full text (pdf)
    FULLTEXT01
  • 20.
    Barbacka, Maria
    et al.
    Polish Acad Sci, W Szafer Inst Bot, Ul Lubicz 46, PL-31512 Krakow, Poland.;Hungarian Nat Hist Museum, Bot Dept, POB 137, H-1431 Budapest, Hungary..
    Gorecki, Artur
    Univ Krakow, Dept Taxon Phytogeog & Palaeobot, Inst Bot, Fac Biol, Gronostajowa 3, PL-30387 Krakow, Poland..
    Pacyna, Grzegorz
    Univ Krakow, Dept Taxon Phytogeog & Palaeobot, Inst Bot, Fac Biol, Gronostajowa 3, PL-30387 Krakow, Poland..
    Pienkowski, Grzegorz
    Polish Geol Inst, Natl Res Inst, Rakowiecka 4, PL-00975 Warsaw, Poland..
    Philippe, Marc
    Univ Lyon 1, 7 Rue Dubois, F-69622 Villeurbanne, France.;CNRS UMR 5276, 7 Rue Dubois, F-69622 Villeurbanne, France..
    Boka, Karoly
    Eotvos Lorand Univ, Dept Plant Anat, Inst Biol, Pazmany P Setany 1-C, H-1117 Budapest, Hungary..
    Ziaja, Jadwiga
    Polish Acad Sci, W Szafer Inst Bot, Ul Lubicz 46, PL-31512 Krakow, Poland..
    Jarzynka, Agata
    Polish Acad Sci, Res Ctr Krakow, Inst Geol Sci, Senacka 1, H-30002 Krakow, Hungary..
    Qvarnström, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Niedzwiedzki, Grzegorz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Early Jurassic coprolites: insights into palaeobotany and the feeding behaviour of dinosaurs2022In: Papers in Palaeontology, ISSN 2056-2799, E-ISSN 2056-2802, Vol. 8, no 2, article id e1425Article in journal (Refereed)
    Abstract [en]

    Analyses of coprolites provide important data on animal feeding and food quality, including information on the taxonomy of the biotope. Knowledge of the diet of extinct animals has implications for our understanding of the evolution of various physiological strategies and feeding adaptations. Here we provide the first description of plant remains preserved in coprolites from early Hettangian deposits at Soltykow (Holy Cross Mountains, Poland). The coprolites probably originated from herbivorous sauropodomorphs, ornithischians and large carnivorous theropods, from which tracks are known from the site. Herbivorous coprolite producers fed on the flora growing on a fluvial plain, and the cuticles that remain in the coprolites originated from crowns of gymnospermous trees or shrubs. Coprolites assigned to large predators contained more diverse plant remains, although they also belonged to the gymnosperms. These were probably ingested together with the stomachs and intestines of prey animals and/or accidentally while drinking or feeding. The plant cuticles originated from seed ferns (including the newly proposed Komlopteris distinctiva Barbacka sp. nov.), cycadophytes, ginkgophytes and conifers. A fragment of a needle leaf, Aciphyllum triangulatum Barbacka & Gorecki gen. et sp. nov., is very similar to the leaves of Pinus, and is the oldest example of such a leaf type in the fossil record. Most ingested plants came from beyond the immediate surroundings of today's outcrop. Palynological analysis of the coprolites yielded 31 taxa of sporomorphs from the herbivore coprolites and 14 sporomorph taxa from the coprolites of predators. Cheirolepidiaceous pollen grains of Classopollis torosus dominated the sporomorph assemblage.

  • 21.
    Bazzi, Mohamad
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University.
    100 million years of shark macroevolution: A morphometric dive into tooth shape diversity2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Few vertebrate clades exhibit the evolutionary longevity and versatility of sharks, which constitute nearly half of all current chondrichthyan biodiversity and represent an ecological diversity of mid-to-apex trophic-level predators in both marine and freshwater environments. The rich fossil record of shark teeth from Mesozoic and Cenozoic rocks also makes the group amenable to large-scale quantitative analyses. This thesis reconstructs the morphological tooth disparity of dominant lamniform (Mackerel sharks) and carcharhiniform (Ground sharks) clades over the last 100 million years. The relative diversity of these major lineages is strongly skewed, with lamniforms, including the famous White shark, making up less than 3% of the total species richness, whereas carcharhiniforms, such as Tiger sharks, comprise over 290 described species. Paradoxically, this long-recognized disproportionate representation was reversed in the distant geological past. Indeed, the fossil record shows that lamniforms accounted for nearly all of the documented shark diversity during the final stages of the Late Cretaceous — the terminal time interval of the ‘Age of Dinosaurs’, which ended 66 million years ago. The causes of this radical diversity turnover are debated, with recent research suggesting that competition and/or climate change drove major shifts in shark evolution. Perhaps more surprisingly, most analyses of diversity dynamics of sharks centre largely on taxonomic data, thus omitting more direct proxies of ecology, such as morphological diversity, or disparity. To mitigate this shortfall, I adopt a Procrustes framework combined with phylogenetic comparative and multivariate statistics to shed light on the deep-time morphological evolution of sharks. My work indicates that the end-Cretaceous mass extinction initiated a sustained evolutionary turnover in ecological dominance between lamniforms and carcharhiniforms. More specifically, the morphospace of these clades, indicate a selective extinction at the K/Pg Boundary affecting ‘large-bodied’ anacoracid lamniform sharks, whereas triakid carcharhiniforms proliferated in the extinction aftermath, perhaps as a response to new prey sources. Overall, my thesis suggests that the modern shark assemblages are the synergistic result of feeding ecology (including dietary niche breadth) and environmental shifts in global sea levels and temperature acting over the last 100 million years.

    List of papers
    1. Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction
    Open this publication in new window or tab >>Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction
    Show others...
    2018 (English)In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 28, no 16, p. 2607-2615Article in journal (Refereed) Published
    Abstract [en]

    The Cretaceous-Palaeogene (K-Pg) mass extinction profoundly altered vertebrate ecosystems and prompted the radiation of many extant clades [1, 2]. Sharks (Selachimorpha) were one of the few larger-bodied marine predators that survived the K-Pg event and are represented by an almost-continuous dental fossil record. However, the precise dynamics of their transition through this interval remain uncertain [3]. Here, we apply 2D geometric morphometrics to reconstruct global and regional dental morphospace variation among Lamniformes (Mackerel sharks) and Carch-arhiniformes (Ground sharks). These clades are prevalent predators in today's oceans, and were geographically widespread during the late Cretaceous-early Palaeogene. Our results reveal a decoupling of morphological disparity and taxonomic richness. Indeed, shark disparity was nearly static across the K-Pg extinction, in contrast to abrupt declines among other higher-trophic-level marine predators [4, 5]. Nevertheless, specific patterns indicate that an asymmetric extinction occurred among lamniforms possessing lowcrowned/triangular teeth and that a subsequent proliferation of carcharhiniforms with similar tooth morphologies took place during the early Paleocene. This compositional shift in post-Mesozoic shark lineages hints at a profound and persistent K-Pg signature evident in the heterogeneity of modern shark communities. Moreover, such wholesale lineage turnover coincided with the loss of many cephalopod [6] and pelagic amniote [5] groups, as well as the explosive radiation of middle trophic-level teleost fishes [1]. We hypothesize that a combination of prey availability and post-extinction trophic cascades favored extant shark antecedents and laid the foundation for their extensive diversification later in the Cenozoic [7-10].

    Place, publisher, year, edition, pages
    CELL PRESS, 2018
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-363937 (URN)10.1016/j.cub.2018.05.093 (DOI)000442111300030 ()30078565 (PubMedID)
    Funder
    Knut and Alice Wallenberg FoundationThe Royal Swedish Academy of Sciences, GS2017-0018
    Available from: 2018-10-23 Created: 2018-10-23 Last updated: 2021-01-06Bibliographically approved
    2. The extinction and survival of sharks across the end-Cretaceous mass extinction
    Open this publication in new window or tab >>The extinction and survival of sharks across the end-Cretaceous mass extinction
    Show others...
    (English)In: Article in journal (Refereed) Submitted
    Keywords
    Selachimorpha, Macroevolution, Extinction recovery dynamics, Geometric Morphometrics, Morphospace-Disparity Framework
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-429931 (URN)
    Funder
    Wallenberg Foundations
    Available from: 2021-01-06 Created: 2021-01-06 Last updated: 2021-01-07
    3. Feeding ecology has shaped the evolution of modern sharks
    Open this publication in new window or tab >>Feeding ecology has shaped the evolution of modern sharks
    Show others...
    2021 (English)In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 31, no 23, p. 5138-5148.e4Article in journal (Refereed) Published
    Abstract [en]

    Sharks are iconic predators in today’s oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary “specialization,” their recent disparity rivals that of “generalist” carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.

    Place, publisher, year, edition, pages
    Cell Press, 2021
    National Category
    Evolutionary Biology Ecology Geosciences, Multidisciplinary
    Identifiers
    urn:nbn:se:uu:diva-429932 (URN)10.1016/j.cub.2021.09.028 (DOI)000729217200002 ()34614390 (PubMedID)
    Funder
    Knut and Alice Wallenberg FoundationAustralian Research CouncilSwedish Research Council, 2020-3423
    Available from: 2021-01-06 Created: 2021-01-06 Last updated: 2024-01-15Bibliographically approved
    4. Southern higher-latitude lamniform sharks track mid-Cretaceous environmental change
    Open this publication in new window or tab >>Southern higher-latitude lamniform sharks track mid-Cretaceous environmental change
    2022 (English)In: Vol. 103, p. 362-370Article in journal (Refereed) Submitted
    Abstract [en]

    The mid-Cretaceous (Albian and Cenomanian, 113–93.9 Myr) marked a transformative interval of shark evolution during which lamniforms (mackerel sharks) diversified as dominant marine predators. Yet, their radiation dynamics relative to major biotic turnovers delimiting the Albian–Cenomanian and Cenomanian–Turonian boundaries are incompletely understood. Here, we use the high-resolution dental fossil record of lamniforms to track changing morphological disparity and tooth size through a succession of mid-Cretaceous shark assemblages from higher-palaeolatitude (up to ∼ 58°S) settings in Australia. Our geometric morphometric analyses and evolutionary model fitting reveal stable disparity throughout the late Albian–late Cenomanian. By contrast, lamniform disparity increased in the early Turonian, which might reflect local habitat differences and/or intraspecific variability through heterodonty. Nevertheless, clade-specific partial disparity increases are evident among small-bodied carchariids, and couple with a trend towards larger teeth as a proxy for body-size in coeval anacoracids. We correlate these signals with recovery after the Oceanic Anoxic Event 2, which severely disrupted latest Cenomanian marine ecosystems and apparently instigated disjunct responses in shark communities occupying epeiric versus outer neritic environments.

    Place, publisher, year, edition, pages
    Elsevier, 2022
    Keywords
    Lamniformes, Albian–Cenomanian, Cenomanian–Turonian, Australia, Geometric morphometrics, Oceanic Anoxic Event 2
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-429933 (URN)10.1016/j.gr.2021.10.012 (DOI)000802182800003 ()
    Available from: 2021-01-06 Created: 2021-01-06 Last updated: 2022-06-23Bibliographically approved
    Download full text (pdf)
    fulltext
    Download (jpg)
    presentationsbild
  • 22.
    Bazzi, Mohamad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Campione, Nicolas E.
    Univ New England, Palaeosci Res Ctr, Sch Environm & Rural Sci, Armidale, NSW, Australia..
    Ahlberg, Per
    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.
    Kear, Benjamin P.
    Uppsala University, Music and Museums, Museum of Evolution.
    Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction2021In: PLoS biology, ISSN 1544-9173, E-ISSN 1545-7885, Vol. 19, no 8, article id e3001108Article in journal (Refereed)
    Abstract [en]

    Sharks (Selachimorpha) are iconic marine predators that have survived multiple mass extinctions over geologic time. Their prolific fossil record is represented mainly by isolated shed teeth, which provide the basis for reconstructing deep time diversity changes affecting different selachimorph clades. By contrast, corresponding shifts in shark ecology, as measured through morphological disparity, have received comparatively limited analytical attention. Here, we use a geometric morphometric approach to comprehensively examine tooth morphologies in multiple shark lineages traversing the catastrophic end-Cretaceous mass extinction-this event terminated the Mesozoic Era 66 million years ago. Our results show that selachimorphs maintained virtually static levels of dental disparity in most of their constituent clades across the Cretaceous-Paleogene interval. Nevertheless, selective extinctions did impact apex predator species characterized by triangular blade-like teeth. This is particularly evident among lamniforms, which included the dominant Cretaceous anacoracids. Conversely, other groups, such as carcharhiniforms and orectolobiforms, experienced disparity modifications, while heterodontiforms, hexanchiforms, squaliforms, squatiniforms, and dagger synechodontiforms were not overtly affected. Finally, while some lamniform lineages disappeared, others underwent postextinction disparity increases, especially odontaspidids, which are typified by narrow-cusped teeth adapted for feeding on fishes. Notably, this increase coincides with the early Paleogene radiation of teleosts as a possible prey source, and the geographic relocation of disparity sampling "hotspots," perhaps indicating a regionally disjunct extinction recovery. Ultimately, our study reveals a complex morphological response to the end-Cretaceous mass extinction and highlights an event that influenced the evolution of modern sharks.

    Download full text (pdf)
    FULLTEXT01
  • 23.
    Bazzi, Mohamad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Campione, Nicolás
    Ahlberg, Per
    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.
    Kear, Benjamin
    The extinction and survival of sharks across the end-Cretaceous mass extinctionIn: Article in journal (Refereed)
  • 24.
    Bazzi, Mohamad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. University of Zurich.
    Campione, Nicolás E.
    Kear, Benjamin P.
    Uppsala University, Music and Museums, Museum of Evolution.
    Pimiento, Catalina
    Ahlberg, Per E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Feeding ecology has shaped the evolution of modern sharks2021In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 31, no 23, p. 5138-5148.e4Article in journal (Refereed)
    Abstract [en]

    Sharks are iconic predators in today’s oceans, yet their modern diversity has ancient origins. In particular, present hypotheses suggest that a combination of mass extinction, global climate change, and competition has regulated the community structure of dominant mackerel (Lamniformes) and ground (Carcharhiniformes) sharks over the last 66 million years. However, while these scenarios advocate an interplay of major abiotic and biotic events, the precise drivers remain obscure. Here, we focus on the role of feeding ecology using a geometric morphometric analysis of 3,837 fossil and extant shark teeth. Our results reveal that morphological segregation rather than competition has characterized lamniform and carcharhiniform evolution. Moreover, although lamniforms suffered a long-term disparity decline potentially linked to dietary “specialization,” their recent disparity rivals that of “generalist” carcharhiniforms. We further confirm that low eustatic sea levels impacted lamniform disparity across the end-Cretaceous mass extinction. Adaptations to changing prey availability and the proliferation of coral reef habitats during the Paleogene also likely facilitated carcharhiniform dispersals and cladogenesis, underpinning their current taxonomic dominance. Ultimately, we posit that trophic partitioning and resource utilization shaped past shark ecology and represent critical determinants for their future species survivorship.

    Download full text (pdf)
    fulltext
  • 25.
    Bazzi, Mohamad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Kear, Benjamin P.
    Uppsala University, Music and Museums, Museum of Evolution.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Campione, Nicolas E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Univ New England, Sch Environm & Rural Sci, Palaeosci Res Ctr, Armidale, NSW 2351, Australia.
    Static Dental Disparity and Morphological Turnover in Sharks across the End-Cretaceous Mass Extinction2018In: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 28, no 16, p. 2607-2615Article in journal (Refereed)
    Abstract [en]

    The Cretaceous-Palaeogene (K-Pg) mass extinction profoundly altered vertebrate ecosystems and prompted the radiation of many extant clades [1, 2]. Sharks (Selachimorpha) were one of the few larger-bodied marine predators that survived the K-Pg event and are represented by an almost-continuous dental fossil record. However, the precise dynamics of their transition through this interval remain uncertain [3]. Here, we apply 2D geometric morphometrics to reconstruct global and regional dental morphospace variation among Lamniformes (Mackerel sharks) and Carch-arhiniformes (Ground sharks). These clades are prevalent predators in today's oceans, and were geographically widespread during the late Cretaceous-early Palaeogene. Our results reveal a decoupling of morphological disparity and taxonomic richness. Indeed, shark disparity was nearly static across the K-Pg extinction, in contrast to abrupt declines among other higher-trophic-level marine predators [4, 5]. Nevertheless, specific patterns indicate that an asymmetric extinction occurred among lamniforms possessing lowcrowned/triangular teeth and that a subsequent proliferation of carcharhiniforms with similar tooth morphologies took place during the early Paleocene. This compositional shift in post-Mesozoic shark lineages hints at a profound and persistent K-Pg signature evident in the heterogeneity of modern shark communities. Moreover, such wholesale lineage turnover coincided with the loss of many cephalopod [6] and pelagic amniote [5] groups, as well as the explosive radiation of middle trophic-level teleost fishes [1]. We hypothesize that a combination of prey availability and post-extinction trophic cascades favored extant shark antecedents and laid the foundation for their extensive diversification later in the Cenozoic [7-10].

    Download full text (pdf)
    fulltext
  • 26.
    Bazzi, Mohamad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Kear, Benjamin P.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Uppsala University, Music and Museums, Museum of Evolution.
    Siversson, Mikael
    Southern higher-latitude lamniform sharks track mid-Cretaceous environmental change2022In: Vol. 103, p. 362-370Article in journal (Refereed)
    Abstract [en]

    The mid-Cretaceous (Albian and Cenomanian, 113–93.9 Myr) marked a transformative interval of shark evolution during which lamniforms (mackerel sharks) diversified as dominant marine predators. Yet, their radiation dynamics relative to major biotic turnovers delimiting the Albian–Cenomanian and Cenomanian–Turonian boundaries are incompletely understood. Here, we use the high-resolution dental fossil record of lamniforms to track changing morphological disparity and tooth size through a succession of mid-Cretaceous shark assemblages from higher-palaeolatitude (up to ∼ 58°S) settings in Australia. Our geometric morphometric analyses and evolutionary model fitting reveal stable disparity throughout the late Albian–late Cenomanian. By contrast, lamniform disparity increased in the early Turonian, which might reflect local habitat differences and/or intraspecific variability through heterodonty. Nevertheless, clade-specific partial disparity increases are evident among small-bodied carchariids, and couple with a trend towards larger teeth as a proxy for body-size in coeval anacoracids. We correlate these signals with recovery after the Oceanic Anoxic Event 2, which severely disrupted latest Cenomanian marine ecosystems and apparently instigated disjunct responses in shark communities occupying epeiric versus outer neritic environments.

    Download full text (pdf)
    fulltext
  • 27.
    Beznosov, Pavel A.
    et al.
    Russian Acad Sci, Ural Branch, Komi Sci Ctr, Inst Geol, Syktyvkar, Russia.
    Clack, Jennifer A.
    Univ Cambridge, Univ Museum Zool, Cambridge, England.
    Luksevics, Ervins
    Univ Latvia, Dept Geol, Riga, Latvia.
    Ruta, Marcello
    Univ Lincoln, Sch Life Sci, Joseph Banks Labs, Lincoln, England.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Morphology of the earliest reconstructable tetrapod Parmastega aelidae2019In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 574, no 7779, p. 527-531Article in journal (Refereed)
    Abstract [en]

    The known diversity of tetrapods of the Devonian period has increased markedly in recent decades, but their fossil record consists mostly of tantalizing fragments(1-15). The framework for interpreting the morphology and palaeobiology of Devonian tetrapods is dominated by the near complete fossils of Ichthyostega and Acanthostega; the less complete, but partly reconstructable, Ventastega and Tulerpeton have supporting roles(2,4,16-34). All four of these genera date to the late Famennian age (about 365-359 million years ago)-they are 10 million years younger than the earliest known tetrapod fragments(5,10), and nearly 30 million years younger than the oldest known tetrapod footprints(35). Here we describe Parmastega aelidae gen. et sp. nov., a tetrapod from Russia dated to the earliest Famennian age (about 372 million years ago), represented by three-dimensional material that enables the reconstruction of the skull and shoulder girdle. The raised orbits, lateral line canals and weakly ossified postcranial skeleton of P. aelidae suggest a largely aquatic, surface-cruising animal. In Bayesian and parsimony-based phylogenetic analyses, the majority of trees place Parmastega as a sister group to all other tetrapods.

  • 28.
    Blazcjowski, Blazcj
    et al.
    Polish Acad Sci, Inst Paleobiol, Twarda 51-55, PL-00818 Warsaw, Poland..
    Niedzwiedzki, Grzegorz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Boukhalfa, Kamel
    Univ Gabes, Fac Sci, City Riadh Zerig 6029, Gabes, Tunisia..
    Soussi, Mohamed
    Univ Tunis El Manar, Dept Geol, Fac Sci, Tunis 2092, Tunisia..
    Limulitella tejraensis, a new species of limulid (Chelicerata, Xiphosura) from the Middle Triassic of southern Tunisia (Saharan Platform)2017In: Journal of Paleontology, ISSN 0022-3360, E-ISSN 1937-2337, Vol. 91, no 5, p. 960-967Article in journal (Refereed)
    Abstract [en]

    Numerous well-preserved remains of a new limulid species from the Anisian-lower Ladinian (Middle Triassic) of the Tejra section of southern Tunisia are described. Comparisons are made with limulids from the Triassic deposits of Europe and Australia. The new specimens are congeneric with the type species of Limulitella, but show some morphological differences. Here we describe Limulitella tejraensis new species, a small limulid with semicircular prosoma, small and triangular opisthosoma, well-defined axial ridge, and pleurae along both ridges of the opisthosoma. The Tunisian Limulitella fossils are associated with conchostracans, bivalves, gastropods, and microconchids. Sedimentological and paleontological data from the Tejra section suggest freshwater to brackish-water conditions during the formation of the fossil-bearing interval and the influence of marine transgression into a playa-like environment. Supposed adaptation to the stressful environment sheds new light on the origin and survival of the extant limulines. This is the first report of limulid body fossils from the Triassic of North Africa and the first documentation of Limulitella in the Middle Triassic of northern Gondwanaland.

  • 29.
    Blieck, Alain
    et al.
    Université Lille – 1, France.
    Zigaite, Zivile
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Early and Middle Palaeozoic Vertebrate Palaeobiogeography: recent advances and critical comments2011In: Palaeozoic Early Vertebrates: II Obruchev Symposium. Abstracts / [ed] Oleg Lebedev and Alexander Ivanov, 2011, p. 28-28Conference paper (Other academic)
    Download full text (pdf)
    Blieck & Zigaite_2011
  • 30.
    Blieck, Alain
    et al.
    Université Lille – 1, France.
    Žigaitė, Živilė
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Paléobiogéographie des vertébrés du Paléozoïque inférieur et moyen: données et interprétations récentes2011In: Résumés des communications du congrès 2011 de l’Association Paléontologique Française / [ed] Bertrand Lefebre, 2011Conference paper (Other academic)
  • 31.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    New birkeniid anaspid from the Lower Devonian of Scotland and its phylogenetic implications2012In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 55, no 3, p. 641-652Article in journal (Refereed)
    Abstract [en]

    Abstract:  A new possible stem gnathostome, Kerreralepis carinata gen. et sp. nov., is described on the basis of a single specimen from the Lower Devonian of the island of Kerrera in the Inner Hebrides, Scotland. It is recognized as an anaspid by the chevron-like arranged rod-shaped scales on the trunk, gill openings extending behind the orbits in a slanting row and a series of median dorsal ridge scales. This specimen also has a series of median ventral plates, indicating the presence of a preanal fin-fold, which in turn has consequences for interpretations of other problematic stem gnathostomes and their phylogenetic context. A cladistic analysis supports a monophyletic Anaspida including the scale-covered birkeniids but excluding Lasanius as well as anaspid-like forms such as Euphanerops and Jamoytius. The establishment of a new genus and species increases the diversity of anaspids and allows for a more detailed study of anaspid interrelationships. An ingroup analysis using Lasanius as an outgroup resolves Birkenia as a rather basal anaspid, sister to all other anaspids, alternatively sister to a clade represented by the taxa from Ringerike, Norway, and the closely associated taxon from Saaremaa Island, Estonia. These topologies agree rather well with the present fossil record of anaspids.

  • 32.
    Blom, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jerve, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Qu, Qin Ming
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Chen, Dong Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Märss, Tiiu
    Tallinn University of Technology.
    Dupret, Vincent
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Sanchez, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Affinities of Lophosteus and the origin of the osteichthyan body plan2011In: / [ed] Streng, Kear, 2011, p. 3-4Conference paper (Refereed)
  • 33.
    Blom, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jerve, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Qu, Qingming
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Chen, Donglei
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Märss, Tiiu
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Dupret, Vincent
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Sanchez, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    The affinity of Lophosteus and the evolution of osteichthyan characters2011Conference paper (Other academic)
  • 34.
    Blom, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jerve, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Qu, Qinming
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Chen, Dong Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Märss, Tiiu
    Tallinn University of Technology.
    Dupret, Vincent
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Sanchez, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    The affinity of Lophosteus  and the evolution of osteichthyan characters2011Conference paper (Refereed)
  • 35.
    Blom, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Märss, Tiiu
    The interrelationships and evolutionary history of anaspids2010In: Morphology, Phylogeny and Paleobiogeography of Fossil Fishes: Honoring Meemann Chang / [ed] David K. Elliott, John G. Maisey, Xiaobo Yu & Desui Miao, München: Dr. Friedrich Pfeil , 2010, p. 45-58Chapter in book (Other academic)
  • 36.
    Blom, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Vaskaninova, Valeria
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Karatajūtė-Talimaa, Valentina
    Zigaite, Zivile
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Thelodont scales from the Lower Devonian of Novaya Zemlya Archipelago, Arctic Russia.2022In: Spanish Journal of Palaeontology, ISSN 2255-0550Article in journal (Refereed)
    Abstract [en]

    Scales of a new thelodont species, Amaltheolepis terranovi sp. nov., are described from the upper Emsian, Lower Devonian Shevchenkinskaya Formation of Novaya Zemlya, Arctic Russia. The new species shows strong resemblance with the Emsian “Verdalen assemblage” from Spitsbergen, supporting an Emsian age for the upper part of the Shevchenkinskaya Formation. This conclusion in the context of the various Amaltheolepisassemblages from Spitsbergen allows for a more accurate comparison and correlation between assemblages from different regions in the Northern Hemisphere, suggesting that the type species, Amaltheolepis winsnesifrom Spitsbergen, is Eifelian in age

  • 37.
    Blom, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Zigaite, Zivile
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology.
    New thelodont findings from the Lower Devonian Andrée Land Group, Spitsbergen, and their implications for biostratigraphy2012Conference paper (Other academic)
  • 38.
    Brazeau, Martin D.
    et al.
    Imperial Coll London, Dept Life Sci, Ascot, Berks, England; Nat Hist Museum, Dept Earth Sci, London, England.
    Giles, Sam
    Nat Hist Museum, Dept Earth Sci, London, England; Univ Birmingham, Sch Geog Earth & Environm Sci, Birmingham, W Midlands, England; Univ Oxford, Dept Earth Sci, Oxford, England.
    Dearden, Richard P.
    Imperial Coll London, Dept Life Sci, Ascot, Berks, England; Sorbonne Univ, CNRS, Museum Natl Hist Nat, CR2P Ctr Rech Paleontol Paris, Paris, France.
    Jerve, Anna
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Imperial Coll London, Dept Life Sci, Ascot, Berks, England.
    Ariunchimeg, Ya
    Nat Hist Museum, Ulaanbaatar, Mongolia.
    Zorig, E.
    Mongolian Acad Sci, Inst Paleontol, Ulaanbaatar, Mongolia.
    Sansom, Robert
    Univ Manchester, Sch Earth & Environm Sci, Manchester, Lancs, England.
    Guillerme, Thomas
    Univ Sheffield, Dept Anim & Plant Sci, Sheffield, S Yorkshire, England.
    Castiello, Marco
    Imperial Coll London, Dept Life Sci, Ascot, Berks, England.
    Endochondral bone in an Early Devonian 'placoderm' from Mongolia2020In: Nature Ecology & Evolution, E-ISSN 2397-334X, Vol. 4, no 11, p. 1477-1484Article in journal (Refereed)
    Abstract [en]

    Endochondral bone is the main internal skeletal tissue of nearly all osteichthyans—the group comprising more than 60,000 living species of bony fishes and tetrapods. Chondrichthyans (sharks and their kin) are the living sister group of osteichthyans and have primarily cartilaginous endoskeletons, long considered the ancestral condition for all jawed vertebrates (gnathostomes). The absence of bone in modern jawless fishes and the absence of endochondral ossification in early fossil gnathostomes appear to lend support to this conclusion. Here we report the discovery of extensive endochondral bone in Minjinia turgenensis, a new genus and species of ‘placoderm’-like fish from the Early Devonian (Pragian) of western Mongolia described using X-ray computed microtomography. The fossil consists of a partial skull roof and braincase with anatomical details providing strong evidence of placement in the gnathostome stem group. However, its endochondral space is filled with an extensive network of fine trabeculae resembling the endochondral bone of osteichthyans. Phylogenetic analyses place this new taxon as a proximate sister group of the gnathostome crown. These results provide direct support for theories of generalized bone loss in chondrichthyans. Furthermore, they revive theories of a phylogenetically deeper origin of endochondral bone and its absence in chondrichthyans as a secondary condition.

  • 39.
    Bremer, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Distribution of Silurian vertebrates on Gotland, Sweden2016Conference paper (Other academic)
  • 40.
    Bremer, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Geology, stratigraphy, and fossil vertebrates of Gotland, Sweden: a review2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Silurian limestones of Gotland, Sweden, and their exceptionally well-preserved fossils have attracted the interest of scientists for more than 200 years. The sedimentary rocks represent approximately 10 million years of time, and were deposited in a shallow, equatorial inland sea named the Baltic Basin. The majority of the sediments are composed of reef-associated strata, but a general transition can be seen along the strike from shallow water in the northeast to deeper shelf environments in the southwest. The understanding of the stratigraphy and the geology of Gotland has greatly improved during the last decades. This research on Gotland has also led to the discovery of a series of stable isotope excursions and extinctions among several faunal groups. These events were probably linked to cycles in atmospheric and oceanic states, and three of them have been recognized globally. The Baltic Basin was also home to a variety of early vertebrates. The first fossil vertebrates from Gotland were reported in 1861, but the most extensive study of these early fishes was performed in the late 1900s. More recently it was shown that the vertebrates were also affected by one of the extinction events. This thesis is an extensive review of previous work and will form a geological basis for future studies. In this work, all previous reports of vertebrates have been gathered, reviewed, and the old samples have been placed in an updated stratigraphical framework. The scale taxonomy of Gotland vertebrates, including the Baltic acanthodians, has been evaluated and partly revised. Additionally, the depositional environments of the sampled areas have been investigated. Studying the vertebrates of Gotland is important for understanding the distribution of vertebrates through time and in different environments during the Silurian. Initial results indicate environmental preferences among vertebrates on both group and species-level, which may prove useful for testing the vertebrate biozonation developed for the Silurian.

    List of papers
    1. An updated stratigraphic and environmental framework for the distribution of Silurian vertebrates on Gotland
    Open this publication in new window or tab >>An updated stratigraphic and environmental framework for the distribution of Silurian vertebrates on Gotland
    2015 (English)In: Estonian journal of earth sciences, ISSN 1736-4728, E-ISSN 1736-7557, Vol. 64, no 1, p. 13-18Article in journal (Refereed) Published
    Keywords
    vertebrate distribution, stratigraphy, facies, Silurian events, Gotland, Sweden
    National Category
    Developmental Biology Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-251824 (URN)10.3176/earth.2015.03 (DOI)000351327700004 ()
    Available from: 2015-04-27 Created: 2015-04-24 Last updated: 2017-08-21
    2. Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland
    Open this publication in new window or tab >>Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland
    Show others...
    2018 (English)In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 155, no 7, p. 1523-1541Article in journal (Refereed) Published
    Abstract [en]

    Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Poland are described from the Winnica and Rzepin sections. Both sites record the uppermost part of the Supianka Member, but represent different depositional environments. The Winnica samples come from a low-energy environment, while the Rzepin sample was taken from a high-energy, oolitic facies. Both sites contain thelodonts Thelodus parvidens, Thelodus trilobatus, an anaspid cf. Liivilepis and a number of acanthodian scales of 'nostolepid', poracanthodid and 'gomphonchid' types. Notable differences between the sites are the addition of the osteostracan Tahulaspis cf. ordinata, the thelodont Paralogania ludlowiensis and acanthodian scales identified as Nostolepis gracilis in the Rzepin section. Placing the vertebrate faunas within the vertebrate biozonation established for the Silurian proved difficult. The suggested late Ludlow age for the Supianka Member based on sequence stratigraphical and chemostratigraphical correlations cannot be definitely confirmed or refuted, but a late Ludfordian age seems the most plausible based on invertebrate and vertebrate faunas. The much lower abundance of poracanthodid acanthodians in the Rzepin sample supports the notion of Poracanthodes porosus Zone as a deep-water equivalent to a number of vertebrate biozones. The presence of P. ludlowiensis only in the oolitic sample confirms a long temporal range, but restricted environmental distribution for this taxon.

    National Category
    Other Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-281657 (URN)10.1017/S0016756817000681 (DOI)000443814900008 ()
    Available from: 2016-03-29 Created: 2016-03-29 Last updated: 2018-11-06Bibliographically approved
  • 41.
    Bremer, Oskar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Silurian vertebrates of Gotland (Sweden) and the Baltic Basin2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    During the Silurian, the Swedish island Gotland was positioned close to the equator and covered by a shallow sea called the Baltic Basin. The sedimentary rocks (predominantly carbonates) comprising most of the island today were initially formed in this warm sea, and the relatively complete succession of rocks often contains fossil fragments and scales from early vertebrates, including heterostracans, anaspids, thelodonts, osteostracans, acanthodians, and a stem-osteichthyan. Fossils of early vertebrates become increasingly more common in younger Silurian rocks, but are mostly represented by fragmentary remains and rarer occurrences of articulated jawless vertebrates (agnathans). However, the record of articulated specimens and jawed vertebrates (gnathostomes) are more numerous in rocks of the following Devonian Period. Isolated peaks of agnathan diversity during the Silurian and disarticulated remains of gnathostomes from this period hint at a cryptic evolutionary history. A micropaleontological approach with broader sampling may provide a better understanding of early vertebrate distribution patterns and hopefully give some insights into this history. The objective of this study was to build upon previous sampling on Gotland and to use established frameworks for disarticulated remains with the aim of making comparisons with similar studies performed in the East Baltic. However, difficulties locating the collections from these previous works necessitated a different focus. Undescribed museum collections and newly sampled material enabled some taxonomical revisions and greatly improved the understanding of vertebrate distribution in the youngest part of the Gotland sequence. It also indicated that this interval may represent the early stages of the diversification of gnathostomes that become increasingly dominant toward the end of the Silurian. Furthermore, the description of samples from partly coeval sections in Poland enabled some preliminary comparisons outside of Gotland, and presented a striking example of restricted environmental occurrences for a thelodont taxon. This is encouraging for future sampling and investigations on Gotland. Together with the establishment of a facies-framework comparable to that developed in the East Baltic and correlations to other areas, this may prove fruitful for an increased understanding of early vertebrate distribution and evolution during the Silurian.

    List of papers
    1. An updated stratigraphic and environmental framework for the distribution of Silurian vertebrates on Gotland
    Open this publication in new window or tab >>An updated stratigraphic and environmental framework for the distribution of Silurian vertebrates on Gotland
    2015 (English)In: Estonian journal of earth sciences, ISSN 1736-4728, E-ISSN 1736-7557, Vol. 64, no 1, p. 13-18Article in journal (Refereed) Published
    Keywords
    vertebrate distribution, stratigraphy, facies, Silurian events, Gotland, Sweden
    National Category
    Developmental Biology Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-251824 (URN)10.3176/earth.2015.03 (DOI)000351327700004 ()
    Available from: 2015-04-27 Created: 2015-04-24 Last updated: 2017-08-21
    2. End-Wenlock terminal Mulde carbon isotope excursion in Gotland, Sweden: Integration of stratigraphy and taphonomy for correlations across restricted facies and specialized faunas
    Open this publication in new window or tab >>End-Wenlock terminal Mulde carbon isotope excursion in Gotland, Sweden: Integration of stratigraphy and taphonomy for correlations across restricted facies and specialized faunas
    Show others...
    2016 (English)In: Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, E-ISSN 1872-616X, Vol. 457, p. 304-322Article in journal (Refereed) Published
    National Category
    Earth and Related Environmental Sciences
    Research subject
    Earth Science with specialization in Historical Geology and Palaeontology
    Identifiers
    urn:nbn:se:uu:diva-299498 (URN)10.1016/j.palaeo.2016.06.031 (DOI)000380598800025 ()
    Available from: 2016-07-21 Created: 2016-07-21 Last updated: 2017-08-21
    3. Vertebrate remains and conodont biostratigraphy in the Ludlow Burgsvik Formation of Gotland, Sweden
    Open this publication in new window or tab >>Vertebrate remains and conodont biostratigraphy in the Ludlow Burgsvik Formation of Gotland, Sweden
    (English)Manuscript (preprint) (Other academic)
    National Category
    Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-328226 (URN)
    Available from: 2017-08-20 Created: 2017-08-20 Last updated: 2017-08-25
    4. Vertebrate remains and conodonts in the upper Silurian Hamra and Sundre formations of Gotland, Sweden
    Open this publication in new window or tab >>Vertebrate remains and conodonts in the upper Silurian Hamra and Sundre formations of Gotland, Sweden
    2020 (English)In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 142, no 1, p. 52-80Article in journal (Refereed) Published
    Abstract [en]

    A long history of geological research on the island of Gotland, Sweden, has resulted in a detailed biostratigraphy based on conodonts for the Gotland sedimentary succession, but the relation between the Hamra and Sundre formations, the youngest strata on southern Gotland, has remained poorly resolved. These formations have also remained relatively poorly described in terms of vertebrates compared to other parts of the succession. A survey of museum collections and newly sampled material reveal that the taxonomical compositions and richness of vertebrate faunas remain similar compared to the underlying Burgsvik Sandstone and Oolite members. However, the relative abundance of the respective groups changes: Paralogania ludlowiensis and rare osteostracan remains of Tahulaspis sp. only occur in samples from the lower Hamra Formation, while Thelodus sculptilis becomes more common in samples from Sundre Formation. Conodont and isotope data give support to previous suggestions that the Hamra and Sundre formations may be largely isochronous, and it is possible that the observed differences in vertebrate faunas reflect changes in depositional setting. This interval on Gotland has been suggested to represent a hiatus in the East Baltic sections, where younger strata show an increased importance of acanthodians in the vertebrate faunas. Gotland could therefore give insights into the early stages of this diversification of gnathostomes during late Silurian times. However, this has to be done in combination with data from other areas, as well as with a review and revision of the scale-based taxonomy of Silurian acanthodians from the Baltic Basin.

    Place, publisher, year, edition, pages
    Informa UK Limited, 2020
    Keywords
    Vertebrate microremains, conodonts, isotope stratigraphy, upper Silurian, Gotland, Sweden
    National Category
    Geology
    Identifiers
    urn:nbn:se:uu:diva-328227 (URN)10.1080/11035897.2019.1655790 (DOI)000487906900001 ()
    Note

    Title in Thesis List of papers: Vertebrate dermal remains and conodont distribution in the upper Silurian Hamra and Sundre formations of Gotland, Sweden

    Available from: 2017-08-20 Created: 2017-08-20 Last updated: 2021-03-25Bibliographically approved
    5. Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland
    Open this publication in new window or tab >>Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland
    Show others...
    2018 (English)In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 155, no 7, p. 1523-1541Article in journal (Refereed) Published
    Abstract [en]

    Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Poland are described from the Winnica and Rzepin sections. Both sites record the uppermost part of the Supianka Member, but represent different depositional environments. The Winnica samples come from a low-energy environment, while the Rzepin sample was taken from a high-energy, oolitic facies. Both sites contain thelodonts Thelodus parvidens, Thelodus trilobatus, an anaspid cf. Liivilepis and a number of acanthodian scales of 'nostolepid', poracanthodid and 'gomphonchid' types. Notable differences between the sites are the addition of the osteostracan Tahulaspis cf. ordinata, the thelodont Paralogania ludlowiensis and acanthodian scales identified as Nostolepis gracilis in the Rzepin section. Placing the vertebrate faunas within the vertebrate biozonation established for the Silurian proved difficult. The suggested late Ludlow age for the Supianka Member based on sequence stratigraphical and chemostratigraphical correlations cannot be definitely confirmed or refuted, but a late Ludfordian age seems the most plausible based on invertebrate and vertebrate faunas. The much lower abundance of poracanthodid acanthodians in the Rzepin sample supports the notion of Poracanthodes porosus Zone as a deep-water equivalent to a number of vertebrate biozones. The presence of P. ludlowiensis only in the oolitic sample confirms a long temporal range, but restricted environmental distribution for this taxon.

    National Category
    Other Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-281657 (URN)10.1017/S0016756817000681 (DOI)000443814900008 ()
    Available from: 2016-03-29 Created: 2016-03-29 Last updated: 2018-11-06Bibliographically approved
    Download full text (pdf)
    fulltext
    Download (jpg)
    presentationsbild
  • 42.
    Bremer, Oskar
    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.
    An updated stratigraphic and environmental framework for the distribution of Silurian vertebrates on Gotland2015In: Estonian journal of earth sciences, ISSN 1736-4728, E-ISSN 1736-7557, Vol. 64, no 1, p. 13-18Article in journal (Refereed)
  • 43.
    Bremer, Oskar
    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.
    Biostratigraphy of early vertebrates on Gotland2014In: 4th Annual Meeting of IGCP 591, Estonia, 10 - 19 June 2014.: Abstracts and Field Guide / [ed] Heikki Bauert, Olle Hints, Tõnu Meidla & Peep Männik, Tartu: University of Tartu, 2014, p. 21-21Conference paper (Other academic)
  • 44.
    Bremer, Oskar
    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.
    Biostratigraphy of Silurian vertebrates from Gotland, Sweden, revisited: understanding spatial and temporal distributions2015In: Abstract volume of the 13th International symposium on Early and Lower Vertebrates / [ed] Kate Trinajstic, Zerina Johanson, Martha Richter and Catherine Boisvert, 2015Conference paper (Other academic)
  • 45.
    Bremer, Oskar
    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.
    Three-dimensional virtual histology of the osteostracan Dartmuthia revealed by synchrotron radiation microtomography2018Conference paper (Other academic)
  • 46.
    Bremer, Oskar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jarochowska, Emilia
    Univ Erlangen Nurnberg, GeoZentrum Nordbayern, Fachgrp Palaoumwelt, Erlangen, Germany..
    Märss, Tiiu
    Tallinn Univ Technol, Dept Geol, Tallinn, Estonia..
    Vertebrate remains and conodonts in the upper Silurian Hamra and Sundre formations of Gotland, Sweden2020In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 142, no 1, p. 52-80Article in journal (Refereed)
    Abstract [en]

    A long history of geological research on the island of Gotland, Sweden, has resulted in a detailed biostratigraphy based on conodonts for the Gotland sedimentary succession, but the relation between the Hamra and Sundre formations, the youngest strata on southern Gotland, has remained poorly resolved. These formations have also remained relatively poorly described in terms of vertebrates compared to other parts of the succession. A survey of museum collections and newly sampled material reveal that the taxonomical compositions and richness of vertebrate faunas remain similar compared to the underlying Burgsvik Sandstone and Oolite members. However, the relative abundance of the respective groups changes: Paralogania ludlowiensis and rare osteostracan remains of Tahulaspis sp. only occur in samples from the lower Hamra Formation, while Thelodus sculptilis becomes more common in samples from Sundre Formation. Conodont and isotope data give support to previous suggestions that the Hamra and Sundre formations may be largely isochronous, and it is possible that the observed differences in vertebrate faunas reflect changes in depositional setting. This interval on Gotland has been suggested to represent a hiatus in the East Baltic sections, where younger strata show an increased importance of acanthodians in the vertebrate faunas. Gotland could therefore give insights into the early stages of this diversification of gnathostomes during late Silurian times. However, this has to be done in combination with data from other areas, as well as with a review and revision of the scale-based taxonomy of Silurian acanthodians from the Baltic Basin.

    Download full text (pdf)
    fulltext
  • 47.
    Bremer, Oskar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Jarochowska, Emilia
    Märss, Tiiu
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Vertebrate remains and conodont biostratigraphy in the Ludlow Burgsvik Formation of Gotland, SwedenManuscript (preprint) (Other academic)
  • 48.
    Bremer, Oskar
    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.
    Reassessment of the ‘last’ goniopholidid: denazinosuchus kirtlandicus from the late cretaceous of New Mexico2013In: Program and Abstract Book, 2013, p. 93-94Conference paper (Other academic)
  • 49.
    Bremer, Oskar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Niedzwiedzki, Grzegorz
    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.
    Dec, Marek
    Polish Acad Sci, Inst Paleobiol, Twarda 51-55, PL-00818 Warsaw, Poland.
    Kozłowski, Wojciech
    Univ Warsaw, Inst Geol, Zwirki & Wigury 93, PL-02089 Warsaw, Poland.
    Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland2018In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 155, no 7, p. 1523-1541Article in journal (Refereed)
    Abstract [en]

    Vertebrate microremains from the upper Silurian Winnica Formation in the Holy Cross Mountains, Poland are described from the Winnica and Rzepin sections. Both sites record the uppermost part of the Supianka Member, but represent different depositional environments. The Winnica samples come from a low-energy environment, while the Rzepin sample was taken from a high-energy, oolitic facies. Both sites contain thelodonts Thelodus parvidens, Thelodus trilobatus, an anaspid cf. Liivilepis and a number of acanthodian scales of 'nostolepid', poracanthodid and 'gomphonchid' types. Notable differences between the sites are the addition of the osteostracan Tahulaspis cf. ordinata, the thelodont Paralogania ludlowiensis and acanthodian scales identified as Nostolepis gracilis in the Rzepin section. Placing the vertebrate faunas within the vertebrate biozonation established for the Silurian proved difficult. The suggested late Ludlow age for the Supianka Member based on sequence stratigraphical and chemostratigraphical correlations cannot be definitely confirmed or refuted, but a late Ludfordian age seems the most plausible based on invertebrate and vertebrate faunas. The much lower abundance of poracanthodid acanthodians in the Rzepin sample supports the notion of Poracanthodes porosus Zone as a deep-water equivalent to a number of vertebrate biozones. The presence of P. ludlowiensis only in the oolitic sample confirms a long temporal range, but restricted environmental distribution for this taxon.

  • 50.
    Bremer, Oskar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Niedźwiedzki, Grzegorz
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Dec, Marek
    Kozłowski, Wojciech
    Vertebrate microremains from the upper Silurian Winnica Formation of the Holy Cross Mountains, Poland2017Conference paper (Other academic)
1234567 1 - 50 of 454
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