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  • 1.
    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, 1075-1089 p.Article 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.

  • 2.
    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, 33-56 p.Article 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.

  • 3.
    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, 60-60 p.Conference paper (Other academic)
  • 4.
    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, 17-29 p.Chapter 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.    

  • 5.
    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, 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.

  • 6.
    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, ISSN 1940-087X, E-ISSN 1940-087X, no 123, 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.

  • 7. 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, 93-109 p.Article in journal (Refereed)
  • 8.
    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, 325-338 p.Article 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.

  • 9.
    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, 455-477 p.Article 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.

  • 10.
    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, 960-967 p.Article 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.

  • 11.
    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, 28-28 p.Conference paper (Other academic)
  • 12.
    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)
  • 13.
    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, 641-652 p.Article 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.

  • 14.
    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, 3-4 p.Conference paper (Refereed)
  • 15.
    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)
  • 16.
    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)
  • 17.
    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, 45-58 p.Chapter in book (Other academic)
  • 18.
    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)
  • 19.
    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)
  • 20.
    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, 13-18 p.Article in journal (Refereed) Published
    Keyword
    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...
    2017 (English)In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, 1-19 p., doi:10.1017/S0016756817000681Article in journal (Other academic) Epub ahead of print
    National Category
    Other Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-281657 (URN)10.1017/S0016756817000681 (DOI)
    Available from: 2016-03-29 Created: 2016-03-29 Last updated: 2017-09-04
  • 21.
    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, 13-18 p.Article in journal (Refereed) Published
    Keyword
    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, 304-322 p.Article 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 dermal remains and conodont distribution in the upper Silurian Hamra and Sundre formations of Gotland, Sweden
    Open this publication in new window or tab >>Vertebrate dermal remains and conodont distribution in the upper Silurian Hamra and Sundre formations of Gotland, Sweden
    (English)Manuscript (preprint) (Other academic)
    National Category
    Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-328227 (URN)
    Available from: 2017-08-20 Created: 2017-08-20 Last updated: 2017-08-21
    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...
    2017 (English)In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, 1-19 p., doi:10.1017/S0016756817000681Article in journal (Other academic) Epub ahead of print
    National Category
    Other Earth and Related Environmental Sciences
    Identifiers
    urn:nbn:se:uu:diva-281657 (URN)10.1017/S0016756817000681 (DOI)
    Available from: 2016-03-29 Created: 2016-03-29 Last updated: 2017-09-04
  • 22.
    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, 13-18 p.Article in journal (Refereed)
  • 23.
    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, 21-21 p.Conference paper (Other academic)
  • 24.
    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)
  • 25.
    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
    Vertebrate dermal remains and conodont distribution in the upper Silurian Hamra and Sundre formations of Gotland, SwedenManuscript (preprint) (Other academic)
  • 26.
    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)
  • 27.
    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, 93-94 p.Conference paper (Other academic)
  • 28.
    Bremer, Oskar
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Niedzwiedzki, 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, Poland2017In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, 1-19 p., doi:10.1017/S0016756817000681Article in journal (Other academic)
  • 29.
    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)
  • 30. Brown, Caleb Marshall
    et al.
    VanBuren, Collin S.
    Larson, Derek W.
    Brink, Kirstin S.
    Campione, Nicolas E.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Vavrek, Matthew J.
    Evans, David C.
    Tooth counts through growth in diapsid reptiles: implications for interpreting individual and size-related variation in the fossil record2015In: Journal of Anatomy, ISSN 0021-8782, E-ISSN 1469-7580, Vol. 226, no 4, 322-333 p.Article in journal (Refereed)
    Abstract [en]

    Tooth counts are commonly recorded in fossil diapsid reptiles and have been used for taxonomic and phylogenetic purposes under the assumption that differences in the number of teeth are largely explained by interspecific variation. Although phylogeny is almost certainly one of the greatest factors influencing tooth count, the relative role of intraspecific variation is difficult, and often impossible, to test in the fossil record given the sample sizes available to palaeontologists and, as such, is best investigated using extant models. Intraspecific variation (largely manifested as size-related or ontogenetic variation) in tooth counts has been examined in extant squamates (lizards and snakes) but is poorly understood in archosaurs (crocodylians and dinosaurs). Here, we document tooth count variation in two species of extant crocodylians (Alligator mississippiensis and Crocodylus porosus) as well as a large varanid lizard (Varanus komodoensis). We test the hypothesis that variation in tooth count is driven primarily by growth and thus predict significant correlations between tooth count and size, as well as differences in the frequency of deviation from the modal tooth count in the premaxilla, maxilla, and dentary. In addition to tooth counts, we also document tooth allometry in each species and compare these results with tooth count change through growth. Results reveal no correlation of tooth count with size in any element of any species examined here, with the exception of the premaxilla of C.porosus, which shows the loss of one tooth position. Based on the taxa examined here, we reject the hypothesis, as it is evident that variation in tooth count is not always significantly correlated with growth. However, growth trajectories of smaller reptilian taxa show increases in tooth counts and, although current samples are small, suggest potential correlates between tooth count trajectories and adult size. Nevertheless, interspecific variation in growth patterns underscores the importance of considering and understanding growth when constructing taxonomic and phylogenetic characters, in particular for fossil taxa where ontogenetic patterns are difficult to reconstruct.

  • 31. Brusatte, Stephen L.
    et al.
    Butler, Richard J.
    Niedzwiedzki, Grzegorz
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Sulej, Tomasz
    Bronowicz, Robert
    Satkunas, Jonas
    First record of Mesozoic terrestrial vertebrates from Lithuania: phytosaurs (Diapsida: Archosauriformes) of probable Late Triassic age, with a review of phytosaur biogeography2013In: Geological Magazine, ISSN 0016-7568, E-ISSN 1469-5081, Vol. 150, no 1, 110-122 p.Article in journal (Refereed)
    Abstract [en]

    Fossils of Mesozoic terrestrial vertebrates from Lithuania and the wider East Baltic region of Europe have previously been unknown. We here report the first Mesozoic terrestrial vertebrate fossils from Lithuania: two premaxillary specimens and three teeth that belong to Phytosauria, a common clade of semiaquatic Triassic archosauriforms. These specimens represent an uncrested phytosaur, similar to several species within the genera Paleorhinus, Parasuchus, Rutiodon and Nicrosaurus. Because phytosaurs are currently only known from the Upper Triassic, their discovery in northwestern Lithuania (the Saltiskiai clay-pit) suggests that at least part of the Triassic succession in this region is Late Triassic in age, and is not solely Early Triassic as has been previously considered. The new specimens are among the most northerly occurrences of phytosaurs in the Late Triassic, as Lithuania was approximately 7-10. further north than classic phytosaur-bearing localities in nearby Germany and Poland, and as much as 40. further north than the best-sampled phytosaur localities in North America. The far northerly occurrence of the Lithuanian fossils prompts a review of phytosaur biogeography and distribution, which suggests that these predators were widely distributed in the Triassic monsoonal belt but rarer in more arid regions.

  • 32.
    Campione, Nicolas E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Evans, David C.
    Brown, Caleb M.
    Carrano, Matthew T.
    Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions2014In: Methods in Ecology and Evolution, ISSN 2041-210X, E-ISSN 2041-210X, Vol. 5, no 9, 913-923 p.Article in journal (Refereed)
    Abstract [en]

    Body mass is strongly related to both physiological and ecological properties of living organisms. As a result, generating robust, broadly applicable models for estimating body mass in the fossil record provides the opportunity to reconstruct palaeobiology and investigate evolutionary ecology on a large temporal scale. A recent study provided strong evidence that the minimum circumference of stylopodial elements (humerus and femur) is conservatively associated with body mass in living quadrupeds. Unfortunately, this model is not directly applicable to extinct bipeds, such as non-avian dinosaurs. This study presents a new equation that mathematically corrects the quadruped equation for use in bipeds. It is derived from the systemic difference in the circumference-to-area scaling relationship of two circles (hypothetical quadruped) and one circle (hypothetical biped), which represent the cross-section of the main weight-bearing limb bones. When applied to a newly constructed data set of femoral circumferences and body masses in living birds, the new equation reveals errors that are significantly lower than other published equations, but significantly higher than the error inherent in the avian data set. Such errors, however, are expected given the unique overall femoral circumference-body mass scaling relationship found in birds. Body mass estimates for a sample of bipedal dinosaurs using the new model are consistent with recent estimates based on volumetric life reconstructions, but, in contrast, this equation is simpler to use, with the concomitant potential to provide a wider set of body mass estimates for extinct bipeds. Although it is evident that no one estimation model is flawless, the combined use of the corrected quadrupedal equations and the previously published quadrupedal equation offer a consistent approach with which to estimate body masses in both quadrupeds and bipeds. These models have implications for conducting large-scale macroevolutionary analyses of body size throughout the evolutionary history of terrestrial vertebrates, and, in particular, across major changes in body plan, such as the evolution of bipedality in archosaurs and quadrupedality in dinosaurs.

  • 33.
    Chen, Dong Lei
    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.
    Sanchez, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Tafforeau, Paul
    Estonian Marine Institute, University of Tartu.
    Märss, Tiiu
    Estonian Marine Institute, University of Tartu.
    Ahlberg, Per E.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus 2017In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 5, 161084Article in journal (Refereed)
    Abstract [en]

    The numerous cushion-shaped tooth-bearing plates attributed to the stem-group osteichthyan Lophosteus superbus, which are argued here to represent the ancient form of inner dental arcade, display a unique and presumably primitive way of tooth shedding by basal hard tissue resorption. They carry regularly spaced, recumbent, gently recurved teeth arranged in transverse tooth files that diverge towards the lingual margin of the cushion. Three-dimensional (3D) reconstruction from propagation phase contrast synchrotron microtomography (PPC-SRμCT) reveals remnants of the first-generation teeth embedded in the basal plate that have never been discerned in any taxa. These teeth were shed by semi-basal resorption with the periphery of their bases retained as dentine rings. The rings are highly overlapped, which evidences tooth shedding prior to adding the next first-generation tooth. Later teeth at the same sites underwent cyclical replacing and shedding through basal resorption, producing stacks of buried resorption surfaces separated by bone of attachment. The number and spatial arrangement of resorption surfaces elucidates that basal resorption of replacement teeth had taken place at the older tooth sites before the addition of the youngest first-generation teeth at the lingual margin. Thus the replacement tooth buds cannot have been generated by a single permanent dental lamina, but must have arisen either from successional dental laminae associated with the predecessor teeth, or directly from the dental epithelium of these teeth. The virtual histological dissection of these Late Silurian microfossils broadens our understanding of the development of the gnathostome dental systems and the acquisition of the osteichthyan-type of tooth replacement. 

  • 34.
    Chen, Donglei
    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, Biology, Biology Education Centre.
    Squamation in Andreolepis from the late Silurian of Sweden2010Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    The origin of osteichthyans (bony fishes and tetrapods) dates back to the Late Silurian, but theearly evolution of osteichthyans is poorly understood. Andreolepis is one of the oldest knownosteichthyans, but exclusively documented by detached and fragmented dermal microremains.Nevertheless, Andreolepis has unequivocally been attributed to the osteichthyan stem group.A variety of isolated scales of Andreolepis from Gotland, Sweden provides a large dataset,which would potentially improve our understanding of the acquisition of the osteichthyanbody plan. In the present study, various forms of Andreolepis scales were classified into tenmorphotypes by landmark-based geometric morphometrics. Based on comparative anatomyand functional morphology, each morphotype was assigned to a specific area of the body anda squamation model of Andreolepis was established. In this model, scales are allocated toanterior-mid lateral flank scales, posterior lateral flank scales, caudal peduncle scales, pectoralpeduncle scales, dorsal flank scales, dorsal fulcral scales, caudal fulcral scales, ventral flankscales, medioventral scales and cranial scales.

  • 35.
    Chen, Donglei
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    The Origin of Tooth Replacement: Three-dimensional Synchrotron Histology Visualizes the Dental Development of Silurian Stem Osteichthyans2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Mechanisms of tooth replacement distribute incongruently among extant gnathostomes (jawed vertebrates): a permanent tooth-generating dental lamina exists in chondrichthyans (cartilaginous fish) and tetrapods but not teleosts, whereas tooth shedding by basal hard tissue resorption occurs in tetrapods and teleosts but not chondrichthyans. Theories about the evolution of tooth development have been biased towards the chondrichthyan conveyor-belt replacement, since there has been no fossil evidence for the origin of osteichthyan (bony fish and tetrapods) tooth replacement until now. 3D virtual dissections with submicron-scale resolution, based on propagation phase contrast synchrotron microtomography (PPC-SRµCT), reveal the growth history of the dentitions of Andreolepis and Lophosteus, 423-Myr-old Silurian stem osteichthyans close to the common ancestor of tetrapods and teleosts. Their marginal jawbones and “tooth cushions” (possible homologues of coronoids) shed teeth by in situ cyclic basal resorption, the earliest examples of osteichthyan-style tooth replacement. The replacement cycles were site-autonomic, and occurred in broad irregular multi-row tooth fields, including at sites separated from the margin of the bone by intervening teeth, showing that the production of replacement teeth did not occur in a single deep dental lamina, but in pockets associated with each tooth, as in many teleosts. It suggests that the functionally and anatomically similar laminae of chondrichthyans and tetrapods are convergent. The marginal jaw bones of both genera carry an initial non-shedding dentition arranged in alternate transverse files, labial to the shedding tooth field, overgrown by later dermal ornament and probably not belonging to the oral domain, but bearing in vivo biting damage showing that they functioned as teeth. The most lingual of these odontodes have been resorbed apically and are overlain by shedding teeth. The first-generation teeth on the tooth cushions display basal resorption in Andreolepis, but semi-basal resorption in Lophosteus. The latter leaves a basal dentine ring from each tooth, implying only odontoclasts are involved in the semi-basal resorption, which is probably the first step towards evolving a site-specific resorption. The polarized displacement of each generation of resorption surfaces reflects the fact that the cyclic replacement, as well as the sequential addition of tooth sites, is closely related to bone growth. Resorption surfaces and growth arrest surfaces also record the life history and the replacement rate. These data provide unique insights into the origin of osteichthyan tooth replacement.

    List of papers
    1. The stem osteichthyan Andreolepis and the origin of tooth replacement
    Open this publication in new window or tab >>The stem osteichthyan Andreolepis and the origin of tooth replacement
    Show others...
    2016 (English)In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 539, no 7628, 237-+ p.Article in journal (Refereed) Published
    Abstract [en]

    The teeth of gnathostomes (jawed vertebrates) show rigidly patterned, unidirectional replacement that may or may not be associated with a shedding mechanism. These mechanisms, which are critical for the maintenance of the dentition, are incongruently distributed among extant gnathostomes. Although a permanent tooth-generating dental lamina is present in all chondrichthyans, many tetrapods and some teleosts, it is absent in the non-teleost actinopterygians. Tooth-shedding by basal hard tissue resorption occurs in most osteichthyans (including tetrapods) but not in chondrichthyans. Here we report a three-dimensional virtual dissection of the dentition of a 424-million-year-old stem osteichthyan, Andreolepis hedei, using propagation phase-contrast synchrotron microtomography, with a reconstruction of its growth history. Andreolepis, close to the common ancestor of all extant osteichthyans, shed its teeth by basal resorption but probably lacked a permanent dental lamina. This is the earliest documented instance of resorptive tooth shedding and may represent the primitive osteichthyan mode of tooth replacement.

    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-310754 (URN)10.1038/nature19812 (DOI)000387318500034 ()27750278 (PubMedID)
    Funder
    EU, European Research Council, 233111Knut and Alice Wallenberg Foundation
    Available from: 2016-12-20 Created: 2016-12-19 Last updated: 2017-11-29Bibliographically approved
    2. Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus 
    Open this publication in new window or tab >>Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus 
    Show others...
    2017 (English)In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 4, no 5, 161084Article in journal (Refereed) Published
    Abstract [en]

    The numerous cushion-shaped tooth-bearing plates attributed to the stem-group osteichthyan Lophosteus superbus, which are argued here to represent the ancient form of inner dental arcade, display a unique and presumably primitive way of tooth shedding by basal hard tissue resorption. They carry regularly spaced, recumbent, gently recurved teeth arranged in transverse tooth files that diverge towards the lingual margin of the cushion. Three-dimensional (3D) reconstruction from propagation phase contrast synchrotron microtomography (PPC-SRμCT) reveals remnants of the first-generation teeth embedded in the basal plate that have never been discerned in any taxa. These teeth were shed by semi-basal resorption with the periphery of their bases retained as dentine rings. The rings are highly overlapped, which evidences tooth shedding prior to adding the next first-generation tooth. Later teeth at the same sites underwent cyclical replacing and shedding through basal resorption, producing stacks of buried resorption surfaces separated by bone of attachment. The number and spatial arrangement of resorption surfaces elucidates that basal resorption of replacement teeth had taken place at the older tooth sites before the addition of the youngest first-generation teeth at the lingual margin. Thus the replacement tooth buds cannot have been generated by a single permanent dental lamina, but must have arisen either from successional dental laminae associated with the predecessor teeth, or directly from the dental epithelium of these teeth. The virtual histological dissection of these Late Silurian microfossils broadens our understanding of the development of the gnathostome dental systems and the acquisition of the osteichthyan-type of tooth replacement. 

    Place, publisher, year, edition, pages
    ROYAL SOC, 2017
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-315882 (URN)10.1098/rsos.161084 (DOI)000402541800020 ()28573003 (PubMedID)
    Available from: 2017-02-22 Created: 2017-02-22 Last updated: 2017-08-02Bibliographically approved
    3. Microstructures of the most primitive form of inner dental arcade and life history of the Silurian stem osteichthyan Andreolepis.
    Open this publication in new window or tab >>Microstructures of the most primitive form of inner dental arcade and life history of the Silurian stem osteichthyan Andreolepis.
    Show others...
    (English)Manuscript (preprint) (Other academic)
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-315883 (URN)
    Available from: 2017-02-22 Created: 2017-02-22 Last updated: 2017-02-22
    4. The marginal dentition of Lophosteus superbus Pander 1856, a Late Silurian stem osteichthyan from Estonia.
    Open this publication in new window or tab >>The marginal dentition of Lophosteus superbus Pander 1856, a Late Silurian stem osteichthyan from Estonia.
    (English)Manuscript (preprint) (Other academic)
    National Category
    Evolutionary Biology
    Identifiers
    urn:nbn:se:uu:diva-315884 (URN)
    Available from: 2017-02-22 Created: 2017-02-22 Last updated: 2017-02-22
  • 36.
    Chen, Donglei
    et al.
    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.
    A Partial Tetrapod Lower Jaw from “Romer’s Gap”2009In: SVP 69th Annual Meeting and the 57th Symposium of Vertebrate Palaeontology and Comparative Anatomy (SVPCA), 2009Conference paper (Other academic)
  • 37.
    Chen, Donglei
    et al.
    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 marginal dentition of Lophosteus superbus Pander 1856, a Late Silurian stem osteichthyan from Estonia.Manuscript (preprint) (Other academic)
  • 38.
    Chen, Donglei
    et al.
    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.
    Blom, Henning
    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.
    Dental Development of the Stem Osteichthyan Andreolepis hedei Revealed by Three-dimensional Synchrotron Virtual Paleohistology2013In: Program and Abstracts: Society of Vertebrate Paleontology 73rd Annual meeting, 2013, 103-103 p.Conference paper (Other academic)
  • 39.
    Chen, Donglei
    et al.
    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.
    Blom, Henning
    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.
    Dental Development of the Stem Osteichthyan Andreolepis hedei Revealed by Three-dimensional Synchrotron Virtual Paleohistology2013Conference paper (Other academic)
  • 40. Chen, Donglei
    et al.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Scale morphology and squamation of Andreolepis from the Late Silurian of Gotland, Sweden.2011Conference paper (Other academic)
  • 41.
    Chen, Donglei
    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.
    Scale morphology and squamation of Andreolepis from the Late Silurian of Gotland, Sweden2011In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 133, no 1-2, 60-61 p.60-61 p.Article in journal (Refereed)
  • 42.
    Chen, Donglei
    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.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Three-dimensional histology of tooth cushions of Lophosteus from the Late Silurian of Estonia2011In: Program and Abstracts: 71st Annual Meeting, Society of Vertebrate Paleontolog, Philadelphia: Society of Vertebrate Paleontology , 2011, 87-87 p.Conference paper (Other academic)
  • 43.
    Chen, Donglei
    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.
    Ahlberg, Per
    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.
    Three-dimensional histology of tooth cushions of Lophosteus from the Upper Silurian of Estonia2011In: Abstracts: The 2nd Wiman meeting: Carl Wiman's Legacy: 100 years of Swedish Palaeontology: Uppsala 17–18 November 2011 / [ed] Benjamin P. Kear and Michael Streng, 2011, 5-6 p.Conference paper (Other academic)
    Abstract [en]

    Lophosteus superbus from the Late Silurian of Estonia is one of the oldest and most plesiomorphic osteichthyans described to date. Unfortunately at present it is known only from fragmented dermal microremains. The affinities of Lophosteus are therefore controversial with the taxon placed as either basal to both actinopterygians and sarcopterygians, or ambiguously linked to either placoderms or acanthodians. To confound matters further, the character states diagnosing actinopterygians and sarcopterygians have recently been brought into question, and even monophyly of the traditional placoderm and acanthodian clades has been challenged. As a possible stem osteichthyan, Lophosteus could thus be central to our understanding of early gnathostome evolution and the origin of the osteichthyan body plan. Often the best-preserved, although incompletely documented, elements of Lophosteus are tooth cushions. These tooth-bearing arched ossicles could arguably be homologous with the parasymphysial tooth whorls in chondrichthyans, acanthodians, and sarcopterygians, or even the parasymphysial tooth plates in tetrapodomorphs. High-resolution synchrotron scans of 6 isolated tooth cushions from the Upper Silurian of Estonia has permitted a detailed reconstruction of their three-dimensional architecture. The absence of an enamel layer and the presence of large hollows (bigger than normal osteocytes) in the deepest lamellar layer confirmed assignment of the specimens to Lophosteus. The external surface displays irregularly distributed denticles and there are large parallel vessels running horizontally on the basal bone that feed the denticle rows internally. The odontodes have two distinct generations (with successive odontodes accreted between those of the preceding buried generation) and are organised in a similar manner to those found on Lophosteus scales. This new histological data on vascularization provides insight into early gnathostome tooth patterning and could contribute to future phylogenetic assessments.

  • 44.
    Chen, Donglei
    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.
    Sanchez, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Tafforeau, Paul
    European Synchrotron Radiation Facility.
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Microstructures of the most primitive form of inner dental arcade and life history of the Silurian stem osteichthyan Andreolepis.Manuscript (preprint) (Other academic)
  • 45.
    Chen, Donglei
    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.
    Sanchez, Sophie
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University, Science for Life Laboratory, SciLifeLab. European Synchrotron Radiat Facil, 6 Rue Jules Horowitz, F-38043 Grenoble, France..
    Tafforeau, Paul
    European Synchrotron Radiat Facil, 6 Rue Jules Horowitz, F-38043 Grenoble, France..
    Ahlberg, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    The stem osteichthyan Andreolepis and the origin of tooth replacement2016In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 539, no 7628, 237-+ p.Article in journal (Refereed)
    Abstract [en]

    The teeth of gnathostomes (jawed vertebrates) show rigidly patterned, unidirectional replacement that may or may not be associated with a shedding mechanism. These mechanisms, which are critical for the maintenance of the dentition, are incongruently distributed among extant gnathostomes. Although a permanent tooth-generating dental lamina is present in all chondrichthyans, many tetrapods and some teleosts, it is absent in the non-teleost actinopterygians. Tooth-shedding by basal hard tissue resorption occurs in most osteichthyans (including tetrapods) but not in chondrichthyans. Here we report a three-dimensional virtual dissection of the dentition of a 424-million-year-old stem osteichthyan, Andreolepis hedei, using propagation phase-contrast synchrotron microtomography, with a reconstruction of its growth history. Andreolepis, close to the common ancestor of all extant osteichthyans, shed its teeth by basal resorption but probably lacked a permanent dental lamina. This is the earliest documented instance of resorptive tooth shedding and may represent the primitive osteichthyan mode of tooth replacement.

  • 46.
    Chen, Donglei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Janvier, Philippe
    Département Histoire de la Terre, Muséum National d'Histoire Naturelle,.
    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.
    Scale morphology and squamation of the Late Silurian osteichthyan Andreolepis from Gotland, Sweden2012In: Historical Biology, ISSN 0891-2963, E-ISSN 1029-2381, Vol. 24, no 4, 411-423 p.Article in journal (Refereed)
    Abstract [en]

    The origin of osteichthyans (bony fishes and tetrapods) dates back to the Late Silurian, but the early evolution of the group is poorly understood. Andreolepis is one of the oldest known osteichthyans, but exclusively documented by detached and fragmentary dermal microremains. A large data-set of Andreolepis scales from the Silurian of Gotland has been used to explore the scale morphology on different parts of the body. Landmark-based geometric morphometrics together with comparative anatomy and functional morphology has allowed 10 morphotypes to be identified and incorporated into a squamation model, in which scales are allocated to anterior-mid lateral flank scales, posterior lateral flank scales, caudal peduncle scales, pectoral peduncle scales, dorsal flank scales, dorsal fulcral scales, caudal fulcral scales, ventral flank scales, medioventral scales and cranial scales. The scale morphology and squamation pattern ofAndreolepis may be primitive for the Osteichthyes and thus informative about the acquisition of the osteichthyan body plan.

  • 47. Cheng, Xinlai
    et al.
    Peuckert, Christiane
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Wölfl, Stefan
    Essential role of mitochondrial Stat3 in p38(MAPK) mediated apoptosis under oxidative stress2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, no 1, 15388Article in journal (Refereed)
    Abstract [en]

    Stat3 is an oncogene, frequently associated with malignant transformation. A body of evidence implicates that phospho-Stat3(Y705) contributes to its nucleic translocation, while phospho-Stat3(S727) leads to the accumulation in mitochondria. Both are of importance for tumor cell proliferation. In comparison to well-characterized signaling pathways interplaying with Stat3(Y705), little is known about Stat3(S727). In this work, we studied the influence of Stat3 deficiency on the viability of cells exposed to H2O2 or hypoxia using siRNA and CRISPR/Cas9 genome-editing. We found dysregulation of mitochondrial activity, which was associated with excessive ROS formation and reduced mitochondrial membrane potential, and observed a synergistic effect for oxidative stress-mediated apoptosis in Stat3-KD cells or cells carrying Stat3(Y705F), but not Stat3(S727D), suggesting the importance of functional mitochondrial Stat3 in this context. We also found that ROS-mediated activation of ASK1/p38(MAPK) was involved and adding antioxidants, p38(MAPK) inhibitor, or genetic repression of ASK1 could easily rescue the cellular damage. Our finding reveals a new role of mitochondrial Stat3 in preventing ASK1/p38(MAPK)-mediated apoptosis, wich further support the notion that selective inhibition mitochondrial Stat3 could provide a primsing target for chemotherapy.

  • 48.
    Choo, Brian
    et al.
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Flinders Univ S Australia, Sch Biol Sci, Adelaide, SA, Australia..
    Zhu, Min
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Univ Chinese Acad Sci, Coll Earth Sci, Beijing, Peoples R China..
    Qu, Qinming
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Univ Ottawa, Ctr Adv Res Environm Genom, Ottawa, ON, Canada..
    Yu, Xiaobo
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Kean Univ, Dept Biol Sci, Union, NJ USA..
    Jia, Liantao
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China..
    Zhao, Wenjin
    Chinese Acad Sci, Key Lab Vertebrate Evolut & Human Origins, Inst Vertebrate Paleontol & Paleoanthropol, Beijing, Peoples R China.;Univ Chinese Acad Sci, Coll Earth Sci, Beijing, Peoples R China..
    A new osteichthyan from the late Silurian of Yunnan, China2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 3, e0170929Article in journal (Refereed)
    Abstract [en]

    Our understanding of early gnathostome evolution has been hampered by a generally scant fossil record beyond the Devonian. Recent discoveries from the late Silurian Xiaoxiang Fauna of Yunnan, China, have yielded significant new information, including the earliest articulated osteichthyan fossils from the Ludlow-aged Kuanti Formation. Here we describe the partial postcranium of a new primitive bony fish from the Kuanti Formation that represents the second known taxon of pre-Devonian osteichthyan revealing articulated remains. The new form, Sparalepis tingi gen. et sp. nov., displays similarities with Guiyu and Psarolepis, including a spine-bearing pectoral girdle and a placoderm-like dermal pelvic girdle, a structure only recently identified in early osteichthyans. The squamation with particularly thick rhombic scales shares an overall morphological similarity to that of Psarolepis. However, the anterior flank scales of Sparalepis possess an unusual interlocking system of ventral bulges embraced by dorsal concavities on the outer surfaces. A phylogenetic analysis resolves Sparalepis within a previously recovered cluster of stem-sarcopterygians including Guiyu, Psarolepis and Achoania. The high diversity of osteichthyans from the Ludlow of Yunnan strongly contrasts with other Silurian vertebrate assemblages, suggesting that the South China block may have been an early center of diversification for early gnathostomes, well before the advent of the Devonian "Age of Fishes".

  • 49.
    Chylenski, Maciej
    et al.
    Adam Mickiewicz Univ, Fac Hist, Inst Archaeol, Umultowska 89D, PL-61614 Poznan, Poland..
    Juras, Anna
    Adam Mickiewicz Univ, Fac Biol, Inst Anthropol, Dept Human Evolutionary Biol, Umultowska 89, PL-61614 Poznan, Poland..
    Ehler, Edvard
    Adam Mickiewicz Univ, Fac Biol, Inst Anthropol, Dept Human Evolutionary Biol, Umultowska 89, PL-61614 Poznan, Poland.;Charles Univ Prague, Fac Educ, Dept Biol & Environm Studies, Magdaleny Rettigove 4, Prague 11639, Czech Republic..
    Malmström, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Piontek, Janusz
    Adam Mickiewicz Univ, Fac Biol, Inst Anthropol, Dept Human Evolutionary Biol, Umultowska 89, PL-61614 Poznan, Poland..
    Jakobsson, Mattias
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology. Uppsala University, Science for Life Laboratory, SciLifeLab.
    Marciniak, Arkadiusz
    Adam Mickiewicz Univ, Fac Hist, Inst Archaeol, Umultowska 89D, PL-61614 Poznan, Poland..
    Dabert, Miroslawa
    Adam Mickiewicz Univ, Fac Biol, Mol Biol Techn Lab, Umultowska 89, PL-61614 Poznan, Poland..
    Late Danubian mitochondrial genomes shed light into the Neolithisation of Central Europe in the 5th millennium BC2017In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 17, 80Article in journal (Refereed)
    Abstract [en]

    Background: Recent aDNA studies are progressively focusing on various Neolithic and Hunter-Gatherer (HG) populations, providing arguments in favor of major migrations accompanying European Neolithisation. The major focus was so far on the Linear Pottery Culture (LBK), which introduced the Neolithic way of life in Central Europe in the second half of 6th millennium BC. It is widely agreed that people of this culture were genetically different from local HGs and no genetic exchange is seen between the two groups. From the other hand some degree of resurgence of HGs genetic component is seen in late Neolithic groups belonging to the complex of the Funnel Beaker Cultures (TRB). Less attention is brought to various middle Neolithic cultures belonging to Late Danubian sequence which chronologically fall in between those two abovementioned groups. We suspected that genetic influx from HG to farming communities might have happened in Late Danubian cultures since archaeologists see extensive contacts between those two communities. Results: Here we address this issue by presenting 5 complete mitochondrial genomes of various late Danubian individuals from modern-day Poland and combining it with available published data. Our data show that Late Danubian cultures are maternally closely related to Funnel Beaker groups instead of culturally similar LBK. Conclusions: We assume that it is an effect of the presence of individuals belonging to U5 haplogroup both in Late Danubians and the TRB. The U5 haplogroup is thought to be a typical for HGs of Europe and therefore we argue that it is an additional evidence of genetic exchange between farming and HG groups taking place at least as far back as in middle Neolithic, in the Late Danubian communities.

  • 50. Clack, Jennifer A.
    et al.
    Ahlberg, Per E.
    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.
    Finney, Sarah M.
    A new genus of Devonian tetrapod from North-East Greenland, with new information on the lower jaw of Ichthyostega2012In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 55, no 1, 73-86 p.Article in journal (Refereed)
    Abstract [en]

    A new genus and species of Devonian tetrapod has been identified from material collected in 1947 from the southern slope of Mt. Celsius, Ymer phi, North-East Greenland. The specimen preserves both lower jaws, partial palate, premaxillae and maxillae, with a natural mould of parts of the shoulder girdle. The new taxon, Ymeria denticulata, shows differences in dentition, skull ornament and lateral line expression from both Acanthostega and Ichthyostega, but it shows a closer resemblance to the latter. A cladistic analysis not only suggests that Ymeria lies adjacent to Ichthyostega on the tetrapod stem, but also reveals substantial topological instability. As the third genus and the fifth species of tetrapod identified from North-East Greenland, it demonstrates the high diversity of Devonian tetrapods in that region.

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