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  • 1.
    Bomfleur, Benjamin
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Klymiuk, Ashley
    Taylor, Edith
    Taylor, Thomas
    Gulbranson, Erik
    Isbell, John
    Diverse bryophyte mesofossils from the Triassic of Antarctica2014Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 47, nr 1, s. 120-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Compared with the fossil record of vascular plants, bryophyte fossils are rare; this circumstance is probably related to a lower preservation potential compared with that of vascular plants. We searched for bryophyte remains in extensive collections of plant-fossil assemblages from the Triassic of Antarctica and identified three assemblages with surprisingly well-preserved bryophyte fossils. Although most bryophyte remains are too fragmented to conclusively place them in a detailed systematic context, they exhibit features sufficient to suggest the presence of at least four types of leafy bryophytes and two orders of thallose liverworts (Pallaviciniales and Metzgeriales) in the high-latitude Triassic ecosystems of Antarctica. The leafy bryophytes exhibit combinations of morphological features (e.g. keeled and entire-margined, ecostate leaves with elongated cells) that today occur in only a few small, systematically isolated groups, but were common among Palaeozoic and especially Mesozoic bryophytes. The diverse morphologies of the bryophyte fossils add further support to previous hypotheses that during warmer periods in the Earth’s history, bryophyte vegetation may have been particularly rich and diverse in high-latitude regions. Through analysis of the sedimentology and taphonomy of these assemblages, we identify a combination of key factors that may explain the preservation of bryophyte fossils in these deposits: (1) punctuated, high-energetic sedimentary events causing traumatic removal and incorporation of bryophytes into sediment-laden flood waters; (2) limited transport distance, and short period of suspension, followed by rapid settling and burial as a result of a rapidly decelerating flow discharging into a floodplain environment; and (3) early-diagenetic cementation with iron hydroxides in locally anoxic zones of the organic-rich, muddy substrate.

  • 2.
    Cornacchia, Irene
    et al.
    Dipartimento di Scienze della Terra, Sapienza Universita di Roma.
    Andersson, Per
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Agostine, Samuele
    Instituto di Geosciencze e Georisorse, CNR, Pisa.
    Brandanao, Marco
    Dipartimento di Scienze della Terra, Sapienza Universita di Roma.
    Strontium stratigraphy of the upper Miocene Lithothamnion Limestone in the Majella Mountain, central Italy, and its palaeoenvironmental implications2017Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 50, nr 4, s. 561-575Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The87Sr/86Sr isotope ratio has been widely used as aphysical tool to date and correlate carbonate successions due to the long Srresidence time in comparison with the ocean mixing time. If this method workson oceanic successions, marginal basins may show different Sr isotope recordsin comparison with the coeval ocean one due to sea-level variations,continental run-off and restricted water exchanges. In this work, we present the87Sr/86Sr isotope record of the upper Miocene carbonateramp of the Lithothamnion Limestone(Majella Mountain, central Apennines), as an example of the onset of restrictedwater exchanges between a marginal basin and the ocean water masses. The overalllatemost Tortonian–earlyMessinian Sr isotope record of the Lithothamnion Limestonefits below the global reference line. This deviation has been interpreted as dueto the strong control that freshwater input and enhanced continental run-off,linked to the migration of the Apennine accretionary wedge and foredeep system,have had on the central Adriatic water chemistry. These results imply that anaccurate oceanographic and geodynamic framework along with diagenetic overprintinvestigation has to be taken into consideration prior to apply SIS oncarbonate successions on marginal basins, even when facies analyses indicatefully marine conditions. This seems to be the case for the upper MioceneCentral Mediterranean carbonate successions, but may have more general validityand be extended to other recent or past marginal basins.

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  • 3.
    Doguzhaeva, Larisa A.
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Weis, Robert
    Musée national d’histoire naturelle, Luxembourg.
    Delsate, Dominique
    Musée national d’histoire naturelle, Luxembourg.
    Mariotti, Nino
    Università ‘La Sapienza’, Roma, Italy.
    Embryonic shell structure of Early–Middle Jurassic belemnites, and its significance for belemnite expansion and diversification in the Jurassic.2014Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 47, nr 1, s. 49-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Early Jurassic belemnites are of particular interest to the study of the evolution of skeletal morphology in Lower Carboniferous to the uppermost Cretaceous belemnoids, because they signal the beginning of a global Jurassic–Cretaceous expansion and diversification of belemnitids. We investigated potentially relevant, to this evolutionary pattern, shell features of Sinemurian–Bajocian Nannobelus, Parapassaloteuthis, Holcobelus and Pachybelemnopsis from the Paris Basin. Our analysis of morphological, ultrastructural and chemical traits of the earliest ontogenetic stages of the shell suggests that modified embryonic shell structure of Early–Middle Jurassic belemnites was a factor in their expansion and colonization of the pelagic zone and resulted in remarkable diversification of belemnites. Innovative traits of the embryonic shell of Sinemurian– Bajocian belemnites include: (1) an inorganic–organic primordial rostrum encapsulating the protoconch and the phragmocone, its non-biomineralized component, possibly chitin, is herein detected for the first time; (2) an organic rich closing membrane which was under formation. It was yet perforated and possessed a foramen; and (3) an organic rich pro-ostracum earlier documented in an embryonic shell of Pliensbachian Passaloteuthis. The inorganic–organic primordial rostrum tightly coating the protoconch and phragmocone supposedly enhanced protection, without increase in shell weight, of the Early Jurassic belemnites against explosion in deepwater environment. This may have increased the depth and temperature ranges of hatching eggs, accelerated the adaptation of hatchlings to a nektonic mode of life and promoted increasing diversity of belemnoids. This study supports the hypothesis that belemnite hatchlings were ‘a miniature of the adults’.

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    Doguzhaeva_etal_2014_Embryonic
  • 4.
    Doguzhaeva, Larisa
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Mapes, Royal
    North Carolina Museum of Natural Sciences.
    Arm hooks and structural features in the Early Permian Glochinomorpha Gordon 1971, indicative of its coleoid affiliation.2014Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, artikel-id DOI: 10.1111/let.12091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Data on the re-examined-type specimens of the Early Permian Glochinomorpha stifeli Gordon 1971 (Coleoidea, Cephalopoda) gives new insight into the evolutionary origination of gladius-bearing coleoids in the Late Palaeozoic and suggests their parallel evolution with the belemnoids and phragmoteuthids. The iron-oxidized arm hooks are found in front of a gladius on an un-illustrated paratype (USNM 170614). Theyare dispersed in a maximum distance equal to 2.5 the gladius length from the incomplete anterior end of the rachis of the gladius. The hook height ranges from less than 1 mm to as much as 4 mm. They have a massive curved base, and a strongly curved shaft with a long thin distal part. The hooks confirm the cephalopod and the coleoid affiliation of G. stifeli that is widely rejected. The iron-oxidized gladii (preserved length is less than 20 mm) show micro-laminations and a fibrous ultrastructure; the fibre bundles are approximately 0.5 lm thick. Lack of calcium and the high content of nitrogen (up to 12% of total weight) confirm the originally non-biomineralized (apparently chitin) composition of the gladii suggested by their fibrous ultrastructure. These data lead to the conclusion that in the evolutionary history of gladius-bearing coleoids, the biomaterial (biochemical) development of the skeleton preceded its morphological transformation. This phenomenon resulted in a recombination of an advanced composition (being non-biomineralized) with archaic features (sensu morphological structure of the posterior part) in the gladius of G. stifeli. The data castdoubt on the hypothesized origination of a gladius from a phragmoteuthid pro-ostracum as well as the evolutionary origination of the gladius-bearing coleoids from pro-ostracum-bearing phragmoteuthids or belemnitids.

  • 5.
    Doguzhaeva, Larisa
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Mapes, Royal
    American Museum of Natural History, USA.
    Beak from the body chamber of the Early Carboniferous (Visean) shelled longiconic coleoid (Cephalopoda) from Arkansas, USA: -2017Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Here we report the discovery of an Early Carboniferous (Late Visean) 3D cephalopod beak displaying significant similarity to the lower beak of Recent coleoids. It was uncovered in a fragmentarily preserved, longiconic shell from the Moorefield Formation in Arkansas, USA. This shell comprises a fractured 29-mm-long body chamber having a maximum diameter of ~14 mm and showing an indistinct pro-ostracum-like structure. The beak-bearing shell could easily have been mistaken for a bactritid or orthocerid if it were not for a coleoid-type, weakly mineralized, evidently organic-rich shell wall which shows a lamello-columnar ultrastructure of a bulk of shell wall thickness and plate ultrastructure of thin outer layer. The specimen is assigned to an as-yet unnamed shelled coleoid of a so far unknown high-level taxonomic group. A partially exposed, 4.0-mm-long portion of the beak is the lower beak in oblique view from its left side. It exhibits fractured anthracite-like black, apparently originally chitin material, helmet-like general shape, broad hood with narrow shallow median groove and small notch posteriorly, pronounced pointed, non-biomineralized upside belt rostrum, high shoulder and about a 90–100 degrees jaw angle. A broad hood and massive rostrum emphasize its similarity to the lower mandible of Recent Vampyroteuthis and signify that its unique, among living coleoids, structure has been existed for at least since Late Visean time (~333 my).

  • 6.
    Doguzhaeva, Larisa
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Weis, Robert
    Musee national d’histoire naturelle, Luxembourg.
    Delsate, Domenique
    Musee national d’histoire naturelle, Luxembourg.
    Mariotti, Nino
    Dipartimento di Scienze della Terra, Universita ‘La Sapienza’, Rome, Italy.
    Embryonic shell structure of Early–Middle Jurassic belemnites, and its significance for belemnite expansion and diversification in the Jurassic2014Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 47, s. 49-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Early Jurassic belemnites are of particular interest to the study of the evolution of skeletal

    morphology in Lower Carboniferous to the uppermost Cretaceous belemnoids,

    because they signal the beginning of a global Jurassic

    –Cretaceous expansion and diversification

    of belemnitids. We investigated potentially relevant, to this evolutionary pattern,

    shell features of Sinemurian

    –Bajocian Nannobelus, Parapassaloteuthis, Holcobelus

    and

    Pachybelemnopsis from the Paris Basin. Our analysis of morphological, ultrastructural

    and chemical traits of the earliest ontogenetic stages of the shell suggests that

    modified embryonic shell structure of Early

    –Middle Jurassic belemnites was a factor

    in their expansion and colonization of the pelagic zone and resulted in remarkable

    diversification of belemnites. Innovative traits of the embryonic shell of Sinemurian

    Bajocian belemnites include: (1) an inorganic

    –organic primordial rostrum

    encapsulating the protoconch and the phragmocone, its non-biomineralized component,

    possibly chitin, is herein detected for the first time; (2) an organic rich closing

    membrane which was under formation. It was yet perforated and possessed a foramen;

    and (3) an organic rich pro-ostracum earlier documented in an embryonic shell of

    Pliensbachian

    Passaloteuthis. The inorganic–organic primordial rostrum tightly coating

    the protoconch and phragmocone supposedly enhanced protection, without

    increase in shell weight, of the Early Jurassic belemnites against explosion in deepwater

    environment. This may have increased the depth and temperature ranges of

    hatching eggs, accelerated the adaptation of hatchlings to a nektonic mode of life and

    promoted increasing diversity of belemnoids. This study supports the hypothesis that

    belemnite hatchlings were ‘a miniature of the adults’.

  • 7.
    Doguzhaeva, Larisa
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Weis, Robert
    Musee national d’histoire naturelle, Luxembourg.
    Delsate, Dominique
    Musee national d’histoire naturelle, Luxembourg.
    Mariotti, Nino
    Dipartimento di Scienze della Terra, Universita ‘La Sapienza’.
    Embryonic shell structure of Early–Middle Jurassic belemnites, and its significance for belemnite expansion and diversification in the Jurassic.2014Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 47, s. 49-65, artikel-id DOI 10.1111/let.12037Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Early Jurassic belemnites are of particular interest to the study of the evolution of skeletal morphology in Lower Carboniferous to the uppermost Cretaceous belemnoids, because they signal the beginning of a global Jurassic–Cretaceous expansion and diversification of belemnitids. We investigated potentially relevant, to this evolutionary pattern, shell features of Sinemurian–Bajocian Nannobelus, Parapassaloteuthis, Holcobelus and Pachybelemnopsis from the Paris Basin. Our analysis of morphological, ultrastructural and chemical traits of the earliest ontogenetic stages of the shell suggests that modified embryonic shell structure of Early–Middle Jurassic belemnites was a factor in their expansion and colonization of the pelagic zone and resulted in remarkable diversification of belemnites. Innovative traits of the embryonic shell of Sinemurian–Bajocian belemnites include: (1) an inorganic–organic primordial rostrum encapsulating the protoconch and the phragmocone, its non-biomineralized component, possibly chitin, is herein detected for the first time; (2) an organic rich closing membrane which was under formation. It was yet perforated and possessed a foramen; and (3) an organic rich pro-ostracum earlier documented in an embryonic shell of Pliensbachian Passaloteuthis. The inorganic–organic primordial rostrum tightly coating the protoconch and phragmocone supposedly enhanced protection, without increase in shell weight, of the Early Jurassic belemnites against explosion in deep water environment. This may have increased the depth and temperature ranges of hatching eggs, accelerated the adaptation of hatchlings to a nektonic mode of life andpromoted increasing diversity of belemnoids. This study supports the hypothesis thatbelemnite hatchlings were ‘a miniature of the adults’.

  • 8.
    Kiel, Steffen
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Altamirano, Ali
    Museo de Historia Natural e Universidad Nacional Mayor San Marcos (MUSM).
    Birgel, Daniel
    Universität Hamburg.
    Helen, Coxall
    Stockholm University.
    Hybertsen, Frida
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Peckmann, Jörn
    Fossiliferous methane-seep deposits from the Cenozoic Talara Basin in northern Peru2019Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931Artikel i tidskrift (Refereegranskat)
  • 9.
    Qvarnström, Martin
    et al.
    Uppsala University.
    Anagnostakis, Stavros
    Nikolaou Plastira 3, Kardia, 57500 Thessaloniki, Greece.
    Lindskog, Anders
    Lund University.
    Scheer, Udo
    Jud. Dâmboviţa, Sat. Mătăsaru 93, RO-137295 Com. Mătăsaru, Romania.
    Vajda, Vivi
    Naturhistoriska riksmuseet, Enheten för paleobiologi. Department of Geology, Lund University, Sweden.
    Rasmussen, Bo W.
    Geomuseum Faxe.
    Lindgren, Johan
    Lund University.
    Eriksson, Mats E.
    Lund University.
    Multi‐proxy analyses of Late Cretaceous coprolites from Germany2019Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 52, s. 550-569Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A total of 462 coprolites from three localities exposing Upper Cretaceous deposits in the Münster Basin, northwestern Germany, have been subjected to an array of analytical techniques, with the aim of elucidating ancient trophic structures and predator–prey interactions. The phosphatic composition, frequent bone inclusions, size and morphology collectively suggest that most, if not all, coprolites were produced by carnivorous (predatory or scavenging) vertebrates. The bone inclusions further indicate that the coprolite producers preyed principally upon fish. Putative host animals include bony fish, sharks and marine reptiles – all of which have been previously recorded from the Münster Basin. The presence of borings and other traces on several coprolites implies handling by coprophagous organisms. Remains of epibionts are also common, most of which have been identified as the encrusting bivalve Atreta. Palynological analyses of both the coprolites and host rocks reveal a sparse assemblage dominated by typical Late Cretaceous dinoflagellates, and with sub‐ordinate fern spores, conifer pollen grains and angiosperm pollen grains. The dinoflagellate key taxon Exochosphaeridium cenomaniense corroborates a Cenomanian age for the Plenus Marl, from which most studied coprolites derive. The findings of this study highlight the potential of a multiproxy approach when it comes to unravelling the origin, composition and importance of coprolites in palaeoecosystem analyses.

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    fulltext
  • 10.
    Topper, Timothy P.
    Geological Museum, Copenhagen.
    Peel, John S.
    Uppsala Universitet.
    Harper, David A.T.
    Durham University.
    Moulting in the lobopodian Onychodictyon from the lower Cambrian of Greenland2013Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 46, nr 4, s. 490-495Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A number of lobopodian taxa from the Cambrian display pairs of sclerotized plates symmetrically positioned along the dorsum of the animal, predominantly above the walking appendages. Most genera were described from complete body fossils exquisitely preserved in the famous Cambrian Lagerstätten, but lobopodian phosphatized plates are found worldwide as typical components of Cambrian small shelly fossil assemblages (SSF). Details regarding intraspecific and ontogenetic variation in lobopod plates are elusive, and the lack of details of ornamentation in Lagerstätte specimens does not minimize the problem. We document here an assemblage of well-preserved isolated plates of Onychodictyon sp. from the Lower Cambrian (Cambrian Series 2, Stage 4) of North Greenland. Two specimens exhibit perfectly conjoined plates from successive moults. Details of ornamentation and the outline and profile of the fixed plates are identical, but width and length of the underlying plate are 24% larger. These specimens boost the body of evidence that lobopodians moulted but also show that plate outline and ornamentation did not vary during ontogeny.

  • 11.
    Werdelin, Lars
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Community-wide character displacement in the lower carnassials of Late Miocene hyenas1996Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 29, s. 97-106Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent studies have found regularities in the pattern of distribution of dental parameters such as canine or carnassial length among sympatric carnivores. These regularities are taken to be indicative of community-wide character displacement. This study documents similar pattern in late Miocene and earliest Pliocene hyaenids from several localities in Eurasia and Africa. Statistical tests show ratios of lower carnassial total lengths and blade lengths between species to be suggestively equal among sympatric late Miocene hyaenas. Other measurements do not show this regular pattern. This finding mirrors that regarding modern canids in the Middle East, suggesting that a process leading to community-wide character displacement was in effect among these hyaenid taxa. Their response to this pattern suggests that they occupied a similarecological role to modern canids. The causal basis for such a process is unknown but is suggested to lie in direct interspecific competition between carnivores rather than being a response to regularly spaced features of the environment.

  • 12.
    Werdelin, Lars
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Hermelin, J. O. R.
    Testing for ecophenotypic variation in a benthic foraminifer1983Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 16, s. 303-307Artikel i tidskrift (Refereegranskat)
  • 13.
    Werdelin, Lars
    et al.
    Naturhistoriska riksmuseet, Enheten för paleobiologi.
    Long, J. A.
    Allometry in the placoderm Bothriolepis canadensis and its significance to antiarch evolution1986Ingår i: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931, Vol. 19, s. 161-169Artikel i tidskrift (Refereegranskat)
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