Sternkopf V.,German Museum |
Liebers-Helbig D.,German Museum |
Ritz M.S.,Friedrich - Schiller University of Jena |
Zhang J.,University of Chicago |
De Knijff P.,Leiden University
BMC Evolutionary Biology | Year: 2010
Background: Based on extensive mitochondrial DNA (mtDNA) sequence data, we previously showed that the model of speciation among species of herring gull (Larus argentatus) complex was not that of a ring species, but most likely due more complex speciation scenario's. We also found that two species, herring gull and glaucous gull (L. hyperboreus) displayed an unexpected biphyletic distribution of their mtDNA haplotypes. It was evident that mtDNA sequence data alone were far from sufficient to obtain a more accurate and detailed insight into the demographic processes that underlie speciation of this complex, and that extensive autosomal genetic analysis was warranted. Results: For this reason, the present study focuses on the reconstruction of the phylogeographic history of a limited number of gull species by means of a combined approach of mtDNA sequence data and 230 autosomal amplified fragment length polymorphism (AFLP) loci. At the species level, the mtDNA and AFLP genetic data were largely congruent. Not only for argentatus and hyperboreus, but also among a third species, great black-backed gull (L. marinus) we observed two distinct groups of mtDNA sequence haplotypes. Based on the AFLP data we were also able to detect distinct genetic subgroups among the various argentatus, hyperboreus, and marinus populations, supporting our initial hypothesis that complex demographic scenario's underlie speciation in the herring gull complex. Conclusions: We present evidence that for each of these three biphyletic gull species, extensive mtDNA introgression could have taken place among the various geographically distinct subpopulations, or even among current species. Moreover, based on a large number of autosomal AFLP loci, we found evidence for distinct and complex demographic scenario's for each of the three species we studied. A more refined insight into the exact phylogeographic history within the herring gull complex is still impossible, and requires detailed autosomal sequence information, a topic of our future studies. © 2010 Sternkopf et al; licensee BioMed Central Ltd.
Cortese G.,Institute of Geological & Nuclear Sciences |
Gersonde R.,Alfred Wegener Institute for Polar and Marine Research |
Maschner K.,German Museum |
Medley P.,University of Colorado at Boulder
Paleoceanography | Year: 2012
The valve area of Fragilariopsis kerguelensis, the most abundant diatom species in the Southern Ocean, strongly changes in size in response to varying conditions in the surface ocean. We examined the link, both in two iron fertilization experiments and in sediment samples covering several glacial Terminations, between size variability in this species and environmental conditions across the Antarctic Polar Front, including sea ice extent, sea surface temperature, and the input of eolian dust. The iron fertilization experiments show valve area to be positively correlated with iron concentrations in ambient waters, which suggests the possibility of a causal relation between valve size of Fragilariopsis kerguelensis and ambient surface water iron concentration. Larger valves are usually found during glacial times and thus seem to be related to lower sea surface temperature and wider sea ice coverage. Moreover, our results indicate that there usually is a strong correlation between larger valve size and increased input of eolian dust to the Southern Ocean. However, this correlation, obvious for the fertilization experiments and for glacial Terminations I, II, III, and V, does not seem to be valid for Termination VI, where size appears to be inversely correlated to dust input. Copyright 2012 by the American Geophysical Union.
News Article | February 3, 2016
He created stunningly lifelike moulages: wax models of the human body in states of disease, once used for training doctors. Later, he turned to art, rising in the 1950s to become a star of the US abstract scene with paintings featuring vibrantly hued geometric shapes. Adolf Fleischmann (1892–1968) had impacts on medicine and art that were equally powerful and strangely divided. This year, two Berlin exhibitions (for which I have contributed to the catalogues) will explore Fleischmann's oeuvre: Surfaces at the Berlin Museum of Medical History at the Charité (which adapts a joint presentation of the Museum of Concrete Art and the German Museum of Medical History, both in Ingolstadt) and the Adolf Fleischmann Retrospective at Daimler Contemporary Berlin. Whereas Surfaces is a survey of Fleischmann's varied life, focusing on medical works made between 1917 and 1927, the Daimler Contemporary retrospective concentrates on Fleischmann's artistic career in the United States, between 1952 and 1965. The German-born Fleischmann trained as a graphic illustrator, then studied fine art in Stuttgart from 1911 to 1913. Heavily wounded in the First World War, he moved to neutral Switzerland in 1917 to work as a medical sculptor at Zurich's Surgical University Clinic. With the encouragement of the eminent moulage-maker Luise (Lotte) Volger and under clinic head and eminent surgeon Paul Clairmont, Fleischmann built up a unique collection of 400 surgical moulages over 10 years. These documented, in graphic 3D, trauma, pathological changes in the body, and therapeutic interventions visible on the patient's skin — such as wounds caused by strong electrical currents, swellings of the thyroid gland and side-effects of X-rays, such as skin atrophy. Impressive moulages of this kind will be on display at the Museum of Medical History. Medical moulage-making, which had begun in cities including Jena, Germany, in the early nineteenth century, blossomed from the 1850s in the European medical centres of London, Paris, Vienna and Berlin. Around 1900, it spread around the world, coexisting with photography and other forms of graphic medical illustration until the 1950s, when the colour slide finally reached a satisfactory technical standard. Creating a moulage involved taking a plaster cast of an area of the patient's skin and filling it with coloured liquid wax. Once detached, the wax shell was painted and finished from life to capture every nuance of form and colour, creating a perfect illusion for teaching. Although the process was clearly mimetic, the observational skill demanded was superb training for the artist's eye: in the topography of diseased and traumatized skin, Fleischmann could study organic form and detect graphic patterns and gradations of colour. Although Fleischmann's moulages are unsigned, he did sign other works in his medical oeuvre, indicating that he felt they stood out visually and even artistically. These are 30 histopathological drawings of skin tissue, held at the Zurich Moulage Museum and largely overlooked. In Zurich between 1918 and 1927, Fleischmann used a microscope to make unprecedentedly subtle and accurate ink drawings of the dermatological evidence of diseases, such as the scaly skin disorder ichthyosis vulgaris, Hodgkin's lymphoma or the systemic autoimmune condition lupus erythematosus. He documented the intricate details of complex structures and interactions of cells, nerves and veins, building his scientific understanding of visible organization and structure. As with the moulages, he reproduced form and colour; but with the drawings he also did more. There is a dynamical element in his mastery of line: the illustrations reveal a subtle movement, sublime gestures, the hidden contours under the skin. In these images, Fleischmann liberates himself as an artist. He had been striving to become a fine artist, and to be seen as one, since the 1920s in Zurich. Here, he was able to absorb expressionist and cubist artworks, in particular those of Munich's Blue Rider group, which included Wassily Kandinsky and Franz Marc. But his path to acceptance was long and strewn with obstacles. The rise of Nazism and the Second World War forced moves to France, Spain, Italy and, post-war, back to Paris. Studying the work of artistic luminaries Robert Delaunay and Piet Mondrian, he finally arrived at his own distinct style in 1950. Settling in New York City two years later, he produced a stream of outstanding abstract paintings and prints that drew heavily on the urban elements of his new home. Fleischmann only occasionally returned to medical imaging. However, there are hints of his microscopic drawings in several of his late works of art, such as the oil painting Composition 71 N.Y. (1956), highlighted in the Daimler Contemporary show. Rounded motifs call to mind a microscope lens, for instance, and intricate grids of horizontal and vertical lines — combined with the 'flickering' appearance of the colours — give the pieces a visual dynamic. Perhaps this is why Fleischmann's artworks, although radically abstract in composition, appear so breathtakingly lively.
Ausich W.I.,Ohio State University |
Bartels C.,German Museum |
Kammer T.W.,West Virginia University
Lethaia | Year: 2013
Fossilized tube feet are described on Codiacrinus schultzei Follmann from the Lower Devonian Hunsrück Slate of Germany. This is the first definitive proof of tube feet on any fossil crinoid. Three lightly pyritized, flattened tube feet are preserved in a single interray of this cladid crinoid. The tube feet were at least 7 mm long. Their preservation is very similar to the tube feet reported previously from a Hunsrück ophiuroid, except that the Codiacrinus tube feet have small papillae, similar to living crinoids. © 2013 The Lethaia Foundation.
Ruedrich J.,University of Gottingen |
Kirchner D.,German Museum |
Siegesmund S.,University of Gottingen
Environmental Earth Sciences | Year: 2011
Damages to natural building stones induced by the action of frost are considered to be of great importance. Commonly, the frost resistance of building stones is checked by standardised freeze-thaw tests before using. Corresponding tests normally involve 30-50 freeze-thaw action cycles. In order to verify the significance of such measurements, we performed long-term tests on four selected rocks over 1,400 freeze-thaw action cycles. Additionally, numerous petrophysical parameters were analysed to compare the behaviour of rocks in the weathering tests according to the current explanatory models of stress formation by growing ice crystals in the pore space. The long-term tests yield more information about the real frost sensibility of the rocks. A clear deterioration cannot be determined in most cases until 50 weathering cycles have been completed. In the freeze-thaw tests, the samples are also stressed by changing temperature and moisture, indicating that different decay mechanisms can interfere with each other. Thus, thermohygric and moisture expansion are important damage processes. © 2010 The Author(s).
Holst S.,German Museum |
Jarms G.,Biozentrum Grindel und Zoologisches Museum
Hydrobiologia | Year: 2010
Several species of scyphozoan medusae occur in river estuaries and other brackish waters but it is often unknown if the planulae settle and the scyphopolyps reproduce in those low-salinity waters. In the present study, scyphozoan species from the German Bight (North Sea) were tested in laboratory experiments to investigate their tolerance of low salinity. Planula larvae released from medusae in salinity 32 were still active after the salinity was reduced to 10 (Cyanea capillata, Cyanea lamarckii) and to 7 (Chrysaora hysoscella) in laboratory treatments. Planulae did not settle on the undersides of floating substrates when salinity was reduced to < 20. By contrast, planulae released from C. capillata medusae in Kiel Bight (western Baltic Sea) in salinity 15 developed into polyps in laboratory cultures. Polyps reared from planulae in salinity 36 survived a reduction to 12 (C. capillata, C. lamarckii) and to 8 (Aurelia aurita). Polyps of all tested species strobrvations, young C. capillata ephyrae were collected in the western Baltic Sea (Kiel Bight) in salinity 15, which indicates that they were probably released by a local polyp population. We suggest that the polyps of the painfully stinging lion's mane, C. capillata, may be more widespread in the Baltic Sea than previously assumed and that the occurrence of the medusae may not only depend on inflow of water masses from the North Sea. © Springer Science+Business Media B.V. 2010.
Holst S.,German Museum |
Laakmann S.,Senckenberg Institute
Journal of Plankton Research | Year: 2014
Detecting fluctuations in the species composition of bloom-forming jellyfish requires the ability to correctly identify each species in each developmental stage. We verified diagnostic morphological and molecular genetic characters to discriminate Cyanea lamarckii and Cyanea capillata from northern European waters. Intrusions in the subumbrellar muscle folds were present in all C. capillata >80 mm r-diameter (between opposite rhopalia tips), but absent in C. lamarckii. Clearly visible wart-like papillae on the central exumbrella were present in all C. lamarckii >10-80 mm r-diameter, but absent in C. capillata. Both morphological features were retained in formaldehyde-seawater (4%) preserved medusae which had shrunk by 12.8% (±2.7%) after 1 year of preservation. Our molecular genetic analyses demonstrated that fragments of mitochondrial cytochrome c oxidase subunit I (COI) and nuclear 18S rDNA clearly distinguished C. lamarckii from C. capillata, with intra- and inter-specific pairwise genetic distances of 0.0-1.5% and 15.5-17.0% (COI) and 0.0 and 0.2% (18S rDNA), respectively. The study revealed various bell colours in both species underlining that the identification based on the bell colours can result in misidentification. Our integrated taxonomic approach can help to correctly identify jellyfish species, which is fundamentally important for understanding the causes of jellyfish fluctuations and the development of jellyfish blooms. © The Author 2013.
Holst S.,German Museum
Marine Biology | Year: 2012
Jellyfish blooms or invasions could be detected in an early phase of development if the youngest medusa stages (ephyrae) and their early growth stages (post-ephyrae) were identifiable in plankton samples but a useful identification key for ephyrae in early growth stages is lacking for most species. In the present study, the identification characteristics of adult North Sea scyphomedusae (Aurelia aurita, Cyanea capillata, Cyanea lamarckii, Chrysaora hysoscella, Rhizostoma octopus) collected around the island of Helgoland (German Bight) in July-August 2003 and 2004 are described. Planula larvae were measured and reared to polyps in the laboratory. The process of ephyrae development asexually produced by the polyps (strobilation) was photo-documented. Photographs of the ephyrae growth stages were combined with drawings of features useful for the species identification. The provided identification key allows discrimination among post-ephyrae from plankton samples, probably leading to conclusions on the development of jellyfish blooms and their causes. © 2012 Springer-Verlag.
Kieneke A.,German Museum |
Ostmann A.,German Museum
Zoomorphology | Year: 2012
The musculature of two species of the gastrotrich taxon Dasydytidae, Dasydytes (Dasydytes) goniathrix and Haltidytes crassus, was investigated and described using phalloidin staining, confocal microscopy and computer-aided three-dimensional data analysis. Dasydytidae is a peculiar taxon of freshwater Gastrotricha, containing species that are characterized by different adaptations to a semiplanktonic lifestyle, a rather uncommon feature among primarily benthic Gastrotricha. Like other dasydytid species studied so far, D. goniathrix and H. crassus possess a system of movable cuticular spines with an associated system of somatic oblique and segmented lateral muscles. The presence of other somatic (dorsodermal muscles R1 and R2) and visceral muscles (musculi ventrales, m. ventrolaterales, m. dorsales, m. helicoidales) known from a wide range of gastrotrich species was confirmed. Regarded from a functional perspective, the earlier proposed antagonistic role of oblique muscles (as spine abductors) and segmented lateral muscles (as adductors) is questioned for the species studied herein. Alternatively, our structural and behavioral observations suggest that muscular spine abduction in D. goniathrix is brought about by synergistic contraction of the musculi obliqua and m. laterales, and a passive adduction due to muscle relaxation and elastic recoil of the trunk and cuticle. For H. crassus, we hypothesize active muscular spine abduction by contraction of the musculi obliqua plus the last segment of m. laterales accompanied by severe cuticle deformations close to the spine insertions. Adduction is achieved by cuticle reformation due to elasticity and increase in tissue pressure brought about by muscle action, possibly of enforced dorsodermal muscles. The newly obtained and published muscular data of further gastrotrich species were gathered in a species-character matrix. Based on this data set, a maximum parsimony analysis of representatives of the Dasydytidae has been conducted. According to this analysis, there are three well-supported monophyletic lineages within likewise monophyletic Dasydytidae. The first lineage comprises the taxa Anacanthoderma, Stylochaeta and Chitonodytes, the second comprises Dasydytes, Setopus and Ornamentula, and the third represents the taxon Haltidytes. Relationships between these clades could be resolved but are only weakly supported. The new phylogenetic hypothesis is used to reconstruct the ancestral character pattern and to infer possible evolutionary transformations within the Dasydytidae. © 2012 Springer-Verlag.
Holst S.,German Museum
Hydrobiologia | Year: 2012
Recent studies have correlated fluctuations in jellyfish abundances with climatic changes, leading to speculation that the warming trend in the North Sea will affect the strobilation activity of Scyphozoa. The present study provides long-term data (10-22 months) on temperature effects on the species Aurelia aurita, Cyanea capillata, Cyanea lamarckii and Chrysaora hysoscella. Strobilation at current winter temperature (5°C) in the German Bight was compared to strobilation at warmer winter temperatures. Simulated winter temperature of 10°C had several positive effects on strobilation, as compared to 5°C: 1. A longer strobilation period or higher ephyra production per polyp in A. aurita, C. lamarckii and Ch. hysoscella; 2. Higher percentages of polyps strobilating in A. aurita and Ch. hysoscella; 3. More ephyrae per strobila in C. capillata and C. lamarckii; 4. A shorter strobilation duration in C. capillata and C. lamarckii. Cold winter temperatures of 5°C promoted strobilation in C. capillata, but inhibited strobilation in A. aurita and reduced ephyra production in C. lamarckii and Ch. hysoscella. These results suggest that climate warming will benefit A. aurita, but not cold-water C. capillata. The distributions of C. lamarckii and Ch. hysoscella probably could expand to the north. © 2012 Springer Science+Business Media B.V.