7 results on '"Lea Numberger"'
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2. Brittle stars looking like starfish: the first fossil record of the Astrophiuridae and a remarkable case of convergent evolution
- Author
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Ben Thuy, Andy Gale, and Lea Numberger-Thuy
- Subjects
Ophiuroidea ,Astrophiuridae ,Amphilimnidae ,New taxa ,Cretaceous ,Convergent evolution ,Medicine ,Biology (General) ,QH301-705.5 - Abstract
The genus Astrophiura, which ranks among the most extraordinary of modern brittle stars, is the type genus of the recently resurrected family Astrophiuridae within the order Ophiurida. On account of its absurdly enlarged and strongly modified lateral arm plates, Astrophiura bears a closer resemblance to a pentagonal starfish than to a typical ophiuroid. Although molecular evidence suggests an ancient origin of the Astrophiuridae, dating back at least to the Early Jurassic, not a single fossil astrophiurid has been reported so far. Here, we describe dissociated lateral arm plates from the Campanian of Cringleford near Norwich, UK, and the Maastrichtian of Rügen, Germany (both Upper Cretaceous) with unambiguous astrophiurid affinities and assign these to a new species, Astrophiura markbeneckei. This represents the first fossil record of the family. In addition, the Rügen material included lateral arm plates that superficially resemble those of A. markbeneckei sp. nov. but differ in having spine articulations that are typical of the ophionereidoid family Amphilimnidae. We assign these plates to a new genus and species, Astrosombra rammsteinensis, an extinct amphilimnid with morphological modifications similar to those of Astrophiura, and thus representing a remarkable case of parallel evolution amongst brittle stars looking like starfish.
- Published
- 2019
- Full Text
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3. New Brittle Stars (Echinodermata, Ophiuroidea) from the Oligocene of the Mainz Basin, Germany
- Author
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Ben Thuy, Kai Nungesser, and Lea Numberger-Thuy
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palaeontology ,Ophiuroidea ,microfossils ,fossil record ,new species ,Cenozoic - Abstract
The fossil record of the Ophiuroidea is still patchy, especially in the Cenozoic. Only four species have been described from the entire Oligocene, which is in stark contrast to the present-day diversity counting more than 2000 species. Here, we describe two new species of ophiuroid, Ophiura tankardi sp. nov. and Ophiodoris niersteinensis sp. nov., from the Lower Oligocene of the Mainz Basin. The species are based on microfossils extracted from the sieving residues of bulk sediment samples from a flush drill in Nierstein, Rhineland-Palatinate. The new species belong to extant genera and add to the poor Oligocene fossil record of the class. Based on present-day distributions, the occurrence of Ophiodoris suggests deep sublittoral to shallow bathyal palaeodepths for the Nierstein area of the Mainz Basin.
- Published
- 2022
- Full Text
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4. Seasonal dynamics and decadal changes of benthic foraminiferal assemblages in the western Baltic Sea (NW Europe)
- Author
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Joachim Schönfeld and Lea Numberger
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0106 biological sciences ,Detritus ,010504 meteorology & atmospheric sciences ,biology ,Ecology ,010604 marine biology & hydrobiology ,Fauna ,fungi ,Paleontology ,Sediment ,biology.organism_classification ,01 natural sciences ,Population density ,Foraminifera ,Sedimentary depositional environment ,Oceanography ,Benthic zone ,Phytoplankton ,14. Life underwater ,Geology ,0105 earth and related environmental sciences - Abstract
Living benthic foraminiferal assemblages were monitored between January and July 2004 in the Kiel Bight, Baltic Sea. Phytoplankton blooms and the deposition of organic detritus were depicted by fluorometer hydro casts and pigment concentrations in surface sediments. Three depositional pulses of organic matter were identified by high phytoplankton concentrations above the sea floor and elevated pigment concentrations in the surface sediment. The foraminiferal assemblage composition remained rather constant but the population density of Elphidium excavatum clavatum showed a two- to six-fold increase within a few days after organic detritus deposition. The foraminiferal assemblage composition was compared to earlier studies in this area. Elphidium excavatum, Ammotium cassis and E. incertum dominated the living fauna in the 1960s and 1970s. The recent survey revealed a predominance of E. excavatum subspecies (more than 90% of the living assemblage). The average population densities were six times higher than in the 1970s. Data structure and model calculations suggested that E. excavatum clavatum is able to reproduce rapidly, with high offspring numbers at elevated food supply. The diminution of A. cassis has occurred in Kiel Bight during the last ten years and was most likely induced by a period of low deep-water salinities in the early 1990s.
- Published
- 2018
5. Bélemnites du Jurassique inférieur (Pliensbachien-Toarcien) de Fresney-le-Puceux (Calvados, France) : taxonomie, chronostratigraphie et diversité
- Author
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Ben Thuy, Andrea Di Cencio, Pascal Neige, Lea Numberger-Thuy, Nino Mariotti, Robert Weis, Olivier Dugué, section Paléontologie, Musée National d'Histoire Naturelle de Luxembourg (MNHN), Biogéosciences [UMR 6282] [Dijon] (BGS), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Scienze della Terra, Università degli Studi di Roma 'La Sapienza' = Sapienza University [Rome], Publication supported by INSU Intervie., Musée national d'histoire naturelle [Luxembourg], Biogéosciences [Dijon] ( BGS ), Université de Bourgogne ( UB ) -AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique ( CNRS ), Morphodynamique Continentale et Côtière ( M2C ), Centre National de la Recherche Scientifique ( CNRS ) -Université de Rouen Normandie ( UNIROUEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ), and Università degli Studi di Roma 'La Sapienza' [Rome]
- Subjects
010506 paleontology ,Outcrop ,stratigraphie ,Toarcien ,Toarcian ,cephalopods ,010502 geochemistry & geophysics ,01 natural sciences ,Paleontology ,Chronostratigraphy ,la Roche Blain quarry ,0105 earth and related environmental sciences ,[ SDU.STU.PG ] Sciences of the Universe [physics]/Earth Sciences/Paleontology ,Ammonite ,ammonites ,biology ,céphalopodes ,Bélemnites ,carrière la Roche Blain ,stratigraphy ,Pliensbachian ,Geology ,biology.organism_classification ,Pliensbachien ,Incertae sedis ,language.human_language ,Normandie ,Normandy ,language ,Taxonomy (biology) ,Chronozone ,[SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology ,Belemnites - Abstract
(IF 1.30; Q2); International audience; The present paper deals with the systematic description of the belemnite assemblages from the Lower Jurassic, collected at the Roche Blain quarry, Fresney-le-Puceux. In spite of the reduced thickness of the succession at Fresney-le-Puceux, 13 successive ammonite chronozones could be documented in this rather unique outcrop situation in mainland Europe. Twelve genera and 26 species of belemnites belonging to the Passaloteuthididae, Hastitidae, Megateuthididae, Salpingoteuthididae, and family incertae sedis are described and illustrated herein. The stratigraphical range of the belemnites is correlated with the standard ammonite zonation, using the chronozone concept: the described specimens range from the lower Pliensbachian (Davoei Chronozone) to the uppermost Toarcian (Aalensis Chronozone) while ammonites indicate the Aalenian (Murchisonae Chronozone) to be present too, but these beds delivered no identifiable belemnites so far. The belemnite diversity from Normandy is compared to data from coeval outcrops in Western and Central Europe.; Cet article traite de la systématique des bélemnites du Jurassique inférieur récoltées dans la carrière de la Roche Blain à Fresney-le-Puceux. Malgré l’épaisseur réduite de la succession de Fresney-le-Puceux, 13 chronozones successives d’ammonites ont été documentées dans cet affleurement assez unique en Europe continentale. Douze genres et 26 espèces de bélemnites appartenant aux Passaloteuthididae, aux Hastitidae, aux Megateuthididae et aux Salpingoteuthididae, ainsi qu’à une famille incertae sedis, sont décrits et illustrés ici. L’extension stratigraphique des bélemnites est corrélée avec la zonation standard des ammonites en utilisant le concept de chronozone : les spécimens décrits s’étendent du Pliensbachien (Chronozone à Davoei) au Toarcien supérieur (Chronozone à Aalensis), tandis que les ammonites indiquent que l’Aalénien (Chronozone à Murchisonae) pourrait être présent, mais ces niveaux n’ont pas livré de bélemnites identifiables jusqu’ici. La diversité des bélemnites de Normandie est comparée à celle d’affleurements équivalents en Europe occidentale et centrale.
- Published
- 2018
- Full Text
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6. Habitats, abundance patterns and isotopic signals of morphotypes of the planktonic foraminifer Globigerinoides ruber (d'Orbigny) in the eastern Mediterranean Sea since the Marine Isotopic Stage 12
- Author
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Christoph Hemleben, Ramona Hoffmann, Joern-Michael Wunderlich, Michal Kucera, Lea Numberger, Andreas Mackensen, and Hartmut Schulz
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Mediterranean climate ,010506 paleontology ,010504 meteorology & atmospheric sciences ,biology ,Stable isotope ratio ,Paleontology ,Plankton ,Oceanography ,biology.organism_classification ,01 natural sciences ,Interglacial ,14. Life underwater ,Glacial period ,Quaternary ,Chemical composition ,Geology ,Globigerinoides ,0105 earth and related environmental sciences - Abstract
article i nfo The chemical composition of shells of the planktonic foraminifer Globigerinoides ruber (white) is frequently used to determine past sea surface conditions. Recently, it has been shown that arbitrarily defined morphotypes within this species exhibit different chemical and isotopic signatures. Here, we investigate the occurrence through time and in space of morphological types of G. ruber (white) in late Quaternary and Holocene sediments of the central and the eastern Mediterranean Sea. In 115 samples representing two distinct time intervals (MIS 1-2 and MIS 9-12) at ODP Site 964 and the piston core GeoTu-SL96, we have defined three morphological types within this species and determined their relative abundances and stable isotopic composition. A quantitative analysis of morphological variation within G. ruber (white) in four samples revealed that the subjectively defined morphotypes occupy separate segments of a continuous and homogenous morphospace. We further show that the abundance of the morphotypes changes significantly between glacials and interglacials and that the three morphotypes of G. ruber show significant offsets in their stable isotopic composition. These offsets are consistent within glacial and interglacial stages but their sign is systematically reversed between the two Sites. Since the isotopic shifts among the three G. ruber morphotypes are systematic and often exceed 1‰, their understanding is essential for the interpretation of all G. ruber-based proxy records for the paleoceanographic development of the Mediterranean during the late
- Published
- 2009
- Full Text
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7. The benthic foraminiferal response to the 2004 spring bloom inthe western Baltic Sea
- Author
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Lea Numberger and Joachim Schönfeld
- Subjects
Chlorophyll a ,education.field_of_study ,biology ,Elphidium ,fungi ,Population ,Paleontology ,Spring bloom ,Oceanography ,biology.organism_classification ,Foraminifera ,chemistry.chemical_compound ,Diatom ,chemistry ,Benthic zone ,Phytoplankton ,education - Abstract
The diatom spring bloom and response of the benthic foraminifera was monitored between January and July 2004 in the Kiel Bight, western Baltic Sea. Phytoplankton production, the deposition of organic detritus, and feeding of Elphidium excavatum clavatum and Reophax dentaliniformis were monitored by pigment concentrations and pigment composition in water samples, surface sediments, and foraminiferal protoplasm. The population dynamics of the dominant species, Elphidium e. clavatum, was assessed by using their size distributions. The main spring bloom was triggered by a sudden rise in the three-day average insolation to above 170 W m(-2) d(-1) and took place during late February. Chlorophyll a concentrations in the protoplasm of Elphidium e. clavatum followed those in the surface water. The chlorophyll a / fucoxanthin ratio was the same as in bacillariophycean diatoms suggesting a "bloom-feeding" behaviour of Elphidium e. clavatum. Alternatively, the pigment composition in Reophax dentaliniformis only occasionally mirrored that of diatoms, indicating prochlorophycean and cyanophycean algae as this species' preferred food source. The size distributions and the abundances of living Elphidium e. clavatum revealed two reproduction events, which were 17 days apart. Both events coincided with an increase in sedimentary chlorophyll a concentrations. The reproduction was preceded by growth and feeding of adult specimens and it was followed by distinct growth phases of young specimens, which lasted a few days only. One reproductive cycle covered the spring bloom and produced many more offspring than the subsequent cycle. The light carbon isotopic signal from diatoms was only transiently recorded in foraminiferal calcite and with a low offset during the spring bloom. The oxygen isotopic composition of foraminiferal calcite mirrors seasonal delta(18)O-seawater-salinity relationships rather than temperature.
- Published
- 2007
- Full Text
- View/download PDF
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