论文摘要
Well known as giants within the Palaeozoic sedentary marine benthos, the species of Gigantoproductus attain a shell area which is 20 times larger than that of coeval species.Not only their size, but also their thickness is impressive, reaching over 1 cm.This is surprising as brachiopods are known – and have been known-to have a low-energy lifestyle（low metabolism, low growth, feeding and reproduction rates）, but this has never been investigated in detail nor satisfactorily explained.Angiolini et al.（2019） offer an explanation for this gigantism, starting from the study of their shell microstructure and inferring their possible diet.The shell fabric of these giants, deemed to be pristine based on multiple screening techniques [cathodoluminescence, Scanning Electron Microscopy, Electron Backscatter Diffraction（EBSD）, Transmission Electron Microscopy（TEM）, geochemistry], comprises a thin pseudopunctate laminar secondary layer and a very thick columnar tertiary layer.Local alterations by chalcedony and microquartz spherulites occurred during an early diagenetic phase, but they did not affect the main shell as shown by EBSD analyses.TEM analyses also showed a pristine columnar layer containing nanometres inclusions, forming trails between calcite grain borders similar to those observed in Recent brachiopod shells.These inclusions were analysed by Nuclear Magnetic Resonance and Gas Chromatography Mass Spectrometry, which showed that an occluded organic fraction is preserved with an amino acid composition comparable to that observed in Recent brachiopods.Carbon-and nitrogen-isotopes analyses of the occluded organic matrix allowed to fingerprint their feeding strategy and to detect the biogeochemical signatures that identify symbioses vs.a normal suspension feeding strategy.The gigantic size and thick carbonate skeleton of these Carboniferous brachiopods is interpreted as the result of a mixotroph lifestyle, by which they could rely on the energy and nutrients derived both from photosymbiotic microbes and from filtered particulate food.
论文目录
文章来源
类型: 国际会议
作者: Lucia ANGIOLINI,Gaia CRIPPA,Karem AZMY,Giancarlo CAPITANI,Giorgia CONFALONIERI,Giovanna Della PORTA,Erika GRIESSHABER,David A.T.HARPER,Melanie J.LENG,Leah NOLAN,Marco ORLANDI,Renato POSENATO,Wolfgang W.SCHMAHL,Vanessa J.BANKS,Michael H.STEPHENSON
来源: 第一届亚洲古生物学大会—暨中国古生物学会成立90周年纪念 2019-11-17
年度: 2019
分类: 基础科学
专业: 生物学,地质学
单位: Dipartimento di Scienze della Terra"A.Desio"Department of Earth Sciences, Memorial University of NewfoundlandDipartimento di Scienze dell’Ambiente e del Territorio e di Scienze della TerraDipartimento di Scienze della Terra, Universitàdegli Studi di TorinoDepartment für Geo-und Umweltwissenschaften, Ludwig-Maximilians Universit?t MünchenDepartment of Earth Sciences, Durham UniversityNERC Isotope Geosciences Facilities, British Geological SurveyBritish Geological Survey, KeyworthDepartment of Geology, University of LeicesterDipartimento di Fisica e Scienze della Terra
分类号: Q91;P534.45
页码: 61-62
总页数: 2
文件大小: 222k
下载量: 1