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Bertrand Lefebvre

Bertrand Lefebvre
CNRS · UMR 5276 LGLTPE, Université Claude Bernard LYON 1

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149
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Publications

Publications (149)
Article
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Understanding variations in body size is essential for deciphering the response of an organism to its surrounding environmental conditions and its ecological adaptations. In modern environments, large marine animals are mostly found in cold waters. However, numerous parameters can influence body-size variations other than temperatures, such as oxyg...
Article
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The Fezouata Shale in Morocco is the only Lower Ordovician Lagerstätte to yield a diverse exceptionally preserved marine fauna. Sediments of this formation have yielded soft to lightly sclerotized taxa that were previously unknown from the Ordovician. Yet the taphonomic pathway of fossils from this formation remains poorly understood. Here, based o...
Article
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It is hypothesized that iron from biological tissues, liberated during decay, may have played a role in inhibiting loss of anatomical information during fossilization of extinct organisms. Most tissues in the animal kingdom contain iron in different forms. A widely distributed iron-bearing molecule is ferritin, a globular protein that contains iron...
Article
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Investigation of the Fezouata Shale has added to our knowledge on the initial diversification of metazoans. These Lower Ordovician deposits yielded abundant and diverse remains of cuticularized to lightly sclerotized organisms, in addition to numerous soft tissues. Described fossilized soft parts recovered from the Fezouata Shale belong mainly to a...
Article
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Intermediate morphologies of a new fossil crinoid shed light on the pathway by which crinoids acquired their distinctive arms. Apomorphies originating deep in echinoderm history among early nonblastozoan pentaradiate echinoderms distinguish Tremadocian (earliest Ordovician) crinoid arms from later taxa. The brachial series is separated from the amb...
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Bolboporites is an enigmatic Ordovician cone-shaped fossil, the precise nature and systematic affinities of which have been controversial over almost two centuries. For the first time, a wide range of techniques (CT-scan, SEM, cathodoluminescence, XPL, UV epifluorescence, EBSD, FT-IR and XRF spectrometry) were applied to well-preserved specimens of...
Article
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Exceptionally preserved fossil biotas provide crucial data on early animal evolution. Fossil anatomy allows for reconstruction of the animal stem lineages, informing the stepwise process of crown group character acquisition. However, a confounding factor to these evolutionary analyses is information loss during fossil formation. Here we identify th...
Article
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Palaeontological collections housing material from the Fezouata Shale Lagerstätte (Lower Ordovician, Morocco) are of a high scientific interest as they testify to the existence of Burgess Shale-type taxa in one of the most critical Palaeozoic period: the Cambrian–Ordovician transition. The preservation of this unique patrimony can benefit from the...
Article
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The extinct echinoderm clade Stylophora consists of some of the strangest known deuterostomes. Stylophorans are known from complete, fully articulated skeletal remains from the middle Cambrian to the Pennsylvanian, but remain difficult to interpret. Their bizarre morphology, with a single appendage extending from a main body, has spawned vigorous d...
Article
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Agglutinated tubes are produced by a variety of marine organisms. Such tubes will readily break down after the death of the producer, and hence are likely to be found only in deposits with rapid burial and/or exceptional preservation. Here we document agglutinated tubes from four localities of Early Ordovician age. The Lower Ordovician (upper Trema...
Article
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Exceptional fossil preservation is defined by the preservation of soft to lightly sclerotized organic tissues. The two most abundant types of soft-tissue preservation are carbonaceous compressions and replicates in authigenic minerals. In the geological record, exceptionally preserved soft fossils are rare and generally limited to only a few strati...
Article
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In the Central Anti-Atlas (Morocco), the lower part of the Fezouata Shale has yielded locally abundant remains of soft-bodied to lightly sclerotized taxa, occurring in low diversity assemblages characterized by strong spatial and taxonomic heterogeneities, and frequently, by the occurrence of small-sized individuals. Size frequency analyses of Celd...
Article
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Several specimens of the genus Ascocystites (Blastozoa, Eocrinoidea) are described for the first time in Late Ordovician deposits (Bou M'Haoud Formation) from the Ougarta Range, Algeria. This genus was previously known in Darriwilian–Sandbian deposits of four other areas of the Mediterranean Province (Czech Republic, France, Morocco and Portugal)....
Article
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Reexamination of the type material of the enigmatic echinoderm Lapillocystites fragilis BARRANDE, 1887 from the Jince Formation (Drumian) of the Barrandian area (Czech Republic) shows that its original description is based on several accumulations of isolated plates representing several echinoderm thecae and two poorly preserved external moulds rep...
Article
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A new solutan echinoderm, Pahvanticystis utahensis gen. et sp. nov. is described from the upper part of the Weeks Formation (Guzhangian). The Cambrian (Series 3) succession of the central House Range in western Utah documents the early diversification of the class Soluta, which is characterized by a major ecological transition from sessile, 'pelmat...
Presentation
Full-text available
Exceptional preservation consists of the preservation of soft to lightly sclerotised organic tissues (e.g. feathers, guts, skins) in the geological record. The transfer of such tissues from the biosphere to the lithosphere is the result of a succession of multiple, complex biological and geological mechanisms. These processes regroup mainly burial,...
Presentation
Full-text available
Exceptional preservation consists of the preservation of soft to lightly sclerotised organic tissues (e.g. feathers, guts, skins) in the geological record. Although the Palaeozoic record of such exceptionally preserved soft-parts in echinoderms is extremely scarce, it represents a unique source of information on the internal anatomy of fossil taxa,...
Conference Paper
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The Furongian–Floian interval represents a key evolutionary transition with the onset of the Great Ordovician Biodiversification Event (GOBE), soon after the Cambrian Explosion. Few Furongian echinoderm faunas are known worldwide, and all of them consist of low diversity assemblages comprising edrioasteroids, eocrinoids, rhombiferans, solutans, and...
Article
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The Fezouata Lagerstätte, discovered in the Lower Ordovician rocks of Morocco, is a Konservat-Lagerstätte of prime scientific importance. It provides access not only to the ‘shelly’ (skeletonized) part of its fossil assemblages, but also to non-biomineralized to lightly sclerotized organisms and to exceptionally preserved soft tissues of a complex...
Article
The primitive blastozoan Felbabkacystis luckae n. gen. n. sp. is described from the Drumian Jince Formation, Barrandian area (Czech Republic) from eleven fairly well-preserved specimens. Its unique body plan organization is composed of a relatively long, stalk-like imbricate structure directly connected to the aboral imbricate cup of the test and o...
Article
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Moroccodiscus smithi represents a new cyclocystoid genus and species based on moldic specimens from the Middle Ordovician Taddrist Formation (Darriwilian) of SE Morocco. This represents the earliest articulated member of the Cyclocystoidea and is the first complete cyclocystoid described from the Ordovician of Gondwana, as well as the first cyclocy...
Article
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The genus Rhopalocystis (Eocrinoidea, Blastozoa) is characterized by both a short stratigraphic range (Fezouata Shale, middle Tremadocian to middle Floian, Lower Ordovician) and a reduced geographic extension (Agdz-Zagora area, central Anti-Atlas, Morocco). Since the original description of its type species (R. destombesi Ubaghs, 1963), three succe...
Article
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We present revision of the taxonomy and palaeoecology of the Ordovician aristocystitid Lepidocalix pulcher from the Zaouïa of Stita (Great Kabylia, Algeria). An emended diagnosis is proposed, highlighting the four-fold ambulacral system and the typical thecal plating organised in circlets. Lepidocalix is here assigned to the subfamily Calicinae of...
Article
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The Furongian (late Cambrian) is an extremely poorly sampled time in the history of echinoderms, with only few localities yielding complete specimens. Here, we document an exquisitely preserved stemmed echinoderm from the Furongian Sandu Formation in South China that provides important new data illuminating the origin of Glyptocystitida, a common P...
Article
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Hybrid depositional systems are created by the interaction of two or more hydrodynamic processes that control facies distribution and their characteristics in terms of sedimentary structures and depositional geometry. The interaction of wave and tide both in the geological sedimentary record and modern environments has been rarely described in the...
Conference Paper
Exceptionally-preserved fossil assemblages have proved critical to our understanding of the Cambrian explosion. Thanks to recently discovered Konservat-Lagerstätten, similarly detailed data on Ordovician marine animal communities are increasingly available. By contrast, the late Cambrian fossil record of ‘soft’-bodied metazoans remains particularly...
Conference Paper
A new solutan echinoderm is described from the upper part of the Weeks Formation (Guzhangian). The Cambrian (Series 3) succession of the central House Range in western Utah (USA) documents the early diversification of the class Soluta, which is characterized by a major ecological transition from sessile, 'pelmatozoan' primitive taxa (Coleicarpus, W...
Article
Full-text available
Seventeen specimens representing three of the four asterozoan classes (Stenuroidea, Asteroidea, Ophiuroidea) are recorded from Ordovician and Silurian strata of the western United States and northwest France; only the Somasteroidea is not represented. New taxa are: the stenuroids Lopidiaster jamisoni nov. gen. and sp. and Lehmannaster spinosus nov....
Article
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Exceptionnally preserved fossils yield crucial information about the evolution of Life on Earth. The Fezouata Biota from the Lower Ordovician of Morocco is a Konservat- Lagerstätte of major importance, and it is today considered as an 'Ordovician Burgess Shale.' This biota was discovered only some 15 years ago, but geological studies of the area da...
Conference Paper
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The Fezouata Shale (Early Ordovician, Morocco) is renowned in the palaeontological community for its Konservat-Lagerstätte (Tremadocian in age) that yielded thousands of exceptionally well-preserved fossils (EPF) from the Great Ordovician Biodiversification Event. Lower Ordovician deposits in the central Anti-Atlas Mountain (Zagora area) are expres...
Article
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The Guole biota contains common shelly fossils and some exceptionally well-preserved soft-bodied fossils. Stratigraphically, it is located in the mudstones and siltstones of the Sandu Formation near Guole Town, Jingxi County, Guangxi, South China. It is the first Furongian (late Cambrian) Burgess Shale-type biota found in the world, thereby filling...
Conference Paper
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La classe Soluta Jaekel, 1901 est un clade d'échinodermes paléozoïques (Cambrien "moyen" à Dévonien inférieur) qui regroupe environ une quinzaine de genres, tous caractérisés par un appendice nourricier unique (brachiole), une thèque asymétrique, plus ou moins aplatie et une structure de type "tige" (homoiostèle) pouvant servir à la fixation ou à l...
Article
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The Lower Ordovician Fezouata Konservat-Lagerstätte from southern Morocco has been one of the major palaeontological discoveries of the last decade. It provides a unique insight into one of the most critical periods in the evolution of marine life: the Cambrian-Ordovician transition. However, its potential for deciphering key trends in animal diver...
Article
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Toutes les occurrences de crinoïdes signalées dans l’Ordovicien de France (Massif armoricain, Montagne Noire, Corbières et Pyrénées) sont examinées et replacées stratigraphiquement. Des restes de crinoïdes complets, en connexion, sont décrits pour la première fois dans le Darriwilien (Ordovicien moyen) du Massif armoricain. Le crinoïde disparide He...
Article
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The Cambrian edrioasteroid Stromatocystites is reported and described from Spain, Sweden and Turkey. All previously known occurrences of the genus are critically reviewed, and S. flexibilis is reinterpreted as a junior synonym of S. pentagularis. Stromatocystites was biogeographically widespread and colonized different areas of Baltica, Gondwana (A...
Article
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The upper Tremadocian to lower Floian messaoudensis.trifidum acritarch assemblage was first described from the Skiddaw Group of England and subsequently from several localities on the Gondwanan margin that were positioned in high southern latitudes during the Early Ordovician. It is here reported for the first time from North Africa, from the Fezou...
Conference Paper
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The Lower Fezouata Formation (Lower Ordovician, Morocco) has yielded a remarkably diverse exceptionally-preserved biota, which provides unique insights into the transition between the Cambrian and Palaeozoic Evolutionary Faunas. Until recently, fossils from these deposits were collected from small isolated excavations, the stratigraphic positions o...
Article
The morphology of the Late Ordovician solutan Dendrocystites is reevaluated based on more than 300 specimens from the Letna and Zahorany formations (Prague Basin, Czech Republic). This genus is reported for the first time from the Bohdalec Formation, and its presence is confirmed in the Vinice Formation. The morphology of all specimens of the strat...
Article
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Articulated echinoderm remains are described for the first time in the Ordovician of Turkey. They occur massively, forming a relatively thick "cystoid bed" within the detrital limestone succession of the Sobova Formation (latest Dapingian-earliest Darriwilian) in the western Taurus Mountains. The "cystoid bed" encompasses a monospecific echinoderm...
Conference Paper
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L'Ordovicien inférieur de la région de Zagora est renommé internationalement pour ses faunes à préservation exceptionnelle (Fezouata Biota) qui documentent la transition jusqu'alors peu connue entre "l'explosion cambrienne" et "la grande biodiversification ordovicienne". Depuis la découverte des premiers gisements au début des années 2000, leur exp...
Conference Paper
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Au cours des années 2000, la découverte de nombreux gisements à préservation exceptionnelle dans la Formation des Fezouata (Ordovicien inférieur), dans la région de Zagora (Anti-Atlas central, Maroc), a permisde documenter, pour la première fois, des assemblages marins particulièrement riches et diversifiés, dont la préservation est comparable à ce...
Article
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En paléontologie, les XIXe et XXe siècles corres- pondent à la mise en place de l’anatomie comparée pour interpréter les fossiles, des corrélations stratigraphiques pour dater les terrains sédimentaires et de l’usage de la biostratigraphie, de la paléoécologie et de la paléogéo- graphie, plus tardivement de la paléobiologie et de sa contribution à...
Article
A new edrioblastoid Cambroblastus guolensis is described from the Furongian (late Cambrian) Sandu Formation (South China). This represents the second occurrence of a Cambrian edrioblastoid, and the first ever reported from Asia, extending the palaeogeographic range of this very rare echinoderm grade. Surprisingly it preserves a complete stem and a...