Elise Nardin | Geoscience environment de Toulouse (original) (raw)
Papers by Elise Nardin
Palaeogeography, Palaeoclimatology, Palaeoecology, 2016
Ciencias Da Terra, Jul 26, 2013
C R Palevol, 2009
Le sous-phylum Blastozoa est un des groupes d’échinodermes les plus diversifiés (dix classes) au ... more Le sous-phylum Blastozoa est un des groupes d’échinodermes les plus diversifiés (dix classes) au début du Paléozoïque. Après révision critique de leur squelette, leurs morphologies en apparence très variées sont en fait homogènes. Leur diversité montre deux pics (Drumien, Sandbien) liés par un événement de fortes apparitions génériques au Cambrien supérieur-Ordovicien inférieur. Les blastozoaires montrent un fort endémisme au Cambrien et un important provincialisme à l’Ordovicien inférieur et moyen. Ils deviennent cosmopolites à l’Ordovicien supérieur, par plusieurs événements migratoires. Ils sont restreints à la Laurentia et à Baltica au Silurien inférieur.The subphylum Blastozoa is the most abundant and among the most diversified of echinoderm groups during the Early Paleozoic. Reappraisal of their highly diverse anatomies suggests that their superficially incomparable morphologies are actually relatively homogeneous among the major blastozoan clades. Their generic diversity shows two peaks (Drumian, Sandbian), linked by a single origination event during the Cambrian-Lower Ordovician interval. During the lower Middle Ordovician, blastozoans were distributed in distinct provinces, but became progressively more cosmopolitan during the Upper Ordovician. After the Late Ordovician crisis event, blastozoans were restricted to the Laurentian and the Baltic margins.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2015
Mesogee, 2008
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very ... more The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one
of the very few Konservat-Lagerstätten known so far in the world to have yielded
numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.
GEOBIOS, Aug 19, 2015
The Cambrian edrioasteroid Stromatocystites is reported and described from Spain, Sweden and Turk... more 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 (Arabian, eastern and western margins) and Laurentia (western Newfoundland). Stratigraphically, it ranged from Cambrian Series 2, Stage 4 to Cambrian Series 3, Drumian. Stromatocystites lived in quiet water environments with stabilized substrates. It was attached directly to the substrate by its aboral surface. As these environments were widespread throughout Baltica, Gondwana and Laurentia, availability of suitable substrates for larval settlement and oceanic palaeocurrents led to the successful development of Stromatocystites colonies.
Geological Society, London, Memoirs, 2013
The palaeobiogeographical distribution of the six major clades of Ordovician echinoderms (asteroz... more The palaeobiogeographical distribution of the six major clades of Ordovician echinoderms (asterozoans, blastozoans, crinoids, echinozoans, edrioasteroids and stylophorans) is analysed based on a comprehensive and up-to-date database compiling 3701 occurrences (1938 species recorded from 331 localities) of both complete specimens and isolated ossicles. Although historically biased towards a limited number of regions (Europe, North America, Russia), the resulting dataset makes it possible to identify six main palaeobiogeographical provinces for Ordovician echinoderms: Laurentia, Baltica, West Gondwana, East Gondwana, Avalonia and Siberia. At a global scale, the high endemicity of echinoderms during the Early to Middle Ordovician coincides with the time of maximum dispersal of continental masses. Late Ordovician faunas tend to become more cosmopolitan, possibly as a consequence of changing palaeogeography and/or relatively higher sea-levels in the Sandbian-Katian interval. Regional biodiversity patterns of Ordovician echinoderms confirm that their major diversification during the Ordovician is not a single, universal evolutionary event, but rather results from the complex addition of contrasted local evolutionary trends.
Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of th... more Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of the eastern Anti-Atlas, Morocco. They have yielded hundreds of exquisitely preserved specimens. Their taphonomy and associated lithology both suggest rapid, in situ burial. Here we discuss the diverse range of assemblages represented and their significance to the diversity of echinoderms in the Lower Palaeozoic. The oldest assemblage (Izegguirene Formation, lowermost Caradoc) is dominated by eocrinoids, large ophi-uroids, and mitrate stylophorans associated with rare crinoids. It shows strong similarities with slightly older faunas described from the underlying Ouine-Inirne Formation (Llandeilian) in the Central Anti-Atlas. The second assemblage (lower part of the Lower Ktaoua Formation, lower-middle Caradoc) is composed of eocrinoids (Cardiocystites) and small ophiuroids (encrinasterid indet.). The third assemblage was collected in the upper part of the Lower Ktaoua Formation (lowermost Ashgill). This 'starfish' bed is dominated by ophiuroids and large solutes, associated with common diploporites and rhombiferans, and rare crinoids and mitrates. Finally, the youngest assemblage (lower part of Upper Tiouririne Formation, lower Ashgill) has yielded abundant remains of edrioasteroids and rhombiferans.
TURKISH JOURNAL OF EARTH SCIENCES, 2014
ABSTRACT Articulated echinoderm remains are described for the first time in the Ordovician of Tur... more ABSTRACT 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 assemblage of densely packed, 3-dimensionally preserved thecae. The presence of numerous suborganised plates with diplopore respiratory structures suggests probable affinities with sphaeronitid blastozoans. Comparable sphaeronitid dense beds are well known in the early Darriwilian of Baltica, and in the mid Darriwilian of the Middle East and Asian terranes.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2016
Ciencias Da Terra, Jul 26, 2013
C R Palevol, 2009
Le sous-phylum Blastozoa est un des groupes d’échinodermes les plus diversifiés (dix classes) au ... more Le sous-phylum Blastozoa est un des groupes d’échinodermes les plus diversifiés (dix classes) au début du Paléozoïque. Après révision critique de leur squelette, leurs morphologies en apparence très variées sont en fait homogènes. Leur diversité montre deux pics (Drumien, Sandbien) liés par un événement de fortes apparitions génériques au Cambrien supérieur-Ordovicien inférieur. Les blastozoaires montrent un fort endémisme au Cambrien et un important provincialisme à l’Ordovicien inférieur et moyen. Ils deviennent cosmopolites à l’Ordovicien supérieur, par plusieurs événements migratoires. Ils sont restreints à la Laurentia et à Baltica au Silurien inférieur.The subphylum Blastozoa is the most abundant and among the most diversified of echinoderm groups during the Early Paleozoic. Reappraisal of their highly diverse anatomies suggests that their superficially incomparable morphologies are actually relatively homogeneous among the major blastozoan clades. Their generic diversity shows two peaks (Drumian, Sandbian), linked by a single origination event during the Cambrian-Lower Ordovician interval. During the lower Middle Ordovician, blastozoans were distributed in distinct provinces, but became progressively more cosmopolitan during the Upper Ordovician. After the Late Ordovician crisis event, blastozoans were restricted to the Laurentian and the Baltic margins.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2015
Mesogee, 2008
The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one of the very ... more The site of Bou Nemrou, in the Western Tafilalt (eastern Anti-Atlas, Morocco) is one
of the very few Konservat-Lagerstätten known so far in the world to have yielded
numerous remains of Late Ordovician softbodied fossils associated with an abundant and diverse marine benthic fauna. This locality has also yielded several levels (starfish beds) extremely rich in exquisitely preserved echinoderms. Their remarkable preservation possibly results from the rapid, in situ burial of large, particularly dense, living communities (echinoderm meadows) by storm deposits. The Bou Nemrou starfish beds are dominated by eocrinoids and stylophorans, associated with crinoids, cyclocystoids, edrioasteroids, and ophiuroids. This composition is typical of the cool assemblages of the Mediterranean Province. The Bou Nemrou starfish beds may result from the opportunistic colonisation of the sea-floor by dense populations of echinoderms, during short phases of environmental disturbance.
GEOBIOS, Aug 19, 2015
The Cambrian edrioasteroid Stromatocystites is reported and described from Spain, Sweden and Turk... more 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 (Arabian, eastern and western margins) and Laurentia (western Newfoundland). Stratigraphically, it ranged from Cambrian Series 2, Stage 4 to Cambrian Series 3, Drumian. Stromatocystites lived in quiet water environments with stabilized substrates. It was attached directly to the substrate by its aboral surface. As these environments were widespread throughout Baltica, Gondwana and Laurentia, availability of suitable substrates for larval settlement and oceanic palaeocurrents led to the successful development of Stromatocystites colonies.
Geological Society, London, Memoirs, 2013
The palaeobiogeographical distribution of the six major clades of Ordovician echinoderms (asteroz... more The palaeobiogeographical distribution of the six major clades of Ordovician echinoderms (asterozoans, blastozoans, crinoids, echinozoans, edrioasteroids and stylophorans) is analysed based on a comprehensive and up-to-date database compiling 3701 occurrences (1938 species recorded from 331 localities) of both complete specimens and isolated ossicles. Although historically biased towards a limited number of regions (Europe, North America, Russia), the resulting dataset makes it possible to identify six main palaeobiogeographical provinces for Ordovician echinoderms: Laurentia, Baltica, West Gondwana, East Gondwana, Avalonia and Siberia. At a global scale, the high endemicity of echinoderms during the Early to Middle Ordovician coincides with the time of maximum dispersal of continental masses. Late Ordovician faunas tend to become more cosmopolitan, possibly as a consequence of changing palaeogeography and/or relatively higher sea-levels in the Sandbian-Katian interval. Regional biodiversity patterns of Ordovician echinoderms confirm that their major diversification during the Ordovician is not a single, universal evolutionary event, but rather results from the complex addition of contrasted local evolutionary trends.
Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of th... more Four distinct echinoderm Lagerstätten have recently been discovered in the Upper Ordovician of the eastern Anti-Atlas, Morocco. They have yielded hundreds of exquisitely preserved specimens. Their taphonomy and associated lithology both suggest rapid, in situ burial. Here we discuss the diverse range of assemblages represented and their significance to the diversity of echinoderms in the Lower Palaeozoic. The oldest assemblage (Izegguirene Formation, lowermost Caradoc) is dominated by eocrinoids, large ophi-uroids, and mitrate stylophorans associated with rare crinoids. It shows strong similarities with slightly older faunas described from the underlying Ouine-Inirne Formation (Llandeilian) in the Central Anti-Atlas. The second assemblage (lower part of the Lower Ktaoua Formation, lower-middle Caradoc) is composed of eocrinoids (Cardiocystites) and small ophiuroids (encrinasterid indet.). The third assemblage was collected in the upper part of the Lower Ktaoua Formation (lowermost Ashgill). This 'starfish' bed is dominated by ophiuroids and large solutes, associated with common diploporites and rhombiferans, and rare crinoids and mitrates. Finally, the youngest assemblage (lower part of Upper Tiouririne Formation, lower Ashgill) has yielded abundant remains of edrioasteroids and rhombiferans.
TURKISH JOURNAL OF EARTH SCIENCES, 2014
ABSTRACT Articulated echinoderm remains are described for the first time in the Ordovician of Tur... more ABSTRACT 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 assemblage of densely packed, 3-dimensionally preserved thecae. The presence of numerous suborganised plates with diplopore respiratory structures suggests probable affinities with sphaeronitid blastozoans. Comparable sphaeronitid dense beds are well known in the early Darriwilian of Baltica, and in the mid Darriwilian of the Middle East and Asian terranes.