Robert Weis

Recherche et collections
Musée national d'histoire natu... · Palaeontological section

Publications

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    ABSTRACT: The belemnite genus Orthobelus NALNJAEVA, in SACHS & NALNJAEVA 1970, was revealed to be a junior homonym of the treehopper genus Orthobelus STÅL, 1869 (Insecta), and it is replaced by Rarobelus NALNJAEVA nom. nov. This Early Toarcian-Early Aalenian Subarctic-Arctic genus is characterised by a marked conical shape at all stages of the ontogeny. Consequently, it does not belong to the family Passaloteuthididae NAEF, 1922, as commonly supposed earlier, but is an early representative of the family Megateuthididae SACHS & NALNJAEVA, 1967b. To date, three species from northern Siberia (Russia) have been described: R. gigantoides (PAVLOW, 1914), R. obscurus (NALNJAEVA, in SACHS & NALNJAEVA 1970), and R. procerus (NALNJAEVA, in SACHS & NALNJAEVA 1970). In this study, we present evidence of a wider geographic distribution for R. gigantoides, i.e. from East Greenland on the west to the Omolon massif region of northeastern Russia on the east. At the end of the earliest Toarcian Dactylioceras tenuicostatum Zone, with the beginning of the Toarcian OAE, a significant extinction event affected the Passaloteuthididae and other Coleoidea in northwestern and Central Europe. While the first, but sporadic appearance of Megateuthididae occurred in the Pliensbachian, a major diversification of this megateuthidid fauna occurred from the Early Toarcian Hildoceras bifrons Zone onward both in and outside Europe. In the Arctic, this family first appeared not later than the beginning of the Early Toarcian Harpoceras falciferum Zone.
    Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 03/2015; · 0.92 Impact Factor
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    ABSTRACT: Belemnites (Belemnitida) played a major role in marine ecosystems at Jurassic and Cretaceous times. Their fossil record suggests a successful diversification already during the Early Jurassic, with a peak during the Toarcian. The aim of this study is to explore the radiation of belemnites at the scale of the western Tethys, and adjacent areas, from the Hettangian to the Aalenian. A comprehensive bibliographic research and original material study allowed obtaining a signal of species diversity and exploring, using statistics and rarefaction techniques, the potential relation between belemnites diversity and the biogeography trough the studied time interval. However, our research reveals that data for Early Jurassic belemnites are largely concentrated in Toarcian and on north-western Europe (Germany, Great Britain, Luxembourg, etc.) whereas little is known from the rest of the Europe (Causses and Quercy Basins, Provence Platform, northern Spain, etc.), and from the Mediterranean areas (Italy, Austria, Southern Spain, North Africa, etc.). In these latter areas and especially for the beginning of the Early Jurassic, data are still dramatically low, and what is known about belemnites is whether old and without any figuration or sparse. This state of facts blurs our perception of the real radiation of belemnites during the Early Jurassic. In order to increase the knowledge in these areas and periods it is necessary to acquire new data. Thus, belemnites appear to us as a rewarding group for future field research, each field campaign being able to significantly improve our knowledge of the belemnites radiation and palaeobiogeography.
    Cephalopods Present and Past, Zürich; 09/2014
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    ABSTRACT: Jurassic belemnites represent promising proxies especially for palaeoecological and also paleobiogeographical reconstructions. However, basic knowledge on taxonomic composition, biostratigraphy and diversity of Lower Jurassic belemnites is still dramatically low, especially for France. The present study provides new data on belemnites from the southern part of the Northwest European Province. More than 700 specimens have been collected along the Tournadous section in the Causses Basin (Southern France); they represent ten genera and 30 species belonging to Hastitidae, Megateuthididae, Passaloteuthididae and Salpingoteuthididae. Furthermore, numerous ammonites have been collected, allowing to establish a standard chronostratigraphical scheme and thus to assign, for the first time, a precise stratigraphical distribution to the Lower Jurassic belemnites of Southern France. The analysis of belemnites diversity and its variations along the section, compared to the well-known fauna of the northern part of the Northwest European province (Germany and England), opens interesting prospective for belemnite palaeobiogeography.
    Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 08/2014; 273(2):155-177. · 0.92 Impact Factor
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    Gondwana Research 07/2014; · 7.40 Impact Factor
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    Robert Weis, Nino Mariotti, Jobst Wendt
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    ABSTRACT: The rare belemnite Rhabdobelus avena (Dumortier in Mayer, 1869) is described for the first time from Tethyan sediments of the Central Apennines (Bosso river valley) and western Sicily (Rocca Busambra). These records extend the stratigraphic occurrence of Rhabdobelus Naef, 1922 from the Upper Toarcian to the uppermost Lower Bajocian. Systematic review of the genus Rhabdobelus enables recognition of five taxa (R. avena, R. donovani, R. aff. donovani, R. exilis, R. serpulatus) and their respective phylogenetic relationships; furthermore, lectotypes are designated for R. avena, R. donovani, and R. serpulatus, and a neotype is designated for R. exilis. The distribution pattern of rhabdobelid belemnites and substantial changes in their rostrum morphology suggest adaptive radiation during the Aalenian and Early Bajocian, with a trend from European shelf environments to Tethyan hemi-pelagic habitats.
    Paläontologische Zeitschrift 02/2014; · 0.94 Impact Factor
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    ABSTRACT: A Middle Oxfordian Jurassic belemnite fauna, associated with ammonites, from the Lar Formation at Rostam Kola (North Iran) is described for the first time. The specimens have been assigned to the following taxa: Hibolithes hastatus, Hibolithes aff. beyrichi, Pachybelemnopsis latesulcatus, Duvalia didayana, Duvalia monsalvensis, Rhopaloteuthis cf. argoviana and Rhopaloteuthis sauvanausa. Ammonites collected from the same belemnite bearing levels allow to refer the belemnite fauna to the Middle Oxfordian Transversarium Zone. Only a few Tethyan belemnite assemblages are recorded in the Middle Oxfordian, but it is possible to establish a close affinity with the taxa of the Mediterranean Province. The ammonites associated with the belemnites as also those from the upper levels of the section show clear Submediterranean affinities. All the ammonites known from previous and present surveys in the study area belong to the families Perisphinctidae and Ataxioceratidae. The species in new samples are Perisphinctes cf. parandieri, Perisphinctes (Subdiscosphinctes) sp. A, Orthosphinctes sp. A, Orthosphinctes sp. B, Lithacosphinctes? sp. A and Passendorferia cf. gygii. Key-words: Belemnites, Ammonites, Lar Formation, Oxfordian, East Alborz, Iran.
    Boletín del Instituto de Fisiografía y Geologia. 12/2013; 83.
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    ABSTRACT: Early Jurassic belemnites are of particular interest to the study of the evolution of skeletal morphology in Lower Carboniferous to the uppermost Cretaceous belemnoids, because they signal the beginning of a global Jurassic–Cretaceous expansion and diversification of belemnitids. We investigated potentially relevant, to this evolutionary pattern, shell features of Sinemurian–Bajocian Nannobelus, Parapassaloteuthis, Holcobelus and Pachybelemnopsis from the Paris Basin. Our analysis of morphological, ultrastructural and chemical traits of the earliest ontogenetic stages of the shell suggests that modified embryonic shell structure of Early–Middle Jurassic belemnites was a factor in their expansion and colonization of the pelagic zone and resulted in remarkable diversification of belemnites. Innovative traits of the embryonic shell of Sinemurian–Bajocian belemnites include: (1) an inorganic–organic primordial rostrum encapsulating the protoconch and the phragmocone, its non-biomineralized component, possibly chitin, is herein detected for the first time; (2) an organic rich closing membrane which was under formation. It was yet perforated and possessed a foramen; and (3) an organic rich pro-ostracum earlier documented in an embryonic shell of Pliensbachian Passaloteuthis. The inorganic–organic primordial rostrum tightly coating the protoconch and phragmocone supposedly enhanced protection, without increase in shell weight, of the Early Jurassic belemnites against explosion in deep-water environment. This may have increased the depth and temperature ranges of hatching eggs, accelerated the adaptation of hatchlings to a nektonic mode of life and promoted increasing diversity of belemnoids. This study supports the hypothesis that belemnite hatchlings were ‘a miniature of the adults’.
    Lethaia 11/2013; · 2.49 Impact Factor
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    Rivista Italiana di Paleontologia e Stratigrafia 07/2013; 119(2):163-174. · 0.52 Impact Factor
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    ABSTRACT: The belemnite family Holcobelidae GUSTOMESOV, 1977 is revised, based on ca. 200 rostra from recent fieldwork as well as historical museum collections. The studied specimens originate from various European localities and are dated from the Early Aalenian to the Early Bajocian (Middle Jurassic). Eight species of the genera Holcobelus STOLLEY, 1927 (including H. elmii n. sp.) and Calabribelus n. gen. (with type species C. pallinii) are described. The evolution of the morphological characters at the family level is outlined and compared with acrocoelitids (Belemnitina) and pachybelemnopseids (Pachybelemnopseina); the possible phylogenetic links between the Holcobelidae and the latter are discussed. The stratigraphic and palaeobiogeographic distribution of holcobelids is analysed in respect to morphological changes, leading to a hypothesis on different lifestyles among the investigated taxa. The peculiar distribution pattern of Holcobelidae represents a colonization event by belemnites in the northern Tethys and a distinctive belemnitid Tethyan fauna developed during the Bajocian, dominated by Pachybelemnopsis and Hibolithes.
    Palaeodiversity. 12/2012; 5:13-49.
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    ABSTRACT: A biostratigraphic and systematic study based on belemnites collected along with ammonites was performed on four sections in the Subalpine Basin (SE France): Lac du Castillon and La Baume (Castellane area), Galabrun and Grand Lara (Gap area). The specimens, originating from hemi-pelagic marl-limestone alternations in the lower part of the “Calcaires à Zoophycos” Formation, are dated from Middle Aalenian (Murchisonae Zone) to Lower Bajocian (Humphriesianum Zone). Five belemnite taxa (Megateuthis elliptica, Holcobelus munieri, H. trauthi, Pachybelemnopsis roettingensis, Hibolithes sp.) have been identified, and two more taxa are reported in an open nomenclature (Belemnitida incertae sedis sp. 1 and sp. 2). The biostratigraphic range of the belemnite fauna is established. The new findings contribute to a more detailed understanding of the paleobiogeography of holcobelid belemnites that flourished at the northern margin of the Tethys Ocean and formed a distinct sub-Mediterranean fauna. The association herein described is similar to the fauna of the Calabro-Peloritani Arc (Calabria, Italy), a further hint for the supposed paleogeographic position of the latter during the Middle Jurassic.
    Geobios 01/2012; 45(1):99-108. · 1.05 Impact Factor
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    Dirk Fuchs, Robert Weis
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    ABSTRACT: Previously, the number of teudopseid coleoids that roamed the European seas during Early Toarcian times has been unclear. Re-study of a large set of teudopseid gladii from different European localities show that three species existed at that time: Teudopsis bunelii Eudes-Deslongchamps, 1835, Teudopsis bollensis Voltz, 1836 and Teudopsis subcostata (Münster, 1843). In the course of taxonomic treatments, the three taxa are re-described, a lectotype is designated for the first one, and neotypes are designated for the latter two. The most striking difference concerns the anterior shape. It is rachis-like in Teudopsis bunelii, triangular in Teudopsis bollensis, and lanceolate in Teudopsis subcostata. Although an out-group comparison is problematic, the pronounced dorsal keel is an unequivocal autapomorphy of the Teudopseina. The gladius of Teudopsis subcostata seems to possess the most ancient character combination. Phylogenetically, the trachyteuthidid lineage might have been originated from Teudopsis subcostata, whereas the palaeololiginid/muensterellid lineage evolved from Teudopsis bunelii. A close phylogenetic relationship between teudopseids and modern decabrachian as sometimes proposed is not supported.
    Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 08/2010; 257(3):351-366. · 0.92 Impact Factor
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    Ferrantia. 01/2010; 62:73-96.
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    Ferrantia. 01/2010; 62:7-8.
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    Fuchs D, Weis R
    Ferrantia. 01/2010;
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    Dominique Delsate, Robert Weis
    Ferrantia. 01/2010; 62:19-34.
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    Dirk Fuchs, Robert Weis
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    ABSTRACT: A new vampyropod coleoid from the late Cenomanian limestones of Hâdjoula (north-west Lebanon) is described. Glyphiteuthis abisaadiorum n. sp. is classified as a representative of the Trachyteuthididae, mainly on the basis of its general gladius morphology. It represents the fourth species of its genus and the second species of its genus recorded from Hâdjoula. Glyphiteuthis abisaadiorum n. sp. differs from Glyphiteuthis libanotica in having a more slender gladius. Additionally, the arms are considerably longer in Glyphiteuthis abisaadiorum n. sp. than in Glyphiteuthis libanotica. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
    Fossil Record 08/2009; 12(2):175 - 181. · 1.23 Impact Factor
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    DIRK FUCHS, GIACOMO BRACCHI, ROBERT WEIS
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    ABSTRACT:   Three previously unknown octopods are described from Upper Cenomanian limestones of the Hâqel and Hâdjoula localities (Lebanon). Keuppia levante gen. nov., sp. nov., Keuppia hyperbolaris gen. nov,. sp. nov. and Styletoctopus annae gen. nov, . sp. nov. are regarded as the earliest representatives of the Octopoda (= Incirrata). This assumption is mainly based on their medially isolated bipartite gladius vestige. As can be inferred from growth increments, Keuppia gen. nov. can be distinguished from the genus Palaeoctopus by blades that grow forwards along their longitudinal axis. The gladius vestige of Keuppia hyperbolaris sp. nov. differs from that of Keuppia levante sp. nov. in having a more heterogeneous course of growth lines. Based on a pair of widely separated stylets, which closely resemble the rods of modern octopods, Styletoctopus annae gen. nov., sp. nov. is assigned to the Recent family Octopodidae. Peculiar encrustations, which are situated in close association with the gladius vestiges of Keuppia levante sp. nov., Keuppia hyperbolaris sp. nov., and Styletoctopus annae sp. nov. are interpreted as basal fin cartilages. The gladius vestige morphology of Keuppia hyperbolaris sp. nov. and Keuppia levante sp. nov. opens the possibility that both the Octopda and the Cirroctopoda originated from loligosepiid vampyropods instead of teudopseid. The surprising existence of a stylet-like gladius vestige in Styletoctopus annae sp. nov. suggests that the octopod clade branched off much earlier than previously believed. Octopod apomorphies such as the development of stylets, loss of fins and cirri must have been occurred before the Cenomanian.
    Palaeontology 12/2008; 52(1):65 - 81. · 1.65 Impact Factor
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    ABSTRACT: Previous reports of belemnite faunas composed by Holcobelus and associated Pachybelemnopseina in the European Middle Jurassic generally lack precise biostratigraphic information. Recent field research in Luxembourg, Italy (Calabria) and France (Normandy and Haute-Provence) showed that Holcobelus appeared and flourished in the Aalenian (Murchisonae and Concavum Zones), but disappeared in the early Bajocian (Discites Zone, Propinquans Zone for Normandy) with the sudden rise of Pachybelemnopsis. The analysis of new data compared to previous publications suggests a peculiar and formerly unrecognized distribution pattern for Holcobelus in the European Boreal-Atlantic area and the peri-mediterranean northern margin of the Tethys Ocean. The faunal associations at the Aalenian-Bajocian boundary (Murchisonae-Propinquans Zones) show strong submediterranean affinities in southern and south-eastern Europe (SE France, Italy, Bulgaria, Romania), while a clear subboreal compositional pattern is observed in NW Europe (Luxembourg, NE France, Germany, N Switzerland). The submediterranean fauna is dominated by Pachybelemnopseina (Holcobelus ssp., Pachybelemnopsis and Hibolithes), meanwhile the subboreal fauna is characterised by Belemnitina (Brevibelus, Megateuthis, Eocylindroteuthis, Homaloteuthis) and the absence of Holcobelus with the exception of a single migrant species, Holcobelus blainvillii. Both faunas mingled in the western Anglo-Paris and the Aquitaine basins (SW England, NW France) where Belemnitina and Pachybelemnopseina are equally well represented.
    3rd international symposium ‘Coleoid cephalopods through time; 10/2008
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    Dirk Fuchs, Robert Weis
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    ABSTRACT: Until today, gladii of loligosepiid vampyropods have been difficult to distinguished owing to their fragmentary state of preservation. Re-study of a large set of loligosepiids from different Lower Jurassic localities has shown that the preservation of growth lines is sufficient to provide an unambiguous determination. Especially the course of growth lines within the hyperbolar zone is a highly characteristic feature. Members of the Loligosepiidae (Loligosepia, Jeletzkyteuthis) display a deeply concave (V-shaped) hyperbolar zone. Members of the Geopeltidae, on the other hand, show weakly concave (Parabelopeltis), or even straightened (Geopeltis) growth lines. Gladii of Loligosepia can be distinguished from Jeletzkyteuthis by the transition lateral field/hyperbolar zone. The genus Loligosepia is characterised by abrupt backwards bent growth lines forming an elongated spine-like projection, whereas the transition is more arcuated in Jeletzkyteuthis. According to the present results, Loligosepia aalensis, Loligosepia bucklandi, Jeletzkyteuthis coriaceus, Geopeltis simplex, and Parabelopeltis flexuosa are re-described. In the course of taxonomic treatment, a lectotype of Jeletzkyteuthis coriaceus is designated and the morphologic independence of Parabelopeltis flexuosa reaffirmed. As can be inferred from the course of growth lines, Parabelopeltis and Geopeltis, members of the Geopeltidae, seems to be phylogenetically closest to Recent Vampyroteuthis infernalis.
    Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen 06/2008; 249(1):93-112. · 0.92 Impact Factor

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