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    ABSTRACT: Belemnites harleyi Mayer, 1866, originally described from the Jurassic of Normandy, has encountered diverging interpretations during the last 150 years of scientific research. It has subsequently been assigned to four different genera (Belemnopsis, Aulacoteuthis, Acrocoelites and Holcobelus). The detailed study of the rostrum morphology and its inner structure allows us to attribute it to a new genus, Lissajousibelus Weis gen. nov., in honor of the French geologist Marcel Lissajous (1863-1921). Key features of the new genus are the overall depressed rostrum, short dorsolateral apical grooves, a long intermediate ventral groove with splitting surface and a shallow dorsoalveolar depression. Bed-by-bed sampling at the classic locality Feuguerolles-sur-Orne (Calvados) enables us to revise the stratigraphic position of Lissajousibelus harleyi (Mayer, 1866) as lowermost Toarcian Tenuicostatum Chronozone. Lissajousibelus Weis gen. nov. is therefore amongst the earliest belemnites with belemnopseine morphology. However, its phylogenetic relationships with younger Belemnopseina from the Aalenian-Bajocian (Middle Jurassic) remain unclear.
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    ABSTRACT: The systematic study of new belemnite assemblages from the Central Apennines and western Sicily revealed several new taxa for Italy. The specimens originate from Lower Jurassic sediments (Sinemurian–Toarcian), and their exact stratigraphic occurrence can be established by accompanying ammonite assemblages. The systematic analysis allows six genera of the suborder Belemnitina to be recognised (Subhastites, Passaloteuthis, Pseudohastites, Bairstowius, Cuspiteuthis, Megateuthis). The coeval occurrence of heterogeneous canaliculate belemnites (with alveolar grooves) was unexpected; their partially incomplete preservation does not allow assigning them safely to any existing genus, with the exception of a well-preserved specimen of Pachybelemnopsis sp. (with phragmocone, protoconch, and siphuncle). This represents the earliest known record of a belemnopseine belemnite. The Italian canaliculate belemnites are tentatively compared with canaliculate belemnites from the European Peri-Tethys, Japan, and New Zealand. A direct comparison is, however, hampered by the incomplete preservation of most of the herein reported specimens. The records of canaliculate belemnites in the Early Jurassic of Italy show remarkably heterogeneous rostrum morphologies, indicating an earlier diversification in belemnites than previously assumed.
    Paläontologische Zeitschrift 05/2015; DOI:10.1007/s12542-015-0265-5 · 1.10 Impact Factor
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    Oksana Dzyuba, Robert Weis
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    ABSTRACT: Major changes in the taxonomy and nomenclature of Megateuthididae Sachs et Nalnjaeva, 1967 are discussed in historical order. According to the revised data, the northern and eastern Russian megateuthidid belemnites are represented by the genera Megateuthis (Pacific coast only), Acrocoelites, Arcobelus, Odontobelus, Paramegateuthis and Rarobelus.
    Contributions to current cephalopod research: Morphology, Systematics, Evolution, Ecology and Biostratygraphy. Proceeding of conference (Moscow, 2 – 4 April, 2012), Moscow; 04/2015
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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; 275(3). DOI:10.1127/njgpa/2015/0465 · 0.54 Impact Factor
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    ABSTRACT: A gastropod fauna has been studied from upper Pliensbachian – upper Toarcian deposits of two sections of the Causses Basin (southern France) in order to investigate the mode of recovery after the early Toarcian anoxic event. The fauna consists of 15 species, one of which is new (Bathrotomaria kronzwilmesorum sp. nov.). Their stratigraphical distribution shows two peaks of diversity – in the Bifrons Zone (Bifrons Subzone) and in the Aalensis Zone (Mactra Subzone) – which reflect brief times during which the oxygen content and bottom consistency favoured the settlement of a relatively diversified fauna. In the Variabilis–Pseudoradiosa zones, gastropods are only represented by two species. This probably indicates more severe and unstable environmental conditions, only allowing the survival of gastropod taxa with wide adaptive capacities. The very low species diversity and the discontinuous and slow faunal recovery were probably determined by physiographic factors. The Causses area was a small basin confined by exposed lands and open towards the central part of western Tethys. Gastropods described here occur exclusively in the Toarcian – early Aalenian communities of the European epicontinental seas, whereas species from the central region of western Tethys are absent. Geographic isolation and marginal location of the Causses Basin restricted faunal exchange with the western European epicontinental seas, preventing fast recovery after the anoxic event. Gastropods of the central region of the western Tethys were probably unable to settle and colonize that area due to the strongly different environment.
    Geological Magazine 02/2015; DOI:10.1017/S0016756814000788 · 2.18 Impact Factor
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    Robert Weis, Ben Thuy
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    ABSTRACT: A belemnite assemblage is described for the first time from the Lower Jurassic Adnet Fm. of the Austrian Alpine Tethys. Six taxa of the family Passaloteuthididae have been recognized (Coeloteuthis oravicus, C. aff. calcar, Nannobelus acutus, Passaloteuthis elongata, P. cf. laevigata, Pseudohastites carinatus). The relatively elevate number of specimens attributed to Coeloteuthis and the apparent absence of Subhastites are the most remarkable features of this assemblage. The taxonomic analysis shows a close similarity of the Glasenbach Gorge fauna with coeval assemblages of the Slovakian Klippenbelt. It provides further evidence that Early Jurassic belemnite faunas were rather uniform in generic composition in Northwest and Tethyan Europe during Late Sinemurian and Early Pliensbachian.
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    ABSTRACT: The anatomy and development of the tails at the posterior part of the mantle were studied in several groups of Recent and extinct coleoid cephalopods; substantial differences in their formation were revealed. Males of the Recent loliginid squid Alloteuthis spp. form their tail by increased growth of the anterior part of the gladius with simultaneous growth of the posterior mantle. As a result, the gladius rolls longitudinally in the tail forming a pseudoconus. The attenuated tail in males of the squid Lycoteuthis springeri (Lycoteuthidae) is supported from inside by the special rod-like apical vacuolated cartilage. Adults of both sexes of recent Onykia robsoni and O. robusta form a carrot-shaped flexible chitinous rostrum supporting the attenuated tail. Adults of several Jurassic belemnites formed an elongated epirostrum posterior to their orthorostrum; the structures differed in growth and microstructure. Counts of growth microincrements within the orthorostrum and epirostrum were used to date their formation and estimate the age of belemnites. The development of the long rigid tail and the corresponding shift of the fin to the middle part of the mantle streamline the body and possibly facilitate the animal’s movement in the water by gliding. The analogous tail formation in several independent groups points to its adaptive nature for the development of a more mobile adult phase in species of coleoid cephalopods.
    Journal of Molluscan Studies 02/2015; DOI:10.1093/mollus/eyu094 · 1.50 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. DOI:10.1127/0077-7749/2014/0421 · 0.54 Impact Factor
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    Gondwana Research 07/2014; DOI:10.1016/j.gr.2014.06.007 · 8.12 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; 89(2). DOI:10.1007/s12542-014-0223-7 · 1.10 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.
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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; DOI:10.1111/let.12037 · 2.19 Impact Factor
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    Rivista Italiana di Paleontologia e Stratigrafia 07/2013; 119(2):163-174. · 0.93 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.
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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. DOI:10.1016/j.geobios.2011.11.012 · 1.19 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. DOI:10.1127/0077-7749/2010/0083 · 0.54 Impact Factor
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