148 research outputs found

    Lower and Middle Cenomanian ammonites from the Morondava Basin, Madagascar

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    Lower and Middle Cenomanian ammonite assemblages have been collected on a bed-by-bed basis from localities at Vohipaly and Mahaboboka, Madagascar, as well as from outcrops around Berekata, all in the Morondava Basin, southwest Madagascar. These collections demonstrate the presence of the upper Lower Cenomanian Mantelliceras dixoni Zone and the lower Middle Cenomanian Cunningtoniceras inerme Zone of the north-western European standard sequence. These records indicate that the striking anomalies in the zonal assemblages of the classic divisions of the Madagascan Cenomanian are based on mixed assemblages, rather than a succession that differs radically from that elsewhere in the world. The dixoni Zone fauna is: Desmoceras cf. latidorsatum (Michelin, 1838), Pachydesmoceras kossmati Matsumoto, 1987, Forbesiceras sp., F. baylissiWright & Kennedy, 1984, F. largilliertianum (d'Orbigny, 1841), Mantelliceras cantianum Spath, 1926a, M. dixoni Spath, 1926b, M. mantelli (J. Sowerby, 1814), M. picteti Hyatt, 1903, M. saxbii (Sharpe, 1857), Sharpeiceras sp., S. falloti (Collignon, 1931), S. mocambiquense (Choffat, 1903), S. cf. florencae Spath, 1925, Acompsoceras renevieri (Sharpe, 1857), A. tenue Collignon, 1964, Calycoceras sp., Mrhiliceras lapparenti (Pervinquičre, 1907), Mariella (Mariella) stolizcai (Collignon, 1964), Hypoturrilites taxyfabreae (Collignon, 1964), Turrilites scheuchzerianus Bosc, 1801, Sciponoceras cucullatum Collignon, 1964, and Sciponoceras antanimangaensis (Collignon, 1964). The presence of Calycoceras in a Lower Cenomanian association represents a precocious appearance of a genus typically Middle and Upper Cenomanian in occurrence, and matches records from Tunisia. The inerme Zone yields a more restricted assemblage: Pachydesmoceras kossmati, Forbesiceras baylissi, Acanthoceras sp. juv., Cunningtoniceras cunningtoni (Sharpe, 1855) and Hypoturrilites taxyfabreae

    Paleozoic echinoderm hangovers:waking up in the Triassic

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    The fossil record of the family Benthopectinidae (Echinodermata, Asteroidea), a reappraisal

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    Fossils assigned to the predominantly deep-sea asteroid family Benthopectinidae Verrill, 1894 are described and their affinities reappraised. Detailed comparative morphology of ambulacrals, adambulacrals and marginal ossicles has revealed that only some extinct taxa fall within the morphological range of the modern representatives of the family. These include Jurapecten hessi Gale, 2011, J. infrajurensis sp. nov. (both Jurassic), J. dhondtae sp. nov. (Upper Cretaceous) and Nearchaster spinosus (Blake, 1973) comb. nov. (Lower Oligocene). A new Late Cretaceous genus, Punkaster gen. nov. (P. spinifera gen. et sp. nov. and P. ruegenensis gen. et sp. nov.), appears to be a highly derived benthopectinid. A possible benthopectinid is described from the Upper Triassic (Carnian) of China. Other described records are distantly related to, but convergent in gross morphology with, benthopectinids. Thus, Plesiastropecten hallovensis Peyer, 1944 is here referred to the Jurassic spinulosidan family Plumasteridae Gale, 2011 and Xandarosaster hessi Blake, 1984 is interpreted as Spinulosida Perrier, 1884 incertae sedis. The mid-Cretaceous Alkaidia sumralli Blake & Reid, 1998 is reassigned to the Forcipulatida (Zorocallina). The “fossil benthopectinid” of Spencer & Wright in Moore (1966) is shown to belong to the goniopectinid genus Chrispaulia Gale, 2005, of which two new Cretaceous species are described, C. wrightorum sp. nov. and C. spinosa sp. nov. Finally, we consider Henricia? venturana Durham & Roberts, 1948 to be an indeterminate asteroid
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