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TitreNew hybodontiform and neoselachian sharks from the Lower Triassic of Oman
AuteurKoot, M B; Cuny, G; Orchard, M J; Richoz, S; Hart, M B; Twitchett, R J
SourceJournal of Systematic Palaeontology vol. 13, issue 10, 2014 p. 891-917, https://doi.org/10.1080/14772019.2014.963179
Année2014
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130122
ÉditeurTaylor and Francis
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1080/14772019.2014.963179
Mediapapier; en ligne; numérique
Formatspdf
Lat/Long OENS 56.0000 60.0000 25.0000 19.0000
Sujetspaléontologie systématique; fossiles; distribution de fossiles; assemblages fossiles; Trias inférieur; paléontologie; stratigraphie; Crétacé; Trias
Illustrationslocation maps; plates; stratigraphic columns; pie charts
ProgrammeBassins sédimentaires du Yukon, GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
Elasmobranchs are reported for the first time from Lower Triassic deposits in Oman. The well-preserved remains consist of isolated teeth, dermal denticles and fin spines, recovered from conodont residues. The low-palaeolatitude sections consist of Lopingian-Olenekian shallow and pelagic carbonates in exotics, olistoliths and breccia blocks that have been redeposited in younger allochthonous strata of the Hawasina Basin throughout the Oman Mountains at Jabal Safra (olistoliths within the Jurassic Guwayza Formation, Olenekian), as well as at Wadi Alwa (exotic Alwa Formation, Lopingian-Olenekian) and Wadi Wasit Block (slope breccia in the Al Jil Formation, Induan), both of which occur in the Ba'id region. The recovered fauna contains a small number of pre-existing genera, but is mainly composed of new hybodont and neoselachian taxa. They are identified as: Omanoselache halli Koot & Cuny sp. nov., cf. Omanoselache sp., Safrodus tozeri Koot & Cuny gen. et sp. nov. and Polyfaciodus pandus Koot & Cuny gen. et sp. nov., based on the majority of the recovered dental remains. Spine fragments are identified as cf. Amelacanthus sp. This fauna represents the second published record of neoselachian teeth from the Induan and the most extensive record from the Lower Triassic in terms of abundance and diversity. The fauna is dominated by Neoselachii, whereas other Early Triassic faunas are hybodont-dominated, and histological study of the neoselachian enameloid significantly adds to our knowledge of the early stages of their evolution. All described taxa are new to the Oman fossil record and that of western Neotethys, apart from Omanoselache and Amelacanthus, which have been recognized from Wordian deposits, and Omanoselache is the second genus from Oman known to have survived the late Permian mass extinction. The level of faunal diversity recognized here is comparable to other Early Triassic faunas but is much reduced compared to the Wordian pre-extinctions fauna.
Résumé(Résumé en langage clair et simple, non publié)
Nouveaux requins hybodontiformes et néosélaciens du Trias inférieur d'Oman. On mentionne pour la première fois la présence de dents et de matières osseuses de requins fossiles (élasmobranches) provenant de dépôts triasiques en Oman. On a trouvé ces fragments bien conservés dans des roches sédimentaires des basses paléolatitudes datant d'environ 248 à 260 millions d'années, ce qui englobe une période d'extinction massive (sur Terre). La faune microfossile, qui comprend de nouveaux genres et espèces, représente le plus vaste ensemble de données post-extinction pour ce qui est de son abondance et de sa diversité. Ces faunes, datées de manière indépendante à l'aide de conodontes associés, donnent un aperçu sur les premiers stades de l'évolution des requins et sur l'ampleur de l'extinction et du rétablissement, en plus de constituer un autre moyen pour dater les strates triasiques.
GEOSCAN ID292767