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TitleNew hybodontiform and neoselachian sharks from the Lower Triassic of Oman
AuthorKoot, M B; Cuny, G; Orchard, M JORCID logo; Richoz, S; Hart, M B; Twitchett, R J
SourceJournal of Systematic Palaeontology vol. 13, issue 10, 2014 p. 891-917,
Alt SeriesEarth Sciences Sector, Contribution Series 20130122
PublisherInforma UK Limited
Mediapaper; on-line; digital
File formatpdf
AreaMuscat; Gulf of Oman; Jabal al Akhdar; Haushi-Huqf; Oman
Lat/Long WENS 56.0000 60.0000 25.0000 19.0000
Subjectspaleontology; stratigraphy; systematic paleontology; fossils; fossil distribution; fossil assemblages; Lower Triassic; Cretaceous; Triassic
Illustrationslocation maps; plates; stratigraphic columns; pie charts
ProgramGEM: Geo-mapping for Energy and Minerals Yukon Sedimentary Basins
Released2014 11 03
AbstractElasmobranchs 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.
Summary(Plain Language Summary, not published)
The teeth and other bony material of fossil sharks (elasmobranchs) are reported for the first time from Lower Triassic deposits in Oman. The well-preserved remains come from low-paleolatitude sedimentary rocks dating from about 260 to 248 million years ago, which brackets a time of mass extinction on Earth. The faunas, which include new genera and species, include the most extensive post-extinction record known in terms of abundance and diversity. The faunas, independently dated by associated conodonts, provide insights into the early stages of shark evolution, the magnitude of extinction and recovery, and in addition provide a further tool for dating Triassic strata.

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