Smithian (Early Triassic) ammonoid faunas from Exotic Blocks from Oman: taxonomy and biochronology

摘要

Ammonoid-rich exotic hocks of Hallstatt facies in Jebel Safra, in Wadi Musjah and at Baid (Oman Mountains) have yielded several well preserved and highly diversified Smithian (Early Triassic) ammonoid faunas (Baidites hermanni fauna, Rohillites omanensis fauna, Flemingites rursiradiatus fauna, Nammalites pilatoides fauna, Owenites koeneni fauna and Anasibirites multiformis fauna). The comparison of these assemblages with data from other Tethyan basins such as the Salt Range, Spiti, Tibet and South China shows that nearly all known Smithian ammonoid faunal assemblages are present in the exotic blocks from Oman. The new Oman data strengthens the remarkably uniform biogeographic distribution of the Smithian ammonoid faunas within the Tethys.One new ammonoid family (Galfettitidae), five new genera (Baidites, Goudemandites, Lucasites, Omanites, Safraites), and twelve new species (Baidites hermanni, Galfettites kyrae, G. omani, Goudemandites sinensis, Kashmirites baidi, Lucasites involutus, L. evolutus, Omanites musjahensis, Paranannites baudi, Pseudaspidites planus, Rohillites omanensis, Safraites simplex) are described. Additionally, a new early Spathian (late Early Triassic) species (Procolumbites safraensis) is described.