New,early ostracods from the Ordovician (Tremadocian) of Iran: systematic,biogeographical and palaeoecological significance |
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| Authors: | Mansoureh Ghobadi Pour Mohibullah Mohibullah Leonid E. Popov Tatiana Yu. Tolmacheva |
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| Affiliation: | 1. Department of Geology, Faculty of Sciences , Golestan University , Gorgan, Iran;2. Department of Geology , University of Leicester , Leicester, LE1 7RH, UK;3. Department of Geology , University of Balochistan , Quetta, Pakistan;4. Department of Geology , National Museum of Wales , Cardiff, CF10 3NP, UK;5. Russian Geological Research Institute , Sredny pr. 74, 199106, St. Petersburg, Russia |
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| Abstract: | New Tremadocian ostracod material from the Alborz Mountains of Iran confirms the early and widespread occurrence of the Ordovician genus Nanopsis, and the apparently simultaneous first appearance of ostracods in the fossil record at the level of the P. deltifer conodont biozone (485.5 Ma) from China to Argentina. Nanopsis pairidaeza sp. nov. adds to the pool of species diversity for the Early Ordovician, though documented Tremadocian ostracod generic diversity remains low, with only four genera. The presence of Early Ordovician ostracods in Alborz, their occurrence elsewhere in palaeocontinental Gondwana, Baltica and China coupled to their marked absence from the Tremadocian of Laurentia and Siberia, supports the notion of the earliest occurrence of ostracods centred on Gondwana/Baltica. |
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| Keywords: | Ordovician Tremadocian ostracods Iran biogeography ecology evolution |
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