The ostracode Lavachilina evae gen. et sp. nov. is described from the Arenig of Western Russia. Its carapace possesses a unique discontinuous velum, developed at both ends as a narrow spinose ridge. The systematic position of L. evae is uncertain. Its character set shows mostly palaeocope affinities but also some features of leiocopes. L. evae is tentatively assigned to the palaeocope family Oepikellidae, possibly representing an early member of that family. Although L. evae existed contemporaneously with palaeocopes such as Laccochilina, it does not appear to be closely related to these early eurychilinoids.
Ordovician ostracods are described for the first time from Iran, enhancing the record of this group from the Lower Palaeozoic of the Middle East. The ostracods occur in the Shirgesht Formation, in the east central part of the country, and comprise Ogmoopsis achaemenid sp. nov., Cerninella aryana sp. nov., Ordovizona amyitisae sp. nov., cf. Aechmina? ventadorni, Vogdesella sp., and podocope taxa tentatively identified as species of Longiscula, Pullvillites, and Rectella. These taxa were hitherto unknown from this region. The ostracod−bearing interval is associated with trilobites (Neseuretinus) and brachiopods (Nicolella) that suggest a late Middle Ordovician age. Although the ostracod fauna is small, it demonstrates biogeographical links at genus−level, and possibly at species−level, with the fauna of the late Middle Ordovician Travesout Formation of western France, which also lay in a peri−Gondwanan palaeogeographical setting. It also suggests the potential use of some ostracods as stratigraphical tools for correlating Ordovician rock successions between Europe and the Middle East.
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