The Mobarak Formation in the Valiabad area (northwestern Alborz, Iran) is composed of bioclastic, oolitic and sandy limestone interbedded with black shale, and is disconformably underlain and overlain by the Cambrian Lalun and Permian Dorud formations, respectively. In this study, 104 foraminiferal species belonging to 12 families and 33 genera were determined. Among them, six genera and nine species are reported for the first time in Iran. Analysis of the foraminiferal assemblages has identified eight local biozones, which can be correlated with the MFZ8 to MFZ14 zones of the Viséan stratotypes in Belgium. The Valiabad equivalents of these biozones are essentially characterized by (1) Eoparastaffella ex gr. rotunda‐‘florigena’–Lysella cf. gadukensis; (2) Eoparastaffella simplex–Lapparentidiscus bokanensis; (3) Ammarchaediscus; (4) Uralodiscus–Glomodiscus; (5) Glomodiscus–Archaediscus; (6) Pojarkovella–Mstinia fallax; (7) Mstinia bulloides–Pseudoendothyra; and (8) Howchinia gibba–Howchinia bradyana–Tubispirodiscus attenuatus. Consequently, the Valiabad section appears to be one of the most complete Viséan sections in Iran. Some taxonomic precisions are provided about the principal taxa. Biogeographically, (1) the MFZ8–MFZ11 biozones are extended to all the shelves of the Palaeotethys (from Ireland to South China) and Urals oceans; nevertheless, due to the complete evolution of archaediscoids, they seem more related to the Perigondwanan assemblages from Sinai and Taurus (including the Antalya Nappes); (2) the MFZ12 assemblage appears relatively endemic; and (3) the impoverished assemblages of the biozones MFZ13‐14 have marked affinities with the Kazakhstan Block. It is currently impossible to indicate precisely if these variations are related with a drift of the Alborz region to the north, or to a change of oceanic currents. Moreover, the double affinity highlights the narrowness of the Palaeotethys in Iran during the Viséan. Copyright © 2014 John Wiley & Sons, Ltd.

Reinvestigation of the Kushk and Chahmir areas (Bafq and Behabad regions) of central Iran has yielded a diverse assemblage of Ediacaran fossils, including several new species, just prior to the Cambrian explosion of complex animals. The Kushk series consists mainly of shallow marine carbonate deposits followed by deep-water calcareous marine shales. Ediacaran fossils occur commonly in the shale deposits and include biostratigraphically-important taxa Cloudina and Corumbella, which confirms a latest Ediacaran age for these deposits, the youngest examples of Kimberellomorphs (stem-group molluscs) that helps bridge the gap between their first occurrence in the middle-Ediacaran and the crown diversification in the Cambrian, and likely sponges, which are rare prior to the Cambrian.

The Kushk Series is a distinctive late Ediacaran succession occurring in the Bafq and Behabad regions of central Iran that has yielded an extensive community of diverse Ediacara biota, including several Precambrian (Chuaria) and Ediacaran (Cloudina, Corumbella) index fossils.The Kushk Series reaches a thickness of up to 518 m and consists of shallow to deep subtidal deposits along a homoclinal carbonate ramp during a transgression/regression cycle. These deposits accumulated as part of an extensional rift basin complex resulting from the opening of the Proto-Paleotethys Ocean in northeastern Gondwana. Latest Ediacaran fossils occur in the deep-water calcareous marine shales, and represent a thriving community at the dawn of animal life.

The late Ediacaran (Nama) Fossil Assemblage from the Kushk Series in the Kushk and Chahmir areas of Central Iran highlights a diverse community of globally distributed, soft-bodied (non-skeletonized) Ediacara biota coexisting with skeletonized tubular forms of likely metazoan affinities. Several biostratigraphically and biogeographically important taxa are reported (i.e., erniettomorphs, rangeomorphs, cloudinomorphs, kimberellomorphs, Chuaria, Corumbella), including Convolutubus dargazinensis new genus new species, a new organic-walled tubular organism, allowing for paleoecological studies to be performed. This study highlights the need for continued investigations into the late Ediacaran of Iran, and suggests a biosphere in transition, with a shift in diversity and abundance from large Ediacara biota to organic-walled and skeletonized tubular organisms at the dawn of the Cambrian Explosion. UUID: http://zoobank.org/350bb98c-5322-488d-a9a5-22c911ab7e53

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