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1

First report on the occurrence of Neseuretinus and Ovalocephalus trilobites in the Middle Ordovician of Iran

100%

Ghobadi P. M. , Popov L. E.

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nr 1

125-133

EN

In the Derenjal Mountains of east Central Iran, the upper part of the Shirgesht Formation (uppermost Darriwilian) contains a distinct trilobite assemblage that includes Neseuretinus birmanicus and Ovalocephalus aff. obsoletus among others. Both genera were previously unknown in Iran. The occurrence of Ovalocephalus represents the earliest sign of westward taxon migration from China towards higher latitudes along the West Gondwanan margin, which may be related to global warming, after a short episode of cooler climate in the early to mid Darriwilian. Patterns of biogeographical distribution of Ovalocephalus and Neseuretinussuggest that Central Iran was part of an “overlap zone” where tropical and high latitude benthic taxa mingled.

2

A new genus of Late Ordovician-Early Silurian pentameride brachiopods and its phylogenetic relationships

100%

Jin J. , Popov L. E.

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nr 2

EN

Protanastrophia repanda gen. et sp. nov. is a reef−dwelling parastrophinid brachiopod in the Lower Silurian (uppermost Telychian) Attawapiskat Formation of the Hudson Bay region of Canada. It is characterized by a small, quasi−smooth shell with gentle anterior costae, a tendency towards an asymmetrical, sigmoidal anterior commissure, and widely separate, subparallel inner hinge plates. Protanastrophia first appeared in the marginal seas of Siberia (Altai, Mongolia) during the Late Ordovician, retaining the primitive character of discrete inner hinge plates in the superfamily Camerelloidea, and preferred a carbonate mound depositional environment. It survived the Late Ordovician mass extinction and subsequently spread to Baltica and Laurentia during Early Silurian (Llandovery) time. Superficially similar asymmetrical shells of Parastrophina portentosa occur in the Upper Ordovician carbonate mound facies of Kazakhstan but differ internally from the new genus in having a septum−supported septalium. Phylogenetic analysis indicates that, within the Camerelloidea, asymmetrical shells with a sigmoidal anterior commissure evolved in Protanastrophia repanda and Parastrophina portentosa independently during the Late Ordovician as a case of homoplasy. The two species belong to separate parastrophinid lineages that evolved in widely separate palaeogeographic regions.

3

A new, unusual rhynchonellide brachiopod with a strophic shell from the Sirurian of Iran

80%

Popov L. E. , Hairapetian V. , Pour M. G. , Modzalevskaya T. L.

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nr 3

EN

A new, unusual rhynchonellide brachiopod Jafarirhynchus alatus assigned to the newly established family Jafarirhynchidae is described from the Silurian (Telychian) of the Boghu Mountains in east-central Iran. It forms a low diversity association with the spiriferide Striispirifer? ocissimus, which exhibits well preserved calcified brachial supports. A strophic shell, well-developed ventral interarea and liberosessile mode of life make this taxon unique among Palaeozoic rhynchonellide brachiopods. In spite of a superficial similarity to spiriferides and the atrypide family Davidsonioidea, Jafarirhynchus retains the typical rhynchotrematoid cardinalia with a septalium supported by the median septum, a septiform cardinal process and long, raduliform crura. It is considered as an offshoot of the local lineage, which includes two successive species of Stegocornu (family Rhynchotrematidae) which proliferated in Central Iran and adjacent Afghanistan during Aeronian time.

4

Middle Cambrian lingulate brachiopods from the Tarbagatay Range, Kazakhstan

80%

Popov L. E. , Holmer L. E. , Gorjansky V. J.

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tom 41

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nr 3

EN

Early Middle Cambrian (Amgian) lingulate brachiopods from the Tarbagatay Range in eastern Kazakhstan represent mostly endemic taxa, which may suggest that the Tarbagatay Range was relatively isolated from adjacent terranes during that time; only Kleithriatreta indicate similarity with the Australian part of Gondwana, as well as with the south and central Kazakhstanian terranes. Late Middle Cambrian (Mayan) taxa from the same area are mostly cosmopolitan. Kostjubella relaxata gen. et sp. n., Prototreta (?) dolosa sp. n. and Stilpnotreta galinae sp. n. are proposed.

5

Late Ordovician brachiopods from the Selety River basin, North Central Kazakhstan

80%

Nikitin I. F. , Popov L. E. , Bassett M. G.

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tom 48

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nr 1

EN

A medium−diversity fauna of late Ordovician rhynchonelliformean brachiopods occurs in the Tauken Formation (upper Caradoc–lowermost Ashgill) of north Central Kazakhstan.It demonstrates close similarity to the approximately contemporaneous faunas characteristic of shallow clastic shelves (BA 2–3) of the Chingiz and Chu−Ili ranges (both in Kazakhstan) and South China, but is characterized by a high proportion of endemic new species, including Tetraphalerella bestiubensis sp.nov., Glyptomena kaskolica sp.nov., Dinorthis taukensis sp.nov., Rhynchotrema seletensis sp.nov., and Nalivkinia (Pronalivkinia)zvontsovisp.nov.The abundance of Rhynchotrema is somewhat unusual by comparison with faunas from other Kazakhstanian terranes, where rhynchonellides of the family Ancistrorhynchidae are usually dominant in near−shore biofacies.The occurrence of the atrypides Sulcatospira and early Nalivkinia demonstrates a clear biogeographical linkage with approximately contemporaneous faunas of South China.

6

Silurian stratigraphy of Central Iran - an update

71%

Hairapetian V. , Ghobadi Pour M. , Popov L. E. , Männik P. , Miller C. G.

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2017

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tom Vol. 67, no. 2

201--233

EN

The Silurian biostratigraphy, lithostratigraphy, and facies of Central Iran including the Kashmar (Boghu Mountains), Tabas (Derenjal Mountains, Ozbak-Kuh), Anarak (Pol-e Khavand) and Kerman regions is reviewed and updated. The current state of knowledge of the Silurian in the Zagros Basin, Alborz, Kopet-Dagh and Talysh regions, as well as in a few areas scattered across the Sabzevar Zone, and the Sanandaj-Sirjan terranes is also reviewed. Silurian volcanism in various parts of Iran is briefly discussed. The end of the Ordovician coincided with a widespread regression across Iran synchronous with the Hirnantian glaciation, and only in the Zagros Basin is there a continuous Ordovician–Silurian transition represented by graptolitic black shales of the Sarchahan Formation. In the Central-East Iranian Platform marine sedimentation re-commenced in the early to mid Aeronian. By the Sheinwoodian, carbonate platform depositional environments were established along its north-eastern margin. In other parts of Iran (e.g., Kopet-Dagh and the Sabzevar Zone), siliciclastic sedimentation continued probably into the late Silurian. The Silurian conodont and brachiopod biostratigraphy of Central Iran is significantly updated facilitating a precise correlation with the Standard Global Chronostratigraphic Scale, as well as with key Silurian sections in other parts of Iran. The Silurian lithostratigraphy is considerably revised and two new lithostratigraphical units, namely the Boghu and Dahaneh-Kalut formations, are introduced.

7

Review of the Ordovician stratigraphy and fauna of the Anarak Region in Central Iran

61%

Popov L. E. , Hairapetian V. , Evans D. H. , Ghobadi Pour M. , Holmer L. E. , Baars C.

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tom Vol. 65, no. 4

403--435

EN

The Ordovician sedimentary succession of the Pol-e Khavand area, situated on the northern margin of the Yazd block, has important differences from those in other parts of Central Iran. It has been established that the presumably terminal Cambrian to Lower Ordovician volcano-sedimentary Polekhavand Formation, exposed in the Pol-e Khavand area, has non-conformable contact with greenschists of the Doshakh Metamorphic Complex. The succeeding, mainly siliciclastic Chahgonbad Formation contains low to moderately diverse faunal assemblages, including brachiopods, cephalopods, trilobites and tentaculitids. The Darriwilian age of the lower part of the formation is well established by the co-occurrence of brachiopod genera Camerella, Phragmorthis, Tritoechia and Yangtzeella. The associated rich cephalopod fauna is different from the Darriwilian cephalopod associations of the Alborz terrane and may show some affinity with warm water faunas of North China and South Korea. It is likely that the Mid Ordovician fauna recovered from the lower part of the Chahgonbad Formation settled in the area sometime during a warming episode in the late Darriwilian. By contrast the low diversity mid Katian brachiopod association includes only three taxa, which occur together with the trilobite Vietnamia cf. teichmulleri and abundant, but poorly preserved tentaculitids questionably assigned to the genus Costatulites. This faunal association bears clear signatures linking it to the contemporaneous cold water faunas of the Arabian, Mediterranean and North African segments of Gondwana. Four brachiopod species recovered from the Chahgonbad Formation, including Hibernodonta lakhensis, Hindella prima, Lomatorthis? multilamellosa and Yangtzeella chupananica are new to science.