1 3 Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-016-1435-8 ORIGINAL PAPER Fusulinoids from the Bashkirian–Moscovian transition beds of the Shahreza region in the Sanandaj–Sirjan Zone, Iran Shirin Fassihi 1 · Masatoshi Sone 1 · Vachik Hairapetian 2 · Fariba Shirezadeh Esfahani 3 Received: 22 May 2016 / Accepted: 4 December 2016 © Springer-Verlag Berlin Heidelberg 2016 reported from Iran for the first time. This study also pre- sents the first occurrence of the genera Aljutovella and Tik- honovichiella in the Sanandaj–Sirjan Zone of Iran. Keywords Bashkirian · Moscovian · Pennsylvanian · Carboniferous · Fusulinoid · Iran Introduction and geological setting Iran has a complex geological structure and is divided into several tectonic units, such as the Zagros, Alborz, Central Iran (Yazd Block), East Iran (Lut and Tabas blocks), and the Sanandaj–Sirjan Zone (Arfania and Shahriari 2009; Ruban 2007; Torsvik and Cocks 2004) (Fig. 1). The San- andaj–Sirjan Zone, where the biostratigraphic section stud- ied is located, is composed mainly of the metamorphic complexes and granitoid intrusions. It includes the Car- boniferous–Permian strata that exhibit different lithological characteristics in comparison with the tectonic blocks of East and Central Iran (Ahadnejad 2013; Alavi and Kishvar 1991; Bahrami et al. 2014). In the Sanandaj–Sirjan Zone, the Carboniferous–Per- mian strata are widely exposed with a nearly complete succession. The lithostratigraphic subdivisions of the Car- boniferous strata are as follows. (1) The Shishtu Group of Mississippian age is represented by the sequence of lime- stone intercalated with the shale and sandstone. Its Mis- sissippian age is based on the conodonts (Boncheva et al. 2007). (2) The Sardar Group of latest Mississippian–Penn- sylvanian age unconformably overlies the Shishtu Group. It consists of the Ghaleh and Absheni formations which cor- respond roughly to the latest Serpukhovian–Moscovian age (Leven and Gorgij 2011b). The Ghaleh Formation is com- posed of limestone with argillite, aleurolite, and sandstone Abstract The presence of the Bashkirian–Moscovian (lower Pennsylvanian) sequence with mixed siliciclastics and fossil-rich carbonates has long been known from the Sanandaj–Sirjan Zone in Iran. However, except for a few studies, its biostratigraphy was not previously investigated in detail. A fusulinoid fauna is recovered from newly meas- ured section, which we named the Asad Abad II section. It is located near the Shahreza town in the Sanandaj–Sirjan Zone. The most important fusulinoids of this assemblage are Aljutovella cf. aljutovica Rauser-Chernosouva, Tik- honovichiella tikhonovichi (Rauser-Chernosouva), and Pro- fusulinella (Depratina) prisca (Deprat); they occur in asso- ciation with species of Ozawainella, Staffellaeformis, and Pseudostaffella. This fauna overall represents a fauna of the latest Bashkirian–earliest Moscovian transition period in the Sanandaj–Sirjan Zone. This new fusulinoid fauna shares some common species with the concurrent faunas of the Alborz, East Iran, and Central Iran. Furthermore, it can be easily compared with those of the Russian Plat- form, Southern and Northern Urals, and Central Taurides (Turkey). The four species of the current fauna, namely Eostaffella compressa Brazhnikova, E. primitiva (Dutk- evich), Pseudostaffella timanica Rauser-Chernosouva, and Profusulinella postpararhombiformis Dzhenchuraeva are * Shirin Fassihi shirin.fassihi@gmail.com 1 Department of Geology, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia 2 Department of Geology, Islamic Azad University, Isfahan (Khorasgan) Branch, PO Box 81595-158, Isfahan, Iran 3 Department of Geology, Faculty of Basic Sciences, Islamic Azad University of Tehran, North Branch, Tehran 1667934783, Iran