Furongian linguliform brachiopods from the Alborz Mountains, Iran LEONID E. POPOV, MANSOUREH GHOBADI POUR, MEHRI HOSSEINI & LARS E. HOLMER FURONGIAN linguliform brachiopods from Gondwana are poorly known. The best documented peri-Gondwanan faunas have been described from Kazakhstanian terranes (Popov & Holmer 1994; Holmer et al. 2001) and North China (Mei 1993); with the exception of Dactylotreta and Treptotreta, most acrotretides described from the middle Cambrian to Furongian of Australia (Rowell & Henderson 1978; Henderson & MacKinnon 1981; Engelbretsen 1996) became extinct by the beginning of the Furongian. This paper analyses linguliform brachiopods from the Furongian part of the Mila Formation of the eastern Alborz Mountains in northern Iran. There are no previous descriptions of micromorphic linguliform brachiopods from the Cambrian of Iran. GEOLOGICAL AND GEOGRAPHICAL SETTING The Mila Formation was first defined by Stöcklin et al. (1964) and it conformably overlies the Early Cambrian Lalun Formation. The Mila Formation is subdivided into five members, of which the lower four comprise dolomites and bioclastic limestones of middle to late Cambrian age. The fifth member (mostly consisting of argillites and siltstones with a bed of quartzose sandstone at the base) was originally referred to the Early Ordovician (Stöcklin et al. 1964). The biostratigraphy of the Mila Formation is based on trilobites (Kushan 1973, Wittke 1984, Peng et al. 1999), but the trilobite faunas from the Mila Formation of the Simeh-Kuh section, the source of the brachiopods studied here, have not been documented in detail. All studied brachiopods come from Member 3 of the Mila Formation in the Simeh-Kuh section, which is located in the eastern Alborz Range, northeastern Iran, about 13 km NW of Damghan (Fig. 1). The geographic coordinates of the zero point in the section in the base of Member 3 of the Mila Formation are N 36°12’40.2”, E 54°13’40.3”, at 1361 m above sea level. In this section, the base of the Furongian coincides with a fault at the lower boundary of Member 3, which is underlain by the dolomites of the Member 1. Six informal units are recognised within Member POPOV, L.E., GHOBADI POUR, M., HOSSEINI, M. & HOLMER, L.E. , 2009:12:24. Furongian linguliform brachiopods from the Alborz Mountains, Iran. Memoirs of the Association of Australasian Palaeontologists 37, 103-122. ISSN 0810-8889. Micromorphic linguliform brachiopods are described for the first time from the Furongian part of the Cambrian Mila Formation, eastern Alborz Mountains, Iran. The assemblage is dominated by acrotretides, including Dactylotreta lamellosa n. sp. and Ottenbyella hyrcanica n. sp. as well as species of the new genera Tapuritreta (T. angusta n. sp.) and Sadrocarta (S. delicatus). The siphonotretide Siphonobolus sp. also occurs in abundance, which is unusual for Furongian lingulate faunas. The newly discovered assemblage shows little similarity to contemporaneous faunas of Laurentia, Baltica and Kazakhstanian terranes, but S. delicatus is also known from the middle Furongian Series of the Malyi Karatau Range in southern Kazakhstan. Leonid E. Popov (leonid.popov@museumwales.ac.uk), Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, United Kingdom; Mansoureh Ghobadi Pour (mghobadipour@yahoo.co.uk), Department of Geology, Faculty of Sciences, Golestan University, Gorgan, Iran; Mehri Hosseini (mehr_geo@yahoo.com), Nonmetallic Material Co., 404 Yas House, Tohid St., Esfahan 8173837311, Iran; Lars E. Holmer (Lars.Holmer@pal.uu.se), Institute of Earth Sciences, Palaeobiology, Uppsala University, SE-752 36 Uppsala, Sweden. Received 28 April 2009. Keywords: Cambrian, Furongian, Brachiopoda, Linguliformea, Siphonotretida, Alborz Mountains, Iran.