A new orthide brachiopod genus from the Middle Ordovician of the Alborz Mountains, Iran

Abstract

A new brachiopod genus and species Simehorthis fascicostellata is described from the upper Darriwilian part of the Lashkarak Formation of eastern Alborz in northern Iran. The taxon appears as a minor component of the Saucrorthis Brachiopod Association and later proliferated as a distinct part of a rich brachiopod-echinoderm fauna in the latest Darriwilian. Simehorthis together with Hesperorthis are the only genera of the Family Hesperorthidae yet documented from the Middle Ordovician. Also there was no previous record of the occurrence of Hesperorthidae in association with the Saucrorthis Fauna, and in the Middle Ordovician of the Austrolasian sector of Gondwana and associated terranes, while Hesperorthis was mainly confined to peri-Iapetus locations in the Darriwilian.

http://zoobank.org/urn:lsid:zoobank.org:act:B6459870-B591-4A48-B9B5-9F8BA9EC5A03

http://zoobank.org/urn:lsid:zoobank.org:pub:ABC9EAEF-5489-453B-AB9C-E85C145931D3

Keywords:

• Brachiopoda
• Hesperorthidae
• taxonomy
• Ordovician
• Darriwilian
• Iran

Acknowledgements

We are grateful to Dr Ian Percival (Geological Survey of New South Wales) and Dr Zhan Renbin (Nanjing Institute of Geology and Palaeontology) for constructive reviews, which were very helpful in improving the manuscript. Mohammad-Reza Kebria-Ee Zadeh thanks the Payam-Noor University for support via a research fellowship. Leonid Popov and Mansoureh Ghobadi Pour acknowledge logistical support from the National Museum of Wales. Research in Iran by Mansoureh Ghobadi Pour was supported by the Golestan University. We are grateful to Amanda Valentine and Christian Baars (National Museum of Wales) for lab assistance. This paper is a contribution to IGCP Project No. 653: The onset of the Great Ordovician Biodiversification Event.