Where: Iran (34.1° N, 56.8° E: paleocoordinates 23.1° S, 144.9° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Lenodus pseudoplanus conodont zone, B5 Member (Shirgesht Formation), Darriwilian (467.3 - 458.4 Ma)

• In the absence of the conodonts, the Darriwilian age of units B5 and B6 is based mainly on ostracods. In particular, Aechmina? ventadorni occurs in the late Darriwilian (Hustedograptus teretiusculus graptolite Biozone equivalents) of western France (Vannier 1986; Vannier et al. 1989); while Cerninella aryana and Ordovizona amyitisae being endemic to Iran are also known from the lower part of the Lashkarak Formation of the Simeh-Kuh section in the eastern Alborz mountains, where they co-occur with conodonts of the Lenodus pseudoplanus conodont Biozone (Ghobadi Pour et al. 2007). The calymenid trilobite Neseuretinus birmanicus occurs together with the Darriwilian Saucrorthis Brachiopod Association in the Naungkangyi Group (localities AM77 and AM78) of northern Shan States, Burma (Cocks & Zhan 1998, p. 112). The pliomerid trilobite Ovalocephalus aff. obsoletus previously reported by Ghobadi Pour & Popov (2009) from the Shirgesht Formation have been reassigned to Ovalocephalus kanlingensis by Zhou et al. (2010) in their comprehensive revision of the genus. In the Bachu area of Tarim, Xinjiang Ovalocephalus kanlingensis occurs in the Lituites cephalopod Biozone, which is considered equivalent to the upper Darriwilian Pygodus serra Biozone equivalent (Zhou et al. 2010, p. 260). Neseuretinus birmanicus and Ovalocephalus kanlingensis have a broad stratigraphical range and are transitional to the Upper Ordovician; however, stratigraphical range of Neseuretinus birmanicus in Central Iran overlaps with Lesueurilla prima, which does not occur in the Upper Ordovician. This can be taken as additional evidence of the Darriwilian age for the uppermost fossiliferous horizons of the Shirgesht Formation in the Derenjal Mountains.

• formation-level stratigraphic resolution

Environment/lithology: argillaceous limestone

Size class: macrofossils

Preservation: cast

Primary reference: J. O. R. Ebbestad, M. Ghobadi Pour, M. G. Bassett and L. E. Popov. 2016. First occurrence of Lesueurilla prima (Gastropoda) from the Middle Ordovician (Darriwilian) of Iran. G F F [P. Wagner/P. Wagner/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 179207: authorized by Pete Wagner, entered by Pete Wagner on 06.06.2016

Creative Commons license: CC BY (attribution)