Palynological analysis of the Shishtu 2 Member (Shishtu Formation) located in the Howz-e-Dorah area (southeast Tabas, central Iran Basin) suggests a middle Tournaisian–late Viséan age for this rock unit. The Shishtu 2 Member consists of shale, sandstone, dolostone and limestone. Three palynological assemblages are recognised and mainly correlated with the miospore biozones of Northern Gondwana. A microfloristic comparison with other sections in Western Gondwana (South America) is also proposed. We identify a sedimentary hiatus between the Shishtu 1 and Shishtu 2 members. Our findings suggest that the Mush Horizon is the lowermost part of the Shishtu 2 Member, contrary to the Iranian literature where it is considered to be the uppermost part of the Shishtu 1 Member.