Rediscovery of the type locality of the Udoteacean alga Boueina hochstetteri Toula, 1884, in the Lower Cretaceous of Serbia

Boueina hochstetteri Toula (type-species of the genus) was published by Toula (1884) in the 10th report of his travel through the Balkan region. He considered this species to be a problematic organism with uncertain systematic affiliation. Later, Steinmann (1901) assigned this fossil to the calcareous algae. Our own field work performed in the autumns of 2015 and 2016 in the Pirot area (SE Serbia) led to re-identification of the rich Boueina hochstetteri type level, close to the confluence of the Temska and Nisava Rivers, the type locality of Toula. The rich Boueina level is part of a succession of bioclastic limestones. The fragments of Boueina thalli are occasionally branched, a feature supporting the interpretation of Boueina as an inarticulate udoteacean alga with rare branching.