Leveilleites hartnageli Foerste, 1923 (Rhodophyta?) from the Ordovician of Laurentia and Silurian of Baltica: Redescription and designation of a neotype

We review the enigmatic Leveilleites hartnageli, a noncalcified algal fossil tentatively assigned to red algae, which was first described from the Ordovician of southern Ontario, Canada, and more recently discovered as a significant part of the exceptionally preserved algal flora of the Kalana Lagerstätte from the Silurian (Aeronian, Llandovery) of Estonia. The morphology of L. hartnageli is described, including morphological changes during different growth phases of the thallus. The new collection from two quarries and several drill cores complements the material from North America and reveals the geographical extent of the species, showing that the species inhabited large areas in both sides of the Iapetus ocean - the epicontinental seas of Laurentia and Baltica. Because the original specimen on which the species was erected is lost and the paratypes are in poor condition, a neotype is designated here.