2381/40483
Hendrik Nowak
Hendrik
Nowak
Thomas H.P. Harvey
Thomas H.P.
Harvey
Huaibao P. Liu
Huaibao P.
Liu
Robert M. McKay
Robert M.
McKay
Pierre A. Zippi
Pierre A.
Zippi
Donald H. Campbell
Donald H.
Campbell
Thomas Servais
Thomas
Servais
Filamentous eukaryotic algae with a possible cladophoralean affinity from the Middle Ordovician Winneshiek Lagerstätte in Iowa, USA
University of Leicester
2017
Winneshiek Lagerstätte
Middle Ordovician
Algae
Ulvophyceae
Small Carbonaceous Fossils
2017-11-03 12:48:43
Journal contribution
https://figshare.le.ac.uk/articles/journal_contribution/Filamentous_eukaryotic_algae_with_a_possible_cladophoralean_affinity_from_the_Middle_Ordovician_Winneshiek_Lagerst_tte_in_Iowa_USA/10212794
Previous studies on the Darriwilian (Middle Ordovician) Konservat-Lagerstätte of the Winneshiek Shale in Iowa (USA) have reported various animal and trace fossils. A search for ‘‘small carbonaceous fossils’’ (SCFs) in palynological samples from the Winneshiek Shale has now led to the discovery of several different kinds of organic-walled microfossils. Here we report on a particular group of filamentous microfossils that occur abundantly throughout the exposed and subsurface successions of the Winneshiek Shale. The fossils are characterised by large, elongated cells (220–600 mm in length, 60– 240 mm in diameter) with thin and delicate walls and occasional branching. The cells often contain dark internal bodies, most likely condensed protoplasmic remains. Together, these features identify these fossils as eukaryotic rather than cyanobacterial in origin. More specifically, the cell size, cross-walls and branching pattern are shared with forms of benthic ulvophycean green algae, a group with a long but sporadic fossil record that is otherwise restricted to Proterozoic Lagersta¨tten. The new specimens therefore expand the known diversity of local primary producers in the palaeoenvironment of the Winneshiek Shale, and suggest that the apparent dearth of delicate filamentous green algae in the Phanerozoic record may be, in part, an artefact of low preservation potential combined with destructive processing techniques.