Problematic fossils (“problematica”) are much celebrated by paleontologists for their odd morphologies, unusual preservation styles, and the phylogenetic insights they may provide. Problematic fossils, as the term suggests, represent organisms whose taxonomic classifications are unclear or controversial.
Shown below is soft-bodied fossil that was first described & named in the 1850s, but is still considered a problematicum in the modern literature. This is a soft-bodied frond called Plumalina plumaria Hall, 1858. Workers usually assign this organism to the hydrozoans (Phylum Cnidaria, Class Hydrozoa) or the gorgonarians (Phylum Cnidaria, Class Anthozoa, Order Gorgonaria), but it’s probably safest to refer to it as “Incertae Sedis” (“uncertain placement”).
Plumalina plumaria Hall, 1858 (6.3 cm tall) in quartzose siltstone, weathered from the South Wales Member of the lower Perrysburg Formation (Canadaway Group, Upper Devonian) of western New York State, USA.
Locality: railroad cut on southern side of railroad adjacent to Rt. 26, southeastern side of Almond Lake, just northwest of Hornell, western Steuben County, western New York State, USA.