A new paper describing and interpreting a new crinoid from the Upper Ordovician of Estonia

I am very pleased to announce that Lena Cole, Bill Ausich, and I have a new article that appeared (on a dramatic election day in the USA!) in Papers in Palaeontology: “A Hirnantian holdover from the Late Ordovician Mass Extinction: Phylogeny and biogeography of a new anthracocrinid crinoid from Estonia.” Lena was our leader and did a fantastic job with the description and analysis. In fact, it was the easiest peer review process I’ve ever seen. Above you meet the star specimen, the calyx of Tallinnicrinus toomae gen. et sp. nov., an anthracocrinid diplobathrid crinoid. The new genus is named after Tallinn, the beautiful capital of Estonia. The species is named after our excellent Estonian colleague Ursula Toom.

The abstract: Relatively few Hirnantian (Late Ordovician) crinoids are known, and none has been previously described from the palaeocontinent of Baltica. This has impaired our ability to understand the patterns of extinction and biogeographic dispersal surrounding the Late Ordovician mass extinction, which triggered a major turnover in crinoid faunas. Here, we describe Tallinnicrinus toomae gen. et sp. nov., an anthracocrinid diplobathrid from the Hirnantian of northern Estonia. Tallinnicrinus is the youngest member of the Anthracocrinidae and the first representative of the family to occur in Baltica. Morphologically, Tallinnicrinus is unusual in that the radial and basal plates are in a single circlet of 10 plates, similar to the anthracocrinid Rheocrinus Haugh, 1979 from the Katian of Laurentia. Phylogenetic analysis further confirms a close relationship between Tallinnicrinus and Laurentian anthracocrinids, suggesting biogeographic dispersal of the lineage from Laurentia to Baltica during the late Katian or early Hirnantian. The occurrence of this new taxon establishes that the family Anthracocrinidae survived the first pulse of the Late Ordovician mass extinction. However, the lineage remained a ‘dead clade walking’ because it failed to diversify in the wake of the end-Katian extinction and ultimately went extinct itself by the end of the Ordovician.

Above is Bill Ausich talking to Ursula during our visit to Tallinn in August 2018. We are in the collections of the Department of Geology, Tallinn University of Technology.

The College of Wooster and The Ohio State University geology programs have had an excellent relationship with Estonian geologists for many years, for which we thank Olev Vinn, who invited me to his lovely country many years ago. Many Wooster and OSU students have done field and laboratory work there, and we now have numerous joint publications. We look forward to visiting again once the COVID-19 pandemic abates.

Reference:

Cole, S.R., Ausich, W.I., and Wilson, M.A. 2020. A Hirnantian holdover from the Late Ordovician Mass Extinction: Phylogeny and biogeography of a new anthracocrinid crinoid from Estonia. Papers in Palaeontology (early view)