A new Early Jurassic gastropod from Ellesmere Island, Canadian Arctic - an ancient example of holoplanktonic gastropods


Authors: Nützel A, Schneider S, Hülse P, Kelly SRA, Tilley L, Veit R

Published in: Bulletin of Geosciences, volume 91, issue 2; pages: 229 - 242; Received 8 December 2015; Accepted in revised form 25 February 2016; Online 19 May 2016

Keywords: Jurassic, Canadian Arctic, pelagic holoplanktonic gastropoda, Pliensbachian, anoxia,

full text (PDF, 5.19 MB)

Export to RIS



A new, most probably holoplanktonic gastropod genus and species, Freboldia fluitans Nützel & Schneider, is reported from the Early Jurassic (Pliensbachian) of Ellesmere Island, Canadian Arctic. Its shell is very thin, small, with a maximum diameter of 8 mm, inflated, planispiral and almost bilaterally symmetric, with deep umbilici. Hundreds of specimens of Freboldia occur in the matrix of transported siltstone concretions. In summary, these characteristics suggest a holoplanktonic lifestyle for Freboldia. Similar shells are present in the modern holoplanktonic gastropod family Limacinidae and in Cretaceous Bellerophinidae, and the new species is assigned to the latter family. The oldest records of holoplanktonic or pelagic gastropods are represented now by seven Early Jurassic genera: Coelodiscus, Tatediscus, Costasphaera, Pterotrachea, Simoniceras, Globorilusopsis and the new genus Freboldia. These are attributed to five different clades, which made their appearance at approximately the same time. We thus speculate that Early Jurassic anoxia triggered the rapid evolution of the holoplanktonic lifestyle in gastropods.