Helcionelloid mollusks from the Lower Cambrian of Southern Sweden
2009 (English)In: Lundadagarna i Historisk Geologi och paleontology XI, 11-12 March, 2009, Abstracts with programme, 2009, 7- p.Conference paper (Other academic)
In 1879 Linnarsson described a diverse shelly fauna from the Exsulans Limestone at Kiviks Esperöd in Scania. A single ‘monoplacophoran’ mollusc was identified - Metoptoma barrandei - and Linnarsson noted that von Schmalensee had found a closely related form at Gislöf further to the south, albeit as fragmentary material. Reinvestigation of the locality at Gislövshammar by PC and JA has yielded close to 500 specimens of a diverse helcionelloid fauna. The material comes from a 40 cm interval of laminated siltstone with intercalated calcareous nodules in the Lower Cambrian Gislöv Formation (Holmia kjerulfi assemblage Zone). The specimens are mostly preserved as internal moulds but also impressions of the external surfaces are seen. A second, smaller collection from a loose block of more compact siltstone near Brantevik yielded two helcionelloid taxa of slightly different affinity to those from Gislövshammar. Altogether seven taxa can be recognized including Pelagiella, Marocella?, Latouchella?, Stenotheca? and two forms of Helcionella? The taxonomic identification of the various forms is preliminary at this stage. The only record of comparable or coeval helcionelloid molluscs from Scandinavia, beside that by Linnarsson (1879), is from the Tømten Member of the Ringsaker formation (Holmia kjerulfi assemblage Zone) in the Mjøsa district in Norway. Kiær (1918) recognised four taxa from this locality: two new species of Scenella and two species of Helcionella. The former he compared with Linnarsson’s form and with material from Newfoundland. Species of the latter genus were considered conspecific with North American material. In the Gislöv fauna only Marocella? enters into close comparison with Linnarsson’s and Kiær’s species, while the Helcionella species from the Brantevik block is most comparable to Kiær’s material. However, close comparison of the new Scanian material with material from eastern North American is pivotal to the taxonomic discussion at this stage. In particular, comparison with Avalonian faunas from south-eastern Newfoundland and New Brunswick described by C.D. Walcott and G.F. Matthews seem profitable. Within a wider scope, the new helcionelloid material opens up possibilities for improving both regional and intercontinental biostratigraphical correlation
Place, publisher, year, edition, pages
2009. 7- p.
IdentifiersURN: urn:nbn:se:uu:diva-111360OAI: oai:DiVA.org:uu-111360DiVA: diva2:280792
Lundadagarna i Historisk Geologi och paleontology XI, 11-12 March, 2009.