First record of an Early Ordovician brachiopod and conodont fauna from Lapland, Sweden

An Early Ordovician fauna of linguliform brachiopods and euconodonts is described from the Alum Shale Formation in northernmost Vasterbotten County, northern Sweden. The fauna was recovered from a single carbonate concretion collected at an exposure near the northern shore of Lake Storvindeln. Despi...

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Bibliographic Details
Published in:GFF
Main Authors: Streng, Michael, Rasmussen, Jan Audun, Ebbestad, Jan Ove R., Weidner, Thomas
Format: Article in Journal/Newspaper
Language:English
Published: Uppsala universitet, Paleobiologi 2022
Subjects:
Ordovician
Tremadocian
linguliform brachiopods
euconodonts
Lapland
Other Earth and Related Environmental Sciences
Annan geovetenskap och miljövetenskap
Geology
Geologi
Storvindeln
Northern Sweden
Online Access:http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-478573
https://doi.org/10.1080/11035897.2022.2032822
Description
Summary:An Early Ordovician fauna of linguliform brachiopods and euconodonts is described from the Alum Shale Formation in northernmost Vasterbotten County, northern Sweden. The fauna was recovered from a single carbonate concretion collected at an exposure near the northern shore of Lake Storvindeln. Despite of the fragmentary and tectonized preservation of the obtained fossils, at least eight different taxa of linguliform brachiopods and four species of euconodonts could be identified. Among the brachiopods, the ephippelasmatid Pomeraniotreta biernatae Bednarczyk, 1986 is most common; it is associated among others with the acrotretids Eurytreta cf. sabrinae (Callaway, 1877) and Ottenbyella sp., and a spinose specimen potentially representing the zhanatellid Thysanotos. Two of the brachiopod taxa appear to present new species, Pomeraniotreta n. sp. and Mytoella? n. sp., but additional material would be needed for a formal description. Euconodont specimens are rare and comprise coniform elements of Drepanodus arcuatus Pander, 1856, Drepanoistodus aff. amoenus (Lindstrom, 1955) sensu Lofgren (1994), Paroistodus numarcuatus (Lindstrom, 1955) and Rossodus aff. manitouensis Repetski & Ethington, 1983. Evaluation of the stratigraphic distribution of the different taxa of brachiopods and euconodonts under consideration of the local geology, suggests that the investigated sample represents a level in the upper part of the Tremadocian (Tr2) part of the Alum Shale Formation. The fauna represents the northernmost occurrence of age diagnostic Early Ordovician (Tremadocian) fossils in Sweden.

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