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The lichid trilobite Radiolichas in the Silurian of Arctic Canada and Gotland, Sweden

Published online by Cambridge University Press:  01 May 2009

Jonathan M. Adrain
Affiliation:
Department of Palaeontology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK
Lars Ramsköld
Affiliation:
Palaeontological Museum, University of Uppsala, Norbyvägen 22, S-752 36 Uppsala, Sweden

Abstract

Radiolichas has been a poorly known and exclusively Devonian genus of very limited diversity. Radiolichas raydaviesi sp. nov. and R. davedaviesi sp. nov. are the best-known members of the genus, and extend its stratigraphic and geographic range to the Wenlock of the central Canadian Arctic. A further Silurian occurrence is an unnamed species from the Wenlock Slite Beds of Gotland, Sweden. Radiolichas is most similar to Dicranogmus. Together, the genera lack any of the robust trochurine apomorphies (linear pygidial postaxial ridge, prominent pygidial border, prominent cranidial fossula) and appear to fall outside the phylogenetic structure of that subfamily. They are similar to members of the Tetralichinae, particularly in pygidial features, but lack the composite cranidial lobe characteristic of that subfamily. Their systematic position is presently unresolved.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1996

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