Reassessment of Ischnacanthus?scheii Spjeldnaes (Acanthodii, Ischnacanthiformes) from the latest Silurian or earliest Devonian of Ellesmere Island, arctic Canada

Articulated specimens of jawed fishes, and assemblages of disarticulated elements that can be assigned to a single biological species, are extremely rare from pre-Devonian deposits. The acanthodian species Ischnacanthus? scheii Spjeldnaes is based on a monospecific assemblage, comprising fin spines,...

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Bibliographic Details
Published in:Canadian Journal of Earth Sciences
Main Author: Burrow, Carole J.
Other Authors: Sues, Hans
Format: Article in Journal/Newspaper
Language:English
Published: Canadian Science Publishing 2013
Subjects:
Arctic
Canada
Canadian Arctic Archipelago
Cornwallis
Cornwallis Island
Devon Island
Ellesmere Island
Greenland
Nunavut
Arctic Archipelago
North Greenland
Online Access:http://dx.doi.org/10.1139/cjes-2013-0068
http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjes-2013-0068
http://www.nrcresearchpress.com/doi/pdf/10.1139/cjes-2013-0068
Description
Summary:Articulated specimens of jawed fishes, and assemblages of disarticulated elements that can be assigned to a single biological species, are extremely rare from pre-Devonian deposits. The acanthodian species Ischnacanthus? scheii Spjeldnaes is based on a monospecific assemblage, comprising fin spines, dentigerous jaw bone fragments and scales, from the ?Siluro-Devonian boundary beds of the Devon Island Formation in central west Ellesmere Island, Canadian Arctic Archipelago, Nunavut. A new examination of the type material, in particular by scanning electron microscopy and thin sectioning of scales, shows that the species is a porosiform poracanthodid that is now assigned to Radioporacanthodes scheii comb. nov. Scales of the same species are also recognized from the upper Pridoli of Cornwallis Island and the ?Pridoli or Lochkovian of north Greenland.

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