The arctic grayling is a beautiful irridescent fish distinguished by its greatly enlarged dorsal fin and its small mouth, which has fine teeth on both jaws. Grayling also have large smooth scales and a lateral line that stretches the length of their body. It inhabits open water of clear, cold medium to large rivers and lakes of North America , primarily in Canada. The specimen scanned here was collected in Michigan, but those populations are now extinct.

There are many named forms of grayling, but the most recent works classify the genus into two species, one in North America (Thymallus arcticus) and one in Eurasia (Thymallus thymallus). Graylings are considered the sister group to the Salmoninae, trouts and salmon, and as such are frequently used as an outgroup for studying relationships of those taxa.

This specimen was collected from above camp and a large pool below camp in Houghton Otter River, Michigan. It was made available to the University of Texas High-Resolution X-ray CT Facility for scanning by Dr. Julian Humphries of the University of Texas, Department of Geological Sciences. Funding for scanning and image processing was provided by a National Science Foundation Digital Libraries Initiative grant to Dr. Rowe.

The specimen was scanned by Matthew Colbert on 1 May 2003 along the coronal axis for a total of 1230 1024x1024 pixel slices. Each slice is 0.1106 mm thick, with an interslice spacing of 0.1106 mm and a field of reconstruction of 44.4 mm.

A status profile of the arctic grayling on the U.S. Fish & Wildlife website.

Information about Thymallus arcticus on NatureServe.

None available.