Ctenacanthus sp. (early shark)
Ctenacanthus spine showing the characteristic comb-like ornamentation. Photo courtesy of Ted Daeschler (ANS).Ctenacanthus sp. is represented by a single fin spine at Red Hill. More complete fossils have been recovered from the Early Carboniferous deposits in Scotland. The Scottish sharks were relatively small (50 cm), but extrapolation from the spine found at Red Hill suggest that this Late Devonian fish was substantially longer.
Ctenacanthid sharks have a pair of dorsal spines ornamented with many fine rows of nodes. This gives the spines a distinctive comb-like appearance, hence the name (ctenacanthus = comb-spine). Instead of plate-like spines found in many other early sharks, the ctenacanthid spines were cylindrical and pointed. These spines, as well as details of their fin anatomy and the structure of their gill arches indicate that ctenacanthids share a common ancestor with the more advanced hybodonts of the Late Paleozoic and Mesozoic and the neoselachians (modern sharks).
The teeth of another shark Ageleodus pectinatus were also found at Red Hill. You can also learn more about Sharks and their Relatives.
- Web:
- Oceans of Kansas' web page on Ctenacanthus:
www.oceansofkansas.com/ctenacanth.html - ReefQuest's web page featuring Ctenacanthus:
www.elasmo-research.org/education/evolution/ancient.htm - Books:
- Carroll, R. L. 1988. Vertebrate Paleontology and Evolution. New York: W. H. Freeman & Co.
- Janvier, P. 1996. Early Vertebrates. Oxford: Claredon Press.
- Long, J.A. 1995. The Rise of Fishes: 500 Million Years of Evolution. Baltimore & London: John Hopkins Univ. Press.
- Maisey, J.G. 1996. Discovering Fossil Fishes. New York: Henry Holt & Co.
- Scientific Papers:
- Schaffer and Williams. 1977. "Relationships of fossil and living elasmobranchs." Amer. Zoologist 17: 293-302.
- Image Credits:
- The Ctenacanthus reconstruction at the top is copyrighted, © Dennis C. Murphy, 2002. (See Terms of Use.) It was based on Shaffer and Williams (1977)