The genus "Hybodus" is represented in the fossil records of Asia, Europe, Africa and North America by skeletons, isolated teeth, cephalic and fin spines. According to Maisey (1996: 104-06), these were marine sharks, but some species would enter freshwater. Taxa formerly included as Hybodus are now included in the Meristodonoides genus page.

Remaining "Hybodus" reports from North American include:

  • H. nevadensis WEMPLE 1906 (Middle Triassic of Nevada),
  • H. shastensis WEMPLE 1906 (Upper Triassic of California),
  • H. butleri THURMOND 1971 (Aptian-Albian of Texas) and also by Welton & Farish (1993: 48-49).
    Bourdon et al (2011) included two hybodontid tooth-designs from the Santonian of New Mexico that may have previously been included in the "Hybodus" wastebasket — Egertonodus and Planohybodus.

    Cappetta (1987: 30-31) describes the "Hybodus" dentition as generally being a clutching-type. Later, in some species, the central cusps are larger and lateral(s) reduced, creating a tearing-type dentition. The "Hybodus" tooth is laterally expanded (to 2 cm) with a large central cusp bearing enameloid ridges and a distinct cutting edge. One or more, smaller, lateral cusps are present. The (weakly) lingually directed root is relatively short and thin. The basal and lingual faces have numerous scattered foramina. Aspects of this description may change after Underwood concludes the revisionary study.

    Selected References

    Bourdon, J., Wright, K., Lucas, S.G., Spielmann, J.A. and Pence, R., 2011. Selachians from the Upper Cretaceous (Ssantonian) Hosta Tongue of the Point Lookout Sandstone, central New Mexico. New Mex. Mus. Nat. His. and Sc., Bulletin 52; 54pp.
    Cappetta, H., 1987. Chondrichthyes II. Mesozoic and Cenozoic Elasmobranchii. In: Handbook of Paleoichthyologie, vol. 3b, Gustav Fischer Verleg, Stuttgart, 193 pp.
    Maisey, J., 1996. Discovering Fossil Fishes. Holt & Company, NY. 223 pp.
    Thurmond, J., 1971. Cartilaginous fishes of the Trinity Group and related rocks (Lower Cretaceous) of North Central Texas. Southeast. Geol., 13, (4), pp 207-227.
    Underwood, C. J. and Cumbaa, S. L., 2010. Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontolgy.Vol. 53(4): 903-944.
    Welton, B. and Farish, R., 1993. The Collector's Guide to Fossil Sharks and Rays from the Cretaceous of Texas. Before Time, Texas. 204 pp.
    Wemple, E. M., 1906, New Cestraciont Teeth from the West-American Triassic: University of California Publications, v. 5, n. 4, p. 71-73.

     

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