Protoplatyrhina was erected by Case (1978) for a tooth-design he deemed comparable with the extant genus of thornbacks (Platyrhina); based on the modern tooth-design (see: Herman et al 1997:150-51), Cappetta (1987:142) rejected this notion and merely attributed them to . Crown and root-design tends to validate Cappetta's more conservative conclusion. Based on reported locations and tooth-design, this taxon was likely a near shore, warm-water species with a crushing dentition probably feeding on invertebrates.

The dentition-design is unknown but can be assumed to be pavement like with multiple alternating files (closely but not tightly-spaced) of small teeth. The crown is basically smooth and globular with a short and wide uvula; the roots are weakly directed lingually with a deep nutrient groove and paracentral foramina. Marginally, each lobe is "notched" at the point of a lingually-positioned marginal foramen.

Relevant reports include:

  • Meyer (1974: 156-57, unpublished) included (fig. 48a,b) as Parahypolophus mcnultii a tooth-design from the Santonian of Mississippi which appears very similar to Protoplatyrhina.
  • Case (1978) described Protoplatyrhina renae from the Judith River Formation (Campanian) of Montana.
  • Case (1987) reported P. renae from the Mesaverde Formation (Campanian) of Wyoming.
  • Cappetta (1987:142) included this genus from the Campanian of North America.
  • Cappetta (1992) erected the family for these teeth.
  • Welton & Farish (1993:133) reported P. renae as common in the Maastrichtian of Texas.
  • Williamson et al (1993:460; figs. 9.11-15) erected Protoplatyrhina hopii for specimens lacking a distinct uvula from the Turonian of Arizona.
  • Case & Cappetta (1997:147) included this tooth-design from the Kemp Clay (Maastrichtian) of Texas. They went on to note that this tooth-design also occurs in New Mexico & New Jersey (no citations or comments).
  • Case et al (2001:93, pl 1, fig 12) reported P. renae from the Santonian of Georgia.
  • Becker et al (2004) included P. renae in the Fox Hills Formation (Maastrichtian) of South Dakota.
  • Heckert et al (2007) included "Protoplatyrhina" from the Menefee Fm. (Late Santonian-Early Campanian) of New Mexico.
  • The New Mexico Museum of Natural History Specimen Database noted P. renae as known from the Fruitland Fm (Campanian).
  • Beker et al (2010:259-61, figs. 7.1-7.3) reported P. hopii from the Turonian of Utah.
  • Bourdon et al (2011:40) reported Protoplatyrhina sp. aff. P. renae from the Pt. Lookout Fm. (Early Santonian) of New Mexico.

    Selected References

    Becker, M., J. Chamberlain, Jr, and D. Terry, Jr., 2004. Chondrichthyans from the Fairpoint Member of the Fox Hills Formation (Maastrichtian), Meade County, South Dakota. Jrnl Vert Paleo. 24(4):780-793.
    Becker, M.A., Wellner, R.W., Mallery, C.S., jr. and Chamberlain, J.A., jr., 2010. Chondrichthyans from the lower Ferron Sandstone Member of the Mancos Shale (Upper Cretaceous: Middle Turonian) of Emery and Carbon Counties, Utah, USA; Journal of Paleontology, 84(2): 248–266.
    Bourdon, J., Wright, K., Lucas, S.G., Spielmann, J.A. and Pence, R., 2011. Selachians from the Upper Cretaceous (Santonian) 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.
    Cappetta, H., 1992. Nouveaux Rhinobatoidei (Neoselachi, Rajiformes) à denture spécialisée du Maastrichtien du Maroc. Remarques sur l'évolution dentaire des Rajiformes et des Myliobatiformes. Neues Jahrbuch fuer Geologie und Palaeontologie. Abhandlungen. Stuttgart, 187(1):31-52, 20 fig.
    Case, G., 1978. A new selachian fauna from the Judith River Formation (Campanian) of Montana. Palaeontographica (A), 160:176-205.
    Case, G. R. 1987. A new selachian fauna from the late Campanian of Wyoming (Teapot Sandstone Member, Mesaverde Formation, Big Horn Basin). Palaeontographica 197:1-37.
    Case, G. and Cappetta, H.. 1997. A new selachian fauna from the late Maastrichtian of Texas. Münchener Geowissenschaften Abhandungen 34:131-189.
    Case, G, D. Schwimmer, P. Borodin and J. Leggett, 2001. A new selachian fauna from the Eutaw Formation (Upper Cretaceous/Early to Middlew Santonian) of Chattahoochee County, Georgia. Palaeontographica Abt. A, 261:83-102.
    Cicimurri, D. 1998. Fossil Elasmobranchs of the Cretaceous System (Neocomian-Maestrichtian) Black Hills Region, South Dakota and Wyoming. Unpublished M.S. thesis, South Dakota School of Mines and Technology, Rapid City, South Dakota, 197 pp.
    Heckert, A,, C. Lewis, S, Lucas, and T. Williamson, 2007. New mixed marine-nonmarine microvertebrate fauna from the Upper Cretaceous (Late Santonian-Early Campanian) Menefee Formation, northwestern New Mexico. Geological Society of America Abstracts with Programs, Vol. 39, No. 6, p. 73
    Herman, J., M. Hovestadt-Euler, and D. C. Hovestadt. 1997. Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supraspecific taxa of chondrichthyan fishes. Part B: Batomorphii No. 2: Order Rajiformes - Suborder: Pristoidei - Family: Pristidae Genera: Anoxypristis and Pristis No. 3: Suborder Rajoidei - Superfamily Rhinobatoidea - Families: Rhidae - Genera: Rhina and Rhynchobatus and Rhinobatidae - Genera: Aptychotrema, Platyrhina, Platyrhinoidis, Rhinobatos, Trygonorrhina, Zanobatus and Zapteryx. Bulletin de L'Institut Royal des Sciences Naturelles de Belgique, Biologie,67: 107-162.
    Meyer, R., 1974. Late Cretaceous elasmobranchs from the Mississippi and East Texas embayments of the Gulf Coastal Plain. Unpubl. PhD dissertation, Southern Methodist Univ., Dallas, xiv+419 p.
    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.
    Williamson, T., J. Kirkland and S. Lucas, 1993. Selachians from the Greenhorn cyclothem ("Middle" Cretaceous: Cenomanian-Turonian), Black Mesa, Arizona, and the paleogeographic distribution of Late Cretaceous selachians. Journal of Paleontology 67(3), pp 447-474.

     

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