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  • Isurus retroflexus


    Fin Lover


    Longfin Mako

    Kingdom: Animalia
    Phylum: Chordata
    Class: Chondrichthyes
    Order: Lamniformes
    Family: Lamnidae
    Genus: Isurus
    Species: Isurus retroflexus
    Author Citation Agassiz, 1843

    Geological Time Scale

    Eon: Phanerozoic
    Era: Cenozoic
    Period: Neogene
    Sub Period: None
    Epoch: Pliocene


    Goose Creek Limestone or Ten Mile Hill Formation (see Additional Information)


    Collector: Erin Osborne
    Date Collected: 07/31/2022
    Acquired by: Field Collection


    Length: 19 mm
    Width: 18 mm
    Height: 23 mm
    Thickness: 5 mm


    Berkeley County
    South Carolina
    United States


    Isurus retroflexus is from the Miocene-Pliocene epochs.  While the vast majority of what I find in this particular location is Miocene-Pliocene in age and is likely to have come from the Goose Creek Limestone formation (early-mid Pliocene), we can't rule out the possibility that it came from an overlying lag deposit called the Ten Mile Hill Formation.  The Ten Mile Hill Formation is mid-Pleistocene and can be found overlying older formations in the area.  Since Miocene-Pliocene fossils have been found in the base of the Ten Mile Hill Formation and this tooth was ex-situ, the formation is undetermined.  


    ID references:
    1. Gale, B. (2020). A Beachcomber's Guide to Fossils.  The University of Georgia Press.
    2. Kocsis, L. (2007). Central paratethyan shark fauna (Ipolytarnóc, Hungary). GEOLOGICA CARPATHICA-BRATISLAVA-, 58(1), 27
    3. Maisch IV, H., Becker, M., & Chamberlain Jr, J. (2015). Chondrichthyans from a lag deposit between the Shark River Formation (Middle Eocene) and Kirkwood Formation (Early Miocene), Monmouth County, New Jersey.  Paludicola, 10, 149-183.
    Stratigraphy information references:
    1. Boessenecker, R. (2008, May 13). The Ashley Phosphate Beds: the Reconstruction Era, Vertebrate Paleontology, Fossil Preservation, and Stratigraphic Confusion in Charleston, South Carolina. The Coastal Paleontologist. https://coastalpaleo.blogspot.com/2018/05/the-ashley-phosphate-beds.html.
    2. Campbell, M. R., & Campbell, L. D. (1995). Preliminary biostratigraphy and molluscan fauna of the Goose Creek Limestone of eastern South Carolina. Tulane    Studies in Geology and Paleontology27(1-4).
    3. Sanders, A. E., Weems, R. E., & Albright III, L. B. (2009). Formalization of the Middle Pleistocene ‘Ten Mile Hill Beds’ in South Carolina with evidence for placement of the Irvingtonian-Rancholabrean boundary. Papers on Geology, Vertebrate Paleontology, and Biostratigraphy in Honor of Michael O. Woodburne, 363-370.

    User Feedback

    sixgill pete


    While I do not believe this is a lag tooth, I am glad you addressed the possibility. Really nice specimen. 

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    Fin Lover



    6 minutes ago, sixgill pete said:

    While I do not believe this is a lag tooth, I am glad you addressed the possibility. Really nice specimen. 

    Thank you!  I don't believe it is from the Ten Mile Hill Formation either, but that area is quite complicated so I wanted to make sure I included the possibilities.  

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