Jump to content
  • Micro Gastropod


    Images:

    I_gotta_rock
    • This came from a bag of mixed micro matrix from the Lee Creek AKA Aurora Mine which was sifted, sifted again and sifted some more. It is a mixture of material from three formations: the Miocene Pungo River Fm., the Pliocene Chowan River Fm., and the Pleistocene James City Fm. 


      After digging through reputable resources covering the area from Maryland down to Florida, the administrators and I have mostly ruled out Miocene as none of the references mention anything similar from that time period. Three names are given for the species from the Pliocene and Pleistocene. Ward and Blackwelder (1987) identify Arene pergemma, with a description and illustration that looks very much like this gastropod and is about the same size, from the Lee Creek Mine1. The Paleobiology Database says that Arene pergemma is an old name and gives Marevalvata tricarinata as the accepted name2. The Neogene Atlas of Ancient Life says that Marevalvata tricarinata is no longer valid either, and has this species recombined as Arene tricarinata3, a name which actually predates Arene pergemma4

       

      The Neogene Atlas does list a very similar shell, Arene agenea, which lived during the early Miocene. However, A. agenea has a circular aperture while the mystery shell has a more elliptical aperture from every angle I use th photograph it. A. agenea also has less defined ornamentation than the shell in question. Furthermore, the Neogene Atlas only lists A. agenea as occurring in the Chipola Fm. of northern Florida4.
       

      All agree that the fossil occurs only in the Pliocene and early Pleistocene from North Carolina down to Florida, but only mention them occurring in North Carolina in the Pleistocene Waccamaw Fm. further south and the Late Pliocene Duplin Fm. to the west. Ward and Blackwelder discuss a couple similar species in their discussion of the genus, but give no identification for them in the book I have available. Given this, I think this specimen is most likely from the Pliocene. However, after deliberating with a TFF malacologist, this might be a new undocumented species altogether that could be from any one of the three time periods and formations.

       

      Bibliography

      1) Ward, Lauck W., and Blake W. Blackwelder. 1987. “Late Pliocene and Early Pleistocene Mollusca From the James City and Chowan River Formations at the Lee Creek Mine.” Geology and Paleontology of the Lee Creek Mine, North Carolina, II, Smithsonian Contributions to Paleobiology. Smithsonian Institution, pp. 163-164.  250-251.

      2) http://www.fossilworks.org

      3) Ward, Lauck W., and Blake W. Blackwelder. 1987. “Late Pliocene and Early Pleistocene Mollusca From the James City and Chowan River Formations at the Lee Creek Mine.” Geology and Paleontology of the Lee Creek Mine, North Carolina, II, Smithsonian Contributions to Paleobiology. Smithsonian Institution, pp. 163-164.  

      4) https://neogeneatlas.net/species/arene-tricarinata/

      5) https://neogeneatlas.net/species/arene-agenea/

    Taxonomy

    Snail

    Kingdom: Animalia
    Phylum: Mollusca
    Class: Gastropoda
    Order: Angarioidea
    Family: Areneidae
    Genus: Arene
    Species: Arene sp.
    Author Citation Adams & Adams, 1854

    Geological Time Scale

    Eon: Phanerozoic
    Era: Cenozoic
    Period: Neogene
    Epoch: Pliocene

    Stratigraphy

    unknown formation

    Provenance

    Collector: Heather Siple
    Date Collected: 07/15/2020
    Acquired by: Purchase/Trade

    Dimensions

    Diameter: 2.5mm

    Location

    Lee Creek Mine near Aurora
    Beaufort County
    North Carolina
    United States

    Comments

    This came from a bag of mixed micro matrix from the Lee Creek AKA Aurora Mine which was sifted, sifted again and sifted some more. It is a mixture of material from three formations: the Miocene Pungo River Fm., the Pliocene Chowan River Fm., and the Pleistocene James City Fm. 


    After digging through reputable resources covering the area from Maryland down to Florida, the administrators and I have mostly ruled out Miocene as none of the references mention anything similar from that time period. Three names are given for the species from the Pliocene and Pleistocene. Ward and Blackwelder (1987) identify Arene pergemma, with a description and illustration that looks very much like this gastropod and is about the same size, from the Lee Creek Mine1. The Paleobiology Database says that Arene pergemma is an old name and gives Marevalvata tricarinata as the accepted name2. The Neogene Atlas of Ancient Life says that Marevalvata tricarinata is no longer valid either, and has this species recombined as Arene tricarinata3, a name which actually predates Arene pergemma4

     

    The Neogene Atlas does list a very similar shell, Arene agenea, which lived during the early Miocene. However, A. agenea has a circular aperture while the mystery shell has a more elliptical aperture from every angle I use th photograph it. A. agenea also has less defined ornamentation than the shell in question. Furthermore, the Neogene Atlas only lists A. agenea as occurring in the Chipola Fm. of northern Florida4.
     

    All agree that the fossil occurs only in the Pliocene and early Pleistocene from North Carolina down to Florida, but only mention them occurring in North Carolina in the Pleistocene Waccamaw Fm. further south and the Late Pliocene Duplin Fm. to the west. Ward and Blackwelder discuss a couple similar species in their discussion of the genus, but give no identification for them in the book I have available. Given this, I think this specimen is most likely from the Pliocene. However, after deliberating with a TFF malacologist, this might be a new undocumented species altogether that could be from any one of the three time periods and formations.

     

    Bibliography

    1) Ward, Lauck W., and Blake W. Blackwelder. 1987. “Late Pliocene and Early Pleistocene Mollusca From the James City and Chowan River Formations at the Lee Creek Mine.” Geology and Paleontology of the Lee Creek Mine, North Carolina, II, Smithsonian Contributions to Paleobiology. Smithsonian Institution, pp. 163-164.  250-251.

    2) http://www.fossilworks.org

    3) Ward, Lauck W., and Blake W. Blackwelder. 1987. “Late Pliocene and Early Pleistocene Mollusca From the James City and Chowan River Formations at the Lee Creek Mine.” Geology and Paleontology of the Lee Creek Mine, North Carolina, II, Smithsonian Contributions to Paleobiology. Smithsonian Institution, pp. 163-164.  

    4) https://neogeneatlas.net/species/arene-tricarinata/

    5) https://neogeneatlas.net/species/arene-agenea/



    User Feedback


    There are no comments to display.



    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now


×