WEIRD SHARKS
This fossil preserved the entire front half of a Cladoselache in a large iron carbonate concretion from the Cleveland shale. Fins (bottom), skin, jaws (left), and even gills are preserved and visible (scale bar = 6 in). Photo by Lauren Fuelling used with permission.
None of the Cladoselache fossils that have been unearthed from the Cleveland Shale have claspers. This leads paleontolo- gists to believe that either all of the fossils found are females, or that Cladoselache lacks this organ altogether. This would mean that female sharks occupied a different habitat than males, or that this shark did not reproduce the same way as all other sharks and rays, though more research would be needed to know for certain.
I first learned about this species when I was doing some additional reading for my undergraduate research project on the Portersville Shale in Athens, Ohio. My research focuses on the vertebrate species present in this locality, specifically the ancient sharks. What made this shark interesting to me is how well preserved the specimens are despite the lack of claspers.
Connor’s entry:
Water goblins. My favorite ancient shark is the genus Scapanorhynchus,
which lived throughout the Cretaceous period and (probably) went extinct alongside dinosaurs during the K-T Boundary impact. The first fossil shark teeth I ever collected in the field were anterior and lateral Scapanorhynchus teeth from the Sardis Formation in Tennessee (see figure right, courtesy of the Cretaceous Research in Tennessee Facebook page).
36 TPG •
Oct.Nov.Dec 2020
A photo of an anterior Scapanorhynchus tooth (lingual side facing upward), from the moment of its discovery in gravels derived from the Sardis Formation in Tennessee. Photo by Joshua Welch, used with permission.
www.aipg.org
My collection of Scapanorhynchus teeth has grown immense- ly and specimens range in size from a few millimeters to over 2 inches in length. I encountered them from central Tennessee to eastern North Carolina as a student in Ryan’s field courses at WSU.
Through collecting these teeth and observing their mor- phology, I learned that they have two different functions. The anterior teeth are long, slender, and allowed the shark to
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