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Showing results for tags 'dorsal spine'.
Hello and good evening! I have passed this fossil a few times and it resides in a large limestone slab. I believe it could be a spine due to presence of Chondrichthyan teeth in the area and how it appears to come to a point. For reference the teeth I have found include teeth from Petalodontiformes, Eugenodontida, and other Chondrichthyans. I will note I have found some petrified wood in the area, but none in a limestone matrix so it could be a Calamite. Location: Missouri Time period: Pennsylvanian Formation: Muncie creek shale member
I'd like to get some opinions on my tentative id of this specimen as a dorsal spine from the Bullhead/Horn shark (Heterodontus sp.). I haven't been able to locate many good images of these spines and this specimen is significantly larger than the few photos I've found. Is this a dorsal spine and if so what is the normal size range? This was collected this past weekend at Ernst Quarries, Slow Curve (Sharktooth Hill), Round Mountain Formation, Middle Miocene. Any help on the id is appreciated. Also curious if the Heterodontus from that period were larger than the extant Pacific species which d