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The pinnacle of snaggletooth shark evolution, adult Giant Hemipristis sharks were one of the top dogs in the Miocene seas. They first appeared in the Oligocene as the more primitive Hemipristis curvatus species soon became extinct. As a result of an abundance of prey, stemming from intensive upwelling in many areas in the world further helped by a warm climate and high sea levels for much of the miocene, like many marine predators they flourished in almost untold abundance. This can be most easily seen when fossil hunting good locations in South Florida (& other miocene localities) as snaggletooth teeth are one of the most common finds (although not as common as bull and lemon shark teeth, but about as common as tiger shark teeth). Even large 1-1.5 inch "hemi" teeth can be found with relative ease (alongside abundant dugong rib bones, one of their preferred snacks) suggesting that many survived to adulthood and thrived. This very successful species continued to survive even in the cooler Pliocene (but past their hay day, much more restricted native range) before finally becoming extinct in the early Pleistocene (about when the first Ice Ages began) but left one small living descendent species- Hemipristis elongata. But as their fossil teeth continue to be found and cherished, they will not soon be forgotten.
Fun facts: -In late 2014, a rare nearly complete 8 to 10 foot H. serra fossil specimen was unearthed near Calvert Cliffs, Maryland (included over 80 vertebrae, jaws with teeth, and even cartilage from its skull)
-Hemipristis serra teeth very rarely grow over 2 inches (the largest I've dug up was just a bit over 1.5") but reportedly there was one on the market once that was 2 5/8" (2.625" or 6.667 cm) from bone valley, FL (mentioned only in passing from a fossil dealer (?) on the Fossil Forum)
-H. serra has one of the most diverse dental assortment of any animal ever (a lot of types of teeth). Despite the thousands of H. serra teeth that have been found, no one can be too sure where exactly any given tooth could be in their jaw, as they had more types of teeth than the smaller living snaggletooth shark and their fossils are practically always scattered (isolated teeth).
-I have personally found at least one early Pleistocene snaggletooth in FL- in Mickler landing, Ponte Vedra beach (2019), and have found a few small snaggletooths in west central florida, which are probably early Pleistocene (if not Pliocene aged)
Discovery of Articulated H. serra
In Late 2014 (same year I started fossil hunting), a very rare well preserved H. serra was found in the Calvert Cliffs area during a house extension project. Professional paleontologists were called out, identified the specimen, and safely removed the whole block to be further prepped. It seemed to be medium sized for the species, estimated 8 to 10 feet long. As far as I know, it has not been exhaustively studied yet nor has a scientific paper come out describing it in detail (but if it has, definitely let me know! Email: pfcp028@yahoo.com)
Story source 2 (disregard the horrendous/misleading news title)
General Links:
-“Quantifying a Possible Miocene Phyletic Change in Hemipristis (Chondrichthyes) Teeth” (study revealing how Hemipristis spp. Teeth changed over time): http://palaeo-electronica.org/2006_1/teeth/teeth.pdf
“The Pliocene marine megafauna extinction and its impact on functional diversity” (full text)
Leisey Shell Pit FL Info (early Pleistocene formation with H. serra teeth) https://markgelbart.wordpress.com/2013/06/16/the-leisey-shell-pit/
General profile: http://www.prehistoric-wildlife.com/species/h/hemipristis.html
Another general profile/ pics http://www.fossilguy.com/gallery/vert/fish-shark/hemipristis/hemipristis.htm
More Coming soon! (Add complete/ near complete personal jaw reconstructions here)
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