JohnBrewer Posted September 9, 2016 Share Posted September 9, 2016 I see 'cookie cutter' ( biscuit cutter in the UK no doubt, hehe) matrix. What does cookie cutter mean in this context? Funny and serious answers both welcome John Map of UK fossil sites Link to comment Share on other sites More sharing options...
caldigger Posted September 9, 2016 Share Posted September 9, 2016 The shark takes out a chunk in a round pattern similar to what it would look like if you were to press a cookie cutter into flesh. Hence the name. The matrix has the teeth from this shark in it. 2 Link to comment Share on other sites More sharing options...
ynot Posted September 9, 2016 Share Posted September 9, 2016 The cookie cutter shark is a small deep sea shark that likes to swim up and take a bite from much larger animals. This action makes the bite look like a cookie was cut from dough, hence the name. The "cookie cutter matrix" is sand that has a fair amount of the teeth from this shark in it. Here is a picture of a cookie cutter tooth. (scal in in millimeters) Tony 2 Link to comment Share on other sites More sharing options...
digit Posted September 9, 2016 Share Posted September 9, 2016 Could not have answered it better than the two responses above. These teeth are pretty small (see Tony's image above) and almost paper thin. As a result they tend to get ground to dust in larger rivers like the Peace River here in Florida. There is at least one tiny creek in Florida that cuts through a deposit of marine matrix and micro-matrix can be gathered very close to the point at which it is eroding from the deposits in the bank so the delicate items survive. This creek (dubbed "Cookiecutter Creek") is known to have a reasonable density of Isistius (Cookiecutter Shark) teeth in it. Jeff (jcbshark), from whom I learned of the existence of this special little creek, estimates about 1 tooth per pound of micro-matrix. Not the most common of shark teeth in the micro-matrix but the fact that these rare teeth are there at all is pretty special. I've had good luck with this micro-matrix and have been able to pull quite a number of teeth from it--including several symphyseal (centerline) teeth. That was a fun experiment on placing multiple images on the new forum software. A bit different from the old days. Cheers. -Ken 3 Link to comment Share on other sites More sharing options...
JohnBrewer Posted September 9, 2016 Author Share Posted September 9, 2016 Thanks guys. So cookie cutter is a specific small shark rather than general small sharks? John Map of UK fossil sites Link to comment Share on other sites More sharing options...
caldigger Posted September 9, 2016 Share Posted September 9, 2016 John here is a pic of the shark, some info on it and a good view of the chompers. As you can see it is quite small, not much bigger than 2 1/2 pencils end to end. But it can make a good size hole in you with a nasty bite. 2 Link to comment Share on other sites More sharing options...
Troodon Posted September 9, 2016 Share Posted September 9, 2016 nasty little shark, definitely not a cookie (biscuit) but cuts holes into its prey similar to one 2 Link to comment Share on other sites More sharing options...
JohnBrewer Posted September 9, 2016 Author Share Posted September 9, 2016 Pretty nasty looking teeth. Thanks for the info and images guys. John Map of UK fossil sites Link to comment Share on other sites More sharing options...
digit Posted September 10, 2016 Share Posted September 10, 2016 17 hours ago, JohnBrewer said: Thanks guys. So cookie cutter is a specific small shark rather than general small sharks? Yup. The Cookiecutter Shark (Isistius brasiliensis) is a specific species of small dogfish sharks. I don't know that anything other than fossilized lower teeth are ever found and so I'm not certain if these fossils represent this same species or another extinct species of cookie cutters. They are a creepily unusual species which latches onto its victim with the teeth of the upper jaw and then closes its outstretched lower jaw lined with a sharp row of slicing teeth to gouge out a plug of flesh (the source of its common name). I've been fascinated with this macabre species ever since I was a kid. It was fun to be able to paw through a bucket of micro-matrix from across the way in Florida to search for teeth from one of my childhood favorites. Due to these teeth being small and fragile, they seem to command unreal high prices on fossil and auction sites--the cool backstory probably also helps to keep them in demand. Cheers. -Ken 3 Link to comment Share on other sites More sharing options...
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