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Catsharks comprise one of the largest extant families of shark with 160 species in 17 genera and there is a good fossil record of the family in addition. The family goes back to the Jurassic and can be found in several well known, heavily collected formations but I have found this to be a very challenging shark to collect. It is tooth that seems to stay in collections which I completely understand. They are tiny, tiny teeth and you have to be hunting for very tiny teeth to find them. They can also be very rare within a fauna which is the case with Sharktooth Hill as I have learned. Extant Catsharks appear in a variety of habitats and at varying depths. This seems to be also be true of extinct Catsharks which can be found in a variety of habitats. The opportunities exist to find cool Catshark teeth but they stay just elusive enough to make them quite a challenge to collect. Scyliorhinidae hold a special place in our collection. They were a shark that we talked about in every Fossils on Wheels shark themed program we did. One of my favorite personal finds is a Scyliorhinus I picked out of some Cretaceous micro fossil mix. I prize that 1mm tooth like few in my collection. Carter and I both believe that our Lebanese shark fossil is that of a Catshark. It is a shark that I am almost always on the lookout for and an STH Scyliorhinus is sort of my white whale lol I am pretty interested to see what Catsharks might lurk in the great collections here. I have seen some really sweet specimens here so I would invite anybody who to share to show us your awesome Catshark teeth.

Many forum members are familiar with Cookiecutter Creek in South Florida. This is a small creek that well-known forum member Jeff @jcbshark was kind enough to share with me a little over 3 years ago. Jeff had posted photos of the tiny Cookiecutter Shark (Isistius triangulus) teeth that he had found picking through micro-matrix from this creek and that started my quest to obtain a tooth from this very unusual little shark. After picking through many gallons of micro-matrix from the Peace River and some of its feeder creeks without once laying eyes upon a single Isistius tooth (but finding tons of other micro fossils), Jeff informed me that he didn't think Cookiecutters could be found anywhere other than one special little creek and agreed to take me and Tammy to collect some micro-matrix there in mid-December 2014. It didn't take long for me to find my first complete Isistius. Several more soon followed including some from the positionally rare symphyseal spot in the middle of the lower jaw. It is possible to identify a symphyseal as the thinner area where each tooth overlaps the adjoining tooth is usually found with one overlap area seen on the inner and one on the outer surface of each tooth but not symphyseals. Since these teeth overlap BOTH the tooth to the left and right (like the top row of shingles on the ridge of a roof) the overlap marks are both found on the inner (lingual) surface of the tooth and no marks are found on the outer (labial) surface. Once you know how the teeth of the lower jaw overlap and how to identify the outer (labial) side of the tooth (the enamel does not stop at a well defined line but extends down from the triangular crown and onto the square root), you can also tell which side of the jaw (left or right) that the tooth came from. Aside from the symphyseal position most of the other teeth cannot be identified to position other than the last one or two posterior positions. These teeth have the crown angled with respect to the root. Here are some of my old posts showing Cookiecutter Creek and the micro-fossils that have come from this unique locality in Florida: http://www.thefossilforum.com/index.php?/topic/51286-collecting-cookiecutter-shark-micro-matrix/ http://www.thefossilforum.com/index.php?/topic/55298-more-micros-from-the-peace-river-and-cookiecutter-creek/ http://www.thefossilforum.com/index.php?/topic/71406-optimizing-micro-matrix-sorting/ Recently, I've been working on a project with a PhD student from the University of Florida which was initiated when it was realized that the Isistius triangulus teeth that I donated to the FLMNH were not yet recognized as occurring in Florida. Additional research revealed that specimens of Squatina (Angelshark) teeth from this creek were also not known from Florida (though I've also found this genus in micro-matrix from the Peace River). I made another collection of micro-matrix from Cookiecutter Creek as I had exhausted my supplies. A couple of flat-rate boxes of this material made their way into the hands of a couple of forum members--who I hope are having fun with this unique micro-matrix. Tony @ynot had sent me photos of another interesting find from Cookiecutter Creek. Jeff had collected some additional micro-matrix on the day that he introduced me to this site. Some of that collection was later made available to Tony as an auction to benefit the forum. While looking through this micro-matrix, Tony discovered a small specimen of what appears to be a Catshark (Scyliorhinidae) tooth. Tony is graciously sending that tooth to me so that I can pass it along to be added to the collection at the Florida Museum of Natural History (FLMNH) as this is the first record of this shark family in the Florida fossil record (and another first for Cookiecutter Creek). Tony's photo if this micro beauty: Since learning of the possibility of this taxon being found in the micro-matrix of Cookiecutter Creek, I've been searching through my remaining stash from this locality hoping to find a second Catshark tooth (no luck yet). While I've (so far) struck out in duplicating Tony's amazing find, I did have a bit of luck last week with something else new from my searching. While picking through the micro-matrix I came across an elongated item just about 10mm in length. If I'd not been familiar with this type of highly unusual shark tooth before I might have passed it by thinking it was just some unidentifiable fragment of bone. Experience and knowledge (even just a small amount) allowed me to recognize this as a tooth type that is reasonable common in another type of wonderful micro-matrix--Shark Tooth Hill (Bakersfield, CA). The unusual tooth from Cookiecutter Creek is actually quite common in STH micro-matrix. It comes from a Horn Shark (Heterodontidae). Since there is currently only a single genus described for this small family of small sharks, it can actually be identified down to the genus Heterodontus. These are placid little sharks that I remember seeing resting on the bottom during the few dives I did among the kelp forests in southern California's Channel Islands. They have distinctive ridges over the eyes and a single spike at the leading edge of their two dorsal fins. They feed mainly on hard-shelled invertebrates (crustaceans, molluscs, and echinoderms). Their name "Heterodontus" derives from the Greek meaning "different teeth" and referring to the fact that the front teeth are pointy with larger central cusp flanked by a smaller cusp on either side. The back teeth elongated with a long ridge running the length of the tooth and are adapted to crushing the hard shells of their prey items. https://en.wikipedia.org/wiki/Horn_shark Currently, most members of this family are found in the Indo-Pacific--like the well-known Port Jackson Shark (Heterodontus portusjacksoni) and only the Californian Horn Shark (Heterodontus francisci), the Galapagos Bullhead Shark (Heterodontus quoyi), and the Mexican Hornshark (Heterodontus mexicanus) are found in the eastern Pacific off the west coasts of North and South America. It's difficult to make any firm conclusions from the scant images available online but the rear teeth of the Mexican species to have a reasonable resemblance to the specimen that turned up in Cookiecutter Creek. Today, there are no species from this family inhabiting the Atlantic (or the Caribbean or Gulf of Mexico regions). Devoid of any factual information but attempting a modestly educated guess, I'm thinking that one of the species of Bullhead Sharks must have extended over into the waters surrounding Florida some time before the Isthmus of Panama formed some 2.8 mya separating the Atlantic and Pacific Oceans and separating the fauna on either side to either develop into distinct species (or to go extinct regionally). Since this family is not currently known from the Atlantic (eastern or western extents) it seems more reasonable to assume that the Florida specimen derived from an eastern Pacific species given the (geologically) recent connection to those waters. Fun to speculate and if Marco Sr @MarcoSr has jaw samples of extant eastern Pacific members of this family, perhaps a better comparison to the anterior teeth might be possible. Both this tiny Heterodontus tooth and Tony's find of the Scyliorhinidae will soon be headed toward Gainesville. I'm hoping to get up to volunteer at Montbrook in the next couple of weeks and plan on dropping off a few donations to expand the museum's diversity of shark teeth from Florida. Cookiecutter Creek is a special little creek and is best known for its relative abundance of Isistius triangulus teeth. The more we investigate this locality and the more micro-matrix we pick through from there the more unusual taxa seem to turn up. Seeing a perfect little Cookiecutter tooth appear from the micro-matrix is always a thrill but this creek is no longer a one-trick pony. It seems to have hidden depths (for a creek that is only knee high ) and I'm looking forward to seeing what else might appear out of the gravel in the future. Cheers. -Ken