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Found 8 results

  1. 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
  2. I enjoy sorting through micro-matrix. Between the times that I'm able to spare a Saturday to drive 3 hours to the Peace River to sift for larger fossils, I like to have some micro-matrix on hand so I can easily scratch the itch when I feel the need to hunt for fossils--even if it is only from the comfort of my office desk. I'm currently working on a project involving micro-matrix (which I'll write-up on TFF once it is complete). This project requires a large number of specimens and so I've collected about five 5-gallon buckets of micro-matrix which now reside in the corner of my home office. Whenever I need a break from working on the computer I can easily grab a cupful of micro-matrix, my omni-useful dental probe, and my well-worn iris decorated paper plate and take a short plunge into the world of tiny fossils. I've recently taken steps to optimize my productivity while sorting micro-matrix so I thought I'd post them here in case any micro-fossil hunters find any utility in my method. Here is my usual setup for sorting micro-matrix--I used to pour out a large amount of micro-matrix onto my plate at one time but I now sprinkle a narrow, nearly complete, ring of micro-matrix around the edge of my paper plate. I use two different colored cups to keep track of which cup I'm pulling from and which cup I'm discarding from. I used to use two blue plastic Solo cups but it's no fun when you get them mixed up and start sorting your discards instead of fresh micro-matrix. Color coding has solved that issue permanently. I purchased a nice large magnifying lens ringed in 100 LED lights which provide nice even lighting in the field of view. The model I purchased is usually made for those doing detailed crafts like needlepoint or those whose vision is not what it was when they were younger so they can minimize eye strain while reading or doing crossword puzzles. As this model is specifically meant to be used while seated, it comes with a heavy weighted base and an adjustable arm so I can move the lens around and adjust the height over my plate for optimal focus. I used to scan micro-matrix using my photographer's loupe which had became rather outdated and useless once I went digital and stopped processing chemically developed slide film. The problem with this is that holding it in front of one eye with the other eye closed for extended periods caused only one eye to focus abnormally close and after a session of micro-fossil hunting my vision would end up blurred for hours afterward--not ideal in any way. The large lighted lens was not inexpensive but being able to see my micro-matrix clearly with both eyes providing some stereoscopic depth and no residual eye strain made the purchase well worth the cost. Though the camera could not quite figure out where and how to focus while viewing through my magnifier, you'll get some idea of how I see my micro-matrix under well-lit magnification. I've sorted many gallons of micro-matrix using just this method with great success. I'm an engineer by trade (computer programming to be specific). I'm always on the look out for ways to optimize my process allowing me to more efficiently search through my micro-matrix to find the tiny prizes hiding within. One of the things that limits my efficiency while sorting is the size range of the items in my micro-matrix. When I collect micro-matrix in the field I use a pair of stacked sifting screens. The top screen has 1/4" mesh and screens out any pieces larger than this approximate dimension. The sifter under that has a piece of metal window screen placed inside it. The mesh spacing on this screen is approximately 1/20". The separate piece of screen material allows me to lift this out of the bottom sifter and flush some of the fine sand through this tighter mesh before dumping it into my collecting bucket. So my collected micro-matrix consists of pieces roughly between 1/4" and 1/20". The mixture of different sized pieces can be seen in the last photo above where larger chunks of black phosphatic pebbles and shell hash mingle with smaller pieces of rock and sand. While sorting through this micro-matrix my search image has to encompass larger shark teeth and ray tooth plates all the way down to tiny drum fish "button" teeth, Dasyatis stingray teeth, fish incisors, and tiny baby shark teeth. I'm pretty good at keeping all of these search images in mind while working through the micro-matrix but consider the scenario of being out on a South African safari and trying to keep an eye out for a heard of African Elephants, a clan of Meerkats, as well as looking out for Dung Beetles rolling by. You might be able to be on the alert for any of these African photo-ops but it would be hard not to know if you'd overlooked something somewhere. I remembered visiting the Florida Museum of Natural History (FLMNH) up in Gainesville a little over a year ago and getting a spectacular tour of the work area where specimens were being prepped and micro-matrix from the Thomas Farm dig site was currently being processed. Dr. Hulbert explained to me and my wife how the bagged micro-matrix from the field was washed through a stacked set of sifting screens with different mesh sizes before being placed in a drying rack where continuous air flow sped up the drying process. I also recently learned that each project (Thomas Farm, Montbrook, etc.) have their own sets of screens to avoid any cross contamination that might make for interesting mix-ups of fossils.
  3. I recently collected some micro-matrix from Rattlesnake Creek in Gainesville. See my other posting if you want to read more about that here: http://www.thefossilforum.com/index.php?/topic/58470-rattlesnake-creek-rendezvous/?p=622403 This morning while sorting through the micro-matrix I spotted an unusual (for me) tiny shark tooth that has me guessing. This little one is only about 4.5 mm across the base of the root and around 5 mm along the long edge of the blade. It is novel solely due to the presence of the side cusp(s). There is an obvious side cusp on the side toward which the main cusp angles and there appears to be a bit up a "bump" in the enamel at the other side of the tooth that is subtle but apparent when looking at the tooth under magnification but, unfortunately, does not photograph very well. Basically, there appears to be a faint "notch" at the base of the long edge of the main cusp and the enamel is ever so slightly raised past this notch. The tooth does not really resemble the tiny Tiger Shark or Sand Tiger teeth which I know to have additional side cusps. The root is too flat and not as U-shaped as I'd expect for a posterior Sand Tiger tooth. It also doesn't seem to have the correct "bend" that I'm used to for the various species of Tiger Shark teeth that I'm familiar with from locations in South Florida. Any help with a possible identification on this tiny little mystery tooth would be welcome and educational--for me and possibly for other readers. Cheers. -Ken
  4. Well, the Peace River was still about 7 feet too high to consider dipping a sifter in it (much less trying to stand upright against the current) so my wife and I set our sights on an alternative destination for our anniversary weekend. Yup, that's right--if you marry well you can actually go fossil hunting as part of your anniversary celebration. In the end we decided upon, not Niagara Falls nor Acapulco, but the relatively closer destination of Gainesville, Florida. We've been wanting to visit with Dr. Richard Hulbert, Collections Manager and Coordinator of the Program of Vertebrate Paleontology at the Florida Museum of Natural History located on the campus of the University of Florida campus in Gainesville and so we thought we'd make a long weekend of it. I'll post more about our visit to the FLMNH collections in a separate topic soon. Once we decided upon Gainesville as a destination we contacted TFF member Khyssa to see if she was available for some hunting in Rattlesnake Creek which, thankfully, she was. We rendezvoused at a local park nearby where we would go hunting (easier for us to find) an then headed off to Rattlesnake Creek. The trick to hunting any of the many creeks that run through Gainesville is to find a good access point. For those unfamiliar with Gainesville (which, I admit, includes me) there is a nice PDF available online produced by the City of Gainesville: https://www.cityofgainesville.org/Portals/0/plan/docs/GIS_Creek_Names.pdf The location we arrived at to explore Rattlesnake Creek must be well known by both the people of Gainesville and the local government as they have provided numerous parking spaces along both sides of the road where it crosses the creek. We parked, changed into shoes that we didn't mind getting wet, grabbed our shovels and sifting gear and scrambled down the slope to the culvert. Anybody considering sifting in these creeks should be wearing shoes with sturdy soles as there is a crazy amount of broken glass--remnants of those with little respect for the natural beauty of wild places. Some people have decided they needed to "beautify" the culvert and overpass by tagging it liberally with multi-chromatic grafitti. We passed through the culvert and emerged on the other side where there is a gravel bed a very short distance from where we had parked. This was important as my main goal was to collect some Rattlesnake Creek micro-matrix and buckets of gravel get mighty heavy when lugging them back to the car. We soon got down to work collecting the micro-matrix. I had brought along the same setup I've used before on the Peace River and Cookiecutter Creek. This consists of two of my normal sifters (one with 1/4" mesh screen and one with the larger and sturdier 1/2" mesh). The process is pretty basic--I place a piece of window screen material (1/20" openings on that mesh) inside the lower sifter and then stack the sifter with the 1/4" mesh on top of that. Then I toss in a few shovels full of sand and gravel dug up from the gravel bed on which we were working. In an area with deeper water it would be relatively easy to use the water to sort the gravel and sand through the sifters. The creek here was only a few inches deep and so with the help of a flexible plastic bucket I was able to scoop up some water and pour it over the sifter stack. This took a lot more time than sifting waist deep in the Peace River and was also much more tough on the lower back (and every single joint below that). Progressing slowly I was able to wash the finer material from the upper sifter into the lower one. Once most of the small stuff had passed through I took the coarser gravel (> 1/4") over to the sand bar where my wife had a quick look through it for larger items. I then shook the lower sifter to get most of the finer sand to pass through the inserted window screen. Once it was relatively sand-free I then picked up the piece of window screen by the corners and carried it over to my waiting bucket where it was dumped. I repeated this process till my 2-gallon bucket was filled (maybe a dozen or more times). I then lugged this bucket up to the larger 5-gallon bucket waiting in my car's trunk. Since the car was nearby it was easy to repeat this over and over till I had all the micro-matrix I felt I needed. -Ken
  5. Finally managed to get out on a Florida fossil hunting trip for the 2014/15 season here in South Florida. Instead of going to the Peace River (where the water level is still dropping from a huge spike due to heavy rains nearly a month ago around Thanksgiving) I contacted Jeff (jcbshark) and we planned an outing at the creek where he collects his world famous cookiecutter shark micro-matrix. Earlier this year I had searched--cup by cup--through nearly a 5-gallon bucket of micro-matrix I had collected from the Peace River looking for cookiecutter shark teeth (to no avail). It seems that cookiecutter shark fossils are absent (or incredibly rare) in the deposits that the Peace cuts through. I've been fascinated with cookiecutter sharks since I learned about them as a kid (yup, I was a fish geek even then). The odd hole-saw-like fused lower dentition of this shark has been on my fossil bucket list since I first saw the images on this forum. Many of these images were posted by people searching through samples of the micro-matrix that Jeff had sent out to TFF members. It was high time I got in on the fun. I met up with Jeff and a few of his wife's relatives (who were new to fossil hunting) on the creek early Saturday morning. We were later joined by Chris (Search4) who came along to try his luck. The air temps were still climbing out of the low 60's but the skies were clear and the temps would later top out in the upper 70's so the chilly water (likely somewhere in the mid 50's) was actually quite bearable once you got used to it (read that as "numb"). The creek was mostly pretty shallow and I didn't get any deeper than about knee-deep all morning. My wife Tammy (always the more practical) was wise enough to bring her waders for comfort (and style). Jeff led us to the location he had previously collected his cookiecutter micro-matrix though he mentioned that there was likely nothing special about this spot and that the same sort of matrix could likely be gathered from anywhere along the creek. The creek which is the source of the cookiecutter micro-matrix. I had brought my micro-matrix collecting gear and soon got to work. I have sifting screens that I've made for searching the gravel beds of the Peace River and its tributaries. I've previously described how I make my sifting screen (and my probe) here: http://www.thefossilforum.com/index.php?/topic/42992-end-of-year-peace-river-trip/#entry467550 I've since converted one of my sifters from 1/4" mesh to 1/2" mesh for when I work areas with coarser gravel or when I want to work through larger amounts of gravel quickly while looking for larger items. I brought my 1/2" sifter along with one of my 1/4" sifters as well as some 1/16" window screen mesh cut to size so that it fits comfortably into the sifting screens. The technique I use to collect micro-matrix is to double sift using a stacked pair of sifting screens. I place the fine window screen mesh inside the sifter with the 1/2" mesh. On top of this sifting screen I stack my sifter with the 1/4" mesh. The arrangement can be seen below: Loose window screen mesh fits inside one sifter and a second sifter fits on top of the first. The stacked sifters efficiently sort out the micro-matrix.
  6. A couple of weeks ago I posted a topic about a rodent incisor that I found in the micro-matrix gravel that I collected from the Peace River at the end of the last river fossil hunting season. Consensus had it as an upper incisor due to curvature of the tooth. That topic can be found here for those who missed it the first time: http://www.thefossilforum.com/index.php?/topic/47538-micro-matrix-incisor-from-the-peace-river/ While sorting through some of the same batch of micro-matrix I came across something else of interest that stood out from the usual tiny shark, ray, drum, porgy and other fish teeth. It was a tiny mammal molar. I'm still working out a good system for micro photography and my current setup reflects back the lighting too much when I use my millimeter ruler scale so the photos are sans scale. The tooth dimensions are approximately 1.5mm x 3.5mm across the occlusal surface and the length is about 4.5mm long to the extent of the root. Based on the size it had to be from some small rodent so I checked my bible, The Fossil Vertebrates of Florida, to see if I could find a match or at least something similar. From my (extremely limited) understanding of rodent molars, I believe this may be a arvicoline rodent molar as they are characterized by the occlusal surface being composed of a series of "triangles" which this tooth seems to show. The two sinuses (I guess that's the proper term) on either side of the tooth between the three triangular lophes/cones seem to point in the same direction (posteriorly, down in the photo below). The overall shape seems to most closely match the dentition examples shown in Fig. 12.13 [C] on page 235 of the aforementioned book. If this is the case that would make this a right m1 (first lower molar) of Ondatra annectens which is known from the early Pleistocene of Texas. Early Pleistocene would seem to match the age range found in the Peace River and I would expect that rodents (much like today) were generally wide ranging. In fact, consulting the checklist of Florida fossil vertebrates on page 58 shows this species as being known from Florida. This is about the extent of my fossil sluthery skills (actually I'm operating well past the comfort zone of my current knowledge). I don't doubt that there are members on this forum who have a much more comprehensive understanding of the arcane skills of mouse molar morphology. I'd love to hear what others make of this tiny little prize. I apologize for the quality of the photos in advance. I'm still trying to come up with a good system for taking pictures of specimens this tiny. I think I'll need to drop some $$$$ for a nice macro lens for my DSLR. Till then I'm stuck with crummy photos with a lack of depth of field and resolution. Here are the photos (such as they are) showing a side view (occlusal surface toward the top) and an occlusal view (anterior side presumably? toward the top): Cheers. -Ken
  7. I've been making progress in the bucket of micro-matrix that gathered from a spot on the Peace River back in May when I made my last sojourn to sift there this season. Looking through my 10x photographer's loupe with one eye while scanning the matrix was giving me a bad case of double vision if I gave into temptation and picked through more than a Solo cup full of micro-matrix. In attempt to find a technique easier on the eyes I purchased a 5MP digital microscope (basically a USB webcam with an adjustable magnifying lens). I found this too slow and cumbersome to use in my search for micro fossils but it does seem to be reasonably proficient in taking acceptable quality images of the finds. I was struck with a brilliant thought yesterday (and I'm afraid I've probably now used up my quota of these for 2014). Being an old gray-haired codger now my eyes seem resistant to focusing on anything close-up. It's not that my eyes are too bad to read restaurant menus but my arms seem to be too short. I do wear contact lenses to help me with my distance vision (and have for decades). I know that without my contacts in place that my close-up vision is actually pretty good after all. The epiphany yesterday was to simply tuck my contact lenses safely in their case and then use no magnifying optics at all to scan for micro fossils in my matrix. It turns out that with the aid of a good LED light that I can clearly spot and identify micros less than half a millimeter with the naked eye. This has greatly speeded-up the search through my micro-matrix and done away with the eye strain and double vision I was experiencing when searching under magnification. This evening while relaxing with a fine sipping rum I searched my way through a plastic Solo cup full of micro-matrix. In addition to the usual very tiny shark teeth and ray plates I came across something novel (and I love novelty). It appears that this micro fossil might be a curved incisor of something mouse-like in size (and construction). Though it is difficult to show in photographs, one end (root) shows a bit of a hollow concavity and the other seems to show a beveled (occlusal) surface. I tried to include a scale in the images but the shiny surface reflected the circle of LED lights in a very distracting way. The actual length of this incisor is about 9mm if that helps to narrow down who could have formerly owned this bit of dentition. I'm assuming something mouse-like but would be curious to hear if any on the Forum have any more detailed opinions. Two sides: Cheers. -Ken
  8. Been having fun picking through my small cache of collected micro-matrix. So far I've found mostly tiny versions of the larger teeth I usually find and some pharyngeal "button" teeth from drums and other fishes. Been looking for the elusive cookie cutter shark tooth but haven't come across one yet. Turned up this in my searching today and I'm thinking this which looks a bit different from the normal micro fossils I've uncovered. I'm assuming it is likely some sort of ray tooth but I'm just learning about these little guys that usually fall through my sifting screen. The scale is in millimeters so it's a little one. Cheers. -Ken
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