SHARKS TEETH BY THE HUNDREDS
The following article was contributed by Tom Caggiano
New Jersey Paleontological Society.
Copyright © 2000-2012 by Tom Caggiano and Mike Everhart
LEFT: Ptychodus mortoni jaw plate found by Mike Triebold, August 16, 1996 in the Smoky Hill Chalk of northeastern Lane County (above marker unit 6, Middle Santonian)
(See updates of latest work on Ptychodus by Tom Caggiano and Mike Everhart at the bottom of this page - Also Tom found a dinosaur!)
We left New Jersey on April 20, 1995, for what has become an annual event. "Maniac Fossil Collecting" is how I try to describe it to friends of the non-fossil kind. Only a maniac would drive thirty hours non-stop to the Midwest to spend seven long days walking up and down hills and valleys in the unpredictable weather of early Spring. But I love it so much that on the thirty hour drive home I'm already looking forward to next years trip.
This year, our first destination was Kansas. We were returning for a second time to the Smoky Hill chalk formation. The chalk was deposited on the bottom of the great inland sea, during the Late Cretaceous, near the end of the Age of Dinosaurs. The calcium rich shells of dying micro-organisms deposited chalk at the rate of about one inch every seven hundred years. While dinosaurs roamed the shores, the sea was home to mosasaurs, turtles, plesiosaurs, sharks and many types of predatory fishes, some of which grew quite large. Pteranodons, a few birds, some smaller fish and a selection of invertebrates rounded out the picture of life.
Trip leader Jim Bourdon planned stops at two university natural history museums on the way out to whet our appetites and inspire fantasies of what we might find. We would, after all, be collecting in the same sediments in which Charles Sternberg made many of his famous discoveries. One of the fossils that had caught my attention was a complete set of sharks teeth. I'd seen two sets, one in the Sternberg Museum at Fort Hays State University, and one in the collection of Mike Everhart, who would be our guide on the trip.
As we rode out on our first day of collecting, my dream was to find a complete shark. Of course, I also needed a mosasaur skull and a complete fish. I always get carried away with fantasies of what I might find, but that's the great thing about this hobby, you never know.............
The lack of a recent heavy rain to expose new material made collecting difficult at the first two sites. To make matters worse, a light rain was falling on us as we made our third stop of the day. We drove into Martins Canyon, which is located on a private ranch where we had permission to collect. After parking on the east edge of the eroded valley, we split up and started walking. Much like the rest of the day, I wasn't finding much of anything.
As I walked down a shallow gully, I noticed some white flashes out of the corner of my eye. When I looked closer, I saw some strange looking teeth scattered down the side of the gully. Most were shiny brown in color while others had what appeared to be a white coating. They were shaped like little rounded pegs, with parallel ridges across the crowns. The larger ones measured about three quarters to one inch across.
|LEFT: Close-up of several of the Ptychodus anonymus teeth.|
I saw Mike in the distance and went over to him to see if he knew what they were. He identified them as teeth from a Ptychodus shark but wasn't sure as to the exact species.
"How many did you find?" he asked.
I said, "A lot!"
He got excited and asked me to show him where the teeth were coming out. We walked back to the site and did a quick survey. Then we started picking the teeth up from the bottom of the gully and worked our way up to the point at which they were eroding out of the chalk.
We then removed some of the chalk overburden and found some additional teeth and some pieces of a reddish brown material that appeared to be shark vertebrae. A little further in, we found five articulated vertebrae, laid out like fallen Dominoes. There were even a few more teeth mixed in with the vertebrae.
We also picked up two teeth from a Squalicorax shark which might indicate that the Ptychodus had been scavenged. With the help of Steve Balliet, I collected some loose teeth that we had missed on the first try. After treating the vertebrae with preservative, I removed and packed them for the ride home.
A count of the teeth later that night came to 208! Needless to say, I had a rather large grin stuck on my face. We spent the next day collecting in other areas in Kansas and then moved on to the Oligocene Badlands of Nebraska, but that's another story.
Known only from the Cretaceous, the genus Ptychodus has about a dozen different species. Species are defined based on tooth shape and differing ridge patterns and ornamentation. They are arranged side by side in rows in the jaw, with size decreasing as they go further from the center of the jaw or symphysis. Based on tooth shape it is reasonable to assume that Ptychodus were predators of shellfish. The rounded peg like teeth are well adapted for crushing and grinding and were laid out to form a solid pavement.
|LEFT: The upper and lower tooth plates of Tom's Ptychodus anonymus specimen|
Once home, I cleaned the teeth and started doing some research on Ptychodus. Based on photographs of articulated specimens in The Collectors Guide to Fossil Sharks and Rays From the Cretaceous of Texas, I was able to mount the teeth in a pattern that is somewhat like the natural arrangement. Even with the excellent pictures in the book, I had some difficulty in finding an exact match when trying to get an identification as to species. The species that seemed to be the closest match was not supposed to occur in the Smoky Hill chalk where I found my specimen.
After making some phone calls, I finally talked to J.D. Stewart at the Los Angeles County Museum of Natural History. He was interested and said that he would like to see the specimen. Fortunately, a month later while vacationing in Los Angeles, I was able to take my find to him for a positive ID. Upon examination, J.D. identified my shark as Ptychodus anonymus. I was told that this species had never been given a proper scientific description, hence the name "anonymus". He photographed the specimen and I left him with some of the matrix from around the vertebrae and a few teeth.
Later, I found out that it was one of only three specimens ever documented that have vertebrae associated with the teeth. In addition, J.D. was able to collect Ptychodus skin denticles from the matrix collected with the fossil. With the knowledge that the fossil was so rare, I contacted Dr. John Maisey at the American Museum of Natural history in New York. Dr. Maisey is a curator of Vertebrate Paleontology specializing in fossil fishes. We discussed my donating the fossil and was pleased to hear that they wanted my specimen.
In December of 1996, I paid a visit to Dr. Maisey at his office and donated the teeth and the accessory finds. When I left his office he had a big grin stuck on his face, too.
POSTSCRIPT: Tom and I co-authored a paper on his discovery and it was published in 2004 in the journal, Paludicola.
|Everhart, M. J. and
Caggiano, T. 2004. An associated dentition and calcified vertebral centra of
the Late Cretaceous elasmobranch, Ptychodus anonymus Williston 1900. Paludicola 4(4), p. 125-136.
The associated remains of a ptychodontid shark, Ptychodus anonymus Williston 1900, were recovered by the authors from the Smoky Hill Chalk Member (Late Cretaceous; late Coniacian) of the Niobrara Chalk Formation of western Kansas. Preserved elements included 208 teeth, five vertebral centra, fragments of centra and calcified cartilage, and oral (pharyngeal) denticles. The presence of calcified vertebral centra indicate that Ptychodus is a neoselachian shark and not a hybodont as previously reported. Whereas individual teeth of the genus Ptychodus are relatively common fossils in Late Cretaceous marine sediments, reasonably complete dentitions and preserved soft tissues are rare, and few have been reported in the literature. Most of the Ptychodus teeth that have been documented previously from the Niobrara Chalk have not included accurate stratigraphic information. In addition to reporting the associated dentition, calcified vertebral centra and oral denticles of Ptychodus anonymus, we also review the fauna association of the specimen and the history of the genus in North America.
|Our annual New Jersey Paleontological Society Field Trip was almost completely rained out in July, 1999, but not before Tom landed a small part of another big fish.... this one is a tooth from a very rare Ptychodontid shark in the Smoky Hill chalk, Ptychodus polygyrus. Click here for another Ptychodus tooth from the same site.... and possibly the same fish, found by Mike Everhart in May of 2000.|
Click here for pictures of a Ptychodus mortoni jaw plate from the Smoky Hill Chalk
Click here for a page of Ptychodus fossils from around the world
EDITOR'S POSTSCRIPT: On May 4, 1998, during the second day of another "Maniac Fossil Collecting Trip" in the Smoky Hill chalk, Tom found a nearly complete set of Protosphyraena perniciosa pectoral fins that were were nearly six feet across. The fins are heavy, have a saw-toothed leading edge and came from a large late Cretaceous fish that must have looked something like a primitive swordfish. Tom had another large grin on his face!
Try to imagine the fish that swam with these rigid, bony fins projecting 2 1/2 feet on either side of it's body! The Protosphyraena would have been at least 10 to 12 feet long, with a sharp, sword-like nose and sharp, saw-toothed edges on it's fins. Stranger, still, it's blade like teeth projected forward from it's jaw. More on Protosphyraena HERE.
This is a close up view of a 6 inch portion of the right fin, showing the characteristic, saw-tooth leading edge.
Presentations (Posters) from the 4th Annual Paleontology Symposium at the
135th Annual Meeting of the Kansas Academy of Science,
Pittsburg State University, Pittsburg, KS, April 12, 2003.
A RARE OCCURRENCE OF THE LATE CRETACEOUS PTYCHODONTID SHARK, PTYCHODUS POLYGYRUS AGASSIZ 1839, IN THE SMOKY HILL CHALK MEMBER (NIOBRARA FORMATION) OF WESTERN KANSAS.
Tom Caggiano, 145 Hayrick Lane, Commack, New York, and Michael J. Everhart, Sternberg Museum of Natural History, Hays, Kansas.
A single tooth of the ptychodontid shark, Ptychodus polygyrus, was recovered from the Smoky Hill Chalk Member of the Niobrara Formation in Gove County by the authors in 1999. The tooth (FHSM VP-15008) was discovered below Hattin's marker unit 3 and is Late Coniacian in age. Individual teeth of the durophagous genus Ptychodus are common fossils in Late Cretaceous marine sediments worldwide. Although individual shed teeth are found most often, a number of articulated jaw plates, occasionally associated with calcified vertebrae and dermal / oral denticles, are also known. Ptychodus mortoni, P. anonymus and P. martini are the three species commonly found in the lower 1/3 of the Smoky Hill Chalk. The first P. polygyrus tooth from the Cretaceous of Kansas was found by Mudge in Ellis County and reported by Cope in 1874. The whereabouts of that specimen is unknown. Williston described a large, single tooth (KUVP 55237) from the "lower beds of the Niobrara Cretaceous of the Smoky Hill River" more than a century ago, but did not elaborate further on the locality or stratigraphy. FHSM VP-15008 represents the third documented occurrence of Ptychodus polygyrus in Kansas, and the first report with accurate lithostratigraphic information.
NOTE ON THE OCCURRENCE OF FIVE SPECIES OF PTYCHODONTID SHARKS FROM A SINGLE LOCALITY IN THE SMOKY HILL CHALK (LATE CRETACEOUS) OF WESTERN KANSAS.
Michael J. Everhart, Sternberg Museum of Natural History, Fort Hays State University, Hays, Kansas, Tom Caggiano, 145 Hayrick Lane, Commack, New York, and Kenshu Shimada, Environmental Science Program and Department of Biological Sciences, DePaul University, Chicago, Illinois.
The teeth of durophagous shark, Ptychodus Agassiz, are common fossils in the Late Cretaceous rocks of Kansas (Greenhorn Limestone through the middle of the Smoky Hill Chalk Member of the Niobrara Formation). The chronological range of each ptychodontid species, however, is generally limited, and it is unusual in Kansas for three or more species to occur in the same locality. We report here on the occurrence of P. anonymus Williston (AMNH 19553 and FHSM VP-14854), P. mortoni Mantell (FHSM VP-15013), P. polygyrus Agassiz (FHSM VP-15008), P. martini Williston, and P. cf. P. latissimus Agassiz (FHSM VP-14853) from a small, 15 m high exposure of the Smoky Hill Chalk in southeast Gove County, Kansas (AMNH = American Museum of Natural History; FHSM = Fort Hays State University, Sternberg Museum of Natural History). The chalk at this locality ranges lithostratigraphically from just below Hattin's Marker Unit 2 to just above Marker Unit 3 (Late Coniacian), and is in Stewart's biostratigraphic zone of Protosphyraena perniciosa. These records provide additional data on the temporal distribution of Ptychodus species prior to their extinction during the Santonian, and on the faunal diversity of the Western Interior Sea during the Late Cretaceous.
|Check out the story of Tom's May 3, 2003 discovery of dinosaur bones (toe bones) in the Smoky Hill Chalk of western Kansas HERE, and what we found that they belonged to.....|
Photo Credits: The opening photograph is a picture taken by Mike Everhart of a Ptychodus mortoni jaw that was found in the chalk (Gove County) by Mike Triebold in 1996. The tooth rows are still partially articulated and show the general arraignment of the teeth in the genus Ptychodus. The other pictures were taken by Tom Caggiano. Tom can be reached by email HERE: