Otodus Transition Series

[bthemoose]

I'm putting together an Otodus sp. transition set of well-matched (similar size and position) teeth, in the approximately 1.4-1.5" range. This is the second such set I've put together, but for my current project I'm looking to build a larger (in number) set that includes examples from as many different locations and time periods as I can, i.e., not just one O. obliquus, one O. angustidens, etc., but hopefully multiples of each representing different time periods and geographic locations for the chronospecies. I'm off to a pretty good start, but there are several locations and a few specific time ranges that I'm still after, and I anticipate that I'll be continuing to build this set for a while.

 

As I've been working on this project, I thought it would be interesting to put together some photo montages of the teeth to illustrate the evolution of Otodus's cusplets and serrations, from O. obliquus to O. megalodon. I've seen similar images elsewhere but wanted to see what I could produce using teeth from my collection. Not all of the teeth shown below are from the set I'm building--I've also included images of teeth that are too large or small for the set but that fill in gaps and help illustrate the transitions.

 

 

 

 

 

[Rock Hound]

I very much enjoy this topic.  

[MarcoSr]

Nice attempt, but I think contrasting Otodus serrations/cusplets overtime is a very daunting task.  I've seen tremendous variation in both serrations and especially cusplets on Otodus sp. teeth from the same location, formation, time-period.  I think you can show a norm tooth and a trend over the millions of years, but there is no guarantee what an individual Otodus sp. tooth will look like in any time-period.

 

Marco Sr.

[bthemoose]

3 hours ago, MarcoSr said:

Nice attempt, but I think contrasting Otodus serrations/cusplets overtime is a very daunting task.  I've seen tremendous variation in both serrations and especially cusplets on Otodus sp. teeth from the same location, formation, time-period.  I think you can show a norm tooth and a trend over the millions of years, but there is no guarantee what an individual Otodus sp. tooth will look like in any time-period.

 

Marco Sr.

 

Yes, I definitely realize it's not a straight line of features appearing/disappearing and there's certainly a lot of variability between individual sharks, though I find the general trends really interesting. I also just really enjoy putting together these kinds of displays.

[MarcoSr]

8 minutes ago, bthemoose said:

 

Yes, I definitely realize it's not a straight line of features appearing/disappearing and there's certainly a lot of variability between individual sharks, though I find the general trends really interesting. I also just really enjoy putting together these kinds of displays.

 

I was able to see the variability among Otodus lineage shark teeth first hand some years ago.  I helped a group of image engineers and software engineers who wanted to use software algorithms on high resolution images of Otodus lineage shark teeth to be able to identify measurable features of the Otodus teeth so that they could be confidently identified to a species.  I came up with some overall tooth measurements/ratios, crown measurements/ratios, root measurements/ratios, in addition to the serration shapes, serration length/wide ratios, serration density per inch, etc. that they were already using.  All the engineers worked for a company that analyzed machine gear wear/damage by running software algorithms against high resolution image data sets of the machine gears.  The gear analyzing software could already determine gear tooth sizes, density, tip shape and take a number of other gear measurements.  One of the engineers modified a copy of the analyzing software, so it could measure the shark tooth dimensions of interest from high quality photos including the tip shapes, density, and length/width ratios of the serrations.  The engineers were also shark tooth collectors who were diving in Alabama and digging many thousands of Eocene shark teeth including hundreds of Otodus lineage teeth from formations under the water. The vast majority of the Eocene Otodus teeth were pristine.  The engineers took high quality photos of the pristine Otodus teeth on a format and then ran the images through their analyzing software.  Below is a picture of one of the many Eocene Otodus teeth that I also sent to them.  The engineers plotted many different measurements/measurement ratios and serration tip shape, length/width ratios, serration density versus other tooth measurements of many of the Eocene Otodus teeth from their Alabama site.  I expected more clustering of data than we saw, which would have led to at least a norm of an Eocene Otodus tooth from that Alabama site.  Looking at Otodus teeth from other Eocene sites only muddied the water more.  Because of the variation among the Otodus teeth studied and other factors the study stopped.  I am really disappointed because I had and still have the belief that this methodology and implementation would have yielded very important scientific results if continued and refined.  The main thing I learned from the limited study is there is a lot of variation in features of Otodus lineage teeth from the same time period and even from the same formation/site.

 

 

 

 

 

Marco Sr.