Today's Massive Desori Mako!

[Archie]

Wow awesome finds!

[JarrodB]

Killer finds. Congrats

[Terphunter]

Wow that is a GREAT find!

[Miocene_Mason]

Awesome finds! Beats my rootless one inch desori

[MeargleSchmeargl]

On 12/1/2017 at 5:03 PM, Sharks of SC said:

Hello Everyone!

It's been a minute since I've had the pleasure of finding any fossils worth posting here, but I was lucky enough today to squeeze in a couple hours of hunting. I noticed several sets of footprints around my usual hunting site - others had picked through the material recently. Undeterred, I made my way along the river visually scouring every square inch of exposed grey-brown Oligocene formation and gravel. Im glad I stuck with it because I was rewarded with several nice (albeit small) teeth from the extinct mega-tooth white shark, Carcharocles angustidens as well as a slew of smaller teeth. Then, just as I was ready to start hiking back to the car, I noticed the root of a VERY large mako tooth sticking out of the ground. When I pulled it up I was reminded of the sword in the stone..it just kept going and going.

At a little over 2.8" it's one of the largest Isurus desori teeth I've ever personally seen. It's in great condition with exceptional color to boot. 

Thanks for taking a look and as always...

Happy hunting!

SOSC

Holy smokes those are some sweet colors! 

 

Awesome haul!

[All Day Rocks]

Great find! That Mako is awesome!

[gwbh]

that is a HUGE mako!

[HoppeHunting]

Incredible. That's a perfect find. Based on the size of their teeth, Isurus desori must have been a very large predator. Does anyone know the approximate dimensions of the shark itself? I've been curious about this, because as seen here it's teeth can rival and even surpass the size of some from the genus Otodus. It must have been at least 20-25 feet in length. I've tried in vain to find size estimates for this specific shark, so any info would be great! 

[Miocene_Mason]

5 hours ago, HoppeFossilHunting said:

Does anyone know the approximate dimensions of the shark itself?

Considering it’s teeth are pretty much identical to I. Oxyrhincus (shortfin Mako), which Maxs our at around 18 feet, I would assume that as ballpark. From teeth like this and the better climate (for sharks and their prey) that existed during this time, I bet they could get bigger, perhaps 25 feet (not scientific, just a guess). Once somebody finds an associated skeleton with teeth it will be easier to deduce such things.

[HoppeHunting]

45 minutes ago, WhodamanHD said:

Once somebody finds an associated skeleton with teeth it will be easier to deduce such things.

Interesting. Finding an actual skeleton must be really rare, and what a significant find it would be! Although I’m sure it’s impossible because of the range of tooth size within the jaws of a single shark, how cool would it be to have some sort of calculator where you could plug in the dimensions and species of the tooth and get an approximate size of the shark it came from? I’d love to know how big of a beast each one of my finds is from. Just a cool thought. By the way, based on your reasoning and guessing would my beloved H. serra be larger than I. desori?

[Miocene_Mason]

22 minutes ago, HoppeFossilHunting said:

Interesting. Finding an actual skeleton must be really rare, and what a significant find it would be! Although I’m sure it’s impossible because of the range of tooth size within the jaws of a single shark, how cool would it be to have some sort of calculator where you could plug in the dimensions and species of the tooth and get an approximate size of the shark it came from? I’d love to know how big of a beast each one of my finds is from. Just a cool thought. By the way, based on your reasoning and guessing would my beloved H. serra be larger than I. desori?

Skeletons associated are rare, oceans have a way of humbling up remains and cartilage disbands quickly but every so often you get a nice one which benefits science. Speaking of which a H. Serra was found at the cliffs (think it was about five years ago) that measured 8-10 feet long. I’ll see if I can find some pictures of tooth size but of course tooth size vary with placement as you know. This would probably be an average specimen size, maybe other ones could get bigger, the teeth if I remember correctly we’re not the upper limit sized (if that makes sense). Hopefully with continuous learning we can get a “shark size calculator”. That’ll be the day...

[Miocene_Mason]

Here we are @HoppeFossilHunting

http://www.fossilguy.com/gallery/vert/fish-shark/hemipristis/hemipristis.htm

[Darktooth]

I don't know how I missed this! Really great finds! Congratulations! 

[HoppeHunting]

1 hour ago, WhodamanHD said:

http://www.fossilguy.com/gallery/vert/fish-shark/hemipristis/hemipristis.htm

Yeah I heard about this! So awesome. The CMM must have some really amazing discoveries along with this one. I went to the museum when I was really young so I don’t remember it, but since I recently got into fossil hunting I’ve been itching to go back. I may join for the Fossil Club there and I’m also thinking about maybe even applying for an internship there over the summer to keep me busy and get some professional experience. Might look good on college apps too! Thanks for the link

[Miocene_Mason]

55 minutes ago, HoppeFossilHunting said:

Yeah I heard about this! So awesome. The CMM must have some really amazing discoveries along with this one. I went to the museum when I was really young so I don’t remember it, but since I recently got into fossil hunting I’ve been itching to go back. I may join for the Fossil Club there and I’m also thinking about maybe even applying for an internship there over the summer to keep me busy and get some professional experience. Might look good on college apps too! Thanks for the link

You should totally do it if you can, they are all very nice, very knowledgeable, and do a lot of good work. Sure it would look great on a college app, someday when my schedule is less full (already volunteering at an archaeological site this summer) I might see if they’ll accept me as a Volunteer or intern. Unfortunately, I was told that the owners of the back yard in which the shark was found reclaimed the shark and currently have it in a room built over the location of the discovery. 

[siteseer]

On 2/15/2018 at 6:37 AM, HoppeHunting said:

Incredible. That's a perfect find. Based on the size of their teeth, Isurus desori must have been a very large predator. Does anyone know the approximate dimensions of the shark itself? I've been curious about this, because as seen here it's teeth can rival and even surpass the size of some from the genus Otodus. It must have been at least 20-25 feet in length. I've tried in vain to find size estimates for this specific shark, so any info would be great! 

 

I've wondered why do the largest mako teeth seem to all come from the Oligocene?  There's the occasional unusually large one from an Eocene or Miocene site but when I see a tooth around or exceeding 2 inches it tends to come from the Oligocene and specifically from South Carolina sites (Chandler Bridge and Ashley Formations).  You certainly don't see teeth that big from specimens caught today.  A really large shortfin mako is something over 10 feet and I think the largest off California was something over 12 feet and the teeth are less than 2 inches though I don't know the tooth size of that 12-footer.  The species is a pursuit predator so it might be counterproductive to grow to a size that slows it down or makes it less maneuverable.  I've also wondered if it evolved to become a pursuit predator to go after prey faster than Carcharocles could catch.  Being fast also allowed it to outrun a hungry Carcharocles.

 

Anyway, the thing about the Oligocene was that it was a block of geologic time when a climatic cooling trend was in full force.  Ice was forming at the poles and a large ice sheet formed over much of Antarctica in the Early Oligocene.  It retreated but then advanced again in the Middle Oligocene.  Sea level fell all over the world.  It's part of the reason we see fewer fossil shark teeth than we do from the Eocene or Miocene although the Oligocene was also much shorter in duration (less than half) than either of those two epochs.  I think the mako might have happened to evolve to tolerate a somewhat cooler environment than Carcharocles did.  Today, the shortfin mako frequents waters over 60 degrees but you don't see it as much in the tropics so it has a definite "comfort zone."  It's possible that it grew larger in certain areas during the Oligocene because Carcharocles was less numerous in certain areas.  Don't get me wrong.  Collectors find a lot of Carcharocles teeth from the Oligocene of South Carolina.  We can see that here on the Forum but Isurus might have had a window of opportunity during that time that it didn't have before and didn't have since until the extinction of megalodon because of cooler waters when it was able to expand its range more successfully.  In the Early Miocene a warming trend started that ended in the Late Middle Miocene.  Carcharocles megalodon evolved during that time and makos seem to become less numerous and smaller in general.  Makos didn't get larger after megalodon died out because other competitors were evolving during the Pliocene (killer whales, the great white shark, etc.).

 

Anyway, getting to the question, it's tough to put a number on the range of the total body length of an extinct shark and no way to confirm it.  We're lucky in this case because I. desori is likely the ancestor of I oxyrinchus (modern shortfin mako) or it might even be just the early form of the same species but it only helps to a point because we don't see modern mako teeth near as large as 2 1/2 inches.  If we look at the modern great white shark, that species has a growth rate around 25-30cm per year but it slows as it reaches maturity (10-14 years) and the shark fills out in the body more as it ages.  I think it's realistic to imagine that a mako with 2-inch teeth could be something around or over 15 feet long and an individual with 2 1/2-inch teeth would be perhaps as large as 20 feet long.