Extant Isurus oxyrinchus (Mako Shortfin Shark) jaw

[MarcoSr]

Here is an Isurus oxyrinchus (Mako Shortfin Shark) jaw that I recently acquired. The jaw is 12.5” wide and 8.5” inches high.

Here is the overall jaw:

To better see tooth details double clique the below pictures. If you mouse over the pictures you will see the file name which has additional positional information.

Continued in the next reply:

Marco Sr.

Edited February 4, 2016 by MarcoSr

[MarcoSr]

Isurus oxyrinchus (Mako Shortfin Shark) does not have symphyseal teeth.

Upper jaw symphysis:

Lower jaw symphysis:

Extreme posterior teeth can widely vary.

Upper jaw left and right side posterior teeth:

Lower jaw left and right side posterior teeth:

Here are the upper jaw A1 teeth left and right side:

Continued in the next reply:

Marco Sr.

Edited April 28, 2016 by MarcoSr

[MarcoSr]

Here are the lower jaw a1 teeth left and right side:

Here are the upper jaw intermediate teeth left and right side:

Here is the upper jaw A2 tooth next to the intermediate tooth left and right side. Note how much smaller the intermediate tooth is:

Continued in the next reply:

Marco Sr.

Edited January 5, 2016 by MarcoSr

[MarcoSr]

Here are some upper jaw lateral teeth left and right side:

Here are some lower jaw lateral teeth left and right side:

I can only see 3 upper rows of teeth. The other rows may have embedded in the jaw during the cleaning and drying of the jaw.

I can see 6 rows of lower teeth:

The upper jaw has 13 tooth files left and 13 tooth files right of the symphysis

The lower jaw has 13 tooth files left and 13 tooth files right of the symphysis

What makes individual tooth identification even more difficult is that there is a species variation which can make another Isurus oxyrinchus jaw and teeth slightly different because of shark age, gender, locality etc. To get a complete feel for Isurus oxyrinchus jaws and teeth you would really need to look at a lot of different jaws from different localities.

Marco Sr.

Edited January 5, 2016 by MarcoSr

[isurus90064]

Excellent post and photos! Thanks.

If you don't mind I'll post a link to this thread from my thread to compare and contrast.

[MarcoSr]

Excellent post and photos! Thanks.

If you don't mind I'll post a link to this thread from my thread to compare and contrast.

Posting a link would be great.

Marco Sr.

[abcwixson]

Looking at that jaw and tooth differences within really does make one question the multiple species of extinct Isurus that are named seeing as just by looking i see teeth that strikingly resemble those identified as desori as well as planus and retroflexus for that matter

Edited January 8, 2016 by abcwixson

[ynot]

Hey Marko,

Another wonderful set!!

Tony

PS How many of these extant jaw sets have You posted?

[MarcoSr]

Looking at that jaw and tooth differences within really does make one question the multiple species of extinct Isurus that are named seeing as just by looking i see teeth that strikingly resemble those identified as desori as well as planus and retroflexus for that matter

What you are seeing is not unusual. There can be a great deal of similarity among some of the teeth positions from different species of shark. The teeth bear the traits and features of common ancestors in a lot of instances or convergent evolution where they are eating the same prey. That is why it can be so difficult to id a single fossil shark tooth at times. That is also why a good shark researcher won't name a new species on just a few shark teeth unless they are extremely unique but should have enough teeth to reasonably see a unique dentition in the teeth. Also seeing a lot of modern shark dentitions helps researchers to better understand fossil shark teeth and dentitions.

Marco Sr.

[MarcoSr]

Hey Marko,

Another wonderful set!!

Tony

PS How many of these extant jaw sets have You posted?

Tony

Five so far. I currently have another twenty species or so of shark jaws to take pictures of and post. I also plan on purchasing a good number more when I see good specimens and prices. I'm also starting to purchase some ray jaws. Time and money are my major constraints to getting more jaws bought and posted.

Marco Sr.