Extant Hemipristis elongatus (Snaggletooth Shark) jaw

[MarcoSr]

Here is a Hemipristis elongatus (Snaggletooth Shark) jaw that I recently acquired. The jaw is 5.25” wide and 3.25” 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.

Hemipristis elongatus jaws must be weak at the symphysis because a lot of the jaws for sale have distortion to both the upper and lower symphysis.

The identification and number of tooth files discussed below are based upon Compagno 1988.

Hemipristis elongatus have both upper jaw and lower jaw symphyseal and medial teeth files.

Upper jaw symphysis:

Upper jaw symphysis showing two files of symphyseal teeth (blue) and two files of medial teeth (red):

Lower jaw symphysis:

Lower jaw symphysis showing two files of symphyseal teeth (blue) and two files of medial teeth (red). Note a partial separation of the lower jaw at the symphysis moved the teeth relative to each other and made it very difficult to show them:

Hemipristis elongatus jaws have one upper posterior tooth file on either side. This jaw did not have a posterior tooth file on the upper right side.

Upper jaw left side posterior teeth:

Hemipristis elongatus jaws have two lower posterior tooth files on either side.

Lower jaw left and right side posterior teeth:

Hemipristis elongatus jaws have two upper anterior tooth files on either side.

Here are the upper jaw A1 and A2 teeth left and right side:

Continued in the next reply:

Marco Sr.

[MarcoSr]

Hemipristis elongatus jaws have five lower anterior tooth files on either side.

Here are the lower jaw a1 through a5 teeth left and right side:

Hemipristis elongatus jaws have nine upper lateral tooth files on either side.

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

Continued in the next reply:

Marco Sr.

Edited February 18, 2016 by MarcoSr

[MarcoSr]

Hemipristis elongatus jaws have seven lower lateral tooth files on either side.

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

Here are pictures that show the number of rows of teeth in this jaw:

I can see 3 rows of upper teeth:

I can see 4 rows of lower teeth:

The upper jaw has 12 tooth files left and 11 tooth files right of the symphyseal and medial tooth files.

The lower jaw has 14 tooth files left and 14 tooth files right of the symphyseal and medial tooth files

To get a complete feel for Hemipristis elongatus jaws and teeth you would really need to look at a lot of different jaws from different localities. According to Compagno 1988 Hemipristis elongatus teeth exhibit ontogenetic heterodonty between the teeth of the young versus those of adults and subadults.

Marco Sr.

Edited February 18, 2016 by MarcoSr

[Raggedy Man]

I always look forward to these posts from you. Seeing the teeth on these jaws and then being able to place the teeth I have into their correct context offers a completely different view of my specimens. Thank you.

By the way, I'm just curious, but many extant shark jaws do you in your collection?

Best regards,

Paul

[MarcoSr]

I always look forward to these posts from you. Seeing the teeth on these jaws and then being able to place the teeth I have into their correct context offers a completely different view of my specimens. Thank you.

By the way, I'm just curious, but many extant shark jaws do you in your collection?

Best regards,

Paul

Paul

Right now I have 51 jaws from 32 shark species. I'm still trying to purchase a few more shark species that I'm having trouble finding. I also plan on purchasing a number of ray jaws. It has been very difficult to confirm the ids of the shark species of jaws that I already have especially among the Carcharhinus species. I must be really dense because the more Carcharhinus jaws I see and the more publications I read the more confused I get.

Marco Sr.

[ynot]

the more publications I read the more confused I get.

Marco Sr.

I feel much the same!!!

As always- EXCELLENT presentation Sir, thank You!!!

Tony

[Ludwigia]

Even though this is not my main field of interest, I certainly do appreciate your knowledgeable posts! Thank you very much!

[MarcoSr]

I feel much the same!!!

As always- EXCELLENT presentation Sir, thank You!!!

Tony

Tony

I'm going to try to concentrate on the publications of just a couple of shark researchers and on recent publications. Looking at everything I could find on the web was just too confusing and too contradictory. I just bought two recent books (2013, 2015) (in the mail) on the sharks of the world by Compagno and Ebert. Compagno has been a renowned shark researcher for many years (I have shark species publications of his going back to 1984) and Ebert seems to be publishing a lot recently on sharks. The books will be probably 99% on shark species physical characteristics, range, habitat etc. But hopefully there will at least be a few useful diagnostic traits that deal with teeth and dentitions more than just a sentence or two of very vague tooth feature descriptions and more than just a not very detailed line drawing of just a single upper and lower tooth. The much older publications had plates with entire dentitions. However, the pictures weren't the best to begin with to see the detailed tooth features and the electronic copies of these publications on the web are mostly xeroxed copies which have lost most if not all of the fine tooth detail.

Marco Sr.

[MarcoSr]

Even though this is not my main field of interest, I certainly do appreciate your knowledgeable posts! Thank you very much!

Thank you. I've spent many years looking at individual fossil shark teeth. Seeing extant shark teeth in extant shark jaws really helps me put fossil shark teeth in perspective. However fossil shark species are described almost entirely based upon their tooth features. Extant shark species are described almost entirely based upon their physical characteristics with tooth and jaw features not really being much of a factor. If fossil shark teeth were described only to the extent of most extant shark teeth not many folks would be able to id much in their fossil shark teeth collections.

Marco Sr.

[old bones]

These are great, Marco Sr.. This particular set of teeth within their proper place in the jaw is especially useful to me, as I have many from the extinct species that I've never been able to 'see where they go' in the jaw.

I love that you are doing this... I will never be very good at IDs of shark teeth, but I will get further with your work.

Julianna

[MarcoSr]

These are great, Marco Sr.. This particular set of teeth within their proper place in the jaw is especially useful to me, as I have many from the extinct species that I've never been able to 'see where they go' in the jaw.

I love that you are doing this... I will never be very good at IDs of shark teeth, but I will get further with your work.

Julianna

Julianna

Thank you. The next jaw that I'll post I think will be the most interesting so far.

Marco Sr.