Extant Heptranchias perlo (Sharpnose Sevengill Cow Shark) jaw

[MarcoSr]

Here is a Heptranchias perlo (Sharpnose Sevengill Cow Shark) jaw that I recently acquired. The jaw is 5.75” wide and 3” inches high. Fossil teeth from this shark genus are very uncommon/rare worldwide. I can’t find anywhere in the literature whether this genus/species of Hexanchidae exhibits sexual dimorphism in its tooth forms.

Here is the overall jaw:

Note that the cartilage in this jaw is very thin compared to the jaws of other species.

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.

Heptranchias perlo have a lower jaw medial tooth in the lower jaw symphysis.

Lower jaw medial tooth:

The upper jaw does not have symphyseal teeth. Here is the upper jaw symphysis where you can see the A1 and A2 teeth.

Also extreme posterior teeth can widely vary and are extremely difficult if not impossible to identify to a species. Heptranchias perlo (Sharpnose Sevengill Cow Shark) have very non-descript commissural teeth.

Upper jaw left and right side commissural teeth:

Lower jaw left and right side commissural teeth:

Here are the upper jaw L3 teeth left and right side

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

Continued in the next reply:

Marco Sr.

Edited January 20, 2016 by MarcoSr

[MarcoSr]

The lower jaw has 5 anterolateral teeth left and 5 anterolateral teeth right of the medial tooth in addition to the non-descript commissural teeth.

Here are these lower jaw anterolateral teeth left and right side:

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

I can see at least 5 rows of upper teeth:

I can see at least 3 rows of lower teeth:

The upper jaw looks like it has 20 tooth files including 2 anterior, 8 lateral and 10 commissural files on the left side and 18 tooth files including 2 anterior, 8 lateral and 8 commissural files on the right side of the symphysis.

The lower jaw looks like it has 14 tooth files including 5 anterolateral files and 9 commissural files left and 14 tooth files including 5 anterolateral files and 9 commissural files right of the medial tooth.

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

Marco Sr.

Edited January 8, 2016 by MarcoSr

[Gizmo]

Fascinating, Thanks Marco!

[SailingAlongToo]

MarcoSr,

This specimen is awesome.

Thanks for sharing. Do you mind if I use a couple of photos on a handout the wife and I are putting together? Happy to include a credit and they would be black and white since it will get photocopied multiple times.

Thanks,

SA2

[ynot]

Wonderful, just wonderful!!

[Troodon]

Very nice, thanks

[MarcoSr]

MarcoSr,

This specimen is awesome.

Thanks for sharing. Do you mind if I use a couple of photos on a handout the wife and I are putting together? Happy to include a credit and they would be black and white since it will get photocopied multiple times.

Thanks,

SA2

Jack

No I don't mind. I hope they are helpful.

Marco Sr.

[MarcoSr]

Fascinating, Thanks Marco!

Wonderful, just wonderful!!

Very nice, thanks

Thank you.

Marco Sr.

[sixgill pete]

Wow! Very nice Marco. I really like this jaw.

[isurus90064]

Very nice indeed, thanks!

[MarcoSr]

Wow! Very nice Marco. I really like this jaw.

Very nice indeed, thanks!

Thank you. I have some really cool other shark jaws that I'll post after I get the time to take pictures.

Marco Sr.

[Coco]

Hi,

Marco, your job is fantastic ! I never seen on my H. perlo jaw the very little commissural teeth ! I just have a look on them with my binocular after read your post !

Coco

[MarcoSr]

Hi,

Marco, your job is fantastic ! I never seen on my H. perlo jaw the very little commissural teeth ! I just have a look on them with my binocular after read your post !

Coco

Coco

Those commissural teeth were very interesting to me. Even after seeing them, I don't know if I would recognize one if one was in matrix that I was searching.

Marco Sr.

[Shazuren]

Beautiful and incredible pics. Thank you for sharing.

[MarcoSr]

13 hours ago, Shazuren said:

Beautiful and incredible pics. Thank you for sharing.

 

Thank you.  I have many more species of shark and ray jaws but just haven't had the time to take pictures.

 

Marco Sr.