Extant Hemitriakis japanica (Japanese Tope Shark) jaw

[MarcoSr]

Here is a Hemitriakis japanica (Japanese Tope Shark) jaw that I recently acquired. The jaw is 4” wide and 2.5” 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.

There are posts where unusual looking teeth get posted and identified as symphyseal teeth. Hemitriakis japanica (Japanese Tope Shark) has a single upper jaw file and a single lower jaw file of medial teeth..

Upper jaw symphysis:

Medial teeth in upper jaw symphysis (Medial teeth are small, often symmetrical but may be asymmetrical and occur at the juncture of the left and right jaws.):

Lower jaw symphysis:

Medial teeth in lower jaw symphysis:

Also extreme posterior teeth can widely vary and are extremely difficult if not impossible to identify to a species.

Upper jaw left and right side posterior teeth:

Continued in the next reply:

Marco Sr.

Edited February 4, 2016 by MarcoSr

[MarcoSr]

Lower jaw left and right side posterior teeth:

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

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

I can see at least 5 upper rows of teeth.

I can see 5 rows of lower teeth.

The upper jaw has 18 tooth files left and 18 tooth files right of the medial tooth.

The lower jaw has 17 tooth files left and 17 tooth 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 Hemitriakis japanica jaw and teeth slightly different because of shark age, gender, locality etc. To get a complete feel for Hemitriakis japanica jaws and teeth you would really need to look at a lot of different jaws from different localities. If you check out the Hemitriakis japanica dentition at the below website you can see some differences especially in the anterior teeth.

http://homepage2.nifty.com/megalodon/jawtriakidaeb.html

Marco Sr.

Edited January 5, 2016 by MarcoSr

[ynot]

I guess this one got missed by most of the others.

Maybe You should link all of the extant jaw threads.

They are very helpful in trying to make sense of shark tooth identifications.

Thanks for putting them together!

Tony

[MarcoSr]

I guess this one got missed by most of the others.

Maybe You should link all of the extant jaw threads.

They are very helpful in trying to make sense of shark tooth identifications.

Thanks for putting them together!

Tony

Tony

I plan on putting a post in "Member Collections" for "My Extant Shark & Ray Jaws" where I will link to all of these posts like I put in a post "Some of My Shark, Ray, Fish and Other Micros" which links to all of my micro posts.

Marco Sr.

Edited January 8, 2016 by MarcoSr

[Coco]

I have just thought of the same thing by reading the comment on Eptranchias perlo... I thought that you should make a post (which would be pinned) finding the links of all your comments on recent selachian jaws

Coco

[MarcoSr]

I have just thought of the same thing by reading the comment on Eptranchias perlo... I thought that you should make a post (which would be pinned) finding the links of all your comments on recent selachian jaws

Coco

Coco

Here is a link to my post that links all of my TFF extant jaw posts. I'll update this post with new links as I post new jaws.

http://www.thefossilforum.com/index.php?/topic/60461-my-extant-shark-jaw-collection/

Marco Sr.

[Coco]

Hi,

Coco