Extant Sphyrna mokarran (Great Hammerhead Shark) jaw

[MarcoSr]

Here is a Sphyrna mokarran (Great Hammerhead Shark) jaw that I bought years ago in Florida. The jaw is 13.4” wide and 11” 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.

Functional Hammerhead teeth tend to be damaged because of what they feed on. The below picture shows a ray barb embedded in this jaw.

The lower jaw teeth files just above the ray barb are crossed probably as a result of the jaw damage caused by the barb.

Sphyrna mokarran teeth are heavily serrated which helps id this species from other hammerheads whose teeth are smooth edged or lightly serrated.

There is extreme variation in the symphyseal teeth of this jaw.

The upper jaw has two rows of symphyseal teeth:

Continued in the next reply:

Marco Sr.

[MarcoSr]

The lower jaw has an obvious pathology in the symphyseal teeth. It looks like two rows of pathological alternate teeth (blue) with a single row of symphyseal teeth (red). Usually Sphyrna mokarran have only a medial tooth in the lower symphysis or sometimes two teeth. Three teeth like those shown below are really unusual.

The pathological alternate teeth:

The single symphyseal tooth file:

According to Compagno 1988 anteriors, laterals and posteriors can be delimited regionally in each jaw half but grade into one another. So I’m not exactly sure where they begin and end.

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

Continued in the next reply:

Marco Sr.

Edited April 23, 2016 by MarcoSr

[MarcoSr]

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

Here are the lower jaw a1 and a2 teeth left and right side:

Continued in the next reply:

Marco Sr.

Edited April 23, 2016 by MarcoSr

[MarcoSr]

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

Continued in the next reply:

Marco Sr.

Edited April 23, 2016 by MarcoSr

[MarcoSr]

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

Continued in the next reply:

Marco Sr.

Edited April 23, 2016 by MarcoSr

[MarcoSr]

Here are some lower jaw anterolateral teeth right side (Continued):

Here are pictures of the posterior portion of the upper jaw left and right side. I’m not really sure where the posterior teeth begin.

Continued in the next reply:

Marco Sr.

Edited April 23, 2016 by MarcoSr

[MarcoSr]

Here are pictures of the posterior portion of the lower jaw left and right side. I’m not really sure where the posterior teeth begin. These may all be anterolaterals:

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

I can see at 6 rows of upper teeth:

I can see 7 rows of lower teeth:

The upper jaw has 18 tooth files left and 17 tooth files right of the symphyseal teeth.

The lower jaw has 16 tooth files left and 16 tooth files right of the symphyseal teeth.

According to Bass 1975 there is a slight sexual dimorphism in Sphyrna mokarran where teeth of adult males are slightly thinner and more erect than those of females but these differences are not marked. To get a complete feel for Sphyrna mokarran jaws and teeth you would really need to look at a lot of different jaws from different localities.

Marco Sr.

Edited April 23, 2016 by MarcoSr

[Coco]

Hi,

Cool to see the pathological teeth and the ray barb !

Coco

[MarcoSr]

Hi,

Cool to see the pathological teeth and the ray barb !

Coco

Coco

I have had this jaw for years and didn't notice the barb until I started taking the pictures of the jaw. I've heard of ray barbs in shark jaws before but this is the first that I've seen personally in a jaw.

Marco Sr.

[old bones]

Marco Sr.,

Very cool! I agree with Coco, it is very interesting to see the ray barb and resulting pathology. That was a bonus on this jaw.

Julianna

[jcbshark]

That is a great specimen with the ray barb in there Marco I've used rays for bait before, the sharks sure do like em!

[MarcoSr]

Marco Sr.,

Very cool! I agree with Coco, it is very interesting to see the ray barb and resulting pathology. That was a bonus on this jaw.

Julianna

Julianna

I probably wouldn't have noticed the ray barb if it wasn't for the tooth pathology. After I saw the tooth pathology under my microscope when taking the pictures, I took out my 10K loupe to look closer at the jaw in that area and noticed the barb. I can't believe that I never noticed it before.

Marco Sr.

[MarcoSr]

That is a great specimen with the ray barb in there Marco I've used rays for bait before, the sharks sure do like em!

Jeff

Are you still catching sharks? I'm just curious what species you might be seeing. Some shark jaws are really tough to id if you don't see the shark that they came from, since extant shark species are named based on their physical characteristics rather than solely on teeth like almost all fossil species. Have you caught a shark or seen one with a ray barb in the jaw before?

Marco Sr,

[jcbshark]

No Marco, I haven't been shark fishing in a few years. I used to do it a good bit but only have a small Jon boat now and it's much easier to do from a boat than off shore. I released most every one we caught with the exception of one small blacktip I wanted to try to eat but didn't get close enough to examine the mouths for barbs in most of them lol. Hammerheads in particular are found of rays as I'm sure you know . Just south of me in Boca Grande there are plenty of stories of old Hitler. Supposedly a monster that patrols there to eat hooked Tarpon. I believe there are a few more than just one there. I hooked a big one about a dozen years ago that we had to chase with the boat for an hour and a half and never even turned his head before we were cut off by a tug coming in. Having never seen him I'm not sure how big but I know we would whip 150 pounders in about ten minutes with the same gear. One of the few places around here I'm not crazy about getting in the water : )

[MarcoSr]

No Marco, I haven't been shark fishing in a few years. I used to do it a good bit but only have a small Jon boat now and it's much easier to do from a boat than off shore. I released most every one we caught with the exception of one small blacktip I wanted to try to eat but didn't get close enough to examine the mouths for barbs in most of them lol. Hammerheads in particular are found of rays as I'm sure you know . Just south of me in Boca Grande there are plenty of stories of old Hitler. Supposedly a monster that patrols there to eat hooked Tarpon. I believe there are a few more than just one there. I hooked a big one about a dozen years ago that we had to chase with the boat for an hour and a half and never even turned his head before we were cut off by a tug coming in. Having never seen him I'm not sure how big but I know we would whip 150 pounders in about ten minutes with the same gear. One of the few places around here I'm not crazy about getting in the water : )

Jeff

I ran into a hammerhead one time diving with about 10 ft max visibility. I saw only part of the head and then part of the caudal fin. If it was a single shark and not two it was pretty big. I don't think I'd want to run into old Hitler diving.

Hammerheads probably evolved their head structure to sense rays buried in the sand. So they have been probably eating them for a long while.

If you rub a shark under its lower jaw it will open its mouth and almost smile at you so you can see inside the mouth and see the teeth. An old fisherman missing at least 3 fingers told me this. lol. Yeah you don't want to be near their mouth if they are still alive and you are catching and releasing them. You even have to be careful with a dead one.

Marco Sr.

[Coco]

Hi,

You even have to be careful with a dead one.

Marco Sr.

Right ! By preparing jaws of sharks I injured myself several times! Teeth are very sharp, especially on Galeorhinus galeus...

Coco

[MarcoSr]

Hi,

Right ! By preparing jaws of sharks I injured myself several times! Teeth are very sharp, especially on Galeorhinus galeus...

Coco

Coco

I have gotten small cuts positioning the jaws taking pictures of them. The worse cuts were from the C. carcharias jaw which had very sharp teeth. I still have a small scar on my thumb from teeth in that jaw.

Marco Sr.