Extant Carcharhinus falciformis (Silky Shark) jaw

[MarcoSr]

Here is a Carcharhinus falciformis (Silky Shark) jaw that I recently acquired. The jaw is 10.5” wide and 6” 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 next reply.

Edited February 21, 2016 by MarcoSr

[MarcoSr]

There are posts where unusual looking teeth get posted and identified as symphyseal teeth. Carcharhinus have both upper jaw and lower jaw symphyseal teeth. There is extreme variation in these symphyseal teeth and they are extremely difficult if not impossible to identify to a species.

Upper jaw symphysis with two files of symphyseal teeth (blue) and one file of medial teeth (red):

Lower jaw symphysis with two files of alternate teeth:

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 next reply

Marco Sr.

Edited February 21, 2016 by MarcoSr

[MarcoSr]

Lower jaw left and right side posterior teeth:

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

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

Here are some upper jaw lateral teeth left side:

Continued in next reply

Marco Sr.

Edited February 21, 2016 by MarcoSr

[MarcoSr]

Here are some upper jaw lateral teeth right side:

Here are some 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 at least 5 upper rows of teeth:

Continued in next reply

Marco Sr.

Edited February 21, 2016 by MarcoSr

[MarcoSr]

I can see 6 rows of lower teeth:

If you look closely at the tooth in the last row, you can see that it hasn't fully formed yet. (The root hasn't formed yet.)

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

The lower jaw has 15 tooth files left and 15 tooth files right of the alternate teeth.

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

Marco Sr.

Edited February 21, 2016 by MarcoSr

[jcbshark]

Thanks for taking the time to post these Marco, it certainly helps to see why certain tooth positions even for common species can be hard to pin down with so many variables I really feel your pain when trying to ID micros when even macro material can be difficult

[cowsharks]

Marco, as you are well aware, the task in front of you is quite daunting but I applaud (and thank you in advance) for any such work. Elasmo (Jim B. and Bill H.) made a good stab at this but sort of stopped beyond posting the jaws and a few images of the teeth. Carcharhinus for sure is really difficult and any headway that you might make will be very much appreciated.

Daryl.

[MarcoSr]

Thanks for taking the time to post these Marco, it certainly helps to see why certain tooth positions even for common species can be hard to pin down with so many variables I really feel your pain when trying to ID micros when even macro material can be difficult

Jeff

The more jaws that I see, the more tooth variation I see for each species. Also I see lots of teeth from different species that look very similar. The posteriors and symphyseal teeth are especially variant.

Marco Sr.

[MarcoSr]

Marco, as you are well aware, the task in front of you is quite daunting but I applaud (and thank you in advance) for any such work. Elasmo (Jim B. and Bill H.) made a good stab at this but sort of stopped beyond posting the jaws and a few images of the teeth. Carcharhinus for sure is really difficult and any headway that you might make will be very much appreciated.

Daryl.

Daryl

I wish they had made their extant jaw pictures larger on elasmo and taken more pictures of individual teeth. It is really difficult to see a lot of detail. I really like the way J-elasmo pulled the teeth out of the extant jaws and showed the extant dentitions. I'm learning a lot looking at these extant jaws especially about symphyseal and posterior teeth.

Marco Sr.

[siteseer]

Marco Sr.,

Great photos. I'm not sure if I've ever seen close-ups of the teeth of this shark before. In general it's interesting that this one can have compound serrations (serrations on serrations) as in the modern bull shark and modern tiger shark. The lowers, as a rule, appear to be weakly-finely serrated.

Yeah, symphyseal teeth would not be good characters for separating species since they are reduced (they have lost features of an ancestor as they became smaller and more simple in form - therefore less able to perform the function they once did effectively) and in the process of disappearing genetically as the dentition becomes more efficient (the same job being effectively done with fewer teeth which saves energy).

Jess

Jeff

The more jaws that I see, the more tooth variation I see for each species. Also I see lots of teeth from different species that look very similar. The posteriors and symphyseal teeth are especially variant.

Marco Sr.

[MarcoSr]

Marco Sr.,

Great photos. I'm not sure if I've ever seen close-ups of the teeth of this shark before. In general it's interesting that this one can have compound serrations (serrations on serrations) as in the modern bull shark and modern tiger shark. The lowers, as a rule, appear to be weakly-finely serrated.

Yeah, symphyseal teeth would not be good characters for separating species since they are reduced (they have lost features of an ancestor as they became smaller and more simple in form - therefore less able to perform the function they once did effectively) and in the process of disappearing genetically as the dentition becomes more efficient (the same job being effectively done with fewer teeth which saves energy).

Jess

Jess

I always try to verify the id I was given for a jaw when I'm taking pictures of it. I see a good number of misidentified jaws especially from Vietnam and folks only selling a jaw or two. Sometimes I even see a misidentified jaw from the big jaw sellers. My wife purchased this jaw for me as a Christmas present years ago. I've looked at a lot of other species of Carcharhinus but haven't found anything else that looked like it might be a better match. So it can be difficult to even id a Carcharhinus jaw with 100% certainty with the lack of good reference material.

Marco Sr.

Edited February 21, 2016 by MarcoSr

[Auspex]

...The more jaws that I see, the more tooth variation I see for each species. Also I see lots of teeth from different species that look very similar...

It never is so cut-and-dried as we'd like, is it? The more you look, the more elusive simple certainty becomes.

Still, try we must! It's in our DNA to catalog and make manageable the wonders around us.

[MarcoSr]

It never is so cut-and-dried as we'd like, is it? The more you look, the more elusive simple certainty becomes.

Still, try we must! It's in our DNA to catalog and make manageable the wonders around us.

Chas

I love to find shark and ray teeth but really don't like to id them. The more I learn about them, the more I realize how little I really know about them.

Marco Sr.

[Auspex]

Chas

I love to find shark and ray teeth but really don't like to id them. The more I learn about them, the more I realize how little I really know about them.

Marco Sr.

"There has been an alarming increase in the number of things I know nothing about."

-Ashleigh Ellwood Brilliant