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Searcher78

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Since I’m in lockdown, I’m going through old teeth. One small tooth in my Flag Pond, MD box had me stumped. I’m now leaning toward a small Galeocerno contortus. It is all black and hard to get a good picture.

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It looks like it. There should be serrations on the distal shoulder I believe. Tooth so black I can’t tell

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A head-on photo would help, but from what I can see that looks correct as well.

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11 hours ago, Searcher78 said:

It is all black and hard to get a good picture.

Here's a tip for black teeth photography--don't photograph on a white background. most of the fossil shark teeth (and other fossils for that matter) are various shades of gray to black here in Florida as well. Cameras try to adjust to get an even exposure when looking at the sum of the entire area seen by the lens. The very high contrast of the bright white forces the camera's exposure system to under expose the black tooth losing much of the detail. I picked up some gray "construction paper" (basically thicker card stock) from one of the art and hobby stores (they use it for scrapbooking and the like). You can also probably find some wherever they sell school supplies for younger kids.

 

By using a medium to darker gray background the camera can brighten the overall image resulting in better detail and less shadows.

 

2019-10-23 19-47-03.jpg

 

Cheers.

 

-Ken

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2 minutes ago, digit said:

 

By using a medium to darker gray background the camera can brighten the overall image resulting in better detail and less shadows.

Great tip! I always shoot teeth on a white background.

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That's the natural inclination to provide a featureless background. Many scientific papers (digitally) cut out photographed specimens and place them on a white background in figures. Best to do that in post-editing and not actually while shooting dark subjects. Using a neutral (grayscale) background is important in that it helps the camera find a proper color balance. If the lighting imparts a cast (cooler blue or warmer red tones) photo editing software can restore a proper color balance using the gray of the background as a neutral color reference. I use gray card stock that has a lot of texture (fibers) in it as it helps in focusing. If I were shooting for a scientific paper where I wanted to digitally "subtract" the background leaving only the photographed item, I'd likely use a smoother gray background.

 

BTW: The tooth in the original posting does resemble a Galeocerdo contortus but at first the lack of detail made it look like a symphyseal Carcharius taurus which are very narrow teeth with the curve perpendicular to the tiger sharks. The lack of detail (shadowed) in the middle image of three above is what makes it resemble this symphyseal tooth. I think the detail of the root in the first image makes me lean toward the Galeocerdo.

 

 

Cheers.

 

-Ken

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8 hours ago, digit said:

That's the natural inclination to provide a featureless background. Many scientific papers (digitally) cut out photographed specimens and place them on a white background in figures. Best to do that in post-editing and not actually while shooting dark subjects. Using a neutral (grayscale) background is important in that it helps the camera find a proper color balance. If the lighting imparts a cast (cooler blue or warmer red tones) photo editing software can restore a proper color balance using the gray of the background as a neutral color reference. I use gray card stock that has a lot of texture (fibers) in it as it helps in focusing. If I were shooting for a scientific paper where I wanted to digitally "subtract" the background leaving only the photographed item, I'd likely use a smoother gray background.

 

BTW: The tooth in the original posting does resemble a Galeocerdo contortus but at first the lack of detail made it look like a symphyseal Carcharius taurus which are very narrow teeth with the curve perpendicular to the tiger sharks. The lack of detail (shadowed) in the middle image of three above is what makes it resemble this symphyseal tooth. I think the detail of the root in the first image makes me lean toward the Galeocerdo.

 

 

Cheers.

 

-Ken

Thanks for the tips. I will have to try it.

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Using a gray background. I also use a microscope which is not the easiest to get the best photos. Here are a few angles.

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Disregard what I was saying before about Carcharias taurus (Sand Tiger) symphyseals--I was thinking about Hemipristis serra symphyseals which are very narrow and resemble the first of four images above when viewed from the side. Your tooth does indeed seem to be Physogaleus contortus. How big is it that you have to photograph it with a scope?

 

Here's an interesting reference showing both Physogaleus teeth and the Hemipristis of which I speak. You'll see the upper and lower symphyseals for this species (11&12 and 15&16) in the figure do resemble your tooth (29&30) when viewed from the side.

 

https://www.researchgate.net/figure/Carcharhiniformes-I-Hemipristis-Galeocerdo-and-Physogaleus-from-the-Chucunaque_fig12_316052378

 

Carcharhiniformes-I-Hemipristis-Galeocerdo-and-Physogaleus-from-the-Chucunaque.png

 

Cheers.

 

-Ken

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40 minutes ago, digit said:

Disregard what I was saying before about Carcharias taurus (Sand Tiger) symphyseals--I was thinking about Hemipristis serra symphyseals which are very narrow and resemble the first of four images above when viewed from the side. Your tooth does indeed seem to be Physogaleus contortus. How big is it that you have to photograph it with a scope?

 

Here's an interesting reference showing both Physogaleus teeth and the Hemipristis of which I speak. You'll see the upper and lower symphyseals for this species (11&12 and 15&16) in the figure do resemble your tooth (29&30) when viewed from the side.

 

https://www.researchgate.net/figure/Carcharhiniformes-I-Hemipristis-Galeocerdo-and-Physogaleus-from-the-Chucunaque_fig12_316052378

 

Carcharhiniformes-I-Hemipristis-Galeocerdo-and-Physogaleus-from-the-Chucunaque.png

 

Cheers.

 

-Ken

It was small (5 mm) like the sharp nose shark teeth I found.

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If it's the size of the Rhizoprionodon teeth then it is from a really small Physogaleus. Nice find. That's the size of my largest Cookiecutter Shark (Isistius triangulus) teeth. :)

 

 

Cheers.

 

-Ken

 

 

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