Micro shark(?) teeth, Shark tooth hill.

[ynot]

Hey-hi Folks,

Here are a couple of micro teeth from the round mountain silt

They do not match any that I have seen before and hope that Somebody will know which spieces they belong to.

Thanks for all help.

scale (white marks) is a millimeter ruler...

Tony

PS I am trying a new method of showing these light colored teeth and it needs some tweaking. Please bear with Me.

[MarcoSr]

Tony

First tooth looks like a Cetorhinus parvus (now Keasius parvus). The second specimen looks like a damaged ray dermal denticle.

Marco Sr.

Edited November 27, 2015 by MarcoSr

[ynot]

Tony

First tooth looks like a Cetorhinus parvus (now Keasius parvus). The second specimen looks like a damaged ray dermal denticle.

Marco Sr.

Thank You Marko!

I thought that the crown looked like a Cetorhinus sp. but got confused because of the "u" shape to the root. Was completely lost on the other one.

Tony

[MarcoSr]

Thank You Marko!

I thought that the crown looked like a Cetorhinus sp. but got confused because of the "u" shape to the root. Was completely lost on the other one.

Tony

Tony

Keasius (Cetorhinus) parvus is my first choice. However it could be just a positional variant of Cetorhinus huddlestoni or even an Alopias sp. According to Cappetta an origin from a primitive stock close to Alopias seems highly probably for Cetorhinus judging by tooth morphology of early Miocene species. So if your tooth is Cetorhinus (Keasius) similarity to Alopias wouldn’t be unexpected.

Marco Sr.

[ynot]

Tony

Keasius (Cetorhinus) parvus is my first choice. However it could be just a positional variant of Cetorhinus huddlestoni or even an Alopias sp. According to Cappetta an origin from a primitive stock close to Alopias seems highly probably for Cetorhinus judging by tooth morphology of early Miocene species. So if your tooth is Cetorhinus (Keasius) similarity to Alopias wouldn’t be unexpected.

Marco Sr.

Thanks again for the wonderful help that You have provided!!

What is the possibility of it being an Alopias sp. rather than a Cetorhinus sp.? How can I determine which is the greater probability?

Tony

[MarcoSr]

Thanks again for the wonderful help that You have provided!!

What is the possibility of it being an Alopias sp. rather than a Cetorhinus sp.? How can I determine which is the greater probability?

Tony

Tony

It is extremely difficult to id some teeth from pictures only. You just can’t see some features clearly enough. I have a good number of teeth in my collection that I can’t positively id and I can look at them from all angles under a microscope. When I look at a tooth for an id, I first get an overall impression of what I think the possibilities are. I’ve given you my opinion on that for this tooth. There may be good possibilities that I might not consider because I just don’t see those species or don’t see a lot of them. I consider species that could be found during the time period of the formation/formations and could be from that location. The fact that a species is not reported from a formation does not rule it out. I have dozens of species that I found in the MD/VA area that have not been reported from the formations that I found them in. Then I look closely at individual features that confirm or eliminate the possibilities. Sometimes the features don’t lead to a positive id. The specimen could even be something new. Things like extent of cutting edges or whether a surface is concave or flat or convex are difficult if not impossible to see in most pictures. If your tooth had a nutrient grove for instance, even extremely faint, I would rule out Cetorhinus and I would switch to an Alopias. But a lack of a visible nutrient grove wouldn’t rule out Alopias. I’m not seeing features that give me a 100% confidence in an id. Maybe someone like Eric or Jess will see a feature that makes them feel very confident in an exact id. I've taken teeth/sent pictures to different shark tooth experts and gotten totally different opinions.

Marco Sr.

[ynot]

Thank You. I appreciate You taking the time to answer My questions. It does help Me to make better choices when trying to determine the ID of My shark teeth.

Tony

[MarcoSr]

Thank You. I appreciate You taking the time to answer My questions. It does help Me to make better choices when trying to determine the ID of My shark teeth.

Tony

Tony

You might take a look at the below PDF "A Key to the Common Genera of Neogene Shark Teeth" by Robert W. Purdy, if you haven't seen it before. It will give you a basic idea of the tooth features that you should be looking at to help id your shark teeth.

http://paleobiology.si.edu/pdfs/sharktoothKey.pdf

Marco Sr.

[ynot]

Thank You for this paper, I think it will help tremendously on My future attempts to identify the shark teeth I find.

Thanks again for all of Your help and for putting up with all My questions!

Tony