Shark tooth ID

[BayFinds]

I FINALLY found some shark teeth today at Chippokes Plantation State Park on the James River in VA. Would you all please help me ID these 3? The other 2 I found were definitely tiger shark. 

[ynot]

Lemon, lemon, white (mako).

[BayFinds]

3 minutes ago, ynot said:

Lemon, lemon, white (mako).

Thank you so much for the ID’s, @ynot!

[Macrophyseter]

1. Negaprion sp.

2. Negaprion?

3. Cosmopolitodus hastalis or Carcharodon plicatilis (posterolateral)

 

First is lemon shark, second might be lemon, but the root lobes seem to be broken so we can't be too sure. Third is a posterolateral ancestral great white.

[BayFinds]

1 hour ago, Macrophyseter said:

1. Negaprion sp.

2. Negaprion?

3. Cosmopolitodus hastalis or Carcharodon plicatilis (posterolateral)

 

First is lemon shark, second might be lemon, but the root lobes seem to be broken so we can't be too sure. Third is a posterolateral ancestral great white.

Thanks, @Macrophyseter!

[BayFinds]

Here’s a close up of the smallest tooth, if it helps. 

[Max-fossils]

16 hours ago, Macrophyseter said:

Carcharodon plicatilis

Is that the same (alternative/old) name for C. hastalis? Or is it a different species?

[Macrophyseter]

6 hours ago, Max-fossils said:

Is that the same (alternative/old) name for C. hastalis? Or is it a different species?

It's another possible scientific name for the former 'Isurus xiphodon'. The taxon was coined by Cione et al (2012), I think in order to allow both Cosmopolitodus and Carcharodon  to remain distinct without causing a paraphyly after noting that some broad-form hastalis variations are distinct enough from the general narrow-form variations and at the same time a putative sister specis of C. carcharias. I can PM you the paper if you'd like.

 

However, like all scientific name proposals during a dispute, especially this one, it should always be remembered that there is no "official" or "correct" one. It all depends on the perspective on the issue. If you're a lumper, you might disagree with that taxon. As for me, I have always supported placing the "mako"-white shark divide at the former I. xiphodon.

[Max-fossils]

13 hours ago, Macrophyseter said:

It's another possible scientific name for the former 'Isurus xiphodon'. The taxon was coined by Cione et al (2012), I think in order to allow both Cosmopolitodus and Carcharodon  to remain distinct without causing a paraphyly after noting that some broad-form hastalis variations are distinct enough from the general narrow-form variations and at the same time a putative sister specis of C. carcharias. I can PM you the paper if you'd like.

 

However, like all scientific name proposals during a dispute, especially this one, it should always be remembered that there is no "official" or "correct" one. It all depends on the perspective on the issue. If you're a lumper, you might disagree with that taxon. As for me, I have always supported placing the "mako"-white shark divide at the former I. xiphodon.

Ok, thanks for the explanation!