2" plus Lee Creek Mako Tooth

[sixgill pete]

Ok, I found this tooth in the Lee Creek mine in 2007. Over the years I have gone back and forth as to the species of mako; hastalis, oxyrhincus, desori. 

 

So now I am asking for your opinion.  I don't think I have posted this tooth on here before so I hope you all enjoy, I think it's a beauty.

 

I would like to post this one on the collections area, but I want to be much more sure about a positive species before I do so. It is just ovewr 2" ( about 2 1/8) and has great color.

[sagacious]

To my mind, Carcharodon hastalis  seems like a less likely fit. Compared to what I'm used to, the root seems too compact, the lobes seem too gracile, and the lingual prominence seems far to shallow apicobasally for a C hastalis lower anterior tooth.

 

Likewise, the crown seems too slender mesiodistally as compared to the C hastalis  lower anterior teeth in my collection. The slightly increased convexity at the distal top 1/3 of the crown also reinforces my opinion that this tooth is Isurus oxyrinchus/desori and not Carcharodon.

 

Definitely a beautiful tooth.

[caldigger]

I was kind of thinking along the same lines.  The root doesn't seem right for hastalis,  too tight and perpendicular to the crown.  Although, I am not familiar with the other species listed, I am feeling a "no" toward C. hastalis.

[sixgill pete]

15 minutes ago, sagacious said:

To my mind, Carcharodon hastalis  seems like a less likely fit. Compared to what I'm used to, the root seems too compact, the lobes seem too gracile, and the lingual prominence seems far to shallow apicobasally for a C hastalis lower anterior tooth.

 

Likewise, the crown seems too slender mesiodistally as compared to the C hastalis  lower anterior teeth in my collection. The slightly increased convexity at the distal top 1/3 of the crown also reinforces my opinion that this tooth is Isurus oxyrinchus/desori and not Carcharodon.

 

Definitely a beautiful tooth.

 

7 minutes ago, caldigger said:

I was kind of thinking along the same lines.  The root doesn't seem right for hastalis,  too tight and perpendicular to the crown.  Although, I am not familiar with the other species listed, I am feeling a "no" toward C. hastalis.

 

Thanks to both of you. Your thoughts on this have helped me confirm my own thoughts. The last label I put on this tooth was Isurus desori. I now believe that is the correct ID. Thanks again.

[Past Hunter]

I have a few that look similar to that one. I always thought they were desori.

They are the three on the bottom right. I will be interested to know what they are also.

[sagacious]

56 minutes ago, Past Hunter said:

I have a few that look similar to that one. I always thought they were desori.

They are the three on the bottom right. I will be interested to know what they are also.

 

To my eye, the fifth tooth and the last six teeth in the fifth row are Isurus oxyrinchus/desori, as well as number four in the fourth row. Very nice collection.

[njfossilhunter]

Past Hunter.....That a very nice collection of mako's you have.....

[siteseer]

On September 25, 2016 at 7:02 PM, sagacious said:

To my mind, Carcharodon hastalis  seems like a less likely fit. Compared to what I'm used to, the root seems too compact, the lobes seem too gracile, and the lingual prominence seems far to shallow apicobasally for a C hastalis lower anterior tooth.

 

Likewise, the crown seems too slender mesiodistally as compared to the C hastalis  lower anterior teeth in my collection. The slightly increased convexity at the distal top 1/3 of the crown also reinforces my opinion that this tooth is Isurus oxyrinchus/desori and not Carcharodon.

 

Definitely a beautiful tooth.

 

 

I have been meaning to get to this thread for a few weeks but lost track of where it was until now (thought it was titled something else).  I looked at Isurus oxyrinchus/desori and Carcharodon hastalis teeth I have from the Sharktooth Hill Bonebed (largest sample I have of C. hastalis and where hastalis has a greater size range) and Pyramid Hill Sand (where I. oxyrinchus is present but not C. hastalis).  I agree with you as well.  C. hastalis anteriors are flatter - less of a labiolingual recurve and not much of a lingual protuberance when compared to I. oxyrinchus.

 

I think the tooth could be a first lower anterior though the angle formed by the lobes looks like it should be more acute than that for that position - maybe a second anterior.

 

 

[siteseer]

On September 25, 2016 at 7:10 PM, caldigger said:

I was kind of thinking along the same lines.  The root doesn't seem right for hastalis,  too tight and perpendicular to the crown.  Although, I am not familiar with the other species listed, I am feeling a "no" toward C. hastalis.

 

 

I. desori is kind of a "gray area species."  I have understood it to be the name for fossil I. oxyrinchus (modern short fin mako) older than the Pliocene but it seems to have been used less in the past 20-25 years.  Most pre-Pliocene teeth are smaller on average than what you tend to see from the Pliocene or modern form and that seemed like enough justification to separate the species but I have also seen teeth (rare though they may be) at least as large as any Pliocene-Recent teeth from Late Oligocene-Early Miocene sites.

 

I haven't noticed any tooth character to separate desori or oxyrinchus and would be interested in reading more comments about desori/oxyrinchus.  If the teeth do belong to one species, it is at least one of the oldest of all modern sharks.

 

This is a very interesting thread and I thought there would be more comments from the "shark people."

 

[siteseer]

Just as an added comment, that is certainly a large tooth for I. oxyrinchus.  It doesn't look like it's from the Yorktown Formation.  I'm thinking one of the Pleistocene formations (James City most likely?) rather than the Pungo River. 

[sagacious]

On ‎10‎/‎19‎/‎2016 at 1:07 PM, siteseer said:

 

 

I have been meaning to get to this thread for a few weeks but lost track of where it was until now (thought it was titled something else).  I looked at Isurus oxyrinchus/desori and Carcharodon hastalis teeth I have from the Sharktooth Hill Bonebed (largest sample I have of C. hastalis and where hastalis has a greater size range) and Pyramid Hill Sand (where I. oxyrinchus is present but not C. hastalis).  I agree with you as well.  C. hastalis anteriors are flatter - less of a labiolingual recurve and not much of a lingual protuberance when compared to I. oxyrinchus.

 

I think the tooth could be a first lower anterior though the angle formed by the lobes looks like it should be more acute than that for that position - maybe a second anterior.

 

 

I agree, the tooth appears to be a second lower anterior.

 

While the tooth looks to be mostly intact, with only minor abrasive wear, the tips of the root lobes (especially the mesial lobe) appear broken and have lost the distinctive slender tips characteristic of I. oxyrinchus anterior lower teeth. I think that aspect of root wear/damage has helped confuse the species identification. I suspect that if the root lobes were completely intact and undamaged, the species ID would likely be without doubt.

[sixgill pete]

Jess, thanks for your responses. I have often been puzzled about the desori / oxyrhinchus species. I have seen teeth assigned to one or the other based on age, but also teeth from older deposits using oxyrhinchus. Jams City Fm would a good candidate I agree. It did not come out of Yorktown sediments, that I can say for sure.

 

agacious, the root lobes are worn some and the one side broken slightly. That may have in fact been part of my flip flopping on the ID. Thanks.