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Otodus, cretalamna?


will stevenson

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will stevenson

Guys I’m having trouble determining whether this. Is a cretalamna appendiculata lower or an otodus obliquus

4F5A4A3B-8FE1-49BD-A191-C6D134C29D1D.jpeg

18AA636B-A799-42B6-AEF3-91C7392EF6AD.jpeg

8FDE4DED-BA3F-4B7F-84BB-6AB605D8E6D0.jpeg

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Nice tooth. I think you might be splitting hairs because cretolamna evolves into otodus obliquus. The tooth looks a bit closer to Otodus to me. 

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will stevenson
4 hours ago, Praefectus said:

Nice tooth. I think you might be splitting hairs because cretolamna evolves into otodus obliquus. The tooth looks a bit closer to Otodus to me. 

Thanks:) I thought this as well, the root shape seems to favour cretalamna more though:) Ive never really noticed transitional teeth between the 2 species here which is weird considering both species are found in the same formation

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Familyroadtrip

I agree... there seems to be a tiny bit of boutlette, which I haven’t seen on my cretalamna... it’s shape also points me towards otodus... but I think it’s probably transitional.

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This appears to be a Cretalamna to me. My handy trick is to look at the cusps. On the anterior and lateral positions at least, Otodus cusps sit on a diagonal slant more or less mirroring each other, whereas Cretalamna cusps sit on pretty much the same horizontal plane. See below for visual ( @HoppeHuntings Otodus)

505A3B9C-DC7A-4B6B-84D9-5225D4C2D7F1.jpeg

573264ED-33EB-4898-9094-CA3CEEE3934D.jpeg

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will stevenson
14 hours ago, Harry Pristis said:

Perhaps these will help:

 

5f6fd1887c75d_shark_cretalamnaorotodus.thumb.jpg.983bbd2795e4d496602e298a4ec0a9f1.jpg

 

 

shark_cretalamnaappend.thumb.jpg.3b3896142287b25fbadb123eb5cfcd66.jpg

Thanks for the resource which ones are otodus though:)

 

36 minutes ago, WhodamanHD said:

This appears to be a Cretalamna to me. My handy trick is to look at the cusps. On the anterior and lateral positions at least, Otodus cusps sit on a diagonal slant more or less mirroring each other, whereas Cretalamna cusps sit on pretty much the same horizontal plane. See below for visual ( @HoppeHuntings Otodus)

505A3B9C-DC7A-4B6B-84D9-5225D4C2D7F1.jpeg

573264ED-33EB-4898-9094-CA3CEEE3934D.jpeg

thanks that’s a handy trick, I think I might put otodus/cretalamna transitional as it seems to be a mix

F3ED4FA7-DF56-4CCC-9E51-AA7A9BAA01BE.jpeg.a9643729ff3ecf1ddfb5605245b5ede0.jpeg

maybe @Al Dentecould help?

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7 hours ago, will stevenson said:

Thanks for the resource which ones are otodus though:)

 

It's the same gold-color tooth among the Cretolamna as among the Otodus.  In other words, in the two images there are two Otodus and three Cretolamna (I use CretOlamna advisedly, as it is the accepted ICZN spelling, the last I heard).

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will stevenson
2 hours ago, Harry Pristis said:

 

It's the same gold-color tooth among the Cretolamna as among the Otodus.  In other words, in the two images there are two Otodus and three Cretolamna (I use CretOlamna advisedly, as it is the accepted ICZN spelling, the last I heard).

thanks for the spelling correction:) im not quite sure i get what you mean about the otodus teeth, so the top image is 2 otodus and the golden one is a cretolamna and the other one is all cretolamna?

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18 hours ago, will stevenson said:

I think I might put otodus/cretalamna transitional as it seems to be a mix

F3ED4FA7-DF56-4CCC-9E51-AA7A9BAA01BE.jpeg.a9643729ff3ecf1ddfb5605245b5ede0.jpeg


I don’t have a lot of experience with Ypresian teeth but I wouldn’t expect a transitional Cretolamna/Otodus to be found in the Ypresian since the two probably separated in the late Cretaceous or Paleocene. Anterior C. appendiculata look a lot like small Otodus. I don’t know how to differentiate them. Your tooth looks like C. appendiculata based on the root shape.

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16 hours ago, Harry Pristis said:

 

It's the same gold-color tooth among the Cretolamna as among the Otodus.  In other words, in the two images there are two Otodus and three Cretolamna (I use CretOlamna advisedly, as it is the accepted ICZN spelling, the last I heard).

Cretalamna is much more widely used in current literature.

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will stevenson
8 hours ago, Al Dente said:


I don’t have a lot of experience with Ypresian teeth but I wouldn’t expect a transitional Cretolamna/Otodus to be found in the Ypresian since the two probably separated in the late Cretaceous or Paleocene. Anterior C. appendiculata look a lot like small Otodus. I don’t know how to differentiate them. Your tooth looks like C. appendiculata based on the root shape.

Thanks a lot for clearing this up:) 

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6 hours ago, WhodamanHD said:

Cretalamna is much more widely used in current literature.

 

Some workers may not be aware of the correction by the ICZN.  Some may just reject it.  What's your excuse?

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2 hours ago, Harry Pristis said:

 

Some workers may not be aware of the correction by the ICZN.  Some may just reject it.  What's your excuse?

I am not (yet) a researcher, I’m stating what I see. My opinion counts for little, but I struggle to see why Cretolamna would be granted priority. The ICZN must have their reasons though.

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4 minutes ago, WhodamanHD said:

I struggle to see why Cretolamna would be granted priority. The ICZN must have their reasons though.

 

It was done to correct an acknowledged spelling error.  The correction proposal met with some resistance.

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3 hours ago, Harry Pristis said:

 

It was done to correct an acknowledged spelling error.  The correction proposal met with some resistance.

Ohm my! Spelling error resistance? 

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On 9/27/2020 at 2:08 PM, Harry Pristis said:

 

It's the same gold-color tooth among the Cretolamna as among the Otodus.  In other words, in the two images there are two Otodus and three Cretolamna (I use CretOlamna advisedly, as it is the accepted ICZN spelling, the last I heard).

Do you have a copy of the ruling? Can anyone find a ICZN ruling that specifically says that Cretolamna is the accepted spelling?
 

In the only reference that I could find, researchers suggested that ICZN erected Article 33.3.1 that applies to similar situations in the future and cannot be retroactively applied to proclaim that Cretolamna is the accepted spelling.

 

See:

http://www.elasmo.com/frameMe.html?file=genera/cretaceous/cretalamna.html&menu=bin/menu_genera-alt.html

 

828F4B35-9C2F-4D31-97F9-79793C5C14AE.png

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1 hour ago, DPS Ammonite said:

In the only reference that I could find, researchers suggested that ICZN erected Article 33.3.1 that applies to similar situations in the future and cannot be retroactively applied to proclaim that Cretolamna is the accepted spelling.

I could ask David Ward, but here’s the rule:

”33.3.1. when an incorrect subsequent spelling is in prevailing usage and is attributed to the publication of the original spelling, the subsequent spelling and attribution are to be preserved and the spelling is deemed to be a correct original spelling.”

Ironic how the actual implementation of this rule led to the prevailing usage to revert to the original.

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On 9/26/2020 at 3:46 PM, will stevenson said:

Thanks:) I thought this as well, the root shape seems to favour cretalamna more though:) Ive never really noticed transitional teeth between the 2 species here which is weird considering both species are found in the same formation

 

Is this a London Clay tooth or is it from an older layer?  In any case It's a worn tooth so some characters have been dulled and that complicates a confident ID.  In another thread Dr, Siverson stated that the oldest Otodus he was aware of came from a deposit of Late-Early Paleocene age (he used the Zone NP3).  That means transitional teeth could be found from rocks that age or from NP1-Np2 (early Paleocene, Danian).  We can't assume that Otodus didn't diverge in the late Cretaceous but it seems more likely that it was part of the radiation of sharks and bony fishes that took place starting in the early Paleocene as life recovered from the K/T extinction.

 

Unfortunately, earliest Paleocene marine exposures are not common, and while some yield shark remains, they aren't super-productive especially for the larger sharks.  Researchers have hunted an early Paleocene layer in the Moroccan phosphates (and perhaps elsewhere in North Africa and the Middle East - the eastern extent of the phosphates), the Lower Hornerstown Formation in New Jersey, sites in Denmark, and sites in Russia.  I think there's a site in New Zealand too.

 

With all that said if the root is still the same shape, I think it's a Cretalamna tooth too.  The distal lobe is a little squared-off as I've seen in Cretalamna.

 

Jess

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On 9/27/2020 at 6:12 AM, WhodamanHD said:

This appears to be a Cretalamna to me. My handy trick is to look at the cusps. On the anterior and lateral positions at least, Otodus cusps sit on a diagonal slant more or less mirroring each other, whereas Cretalamna cusps sit on pretty much the same horizontal plane. See below for visual ( @HoppeHuntings Otodus)

505A3B9C-DC7A-4B6B-84D9-5225D4C2D7F1.jpeg

573264ED-33EB-4898-9094-CA3CEEE3934D.jpeg

 

 

I haven't heard of the plane(s) of the cusplets being a distinguishing character before but it could be worth testing.  The slant of the cusplets may be a result of the teeth getting larger so the width of the teeth decreased relative to the space on the jaw so that they could all be accommodated with symphyseal positions beginning to disappear across time.

 

I have heard that Otodus cusplets tend to diverge - point outward - while Cretalamna cusplets tend to point straight up.

 

Both Otodus and Cretalamna have prominent lingual protuberances in the lower teeth but the protuberance in Otodus tends to be more distinct from the rest of the root.  It doesn't gradually rise from the root as in Cretalamna.

 

Otodus has a clear bourlette (=neck) though this can be obscured or erased by water-wear/damage.

 

Otodus has foramina (sometimes rather large) spread out horizontally on the lingual face of the root while they are more of a cluster on Cretalamna teeth.  This can be hard to judge depending on the preservation of the tooth.  

 

I think we have to take all the tooth characters into consideration and then decide how the combination of characters adds up.  I'm leaning toward Cretalmna.

 

Jess

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will stevenson

@siteseer thanks so much for helping me with this, i can confirm the tooth is definitely london clay as there are no exposures other than this in the area and the sea is sheltered so little transportation occurs, in fact the only part of the formation that produces teeth is division D, B2 is the other one present at the site which produces the phosphatic nodules, so the stratiagraphy is definitely correct, with all the evidence youve given im leaning towards cretalamna as well but its condition may prevent a solid ID:) thanks once again for your help

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