Upper Paleocene Lamniforms (Mitsukurinidae and Odontaspididae) ID from Chile

[terminatordiego]

Hello to all guys!!!, I would like to ask again for help in the ID of some teeth.

 

I´ve been searching in a local university's museum for teeth of the original strata (Upper Paleocene), and I have found a very interesting set of boxes containing a bunch of different teeth, all labeled as "Scapanorhynchus sp.", maybe existing a missidentification.

 

The question would be if any of you guys can ID the pieces and how to differentiate the Scapanorhynchus sp. from Striatolamia striata or Sylvestrilamia teretidens, the options I´m leaning for the ID of the teeth. I would also like to check if you guys @will stevenson , @MarcoSr or @bthemoose have any info about it. You guys are awesome!!

 

The ruler is a 1mm step grid, and I'll try to order them from anterior to posterior (I am aware that each one can be of different taxa), all of them have a stronger or weaker folded surface in lingual side. Any help or info is welcome, thanks guys!!! and greetings from Chile.

 

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12) Finally, this one has the weakest folding:

Edited February 3, 2022 by terminatordiego

[MarcoSr]

There were two genera of Goblin sharks in the Cretaceous, Scapanorhynchus and Anomotodon.  Only Anomotodon is described in the Paleocene.  If your formation is Paleocene, then the teeth shouldn’t be Scapanorhynchus.  Paleogene Anomotodon features are different from Scapanorhynchus i.e. smooth crowns, usually without cusplets (rarely sometimes a single small cusplet).  So your teeth are not Anomotodon.  Both Striatolamia striata and Sylvestrilamia teretidens are described in the Paleocene.  Based upon the cusplets and crowns that I’m seeing, most of your teeth don’t really look like Striatolamia striata to me.  They look more like Sylvestrilamia teretidens.  However, you could have both species.  Some positions are too similar looking to try to differentiate them from pictures.

 

Marco Sr.

Edited February 3, 2022 by MarcoSr
Added Paleogene

[terminatordiego]

58 minutes ago, MarcoSr said:

There were two genera of Goblin sharks in the Cretaceous, Scapanorhynchus and Anomotodon.  Only Anomotodon is described in the Paleocene.  If your formation is Paleocene, then the teeth shouldn’t be Scapanorhynchus.  Anomotodon features are different from Scapanorhynchus i.e. smooth crowns, usually without cusplets (rarely sometimes a single small cusplet).  So your teeth are not Anomotodon.  Both Striatolamia striata and Sylvestrilamia teretidens are described in the Paleocene.  Based upon the cusplets and crowns that I’m seeing, most of your teeth don’t really look like Striatolamia striata to me.  They look more like Sylvestrilamia teretidens.  However, you could have both species.  Some positions are too similar looking to try to differentiate them from pictures.

 

 

Marco Sr.

Thank you so much Marco!!!!! 

[Notidanodon]

If we're 100% sure that it is palaeocene then i would agree that the majority are sylvestrilamia, though the 1st looks more like carcharias hopei to me, but sand tiger identification will allways be difficult with no faunal list  

try this website, it has species of similiar age  https://savage-seas.weebly.com/

[terminatordiego]

3 hours ago, will stevenson said:

If we're 100% sure that it is palaeocene then i would agree that the majority are sylvestrilamia, though the 1st looks more like carcharias hopei to me, but sand tiger identification will allways be difficult with no faunal list  

try this website, it has species of similiar age  https://savage-seas.weebly.com/

thanks Will !!!!

[MarcoSr]

17 hours ago, will stevenson said:

If we're 100% sure that it is palaeocene then i would agree that the majority are sylvestrilamia, though the 1st looks more like carcharias hopei to me, but sand tiger identification will allways be difficult with no faunal list  

try this website, it has species of similiar age  https://savage-seas.weebly.com/

 

There is disagreement among researchers on whether to use Carcharias hopei (Ward) or Hypotodus verticalis (Cappetta) as the correct identification for a group of sand tigers.  Irrespective of this disagreement, both have smooth crowns, based upon all the specimens that I have collected in the Paleocene of Maryland and the Eocene of Virginia.  I see striations or folds in the pictures for that first tooth.  If that is indeed the case, the tooth wouldn’t be C. hopei or H. verticalis.  However, looking back at this tooth is causing me to question the scales in the pictures.  Sylvestrilamia teretidens are a lot smaller than Striatolamia striata.  Of the hundreds of Sylvestrilamia teretidens that I have collected in Virginia, the specimens are all smaller than 1 inch.  I had assumed that the squares in the pictures were 5 mm on a side.  If the squares are larger than that, then a number of these teeth would be too large to be Sylvestrilamia teretidens.

 

Marco Sr.

[terminatordiego]

28 minutes ago, MarcoSr said:

 

There is disagreement among researchers on whether to use Carcharias hopei (Ward) or Hypotodus verticalis (Cappetta) as the correct identification for a group of sand tigers.  Irrespective of this disagreement, both have smooth crowns, based upon all the specimens that I have collected in the Paleocene of Maryland and the Eocene of Virginia.  I see striations or folds in the pictures for that first tooth.  If that is indeed the case, the tooth wouldn’t be C. hopei or H. verticalis.  However, looking back at this tooth is causing me to question the scales in the pictures.  Sylvestrilamia teretidens are a lot smaller than Striatolamia striata.  Of the hundreds of Sylvestrilamia teretidens that I have collected in Virginia, the specimens are all smaller than 1 inch.  I had assumed that the squares in the pictures were 5 mm on a side.  If the squares are larger than that, then a number of these teeth would be too large to be Sylvestrilamia teretidens.

 

Marco Sr.

 

Very informative data Marco. 

I could especified better in the main redaction about the sizes. 

The ruler of 1mm is the one which contains the blue lines. 

Each side of the squares of the paper is around 7mm (just have measure it).

Thanks for the info! 

[MarcoSr]

36 minutes ago, terminatordiego said:

Very informative data Marco. 

I could especified better in the main redaction about the sizes. 

The ruler of 1mm is the one which contains the blue lines. 

Each side of the squares of the paper is around 7mm (just have measure it).

Thanks for the info! 

 

Squares that size would put these teeth under 1 inch, except for maybe the first tooth.  So I'm still OK with a Sylvestrilamia teretidens ID for most of them.

 

Marco Sr.