Amazing (But largely overlooked) Carcharocles (Otodus) megalodon fossil of rostral node from Pilocene North Carolina

[Joseph Fossil]

This is something I just found out yesterday, but feel is amazing enough to share on the fourm (especially to all those who study Carcharocles (Otodus) megalodon)!!!

 

I was researching shark diversity during the late Eocene when I came across some info on a fossil Shark rostral node specimens from the Zanclean Pilocene sections of the Yorktown Formation dating around 5.3-3.6 Million Years ago in what is now North Carolina. The Specimens USNM 474994, 474995, 474996, 474997, 474998, and 474999 belongs to juvenile sharks (with USNM 474998 belonging to an individual shark of about 1.46 meters (4.8 feet) in length). 

 

Originally believed to be rostral nodes of a Lamna sp., they were reanalyzed and discovered by Scientists Dr. Frederik H. Mullen and Dr. John W.M. Jagt to be from Juvenile Otodontidae Sharks.

 

(also, USNM = National Museum of Natural History, Washington D.C., U.S.A.)

 

Mollen, F.H. and Jagt, J.W.M. (2012). The taxonomic value of rostral nodes of extinct sharks, with comments on previous records of the genus Lamna (Lamniformes, Lamnidae) from the Pliocene of Lee Creek Mine, North Carolina (USA). Acta Geologica Polonica, 62(1), 117–127.

https://www.researchgate.net/publication/262142193_The_taxonomic_value_of_rostral_nodes_of_extinct_sharks_with_comments_on_previous_records_of_the_genus_Lamna_Lamniformes_Lamnidae_from_the_Pliocene_of_Lee_Creek_Mine_North_Carolina_USA 

 

Reconstruction by Tyler Greenfield, 2021

 

This research also strongly indicates/directly suggests these rostral node specimens might belong to fetal or newborn individuals of Carcharocles (Otodus) megalodon!!!

 

If correct, it would be the one of the most significant finds in terms of non-tooth C. megalodon fossil material since the relatively recent discovery of specimen IRSNB P9893 (also known as IRSNB 3121), a pretty complete C. megalodon fossil vertebrae column from a Miocene Formation in what is now Belgium!!!

 

Shimada, Kenshu & Bonnan, Matthew & Becker, Martin & Griffiths, Michael. (2021). Ontogenetic growth pattern of the extinct megatooth shark Otodus megalodon —implications for its reproductive biology, development, and life expectancy. Historical Biology. 33(12), 1-6. 10.1080/08912963.2020.1861608.

https://par.nsf.gov/servlets/purl/10293771

 

 

[Joseph Fossil]

The only other Otodontid Shark from the area these rostral node fossils could possibly belong to are Juvenile Paratodus sp. Still it would be an incredible discovery!!! This has been making me wonder though why hasn't these specimens become more well known given their potential paleontological significance?

[Al Dente]

16 minutes ago, Joseph Fossil said:

The only other Otodontid Shark from the area these rostral node fossils could possibly belong to are Juvenile Paratodus

What about Carcharodon hastalis?

[Joseph Fossil]

13 hours ago, Al Dente said:

What about Carcharodon hastalis?

 

@Al Dente I believe the 2012 Paper did suggest Carcharodon hastalis as a possibility too, thanks for pointing that out. Also, I thought it's Cosmopolitodus hastalis (It's definitely known it's a really close relative (unlike Carcharocles (Otodus) megalodon) to the Great White Shark, but I'm not sure if C. hastalis was in the Carcharodon genus)?

[Al Dente]

10 minutes ago, Joseph Fossil said:

Also, I thought it's Cosmopolitodus hastalis (It's definitely known it's a really close relative (unlike Carcharocles (Otodus) megalodon) to the Great White Shark, but I'm not sure if C. hastalis was in the Carcharodon genus)?

You might be interested in this paper-https://onlinelibrary.wiley.com/doi/full/10.1111/j.1475-4983.2012.01201.x

[Joseph Fossil]

2 minutes ago, Al Dente said:

You might be interested in this paper-https://onlinelibrary.wiley.com/doi/full/10.1111/j.1475-4983.2012.01201.x

 

@Al Dente Thanks for sharing this paper! I'll definitely give it a read!!

[Al Dente]

I'm a little skeptical on being able to identify rostral nodes to the species level. I have several from Lee Creek and no two are alike. Several years ago, I was at the beach and found several Rhizoprionodon carcasses in different states of decay. One thing I noticed was that the rostral nodes had different amounts of calcification. Here's a photo I took of three that are about the same size (same age?). The two on the outside have pretty good calcification, but the center has none.

 

 

 

[Joseph Fossil]

4 hours ago, Al Dente said:

I'm a little skeptical on being able to identify rostral nodes to the species level. I have several from Lee Creek and no two are alike. Several years ago, I was at the beach and found several Rhizoprionodon carcasses in different states of decay. One thing I noticed was that the rostral nodes had different amounts of calcification. Here's a photo I took of three that are about the same size (same age?). The two on the outside have pretty good calcification, but the center has none.

 

 

 

 

@Al Dente These are pretty neat! Were you able to find out what happened to those Rhizoprionodon individuals (it seems odd that several of these sharks (as requiem sharks) would just naturally wash up dead on the shore)? Do you think it was something like illegal fishing or just a natural event? 

[Joseph Fossil]

4 hours ago, Al Dente said:

I'm a little skeptical on being able to identify rostral nodes to the species level. I have several from Lee Creek and no two are alike. Several years ago, I was at the beach and found several Rhizoprionodon carcasses in different states of decay. One thing I noticed was that the rostral nodes had different amounts of calcification. Here's a photo I took of three that are about the same size (same age?). The two on the outside have pretty good calcification, but the center has none.

 

 

 

 

@Al Dente I can definitely understand if your skeptical on the fossil rostral nodes being able to be identified to a species or even genera level. I hold some skepticism too. But the size of these fossil rostral nodes leaves only three likely contenders amongst the native marine Pliocene species of the Yorktown Formation...Carcharodon (Cosmopolitodus) hastalis, Carcharocles (Otodus) megalodon, or Paratodus sp.

[Joseph Fossil]

@Boesse What do you think of the Yorktown Formation Rostral node specimens? Have you heard of these specimens before? 

 

Also, do you think they belong to Carcharodon (Cosmopolitodus) hastalis, Carcharocles (Otodus) megalodon, or Paratodus sp.?

[Al Dente]

4 hours ago, Joseph Fossil said:

Do you think it was something like illegal fishing or just a natural event?

 

Probably natural. I've seen some strange species-specific die offs. Last year I found several dozen dead moonfish (Selene setapinnis) washed up on the beach. No other fish with them. I had never seen this species before. Another time it was red hake (Urophysis chuss).

 

 

[Boesse]

I'm pretty skeptical about how diagnostic these are as well. if I recall correctly, the specimen was originally identified in Purdy et al. 2001 as Lamna, salmon/porbeagle shark. I did not quite completely following the reasoning behind identifying it as a juvenile otodontid.

[Joseph Fossil]

On 8/22/2023 at 6:32 PM, Boesse said:

I'm pretty skeptical about how diagnostic these are as well. if I recall correctly, the specimen was originally identified in Purdy et al. 2001 as Lamna, salmon/porbeagle shark. I did not quite completely following the reasoning behind identifying it as a juvenile otodontid.

 

@Boesse I believe the main point Dr. Mollen and Dr. Jagt utilized for the justification in classifying the Specimens USNM 474994, 474995, 474996, 474997, 474998, and 474999 as Otodonid was that the lateral cartilage of the rostral node specimens join together but individually the rostral node where for Lamna the lateral cartilage would form it as "abutting ones" (Mollen and Jagt, 2012). 

 

I agree with you that this does verge on the confusing a bit.

[Joseph Fossil]

@Boesse The fact that Carcharodon hastalis is in Lamnidae like the genera Lamna and Carcharodon could mean it had lateral cartilage in it’s to steal nodes that were abutting unlike the Lee Creek Formation Specimens. This does I’ll admit leave open the possibility these to steal node specimens do belong to individuals of either Paratodus benedenii or juvenile Carcharocles (Otodus) megalodon. 
 

Still, more justification I feel should be given before assigning these Lee Creek Formation Rostral node specimens that classification.