Are these Galeocerdo Mayumbensis?

[DevilDog]

Found on Topsail Island, NC in an area known for Oligocene and Miocene fossil shark teeth.

DD

[ynot]

I do not know, but have heard (here on TFF) that there are a lot of Galeocerdo sp. and it is hard to tell them apart.

Others here will probably give a better idea of the species.

Tony

[Al Dente]

The beach renourishment on North Topsail comes from the River Bend Formation which at least part of is early Oligocene. There is a Formation in North Carolina called the Belgrade Formation that is late Oligocene and contains a tooth that is the same or similar to G. Mayumbensis. I have a few Galeocerdo teeth from the River Bend and the lateral ones look like G. mayumbensis but the anterior are very much like G. eaglesomei. I think the teeth from the River Bend are intermediate between the two. G. eaglesomei are found in the Eocene.

[DevilDog]

Perhaps these teeth are not from the River Bend Formation? Before the beach renourishment, weren't Miocene teeth being found at North Topsail? I find G.Cuvier there often, and both it and G. Mayumbensis are Miocene, right?

DD

[Vball]

Eocene= Galeocerdo eaglesomi
Early Oligocene = Galeocerdo casei
Late Oligo-Miocene = Galeocerdo mayumbensis

I believe that is the progression. Those look like early mayumbensis to me. I'm not sure what the determining factor is between mayumbensis and casei. I will say my casei teeth are a little more like eaglesomi than these.

[Al Dente]

Eocene= Galeocerdo eaglesomiEarly Oligocene = Galeocerdo caseiLate Oligo-Miocene = Galeocerdo mayumbensis

I believe that is the progression. Those look like early mayumbensis to me. I'm not sure what the determining factor is between mayumbensis and casei. I will say my casei teeth are a little more like eaglesomi than these. P1050424edit.jpg

Muller named Galeocerdo casei for teeth from the Belgrade Formation which is late Oligocene but some think it is early Miocene. Most likely, G. casei are G. mayumbensis.

[Al Dente]

Perhaps these teeth are not from the River Bend Formation? Before the beach renourishment, weren't Miocene teeth being found at North Topsail? I find G.Cuvier there often, and both it and G. Mayumbensis are Miocene, right?

DD

Galeocerdo cuvier is found in Pliocene and Pleistocene sediments in North Carolina. G. mayumbensis ranged from the Oligocene through part of the Miocene.

[DevilDog]

Please help a confused novice. I've read in several different places that North Topsail specifically, and North Carolina beaches in general are associated with Miocene and Pliocene fossils. Are you saying that North Topsail beaches are only associated with Oligocene, Pliocene and Pleistocene fossils and not Miocene?

DD

[Al Dente]

Please help a confused novice. I've read in several different places that North Topsail specifically, and North Carolina beaches in general are associated with Miocene and Pliocene fossils. Are you saying that North Topsail beaches are only associated with Oligocene, Pliocene and Pleistocene fossils and not Miocene?

DD

There probably are Miocene fossils washing up on the beaches. In the past there have been Miocene, Pliocene and Pleistocene deposits in the region but these deposits have been stripped off exposing Oligocene deposits just offshore. When the deposits erode away, sometimes the finer material gets washed away leaving some coarse pebbles and fossils behind. In this case, coarse pebbles and fossils that are Miocene and younger sitting on top of Oligocene deposits, occasionally washing onto the beach along with the more abundant Oligocene fossils.

[DevilDog]

Thank you for that explanation!

DD

[siteseer]

On 7/25/2016 at 8:03 PM, Vball said:

Eocene= Galeocerdo eaglesomi
Early Oligocene = Galeocerdo casei
Late Oligo-Miocene = Galeocerdo mayumbensis

I believe that is the progression. Those look like early mayumbensis to me. I'm not sure what the determining factor is between mayumbensis and casei. I will say my casei teeth are a little more like eaglesomi than these.

 

On 7/26/2016 at 4:53 AM, Al Dente said:

Galeocerdo cuvier is found in Pliocene and Pleistocene sediments in North Carolina. G. mayumbensis ranged from the Oligocene through part of the Miocene.

 

 

Vball and Al Dente,

 

I'm in Florida this week helping a friend get ready for a trade show.  He's got a pile of Bone Valley fossils from the 80's that he collected and I'm sorting them out by at least genus.  He also has some tiger shark teeth from the Peace River, a few of which look like G. mayumbensis.  He told me that you can get Middle Miocene shark teeth in the Peace and the phosphate mines but they only come out of the lower part of the Bone Valley Formation which is Middle Miocene (roughly Hemingfordian-Barstovian Mammal Age/13-15 million years old.  He added the Gainesville creeks have Middle Miocene sharks, some younger land mammals, and younger shark teeth.  You get G. mayumbensis there as well.

 

For a long time I had assumed G. mayumbensis was a Late Miocene to perhaps Early Pliocene shark and maybe even just a variation of G. cuvier.  After reading isolated bits about what people have found in different places, especially here on the Forum, I see it is probably a descendant of G. eaglesomei and perhaps the last of that lineage depending on how you place G. cuvier.  The only reason you could get cuvier and mayumbensis together is that they can wash out of formations that happen to get exposed by the same waterway.

 

It appears the distinguishing characteristics of mayumbensis are:

 

"U" shaped (not "V" shaped) basal root margin though I've also seen that described as more arched roots

mesiodistally compressed (narrower) teeth which makes them higher than a same-size cuvier

coarser serrations

I would also say the cusp angle always seems to be higher in mayumbensis and the distal edge of the cusp is shorter than in cuvier.

 

My question is what destinguishes a G. cuvier symphyseal from one of G. mayumbensis?  I assume they would be at least similar in size and shape.

 

It was interesting to read about G. casei and/or Oligocene occurrences of G. mayumbensis.  I don't think I have anything like that at home and will have to check.

 

Jess

 

 

Edited May 21, 2019 by siteseer
additional comment

[Al Dente]

2 hours ago, siteseer said:

My question is what destinguishes a G. cuvier symphyseal from one of G. mayumbensis?  I assume they would be at least similar in size and shape.

I don’t know. I’m not sure if I have seen a mayumbensis symphyseal. Modern cuvier symphyseal teeth are highly variable in size and shape.

[siteseer]

6 hours ago, Al Dente said:

I don’t know. I’m not sure if I have seen a mayumbensis symphyseal. Modern cuvier symphyseal teeth are highly variable in size and shape.

 

My friend has a tooth that might be a symphyseal or at least the position next to it.  I'll see if he'll let me get and post a photo.

 

I edited my previous post to include a comment that the distal cutting edge of the cusp is shorter in G. mayumbensis than in cuvier.  It leaves the cusp looking more broad-based with the effect of adding more surface area to the labial and lingual faces because of the higher cusp angle.

 

I haven't seen what a lateral to posterior position would look like.  My friend has a few specimens from the Peace River.  A couple of them are mayumbensis but a couple of others (laterals) look like cuvier.  Unfortunately, you can get both mayumbensis and cuvier there because the lower and upper Bone Valley layers are exposed by the river.  I would think the cusp angle would decrease toward the commissure and the overall width would increase to the point that the tooth would look like a cuvier.

 

Jess

[siteseer]

While looking for more mayumbensis information, I found a couple of interesting images...and right here on the forum.  Northern Sharks has a shot with an apparent symphyseal and lateral tooth.  Check out the photo with the two teeth.

 

[siteseer]

Here are two images of some Peace River teeth my friend has.  For scale that first tooth is 3/4 inches (2cm) wide  The first one shows teeth I think are Galeocerdo cuvier.  The first one in the second row is a symphyseal.  I have seen G. cuvier sysmphyseals of that shape before, including two modern teeth.  On this forum alone I've seen at least three different symphyseal forms for G. cuvier.

 

The second shows teeth that I think are Galeocerdo mayumbensis including the second tooth in the second row (11/16 inches/18mm wide) that may be a symphyseal (a narrower tiger tooth among narrow tiger teeth and not a form I've seen in any of the G. aduncus nor G. cuvier teeth, symphyseal or otherwise).  I'd like to know what others think.

 

Thanks,

 

Jess

[siteseer]

Here is a clearer shot of the Galeocerdo symphyseal in the first photo of the previous post.  I think this one is G. cuvier.

 

 

[Paleoc]

When you read scientific papers from equatorial South America, ALL the tiger shark teeth are mayumbensis.  The further south you go towards the equator, the more common they are found.  I.e., they are more prevalent in Florida than the Carolina's.  Once you get to South America, G. cuvier disappears and G. mayumbensis takes over.  I would love to see modern tiger shark jaws from the equatorial South America Atlantic.

 

In Neogene sharks and rays from the Brazilian ‘Blue Amazon - by Orangel Aguilera, Zoneibe Luz, Jorge D. Carrillo-Briceño, La´szlo´ Kocsis, Torsten W. Vennemann, Peter Mann de Toledo, Afonso Nogueira, Kamilla Borges Amorim, Heloı ´sa Moraes-Santos, Marcia Reis Polck, Maria de Lourdes Ruivo, Ana Paula Linhares, Cassiano Monteiro-Neto;  there are 3 tiger shark teeth illustrated.  All are mayumbensis, no cuvier. 

 

In Chondrichthyan Fauna from the Pirabas Formation, Miocene of Northern Brazil, with Comments on Paleobiogeography - by Márcia Aparecida Fernandes dos Reis,; again there is 1 tiger shark tooth illustrated.  It is called G. cuvier, but from the picture it is very obvious that it is G. mayumbensis again.

 

In Shark teeth from Pirabas Formation (Lower Miocene), northeastern Amazonia, Brazil - by Sue Anne Regina Ferreira Costa,  Martha RichterI,  Peter Mann de Toledo. Heloísa Maria Moraes-Santo;, there are 12 tiger shark teeth pictured and identified as Galeocerdo sp.  All of them are G. casei/mayumbensis (in the early Miocene many shark species were transitioning).



 

[hemipristis]

On ‎7‎/‎27‎/‎2016 at 8:12 AM, Al Dente said:

There probably are Miocene fossils washing up on the beaches. In the past there have been Miocene, Pliocene and Pleistocene deposits in the region but these deposits have been stripped off exposing Oligocene deposits just offshore. When the deposits erode away, sometimes the finer material gets washed away leaving some coarse pebbles and fossils behind. In this case, coarse pebbles and fossils that are Miocene and younger sitting on top of Oligocene deposits, occasionally washing onto the beach along with the more abundant Oligocene fossils.

Good summary.  I concur completely.

 

Did my thesis on NTB, and spent a lot of time on those beaches, and boating off those islands.  Onslow Bay offshore of NTB and Onslow Beach is sand-starved. Much of the overlying sediment is gone, and the bay consists of scattered patches of Holo-Pleistocene sand atop the Oligocene hardgrounds.  One can actually see the Oligocene oyster reefs and hardgrounds from the air when the tide is low. Side note: due to the hardgrounds and proximity of the Gulf Stream, it's not uncommon to find subtropical fish & coral patch reefs building atop the old Oligocene reefs, with species not normally found at in NC.

[hemipristis]

On ‎7‎/‎26‎/‎2016 at 9:29 AM, Al Dente said:

The beach renourishment on North Topsail comes from the River Bend Formation which at least part of is early Oligocene. There is a Formation in North Carolina called the Belgrade Formation that is late Oligocene and contains a tooth that is the same or similar to G. Mayumbensis. I have a few Galeocerdo teeth from the River Bend and the lateral ones look like G. mayumbensis but the anterior are very much like G. eaglesomei. I think the teeth from the River Bend are intermediate between the two. G. eaglesomei are found in the Eocene.

Could you post some photos?   I too have some curious "tiger" teeth from the River Bend and Castle Hayne that are unusual, and would like to compare

[hemipristis]

On ‎7‎/‎26‎/‎2016 at 10:03 AM, Vball said:

Eocene= Galeocerdo eaglesomi
Early Oligocene = Galeocerdo casei
Late Oligo-Miocene = Galeocerdo mayumbensis

I believe that is the progression. Those look like early mayumbensis to me. I'm not sure what the determining factor is between mayumbensis and casei. I will say my casei teeth are a little more like eaglesomi than these.

with G. aduncus stemming from....?

[Al Dente]

3 hours ago, hemipristis said:

Could you post some photos?   I too have some curious "tiger" teeth from the River Bend and Castle Hayne that are unusual, and would like to compare

Here are the two teeth I have from the River Bend Formation. The lower tooth is 29 mm across the base. The anterior tooth still has some River Bend limestone attached. The lateral tooth looks a lot like mayumbensis but the anterior has some eaglesomei features.