Mississippian Shark Tooth

[fossilsonwheels]

I found this unidentified Carboniferous Shark tooth on line and was hoping I might get some ID assistance. The tooth is from the Harroldsburg Limestone, Washington County Indiana. The tooth is 16 mm. I did not find any publications on the formation so I have been researching recent discoveries and evaluations of existing taxa from the Paleozoic. I know the ID's with the Cladodont type teeth can get tricky and I have been trying to read up to see if I can get close to an ID. In my research, I found some Saviodus teeth from Ireland that look very similar. The tooth is figure E looks quite similar in my opinion but I am far from an expert so I wanted to put it to the forum.

 

Any thoughts or knowledge to share, feel free !

[Bullsnake]

@Archie

[Elasmohunter]

I agree that this tooth is "likely" (see below) a member of the genus Saivodus. As per the handbook of Paleoichthyology, members of this genus have slender, long median cusps that are covered with thin, parallel lines (cristae) along the bottom two thirds of the central cusp and a smooth surface along the top third of the tooth. This tooth clearly exhibits this. Furthermore, Saivodus sp. teeth are typically sigmoidal ("S"-shaped), and this tooth appears to be sigmoidal, although it's difficult to tell without a side profile. In addition, the tooth bears numerous cusplets between the main and lateral cusps.

Here's where it gets interesting: the Handbook of Paleochthyology argues that there exists only one member of this genus: "Cladodus" (Saivodus) striatus AGASSIZ 1843. It posits that the other members included in this genus belong elsewhere. (Many paleozoic cladodonts need a lot of taxonomic revision, and this genus appears to be no exception.) S. striatus has been reported from the Mississippian of Indiana, so this tooth could well be that species.

[siteseer]

Hi Kurt,

 

I have seen this tooth form identified as Symmorium at fossil shows.  I know that's not much help but maybe an avenue to check out.  I don't read as much about Paleozoic chondrichthyans so I don't really have an educated opinion on that.

 

Jess

[fossilsonwheels]

1 hour ago, Elasmohunter said:

I agree that this tooth is "likely" (see below) a member of the genus Saivodus. As per the handbook of Paleoichthyology, members of this genus have slender, long median cusps that are covered with thin, parallel lines (cristae) along the bottom two thirds of the central cusp and a smooth surface along the top third of the tooth. This tooth clearly exhibits this. Furthermore, Saivodus sp. teeth are typically sigmoidal ("S"-shaped), and this tooth appears to be sigmoidal, although it's difficult to tell without a side profile. In addition, the tooth bears numerous cusplets between the main and lateral cusps.

Here's where it gets interesting: the Handbook of Paleochthyology argues that there exists only one member of this genus: "Cladodus" (Saivodus) striatus AGASSIZ 1843. It posits that the other members included in this genus belong elsewhere. (Many paleozoic cladodonts need a lot of taxonomic revision, and this genus appears to be no exception.) S. striatus has been reported from the Mississippian of Indiana, so this tooth could well be that species.

Excellent information. Thank you. I agree with the much needed taxonomic revisions for Paleozoic shark teeth. I will go with likely Saivodus unless I find some information that would sway me in another direction.

[fossilsonwheels]

1 hour ago, siteseer said:

Hi Kurt,

 

I have seen this tooth form identified as Symmorium at fossil shows.  I know that's not much help but maybe an avenue to check out.  I don't read as much about Paleozoic chondrichthyans so I don't really have an educated opinion on that.

 

Jess

Hi Jess

 

I hope you are doing well. Thank you for the input. I considered and looked into Symmorium. I see a few teeth out there labeled as Symmorium and they are all different from one another. I think that is a genus that might need a revision too. It could be one for sure but I lean Saivodus for the moment based on the publications I am seeing. That is part of the fun with these Cladodont teeth. What creatures did these belong too ? I enjoy the research myself.

 

Kurt

 

Kurt

[Archie]

Beautiful tooth, I agree with @Elasmohunter its strikingly similar to specimens of S. saivodus from the British Isles and Russia. 

[fossilsonwheels]

1 hour ago, Archie said:

Beautiful tooth, I agree with @Elasmohunter its strikingly similar to specimens of S. saivodus from the British Isles and Russia. 

I agree. It is a striking similarity. Thank you !

[Elasmohunter]

7 hours ago, fossilsonwheels said:

Hi Jess

 

I hope you are doing well. Thank you for the input. I considered and looked into Symmorium. I see a few teeth out there labeled as Symmorium and they are all different from one another. I think that is a genus that might need a revision too. It could be one for sure but I lean Saivodus for the moment based on the publications I am seeing. That is part of the fun with these Cladodont teeth. What creatures did these belong too ? I enjoy the research myself.

 

Kurt

 

Kurt

Saivodus is actually a member of the order Ctenacanthiformes GLIKMAN 1964 and not Symmoriiformes ZANGERL 1981, so it is not a "Symmorium." Both of these orders occur within the superorder Cladodontomorphi GINTER, HAMPE, & DUFFIN  2010, however. I wish that fossil dealers would be more careful in how they label their teeth! To their credit, though, it goes to show how difficult identifying cladodont teeth can be. . . .

Cladodont teeth such as this belonged to cartilaginous fish, specifically sharks, or members of Elasmobranchii. Perhaps one of the most well-known cladodonts would be Stethacanthus sp.; here's an image from Wikimedia Commons of two different species of Stethacanthus. These sharks are well-known because of the "radar-dome" like structure on their backs.



As far as I know, cladodont sharks have all gone extinct, and we don't have anything left like them.

[fossilsonwheels]

11 hours ago, Elasmohunter said:

Saivodus is actually a member of the order Ctenacanthiformes GLIKMAN 1964 and not Symmoriiformes ZANGERL 1981, so it is not a "Symmorium." Both of these orders occur within the superorder Cladodontomorphi GINTER, HAMPE, & DUFFIN  2010, however. I wish that fossil dealers would be more careful in how they label their teeth! To their credit, though, it goes to show how difficult identifying cladodont teeth can be. . . .

Cladodont teeth such as this belonged to cartilaginous fish, specifically sharks, or members of Elasmobranchii. Perhaps one of the most well-known cladodonts would be Stethacanthus sp.; here's an image from Wikimedia Commons of two different species of Stethacanthus. These sharks are well-known because of the "radar-dome" like structure on their backs.



As far as I know, cladodont sharks have all gone extinct, and we don't have anything left like them.
 

I am fairly familiar with Stethacanthus as we have a couple of teeth from S. altonensis  and we recently picked up a tooth from the Manse Burn Formation of Bearsden Scotland that is likely from Akmonistion. Kids LOVE learning about these strange creatures !

I think dealers go with an ID just to be able to sell items. Easier to sell a "Symmorium" than an unidentified shark tooth. I see this with dinosaur material pretty frequently. I do my best to educate myself before purchasing.

 

I read an interesting article that suggested Frilled Sharks MIGHT be related to Cladodonts. It was an interesting theory anyway. I will see if I can find that article again. Thank you for all the great information. I love learning about Paleozoic sharks and any information is welcomed.

[Joseph Fossil]

On 12/30/2019 at 8:57 PM, fossilsonwheels said:

I found this unidentified Carboniferous Shark tooth on line and was hoping I might get some ID assistance. The tooth is from the Harroldsburg Limestone, Washington County Indiana. The tooth is 16 mm. I did not find any publications on the formation so I have been researching recent discoveries and evaluations of existing taxa from the Paleozoic. I know the ID's with the Cladodont type teeth can get tricky and I have been trying to read up to see if I can get close to an ID. In my research, I found some Saviodus teeth from Ireland that look very similar. The tooth is figure E looks quite similar in my opinion but I am far from an expert so I wanted to put it to the forum.

 

Any thoughts or knowledge to share, feel free !

 

@fossilsonwheels I have almost no doubt in my mind this is a specimen of Saivodus striatus! This is a truly awesome find!!

[Joseph Fossil]

@fossilsonwheels Where exactly in Washington County, Indiana did you find this? What it a road side cut and how would one get there?

[fossilsonwheels]

14 minutes ago, Joseph Fossil said:

@fossilsonwheels Where exactly in Washington County, Indiana did you find this? What it a road side cut and how would one get there?

I purchased this tooth on line so unfortunately I can’t provide any information beyond the basic geological information.