Xenacanthus or Orthacanthus? What is the Difference?

[Jesuslover340]

Hello everyone,

Curious if anyone knows the difference between Xenacanthus and Orthacanthus shark teeth? Particularly as it concerns shark teeth from the Permian site in Waurika, Oklahoma? Have quite a few shark teeth from there and am unsure how to determine which is which. There's also Barbclabornia, to complicate matters! Any help would be appreciated (and yes, I have seen the rhynie chert website on them, but it doesn't show/tell the difference between the three kinds)

[fossilsonwheels]

I believe the teeth from Waurika are going to be Orthacanthus and Barbclabornia. I do not think any are considered Xenacanthus. I have read there are a couple of distinguishing factors. I believe one is cross section of cusp points. Another is microscopic anatomy I think.

 

The larger teeth from Waurika are often assigned to O. compressus or O. texensis, the smaller ones to O. platypternus. You can differentiate between which of the larger species is which but I have never tried to get that specific.

 

Barbclabornia will be very smaller and lack the small central cusp. They are Bransonelliformes, a sister taxon to Xenacanthiformes.

[Troodon]

Here is a publication that may help

 

https://geojournals.pgi.gov.pl/agp/article/view/10334/8846

 

[Jesuslover340]

2 hours ago, Troodon said:

Here is a publication that may help

 

https://geojournals.pgi.gov.pl/agp/article/view/10334/8846

 

Wowza. Yep...it would...if I could wade through it all and understand what is being said to differentiate them 

[Jesuslover340]

5 hours ago, fossilsonwheels said:

I believe the teeth from Waurika are going to be Orthacanthus and Barbclabornia. I do not think any are considered Xenacanthus. I have read there are a couple of distinguishing factors. I believe one is cross section of cusp points. Another is microscopic anatomy I think.

 

The larger teeth from Waurika are often assigned to O. compressus or O. texensis, the smaller ones to O. platypternus. You can differentiate between which of the larger species is which but I have never tried to get that specific.

 

Barbclabornia will be very smaller and lack the small central cusp. They are Bransonelliformes, a sister taxon to Xenacanthiformes.

 

It would seem you are right. My information must be outdated or misidentified,  as I am going off of the little identification placard that a website sends with their matrix from the area. It mentions Xenacanthus sp., but I note that Orthacanthus is now mentioned with similar species'name, so I am guessing the genus has been changed.

 

Anyways...so Barbclabornia is only 1-2 mm in size amd lacks the central cusp, yes? I am having difficulty finding just a rough generality to determine between O. compressus, O. texensis, and O. platypternus. I just have quite a few teeth that I'd like to try and separate them into perhaps more specific groups, if at all possible,  without being too worried about being precise for every tooth. If that makes sense. I'd like to narrow them down to species generally if I can, but not too stressed about definitively identifying each tooth down to the species level. 

[fossilsonwheels]

Yeah Barbclabornia are very small and lack the small third cusp. If you some research and you can probably figure out how to separate the Orthacanthus. You can also try putting a few on here to see if you can get an ID.