Cretaceous shark teeth IDs #2 (Squalicorax)

[bthemoose]

Here are the Squalicorax sp. shark teeth I mentioned in my earlier post. As with the others, these didn't come with specific location information, but were most likely collected in the North Texas area. My IDs may be way off, so please correct me if I'm wrong. Thanks for looking!

 

The scale in the photos is in centimeters.

 

#1 - Squalicorax baharijensis

 

 

#2 - Squalicorax pawpawensis

 

 

#3 - Squalicorax falcutus

 

 

#4 - Squalicorax sp. - I'm not sure what species this might be. The blade is finely serrated in case it's hard to tell from the photos.

 

[Praefectus]

Very nice teeth! 

 

Identifying the early Squalicorax teeth is very hard and I'm far from an expert at it. Having the age and formation for where they were found would go a long way towards finding an accurate ID. I think that most of the teeth posted in pictures 1-3 generally fit what most call Squalicorax falcatus. This may be because S. falcatus is sometimes treated like a paleobucket with multiple species listed under the same name. Interestingly, I've heard some talk that S. falcatus has a type locality in Europe and that all the American species should be labelled S. hartwelli instead. I'm personally unsure of what all this means for Squalicorax identification. Hopefully, future research can resolve some of this. 

 

I've copied an ID image from Siverson et al. 2006 and a few teeth from my collection below for reference. 

 

 

 

 

[bthemoose]

Thanks, @Praefectus! Really helpful figure and photos.

 

In searching for images of potentially similar teeth a few days ago, I found this 2005 newsletter, which includes the following photo of Squalicorax teeth from the Eagle Ford group in Hays County, TX, that look quite similar in terms of coloration to the ones in my images #2 and #3. It's a low resolution photo and certainly not definitive, but perhaps they're from around there or another outcropping of the Eagle Ford. These were labeled as Squalicorax falcatus in the newsletter.