Campanian hunters and shark experts... have you seen this shark tooth?

[Mikrogeophagus]

Hey everyone,

 

I've recently been interested in a weird tooth morphology I have found a couple times in the Middle Campanian Ozan of Austin. At the moment, I have it ID'd as Serratolamna cf. caraibaea based off of a paper on Aguja sharks (https://doi.org/10.1016/j.cretres.2016.08.008). My specimens seem to be a single anterior and single lateral. These teeth appear to have a nutrient groove, multiple pairs of cusplets, smooth labial and lingual faces, and a basal bulge overhanging the root. They are each about 11 mm from root to tip of the cusp. Something to note is that S. caraibaea had previously only been found in Mexico, Trinidad, and West Africa. I wonder if it's some warmer water species? I wish I could read the species's original description, but alas I have no access to the paper.

 

(Left): Anterior tooth (L) and lower? lateral tooth (R); (Right): Anterior tooth (L) and lateral tooth (R)

(Left): Labial view lower? lateral tooth; (Right): Lingual view lingual tooth

 

I've done some digging trying to find this tooth online from places like the NSR and New Jersey, but the closest I can find is Carcharias samhammeri which I think has too many differences. C. samhammeri imo has a more pronounced lingual protuberance, only a single pair of cusplets, and no basal bulge on the labial side, and "thinner root lobes" (hard to put into words sorry). Carcharias holmdelensis has similar issues along with the presence of striations on the lingual face. Scapanorhynchus doesn't look right and neither does Cretalamna.

 

In fact, what partly prompted me to make this post was noticing this tooth's apparent similarity to a Paleocene/Eocene taxon called Brachycarcharias lerichei. What makes the story even more interesting is its criminal history, formerly being under the name Serratolamna lerichei before the creation of Brachycarcharias of the family Odontaspididae.

 

Brachycarcharias lerichei from elasmo.com. Note the anteriors and laterals!

 

Brachycarcharias lerichei lower lateral from elasmo.com

 

The genus Serratolamna itself also has some shakiness to its name. A similar taxon, Serratolamna khderii, of the Campanian in France and Jordan has a past of jumping in and out of the families Odontaspididae and Serratolamnidae. All this to say I'm beginning to wonder if there is a taxonomic connection between my specimens and the genus Brachycarcharias or at least Odontaspididae that isn't yet recognized in academia.

 

One major issue though, is that I only have a couple of these teeth (I've got a really bad itch to hunt in Austin again, but that'll have to wait). I am wondering if any other Campanian hunters have come across something similar and has photos to share? And for the shark experts, I wonder what are your thoughts on this information? Does it pique your interest or is it a "nothing burger"? Any clarification is immensely appreciated!

 

It's not the craziest or coolest tooth design by any means, but it's enough to keep me longing for some answers.

 

 

 

 

 

Edited May 30, 2023 by EPIKLULSXDDDDD
Photos

[rocket]

Interesting finds, found some similar ones many year ago in northern german campanian sediments and placed them to "Cretalamna".

very variable genus...

 

 

app20120137.pdf

[Mikrogeophagus]

4 hours ago, rocket said:

Interesting finds, found some similar ones many year ago in northern german campanian sediments and placed them to "Cretalamna".

very variable genus...

Any pics of your finds? 

 

Cretalamna has become a favorite of mine in part because that paper sheds so much light on its diversity. I feel much more complete labeling my finds with names that aren't just buckets like Squalicorax falcatus. 

 

I've looked at the Campanian teeth from that paper in the past. I have found some Cretalamna sarcoportheta in Austin. However, I don't think the "Serratolamna cf. caraibaea" specimens line up well with C. sarcoportheta or Cretalamna borealis, another Campanian species listed. The Cretalamna don't have extra cusplets and I don't see as prominent of a nutrient groove if any at all. The cusplets are also a different shape. Cretalamna seems less pointed and tend to direct outward from the midline of the tooth. My teeth are more triangular and the lateral seems to have cusplets that curve inward. That being said, there also many similarities between the teeth, so maybe I'm getting too hung up on subtleties.

[rocket]

I will look for some pics, most of my westfalian material is housed in two museums

I add two pics of turonian finds from Westphalia, one was taken around 1990 and is a scan

so, the Quality of the pic is a fossil, too..

 

[Rock Hound]

There are soooooooo many different species of shark teeth known, and who knows how many unknown.

 

Nice teeth.

[ThePhysicist]

I haven't seen Cretalamna of this position with a nutrient groove, so that feature comfortably precludes that diagnosis. Unfortunately my knowledge of Campanian sharks is failing me here. Interesting teeth.

[Al Dente]

On 5/30/2023 at 2:17 AM, EPIKLULSXDDDDD said:

At the moment, I have it ID'd as Serratolamna cf. caraibaea based off of a paper on Aguja sharks

 

I think your teeth and the Aguja teeth are probably the same species. Not sure if S. caraibaea is accurate for either. I think S. caraibaea is Maastrichtian. Do you find any S. serrata at your site? These are mostly Maastrichtian but also late Campanian. The anterior teeth look similar to your teeth. 

[Mikrogeophagus]

No sign of S. serrata at my site. Besides these teeth, I only have Squalicorax and Scapanorhynchus texanus from the matrix. I didn't seriously consider S. serrata before since my presumption was that the Cen TX Ozan/Sprinkle Formation was Middle Campanian in age which I thought was too early. Maybe the Sprinkle extends into Late Campanian seeing as it's supposed to be an upper portion of the Ozan. If I could find a lateroposterior tooth in the future, that would straighten things out. It's just weird to think they wouldn't come out of the heavily hunted NSR's Ozan despite coming out here. 

 

I should mention this place is definitely Ozan/Sprinkle. It is referenced in multiple papers and the usgs map as such.

[siteseer]

On 6/1/2023 at 5:12 AM, Al Dente said:

 

I think your teeth and the Aguja teeth are probably the same species. Not sure if S. caraibaea is accurate for either. I think S. caraibaea is Maastrichtian. Do you find any S. serrata at your site? These are mostly Maastrichtian but also late Campanian. The anterior teeth look similar to your teeth. 

 

I have a tooth like those from the Maastrictian of Morocco and it was identified as an S. serrata lower tooth.  I bought it at a Tucson show as part of a small lot with a couple of pathologic teeth.  Anterior and lower teeth of S. serrata are less often found than the uppers so it's a little weird for that tooth to be found in the absence of the more common uppers but it's a definte avenue to look into.  Unfortunately, I can't find my specimen, but when I do, I will get it photographed.