Search the Community
Showing results for tags 'cretaceous sharks'.
-
From the album: Sharks
Just a handful of Cretaceous species, most from North Texas. The sea that bisected North America ~85 million years ago played host to a diverse and burgeoning ecosystem that supported many species of sharks. It was likely due to specialization that allowed these sharks to all live in the same place and time.-
- ginsu shark
- shark teeth
- (and 12 more)
-
Hey all, I'll try my best to be brief but detailed in my question, but I'd like it to be a discussion as well, if there is one to be had. From what I understand, the Western Interior Seaway had what appeared to be too many large, active predators for a similar environment to support, especially when one considers how shallow the seaway was. There were the many species of Mosasaurs, with other large predators like Xiphactinus, with the typical western interior seaway sharks as well. This would make me think that that there are two possible outcomes - either an absolutely enormous supply of prey at the lower trophic levels, or some serious competition among the predators of the higher trophic levels...or maybe both. Now, I understand niche partitioning plays a role. For example, evidence suggests Squalicorax primarily scavenged, while Cretoxyrhina were likely sight oriented, agile top predators. While that may put these particular sharks away from competing with each other, other predators, for example, did theoretically fill the same niches as Cretoxyrhina. For example, the fact that Xiphactinus, Cretoxyrhina, and some large Mosasaurs can all be found in the same locales sometimes suggests not only that that these large, agile, theoretically "top predators" not only lived at the same time, competing for (probably) the same prey, but were in each other's neighborhood as well. How is this possible, or sustainable? Now, perhaps I have my time lines wrong, perhaps a million years this way or that..So this is where I have a few more species specific questions. For example: Tylosaurus is a genus that can be found, for example, in the north sulfur river, and is late Cretaceous. Mosasaurus maximus is also late cretaceous, and the one specimen I know of that comes to mind was found in Austin, supposedly in the "Navarro" formation, whereas the NSR is Ozan. While I couldn't find an exact age for the Navarro, both are late Cretaceous, and at first glance there's not much to suggest that M. maximus and Tylosaurs were much different from each other... did they really evolve to be in direct competition? The same could be said with Cretoxyrhina and Cretodus. I found shockingly little about Cretodus on the web, but what I did find was that they were able to determine from that lovely speciman from Kansas that at least Cretodus houghtonorum could reach somewhere around 22 feet in length, whereas it's thought Cretoxyrhina could achieve lengths of 26 feet. Again, these are both large active predators that (I think) lived at the same time, and if looking at the teeth on Cretodus, it does seem reasonable to think that they were active predators - putting them in direct competition with each other and the rest of the active seaway predators. If you made it this far through my ramblings, thank you! If you know more than me please chip in - I'm quite specifically curious about Cretodus's role in the the food web, but have a broader interest too in trying to understand how all these mega sized predators co-existed with one another.
- 11 replies
-
- 2
-
- western interior seaway
- cretaceous sharks
-
(and 1 more)
Tagged with:
-
Any tips to differentiating Cretodus and Cretolamna teeth?
Jared C posted a topic in General Fossil Discussion
Hey ya'll - despite my best efforts I have a very tough time telling apart the teeth of Cretodus and Cretolamna - most of what I gather so far is that it *seems* that the blade on a cretodus is sometimes slightly longer and less robust compared to cretolamna, but this has large variation and might not even be a real pattern worth noting. Any tips?- 2 replies
-
- cretodus
- cretolamna
-
(and 1 more)
Tagged with:
-
Scientific information about Cardabiodon
fossilsonwheels posted a topic in General Fossil Discussion
I had never heard of Cardabiodon prior to joining The Fossil Forum. I understand that it is a fairly recently described shark, I believe around 20 years or so. I have no intention of adding a tooth to our fossil line up. I have not seen many for sale and the one I did see was very expensive. It is still an interesting shark to consider adding to the presentation, even without having a fossil to represent it. It is a mystery to me. I know very little about it but a giant Cretaceous era shark would be of interest to the kids I am pretty sure. Can anyone point me in the direction of more information on Cardabiodon? A scientific paper or a bit on the ecology of the shark. I have not found much in my own search so I figure there are probably people here that would know more or point me in the right direction.- 2 replies
-
- fossil information
- scientific information
- (and 2 more)