Over 100 Fossil Collectors Hit the Creek

[BobWill]

How do you know it is from a Leptostyrax, if I may ask?

We don't. The caption should have said "probably a Leptostyrax". Since we don't know of another shark of that size from the Duck Creek Formation it's the current best guess based on a paper by Joseph Frederickson from 2015.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0127162

Edited April 25, 2016 by BobWill

[BobWill]

I just looked up the Dallas Paleontological Society of FB and asked to join! I would love drive down for a hunt sometime with my daughter! It's a little bit of a trek, but I would drive 4-5 hours for a good hunt sometime! I browsed the page and looks like an excellent resource! I'm excited to learn more!

Thanks!

The Dallas group is sponsoring another field trip on May the 7th. This one is much closer to where you live. An abandoned rock quarry near Gore Oklahoma is known for blastoids and we visit it almost every year. We can't find them in Texas so we make the drive to Ok. On the way back we also stop at a great Pennsylvanian age site for fossil plant material also much closer for you. Keep track of the calendar on our website for future trips.

http://www.dallaspaleo.org/event-2223477

[MikaelS]

I don't think Leptostyrax can be linked to those vertebrae. It's teeth are not nearly wide enough (especially in lateral files) and tooth-width is more directly linked to jaw size (and body size) than is tooth-height. Vertebrae extremely close in morphology to those described by Joseph occur in the Albian of Australia and are invariably associated with cardabiodontid dentitions (material includes partial skeletons). There are probably misidentified cardabiodontid teeth in various collections from the Duck Creek Formation given that cardabiodontid teeth occur in the Kiowa Shale in Kansas. Cardabiodontid vertebrae have very high preservation potential due to their robust construction and very large size. This may give the false impression that they were a common shark in a given area.

We don't. The caption should have said "probably a Leptostyrax". Since we don't know of another shark of that size from the Duck Creek Formation it's the current best guess based on a paper by Joseph Frederickson from 2015.

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0127162

[BobWill]

I don't think Leptostyrax can be linked to those vertebrae. It's teeth are not nearly wide enough (especially in lateral files) and tooth-width is more directly linked to jaw size (and body size) than is tooth-height. Vertebrae extremely close in morphology to those described by Joseph occur in the Albian of Australia and are invariably associated with cardabiodontid dentitions (material includes partial skeletons). There are probably misidentified cardabiodontid teeth in various collections from the Duck Creek Formation given that cardabiodontid teeth occur in the Kiowa Shale in Kansas. Cardabiodontid vertebrae have very high preservation potential due to their robust construction and very large size. This may give the false impression that they were a common shark in a given area.

This not a topic I have much personal experience with. I suppose the common appearance of Leptostyrax teeth in north Texas and their being the largest found here could be the reason for the assumption but there may have also been finds with associated material. Maybe some local shark hunters can help us with this. I see where Cardabiodon teeth appear to be less narrow and are normally found only in Austrailia, Canada and Europe. If they are here too that deserves some research, maybe a paper.

[MikaelS]

In the mid-Cenomanian to mid-Turonian Cardabiodon's main area of distribution was the Western Interior Seaway of North America. In the Albian however cardabiodontids (which includes other genera as well) seem to have been most common in the great inland sea that covered eastern Australia. Joseph's identification of those big vertebrae will be revised in forthcoming publications. Shark vertebrae have proved to be far more diagnostic than people have realised, as shown by research done by, in particular, Mike Newbrey. Would be interesting if people posted images of lamniform teeth from the Duck Creek Formation.

I think I mentioned in another post that vertebrae of Cardabiodon ricki are the only non-anacoracid centra I have found at the type locality of that taxon and yet its isolated shed teeth make up less than 1% of all surface collected non-anacoracid lamniform teeth found at that locality. This exemplifies the durability of cardabiodontid vertebrae.

Edited April 26, 2016 by MikaelS

[BobWill]

In the mid-Cenomanian to mid-Turonian Cardabiodon's main area of distribution was the Western Interior Seaway of North America. In the Albian however cardabiodontids (which includes other genera as well) seem to have been most common in the great inland sea that covered eastern Australia. Joseph's identification of those big vertebrae will be revised in forthcoming publications. Shark vertebrae have proved to be far more diagnostic than people have realised, as shown by research done by, in particular, Mike Newbrey. Would be interesting if people posted images of lamniform teeth from the Duck Creek Formation.

I think I mentioned in another post that vertebrae of Cardabiodon ricki are the only non-anacoracid centra I have found at the type locality of that taxon and yet its isolated shed teeth make up less than 1% of all surface collected non-anacoracid lamniform teeth found at that locality. This exemplifies the durability of cardabiodontid vertebrae.

The Collector's Guide to Fossil Sharks and Rays From the Cretaceous of Texas 1993 Before Time by Bruce Welton has Leptostyrax teeth occurring in "Weno, Pawpaw, Duck Creek, Grayson and Del Rio Formations of the Albian and Woodbine and Pepper Formations of the Cenomanian throughout Texas". Have Cardabiodon teeth been found in Texas too?

[Barerootbonsai]

Wow