DPS Moss Creek Field Trip: Micro Highlights!

[Mikrogeophagus]

Hm I should expect as much from a shark called “heterodontus”.

[Jared C]

22 hours ago, EPIKLULSXDDDDD said:

NSR Guidebook lists these as Stephanodus

I've paged through that guidebook before with @GPayton, and we noticed several errors - one of them being this (I can also vouch that these are Hadrodus). I didn't spot any more cretaceous errors that I can remember beyond that, but I'm no expert. Graham's strong suit is the Pleistocene and he noticed some conspicuous errors in their Pleistocene section as well. It's a good book, but when it comes to ID'ing the weirdos, it might be worth considering it with a pinch of salt. 

Edited October 4, 2022 by Jared C
elaboration

[Mikrogeophagus]

Yeah I went back to take another look and saw the book is from 2001. I’m sure a lot has changed since then regardless of errors on the writer’s part. I guess these identifications aren’t as rock solid as I would have liked, but that’s how it is sometimes. I walked out of the library with a nice book on Oklahoma sites so the stop was worthwhile at least.

[ClearLake]

21 hours ago, EPIKLULSXDDDDD said:

Yeah I went back to take another look and saw the book is from 2001. I’m sure a lot has changed since then regardless of errors on the writer’s part.

 

On 10/4/2022 at 2:35 PM, Jared C said:

It's a good book, but when it comes to ID'ing the weirdos, it might be worth considering it with a pinch of salt.

Again, I will emphasize, there is a much more recent (2019) 2nd edition of this book.  Its almost always best to go with the more recent as things do change in the scientific world in almost 20 years.   I think we're quite lucky that the guide has been updated and is still very useful for this popular collecting locality.  And its still available from the Dallas Paleo Society for a very reasonable price (and no, I am not getting any royalties -haha, just trying to offer a helpful suggestion):  https://www.dallaspaleo.org/Store

[Mikrogeophagus]

Welp, it seems like every time I open up a book on Cretaceous sharks, I learn something new about this batch. Can't really complain though, it's always fun to sort things out and add a new genus to the list. Fitting with a common theme in this thread, the issues first began when I assumed a tooth was simply broken and not entirely its own thing.

 

 

Here's the pic of what I once thought was all Ischyrhiza. Turns out, as had been pointed out by @MarcoSr, there is a little Squatina in the red circle. A small Cantioscyllium also managed to slip through in the very middle of all the teeth. I've looked at these teeth so much, they are practically seared into my mind. The one just to the left of the biggest Ischyrhiza in the picture was the specimen I had assumed was chipped, though I maintained some suspicions. Well today, when going through Farish's guide to sharks and rays, I happened to recognize a familiar shape. 

 

 

Scyliorhinidae (cat shark) is the genus shown above. After reading about it, I quickly dug through my Moss Creek specimens to do some comparison. I tried to take pics, but obviously it can be a struggle with things so small.

 

Notice the lack of a nutrient groove

 

There are a couple characteristics too fine to capture on camera. Firstly, the little "hole" shown in 1a from Farish's book is present on my specimen (trust me  ). Unlike the tooth from 1a, but like other cat shark teeth from online and elsewhere in the book, there is some faint wrinkling on the base of the crown as it connects with the root. I'm fairly confident in the genus and have no idea in terms of species. If you have any thoughts/criticism please feel free to share!

 

P.S. I am using a library loan of Farish's book. It's pretty old, so my source could be outdated!