Protosphyraena Or Saurodon Rostrum And Additional Material

[sward]

Last Friday, I went to the hillside I normally hunt and found this:

Auspex and Dan were both kind enough to identify it as a rostrum (my first), possibly from either Protosphyraena or Saurodon.

I happened to find this in a gully just as I was leaving so I didn't have time to poke around the area. Being located in one of the gullies, I kind of assumed it might just be from wash and might have come from further up the hill.

Yesterday, I went back to the same spot and searched up-hill from where I found the rostrum, assuming it may have washed down the gully, but to no avail. I went back to the same spot that I found the rostrum and started digging just a little and came up with this:

After some clean-up and reassembly:

[toren]

I hope u returned the ruler to Denise

PS VN

Edited June 9, 2013 by toren

[sward]

I hope u returned the ruler to Denise

Mine's packed away. Just borrowed hers. She doesn't even know so don't tell her.

[KansasFossilHunter]

It's not from a Saurodon- way to thick. I think Protosphyraena would be a safe bet.

[Uncle Siphuncle]

very cool!

[Fossildude19]

Awesome find, Steven!

Congratulations on a very cool find!

Regards,

[lissa318]

That was DEFINITELY a productive return trip... lol Congrats!

[vertman]

Wow Steven nice find! It looks like a proto rostrum to me. I have a couple here you can use for comparison if you want.

[sward]

As I mentioned, this came from one of the gullies on my hillside and the remaining material that I dug out yesterday came from the side of the gully. I continued to dig a little further into the side of the gully, but didn't find anything else. I contoured the part that I dug out so that as the gully washes out more, it may reveal more of this critter, if there's anything else there.

Now all I need are some more good rains to do the work for me.

[Uncle Siphuncle]

keep looking for rootless tooth blades about an inch long or so.... don't dismiss any blades in the area as "just rootless shark tooth blades" without close scrutiny and/or images presented on the forum. proto had a cool tooth or 2 near the base of the rostrum. auspex nailed it right off the bat. i once found a tooth down by me in the corsicana fm which brent immediately pegged as P. permicosa.

[sward]

keep looking for rootless tooth blades about an inch long or so.... don't dismiss any blades in the area as "just rootless shark tooth blades" without close scrutiny and/or images presented on the forum. proto had a cool tooth or 2 near the base of the rostrum. auspex nailed it right off the bat. i once found a tooth down by me in the corsicana fm which brent immediately pegged as P. permicosa.

From looking at some of the google images and seeing the teeth you're referring to, I was kind of surprised that I didn't find any indication of teeth yesterday. You can bet I'll be keeping an eye on that spot as it continues to wash.

I'll have to go back through some of my "rootless shark tooth blades" that I've found in the past to examine them a bit more closely now that I know I'm dealing with Protosphyraena.

[Uncle Siphuncle]

the proto teeth will look more symmetrical about the plane going through the leading edge of the tooth than a shark tooth blade, which will have a more curved lingual than labial side.

[vertman]

I was thinking about this post off and on during the day and I came up with a question. Does anyone know the known age range for Protosphryaena?

[sward]

I was thinking about this post off and on during the day and I came up with a question. Does anyone know the known age range for Protosphryaena?

Per wiki...

"...Upper Cretaceous Period (Coniacian-Maastrichtian)..."

Also from wiki...

"Perhaps the oldest remains of Protosphyraena in North America have come from the upper beds of the Dakota Sandstone (middle Cenomanian) in Russell County, Kansas (Everhart, 2005; p. 91)."

[vertman]

Per wiki...

"...Upper Cretaceous Period (Coniacian-Maastrichtian)..."

Also from wiki...

"Perhaps the oldest remains of Protosphyraena in North America have come from the upper beds of the Dakota Sandstone (middle Cenomanian) in Russell County, Kansas (Everhart, 2005; p. 91)."

How does the age of the Grayson Formation compare to that of the Dakota Sandstone?

[sward]

How does the age of the Grayson Formation compare to that of the Dakota Sandstone?

Based on my resources, it appears the Grayson might be considered "lower Cenomanian", maybe a little older than "middle Cenomanian".

[erose]

Based on my resources, it appears the Grayson might be considered "lower Cenomanian", maybe a little older than "middle Cenomanian".

1-s2.0-S0195667107000985-gr2.jpg

Can you share where that chart comes from? I have recently been collecting Grayson/Del Rio material and most of my references show it as the very top of the Lower Cretaceous. But a few say upper. I'd like to get a better handle on this.

OH, and that is a really great fossil and all the cooler for the extra effort you put in to make sure you found as much of it as you could. That site obviously will keep on giving.

[sward]

Can you share where that chart comes from? I have recently been collecting Grayson/Del Rio material and most of my references show it as the very top of the Lower Cretaceous. But a few say upper. I'd like to get a better handle on this.

OH, and that is a really great fossil and all the cooler for the extra effort you put in to make sure you found as much of it as you could. That site obviously will keep on giving.

Here's the link I used to get the chart you asked about.

http://www.sciencedirect.com/science/article/pii/S0195667107000985

You'll find the chart on the left side of the screen. Click on it, then click "Figure Options" and it appears on the right side of the screen in a larger format.

I've seen the same thing about the Grayson being on the borderline of upper and lower cretaceous.

[erose]

Thanks! At 2008, that is one of the newest references I have seen with the Grayson in the Upper Cretaceous.

[sward]

Here's the link I used to get the chart you asked about.

http://www.sciencedirect.com/science/article/pii/S0195667107000985

You'll find the chart on the left side of the screen. Click on it, then click "Figure Options" and it appears on the right side of the screen in a larger format.

I've seen the same thing about the Grayson being on the borderline of upper and lower cretaceous.

Everything I've read puts the Grayson in the Washita Group. The problem for me is that the Washita Group is in both the upper and lower Cretaceous (upper Albian and lower Cenomanian). According to this chart, the Grayson appears above the Albian to me.

Here's a couple more references I've found dealing with the Grayson, but they're too large to attach. You might be able to do a google search and download them yourself.

Geology of Texas Volume 1 - Stratigraphy by Sellards, Adkins & Plummer dated August, 1932. This is the University of Texas Bulletin number 3232. (89.5Mb - 1018 pages)

Starting on page 270 of this document is a nice chart referencing the groups and what formations make up each group. This charts makes me believe the Grayson may be considered lower cretaceous, but remember, it's dated 1932.

Washita Group in the Valley of the Trinity River, Texas - A Field Guide by Perkins and Albritton dated 1955 (3.65Mb - 38 pages).

I hope this helps some. I have trouble finding much info about the Grayson in Texas, too. If you've got some other info, I'd like to see what reference material you may have. I don't figure there's such a thing as "too much info".

[erose]

I have the first and will look for the second reference. I use the one by Sellards all the time. I think the position of that boundary between upper and lower KT was always in flux since I have seen it both ways several times. Makes me want to see who is doing current work on that issue.

[Foshunter]

sward----Here is some Proto teeth from the North Sulphur-----Tom

Edited June 11, 2013 by Foshunter

[sward]

Can you share where that chart comes from? I have recently been collecting Grayson/Del Rio material and most of my references show it as the very top of the Lower Cretaceous. But a few say upper. I'd like to get a better handle on this.

Here's another resource that shows the Grayson considered as upper Cretaceous:

Integrated Albian-Lower Cenomanian Chronostratigraphy Standard, Trinity River Section, TX

(too large to attach here)

http://precisionstratigraphy.com/documents/ScotEtal2003%20NTx%20Alb-Cen.pdf

This one has a strat chart clearly showing the Grayson as the first formation in the upper Cretaceous. Apparently there's no real consensus on upper or lower Cretaceous.

Edited June 11, 2013 by sward

[sward]

sward----Here is some Proto teeth from the North Sulphur-----Tom

Thanks Tom. I'm going to have to go back through some of my teeth to check. I've found some that I knew weren't shark teeth blades. Maybe I can start narrowing some of them down.

[Shamalama]

That find really shows that it's good to not only poke around where you found something but also go back and check later to see if there was anything missed. Congrats!