North Texas Ammonite With Rostrum

[BobWill]

NSR King spotted this ammonite with a complete rostrum at the end of a hunt last week with no time to chisel it out so I went back to get it for him. The matrix was already cracked but I was able to get all the pieces that came out easily and glued it back together. I noticed the notches on the ribs of the phragmocone which I think is a kind of Schloenbachia but it may be a species of Mortoniceras. Both are supposed to be found in the Duck Creek Formation here. It's lower Cretaceous. I think Dan Woehr corrected me on this ID before but I couldn't find the reference.

[Foshunter]

Nice, difficult to find with the rostrum----Tom

[Raggedy Man]

Well, look at that...fantastic find!

[fossilized6s]

Very nice find! I wish the piece as a whole was in better condition for ya.

[Ptychodus04]

Well done. I would say it's a Mortnoiceras. Schloenbachia has very pronounced tubercles on the ribs if I remember correctly.

[JustPlainPetrified]

Wow! Very nice find indeed!

[Uncle Siphuncle]

i'll play it safe with mortoniceras sp. on that one.

[BobWill]

Thanks all. I won't see N.S.R King for a few weeks so I didn't think he would mind me posting this for him. I think I would have needed a rock saw and plaster jacket to get those ribs out without breaking. Even then some of it just wasn't solid rock at all. Many Morts have tubercles too Kris, some three rows, but it's hard to see them on this except the ventrolateral row in the one view.

What bugs me is the notches on the ribs before the body chamber. They are hard to see well here, I'll try to get a close-up. It makes them very different from the other Morts I find here. I often see these with just the phragmocone left and notches on all the ribs. I can't find anything with those in the description in my references but I think I've seen it in print somewhere before. The only picture I find with obvious notches on ribs is in Chuck Finsley's field guide labeled Schloenbachia but other references don't show or mention any for those either. It just seems like an excellent distinction to be left out of a description.

Edited September 19, 2014 by BobWill

[BobWill]

I found it! I knew I'd seen the description before. It was Elobiceras artiforme Spath 1922 until 1982 when it became Mortoniceras (M.) artiforme reclassified by Renz.

At least that is where I had seen the description of the notches on the ribs. The only problem with that is it's supposed to be in the Kiamichi Formation which I might believe could be at the base of the Duck Creek here except this was found in a solid layer at the very top of this site which has Duck Creek material all through it.

It looks like for now the label will read Mort sp. like Dan suggested.

[Ptychodus04]

You may be holding a range extending ammonite if that's the case! That makes it seven more interesting.

[NSRhunter]

Thanks so much BobWill for your hard work! I just discovered this post by accident but thank you so much for getting out the specimen and prepping it for me. It sits highly on one of the shelves in my collection

[nearpass]

Thanks so much BobWill for your hard work! I just discovered this post by accident but thank you so much for getting out the specimen and prepping it for me. It sits highly on one of the shelves in my collection

I would love to see what it looks like now after prep

[BobWill]

I think NSRhunter is just thanking me for removing it. Maybe he did some prep on it since a year and a half ago. I'm anxious to see the new one he just found when it gets prepped. It has a longer rostrum and is complete. See it on the "fossil hunting trips" sub-forum under "over 100 fossil hunters..."

[JarrodB]

Killer find Jordan. You have a real eye for spotting rare fossils. Great job getting it out Bob.

[Ludwigia]

Neat!

[Boehm1969]

Sweet!!!