GSA Las Vegas

Well, Wes found out he cant give the talk at the GSA meeting in Las Vegas. The honor falls to Me!

Paper No. 12-9 11:00AM-11:20AM, March 20, 2008

A first time for everything I guess.

Clypeoceras may be Guodunites

A hint in the air of an upcoming publication in which the "Koninckites" > Clypeoceras of the Confusion Range will be assigned to the Genus Guodunites.

see this post http://ammonoidea.blogspot.com/2007/07/un-identified-ammonoids.html

Churkites vs Arctoceras

Churkites noblei Jenks 2007

The ornamentation is exactly like Arctoceras tuberculatum, the only difference is the shape of the venter. These have an acute venter, becoming almost oxyconic in large shells and Arctoceras has a well rounded venter (almost semi-circular). This could be sexual dimorphism with the round ventered forms being female and the acute ventered forms male.

Of course there are two different sizes found in the Confusion Range, the small 100-180mm and the large 300mm, perhaps these are dimorphs of Churkites and Arctoceras isnt congeneric.


Jenks, J. F., 2007, Smithian (Early Triassic) Ammonoid Biostratigraphy at Crittenden Springs, Elko County, Nevada and a New Ammonoid From the Meekoceras Gracilitatis Zone, in, Lucas S. G. and Spielmann, J. A. eds., Triassic of the American West, New Mexico Museum of Natural History and Science Bulletin 40

Opportunistic Bloom?

I am really starting to wonder if the Anasibirites Beds could preserve an opportunistic bloom. If the Prionitids (and not all the other ammonoids) began or found a way to prey on the micro gastropods of the time they may have had a great advantage and a large amount of food. Whether the beds in the Confusion Range preserve a mass mortality event or just the preservation of an unusually high amount of dead shells would need an answer.
An extinction at the base of the anasibirites beds, and a small climate gradient left the anasibirites beds to be very cosmopolitan. Perhaps they were just the most common ammonoid in the latest smithian so any unfavorable water or climatic condition would have killed only the anasibirites fauna.

Still so much to learn and figure out in all this.

Galfetti, T., H. Bucher, A. Brayard, P. A. Hochuli, H. Weissert, K. Guodun, V. Atudorei, J. Guex, 2007, Late Early Triassic climate change: Insights from carbonate carbon isotopes, sedimentary evolution and ammonoid paleobiogeography,
Palaeogeography, Palaeoclimatology, Palaeoecology 243, 394–411

Kidwell, S.M. 1991. The stratigraphy of shell concentrations. In: P.A. Allison and D.E.G. Briggs (eds.), Taphonomy: Releasing the Data Locked in the Fossil Record, 211–290. Plenum Press, New York.

DIANA L. BOYER, DAVID J. BOTTJER and MARY L. DROSER, 2004, Ecological Signature of Lower Triassic Shell Beds of the Western United States, PALAIOS, v. 19; no. 4; p. 372-380

Syngastrioceras websteri

Three views of what I think now is Syngastrioceras websteri Titus 2000. The top two are latex casts of the external mold (bottom).

Eumorphoceras girtyi zone

I found a mold of either Eosyngastrioceras inexpectans or Syngastrioceras websteri in the E. girtyi zone yesterday. These two are nearly identical going by shell shape and ornamentation, the suture would really tell the story, but there are no sutures in fossils that only have external molds.

Cardioceras hyatti

Found these Cardioceras hyatti in the Redwater Member of the Stump Formation. I had been looking for new collecting localities on Google Earth all summer, and decided to stop by on the way home from Big Wonderful this weekend, glad I did!

Ammonoid collecting

Dieter Korn on the left and Alan Titus on the right. at Granite Mt., Juab County Utah September 1, 2007

I went collecting with Dr's Alan Titus and Dieter Korn on August 30 thru Sept. 3, 2007. It just happened to be the hottest September day on record, 104 on the 2nd. Still, I had a great time and learned alot from these guys.