Flemingitid?

View showing longitudinal sculpture

Apertural view

Close-up of the exposed sutures

Flemingitid? Suture

Suture of the Flemingitid? the top is the last one

showing the suture near the umbilicus.


The specimen has a lot of phosphate replacement like most of the other fossils from this quarry. I dont know if this has deformed the suture line, some look distorted but for the most part, the suture line shown seems to be fairly well preserved.

Flemingitid ?

From my old "Meekoceras" quarry (in section DH-4), w/Aspenites, Inyoites, Proptychitid. Bed & stratigraphic position unknown but possibly equivalent to bed 9???

Manuscript resubmitted

AMMONOID BEDS IN THE LOWER TRIASSIC THAYNES FORMATION OF WESTERN UTAH, USA
Daniel A. Stephen, Kevin G. Bylund, Paul J. Bybee, and Wesley J. Ream

Dan sent in the revised manuscript and figures last night. Reviewers should be getting a copy shortly. I think it looks and reads great. Between me and the reviewers, Dan had a handful, trying to keep everyone happy and still writing what he wanted, I thank him for his patience and understanding.

Lanceolitidae

Lanceolites ?bicarinatus on the left and the one I found in April (this post) on the right. They seem to have all the same elements but the L. ?bicarinatus seem to be a little more ammonitic. Perhaps the ammonitic elements were worn off of the right specimen?

DH1 Annotated Outcrop Photo

Just because the beds show up so well through the snow.

Dan's Paleontology Class

Dan and his paleo students in the Wheeler Amphitheater looking for Trilobites

At Jims house

Jim Jenks, Dr. Hugo Bucher, Dr. Arnaud Brayard and Kevin Bylund
a very small part of Jim's fantastic collection seen over my shoulders.

In the Field

Dr. Hugo Bucher, Dr. Arnaud Brayard and Jim Jenks
out on the outcrop

Arnaud at DH-1 in the snow



Dawn getting ready to take vengence on a fossil

DH-1 Bed 10

Something found this weekend. Sutures show well on the lower part of the whorl (bottom of photo), above the crack (on the left) are the inner sutures (in the impressed zone).

Another view of the same specimen.

Xenoceltites

An update for this old post

Xenoceltites-Boreoceras-Wyomingites

I found an old photo of the specimen on display at the museum. Where did those constrictions come from? I am leaning more toward Xenoceltites now, as the sculpture, especially on the early whorls, is more like it than of Wyomingites. I could have swore all the whorls were smooth.

Measuring Early Triassic Sections

Section DV-2 is just on the other side of this outcrop. Shown are beds 1-4 with many smaller or unfossiliferous beds in with them. Only the beds containing ammonoids are numbered.

Jim, Dawn and Dan standing on Bed 4 at DV-1

Baby Ammonoids, Baby Gastropods

Small ammonoids among small gastropods

A newly hatched Baculites ?

More small ammonoids and gastropods with a fish scale.

From the Cretaceous Mancos Shale, Scaphites whitfieldi Zone, the coiled ammonoids could be Scaphites whitfieldi or Prionocyclus novamexicanus.

See our paper: Daniel A. Stephen, Kevin G. Bylund, Patricia Garcia, R. Dawn McShinsky, Holley Jean Carter, 2012, Taphonomy of dense concentrations of juvenile ammonoids in the Upper Cretaceous Mancos Shale, east-central Utah, USA. Geobios 45(1):121-128. for updated information.

DH-1 Bed 7.6

From lavender beds below bed 8

DH-2 Photos

A large Arctocerid mold, the body chamber was filled with mud so it is preserved, the phragmocone was probably crushed after it left it's imprint in the soft bottom.



Jim collecting DH-2 bed 1



The DH-2 anticline looking south.
Permian red beds in the foreground, the basal Thaynes limestone on the south side of the north DH-2 fault well exposed beyond.

Something new (at least to me)

I found this while doing a little mapping this weekend. I think it is some form of Ussuriid. From the Early Triassic

See this post for update

Presentation on line

If you go to the abstract, you can now download a pdf file of the presentation I gave at the GSA meeting in Las Vegas last month.

Abstract for Presentation 12-9

4.8 Mb presentation handout download.

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