OK. Pulled off of fish to work on one of our dinos. I'm currently prepping out skull material in hopes of narrowing down the beastie. Just started so no pics yet.

The basics:

Centrosaur from the upper Judith River formation of Montana.

Prepped so far: Maxilla, metacarpal, coracoid, dorsal vertebra, few phalanges. In prep: possible quadrate, possible frill (very root rotted).

What I need to know: What are the critters running around there at that time, and what can be diagnostic? Stuff I should be looking for, what stuff I should be looking for should look like.

Preliminary diagnosis by the field crew was Monoclonius. Rostrum reportedly present, but I haven't run into it yet. And again, any references would be helpful (espescially PDFs).

Well, from the Judith River you have only two known so far: Avaceratops and Monoclonius. However, I keep hearing that "Monoclonius" could be pulled as a valid species...we will just have to wait for the publication on that one. Right now it is listed as a possible centrosaur. Depending on how high or low in the section you are and assuming that you are positive you are in the Judith River, there are some known from the Two Med (Einiosaurus, Achelousaurus, "Brachyceratops").
What part of Montana was it found if (if you know and can tell)?

Unfortunatly these guys are all known by thier skulls. Avaceratops had a skeleton with both humeri, some verts and ribs, left radius and ulna, both femora, tibiae, and fibulae, several metacarpls and metatrsals and numerous phalanges. All of this is figured in Penkalski and Dodson's paper - JVP 19(4): 692-711. I have a copy if you need it. I will see if I have it as a PDF when I get home tonight. The skull also had maxillae, both quadrates, quadratojugals, squamosal (left) and parietal (among other parts).

Most of my papers are chasmosaurines but I can look and see what I have for the centrosauries, particuarly for the Montana area.

Please post some pictures as soon as you can! I am really interested in seeing what you have :D . What is it's ultimate fate?

I don't have the Avaceratops paper as a PDF, but I can mail you a copy if you send my your address.

Thanks for the help. We are definitely in the Judith River fm, fairly high in the section, near the contact with the Bearpaw shale. our site is in "north central Montana".

Skull material we have so far includes a maxilla, quadrato-jugal, and a section of frill with at least 4 of the little knobbies on it. The beast was weathering out skull first, and it appears to have slumped a bit. The skull is disarticulated, fractured, weathered, and root-rotted. Yuck. Camera out of service now, but I should be able to get a few photos out by Friday.

Ok, sounds sweet! Looking forward to seeing what it looks like. I sent you the paper today. Thanks for telling us about it :D

Got my camera back from my wife today, so I can take picos tomorrow. The frill that I have exposed is really in bad shape, but you can see the general shape just fine. I may have to do some outlining in MS paint. There is a very shattered piece unser the frill which may be more frill, or pelvic girdle. I'm calling it "frillium".

Just to keep those watching from the sidelins in the know, there has been some behind the scenes photo/paper exchanges between me and Dinochick. From what I have understood:

Front runner is Avaceratops, though our material is much larger than the holotype.

Monoclonius is the only other known Judith River ceratopsian.

Two Medicine formation centrosaurs should not be ruled out though (same age, different part of Montana)

I'll post some pics when I remember not to delete them from my camera after downloading them at work. ???