Allosaurus Posted April 5, 2015 Posted April 5, 2015 While on my first dig of the year in Montana, I came across this weird little piece laying out on the ground. I'm not really sure what it could be, but it does vaguely remind me of something I found last year that is still unidentified. Two Medicine Formation, western Montana. More pictures soon to come.
Allosaurus Posted April 5, 2015 Author Posted April 5, 2015 Size comparison pic and a zoomed in photo
Allosaurus Posted April 5, 2015 Author Posted April 5, 2015 Underside and another couple semi closeups. Like I said I'll take a couple more in focused closeup pics as soon as I get home.
bone digger Posted April 6, 2015 Posted April 6, 2015 Looks a lot like an ossicle from an ankylosaur!
Allosaurus Posted April 6, 2015 Author Posted April 6, 2015 Really? Oooo, that's exciting. Now I've ready a couple definitions of the term of ossicle, one referring to part of a bone in the ear, and another referring to the bony part of the skin (similar to an osteoderm).So what exactly is an ossicle?
bone digger Posted April 6, 2015 Posted April 6, 2015 Yes, basically small armor scutes that were between the larger scutes or on areas where they could only have small pieces of armor. I hope that is what it is, lets see what others think as well.
Carl Posted April 6, 2015 Posted April 6, 2015 Sorry - definitely not an ankylosaur osteoderm. This looks like a rock with some sort of natural acid etching.
Auspex Posted April 6, 2015 Posted April 6, 2015 ...This looks like a rock with some sort of natural acid etching. ...or pyritization? "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease!
Opisthotriton Posted April 6, 2015 Posted April 6, 2015 Ankylosaur ossicles have a crosshatched texture on their flat bottom side. Very distinctive.
Allosaurus Posted April 6, 2015 Author Posted April 6, 2015 Oh well sad day. I found another one similar to this a couple inches away but forgot to pick it up. I'll be there again this weekend so can take some photos and post them here. Its kind of a dusty earth brown/orangish color. What exactly would cause acid etching like that to form a pebbled texture? As far as pyritization goes, what conditions might form something like this?
Auspex Posted April 6, 2015 Posted April 6, 2015 ...As far as pyritization goes, what conditions might form something like this? Several of the various mineral forms of iron can yield this appearance. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease!
bone digger Posted April 6, 2015 Posted April 6, 2015 Well sorry Allosaurus! I did have some reservations on calling it an osteoderm. However not all osteoderms of this size will have the crosshatched texture. It should have blood vessel holes though. I will post some photos of mine tonight.
Allosaurus Posted April 6, 2015 Author Posted April 6, 2015 No problem bone digger. This just means I'll have to keep looking for one.
jpc Posted April 6, 2015 Posted April 6, 2015 I agree... strange weathering pattern on a limestone pebble. I have seen some of these (maybe in the Two Med FM?) but also in the Sahara where they are very common in some places. The patterning is rather distinctive.
Herb Posted April 6, 2015 Posted April 6, 2015 It looks geological to me also "Absence of evidence is not evidence of absence"_ Carl Sagen No trees were killed in this posting......however, many innocent electrons were diverted from where they originally intended to go. " I think, therefore I collect fossils." _ Me "When you have eliminated the impossible, whatever remains, however improbable, must be the truth."__S. Holmes "can't we all just get along?" Jack Nicholson from Mars Attacks
Allosaurus Posted April 6, 2015 Author Posted April 6, 2015 Thank you to everyone for their help in identifying this geologic specimen.
bone digger Posted April 7, 2015 Posted April 7, 2015 Yes I have seen rocks with the same pattern as well. What really had me thinking osteoderm was the colour and texture of the "underside" photo. The top side did not really look like a scute. Here is some photos of some of my scutes/ osteoderms to give you a better idea of what to look for.
bone digger Posted April 7, 2015 Posted April 7, 2015 Some more photo's. The last one shows the fibrous/crosshatched pattern that is on the bottom of some scutes. Give you an idea of what to look for anyway, good luck!
Allosaurus Posted April 7, 2015 Author Posted April 7, 2015 Ah okay, I see now. Thank you for all the pictures. I'm going to be back out in the field again this weekend so now I know exactly what to look for!
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now