Jaw Bone Segment

[Boesse]

That strikes me as being very artiodactyl like; but alas, I'm no expert on mammals that really "chew". Bobby

[siteseer]

I wonder where they are now? (Hint - one of them is in Florida now, and one is Delaware. )

Smilodon,

Are you referring to teeth or jaw sections? I know one of the jaw sections is in the Buena Vista Museum. I don't think Bob sold any of his STH Desmostylus teeth. There were some other collectors well-known in the Bakersfield area who had some great rare stuff too. A few have passed away and their heirs have let some specimens go. Also, there is a dealer who used to live there who has been selling parts of his collection.

I have seen an STH Desmostylus jaw section for sale in Florida and have wondered who found it.

I was never lucky enough to find a complete one - dug up a partial tooth once and looked all around for other pieces. It was a real heartbreaker because it had a mix of colors in it.

[siteseer]

Jess - LACM just finished preparing a nearly complete skeleton of a Paleoparadoxia from the Monterey Formation, which I believe is just missing the legs below the knees. Either way, it looks like a really incredible fossil. Which reminds me - Stan Jarocki may have the proximal end of a desmostylian femur from the Santa Margarita - it's pretty huge (and we can safely say it isn't from Dusisiren!).

Bobby

Bobby,

I want to see that. I haven't seen the cast at SLAC yet. Steve Kunkel once saw the actual bones they have in storage.

I lost Stan's number (that's what I get for writing notes on the backs of envelopes and receipts).

Jess

[Straus]

Meeting with Profesor Orr on Tuesday to (hopefully) identify just who these teeth belong to. I will let you know what he says.

[Boesse]

Bobby,

I want to see that. I haven't seen the cast at SLAC yet. Steve Kunkel once saw the actual bones they have in storage.

I lost Stan's number (that's what I get for writing notes on the backs of envelopes and receipts).

Jess

Hey Jess,

I've seen the actual skeleton of the Stanford skeleton (P. repenningi) a couple of times at berkeley - it is really, really, really big. The lower jaw is about a full two feet long.

Straus, good luck meeting with Dr. Orr. Bobby

[jeremyh]

whale teeth!

[Straus]

I just got back from a meeting with Dr. Orr (who is amazingly gracious). This is the lower, left mandible of a sloth that was about the size of a spaniel. The teeth are agatized. The crystals filling one molar are chalcite and with a jewlry loop he and the other professor spotted pyrite crystals as well. It is 6 to 7 million years old. We showed them two other fossils. One is a vertebra from a porpoise, from the neck. It is 60 to 70% intact but is surrounded by a thick rock matrix. the last one we just showed him for fun, not thinking it was identifiable (didn't seem specific enough to us) but he immediately said it was a piece of jaw bone from a baleen whale. Since all of them were from the Empire formation I guess I can assume that the others are 6 to 7 million yrs old too, huh? It was so much fun to hear what he had to say, I was beside myself! Sloth teeth! How cool is that?

[Auspex]

How cool is that?

Waaaaaaaaaaaaay cool!

You found a good fossil, got to meet with a Doctored-up professional, and you found and joined our Forum

[TourmalineGuy]

That is incredible! I really don't know what else to say. Really cool fossil.

[Harry Pristis]

I just got back from a meeting with Dr. Orr (who is amazingly gracious). This is the lower, left mandible of a sloth that was about the size of a spaniel. The teeth are agatized. The crystals filling one molar are chalcite and with a jewlry loop he and the other professor spotted pyrite crystals as well. It is 6 to 7 million years old. We showed them two other fossils. One is a vertebra from a porpoise, from the neck. It is 60 to 70% intact but is surrounded by a thick rock matrix. the last one we just showed him for fun, not thinking it was identifiable (didn't seem specific enough to us) but he immediately said it was a piece of jaw bone from a baleen whale. Since all of them were from the Empire formation I guess I can assume that the others are 6 to 7 million yrs old too, huh? It was so much fun to hear what he had to say, I was beside myself! Sloth teeth! How cool is that?

That's great to hear! Which sloth is it? . . . the scientific name?

[siteseer]

I just got back from a meeting with Dr. Orr (who is amazingly gracious). This is the lower, left mandible of a sloth that was about the size of a spaniel. The teeth are agatized. The crystals filling one molar are chalcite and with a jewlry loop he and the other professor spotted pyrite crystals as well. It is 6 to 7 million years old. We showed them two other fossils. One is a vertebra from a porpoise, from the neck. It is 60 to 70% intact but is surrounded by a thick rock matrix. the last one we just showed him for fun, not thinking it was identifiable (didn't seem specific enough to us) but he immediately said it was a piece of jaw bone from a baleen whale. Since all of them were from the Empire formation I guess I can assume that the others are 6 to 7 million yrs old too, huh? It was so much fun to hear what he had to say, I was beside myself! Sloth teeth! How cool is that?

Straus,

That must be one of the oldest sloth fossils in Oregon if it's 6-7 million years old. It would also be from one of the earliest sloth taxa to enter North America (Pliometanastes/close relative or Thinobadistes/close relative).

[Straus]

Wow, that is amazing. I was going to figure out what kind of sloth it had to be today. The two you mentioned gives me a good head start. I know he said it was about the size of a dog. My husband said that he mentioned spaniel size, so I fugured it had to be the kind that went arboreal, right? What research I've done (just starting) tells me thst there were only three varieties in Oregon, but they seem to be described as huge ground sloths. Dr. Orr said that this was not a juvenile, but a small sloth. I will post more if I learn anything. Thanks for your info. I am speechless! (Which doesn't happen often!)

[Straus]

I was unable to determine which kind of sloth it might hav been so I emailed Dr Orr and asked him. He said the sloth genus is Nothrotherium. It would be the size of a very small pony or large dog (not a spaniel as I said before.)

Edited April 9, 2010 by Straus

[Auspex]

That's really wonderful!

Nothrotherium is, i believe, also known from Rancho La Brea.

[Harry Pristis]

I was unable to determine which kind of sloth it might hav been so I emailed Dr Orr and asked him. He said the sloth genus is Nothrotherium. It would be the size of a very small pony or large dog (not a spaniel as I said before.)

I am skeptical about this identification. Dr. Orr can't be a mammologist. There is so much wrong with this ID, I scarcely know where to start.

Nothrotherium is thought to be a related South American sloth. The North American version has been placed in Nothrotheriops, a Pleistocene taxon. This sloth went extinct only about 11,000 years ago.

Nothrotheriops (=Nothrotherium) has three, ovate peglike cheek-teeth with single roots. There is no canine tooth. I don't think your jaw fits this description at all.

Here is an image of a Nothrotheriops jaw. Note the diastemata between the teeth.

[Straus]

I just wish that I was not so ignorant about all of this. I have to painstakingly look up everything that you guys say! I surely agree with you that these tooth don't match the Shatsta Nothrotherium, which was also much bigger wasn't it? If it is sloth would it be more likely to be Nothrotherium escrivanense ? I know that almost any sloth info I found is Pleistocene, not miocene, but they were around in miocene. Dr Orrs identifification was qualified with "the best I can determine without the crowns..." Because I am admittedly ignorant on this subject the only other thing I can tell you is that he kept turning to the other professer and pointing out the "8" shape within the structure of the tooth. I can't question his expertise, it truly is above reproach. More realistic to question the condition of my fossil, and the lack of the defining crowns.

[tracer]

these sorts of id's can be problematic. i posted this jaw piece a while back looking for an id and didn't get any takers. it is a similar situation to yours in a way in that the jaw bone part seems much wider and shaped differently than that of most aminals. can't be from most aminals, so what's it from? well, you see "weird bones" sometimes, and you start thinking sloth, because, well, edentates are weird (sorry, sloth lovers). but as was pointed out, sloths tend to have "peggy" teeth (also weird) that aren't really enamel and that have more or less monolithic structure with one root with a cavity in it (maybe - i'm on thin ice as usual, not having seen enough of them or researched enough or visited the sloth dentist, because he lives all the way across town.) anyway, the way you usually identify jaw fragments if from the occlusal (chewing) surface of the remaining teeth. break off the teeth, and you're left posting the bone fragments on the interwebz and hoping weirdos like me don't come out of the woodwork and post on your topic without actually helping with the id.

oops

[Harry Pristis]

I just wish that I was not so ignorant about all of this. I have to painstakingly look up everything that you guys say! I surely agree with you that these tooth don't match the Shatsta Nothrotherium, which was also much bigger wasn't it? If it is sloth would it be more likely to be Nothrotherium escrivanense ? I know that almost any sloth info I found is Pleistocene, not miocene, but they were around in miocene. Dr Orrs identifification was qualified with "the best I can determine without the crowns..." Because I am admittedly ignorant on this subject the only other thing I can tell you is that he kept turning to the other professer and pointing out the "8" shape within the structure of the tooth. I can't question his expertise, it truly is above reproach. More realistic to question the condition of my fossil, and the lack of the defining crowns.

'Strauss' . . . I don't mean to seem harsh or snippy, but let me point out the facts as they've emerged here:

There is no Shasta Nothrotherium. The North American sloth is the monotypic genus, Nothrotheriops. Monotypic means there is only ONE species in the genus, Nothrotheriops shastensis.

Nothrotherium escrivanense is a South American genus and species of sloth.

Looking things up is good for you; it's part of an education.

Dr. Orr was pointing to the figure-eight shape of the roots because this root configuration is not consistent with sloth. It is consistent with some artiodactyls, a huge group of animals.

You CAN question Dr. Orr's expertise, and you should! You may have been ignorant of sloths; but, now you know more about this sloth than does Dr. Orr, evidently. A Ph.D. does not make someone omniscient. Give me his full name, and I'll tell you what he knows professionally.

I can think of several possible reasons why Dr. Orr would give you such obviously-wrong information, and none of them is very flattering to Dr. Orr.

A professional paleontologist should be treated like your local automobile mechanic. You try him out on some basic stuff. If he performs well, you learn to trust him with your most valuable asset - your knowledge-base. If he doesn't perform well consistently, you move on to find a more competent mechanic.

Edited April 10, 2010 by Harry Pristis

[TourmalineGuy]

Harry,

Dr. William N. Orr is held in pretty high regard in Oregon. I have no personal experience with him, but he wrote the best book I can find on Oregon Fossils. Now, I know that doesn't make him a mammalogist or a good paleontologist, but he is the director of this, a rather large fossil collection. But, I believe he may be more of a geologist, than a paleontologist, so you are right in some respect (I could be wrong about that though).

In either case, we shouldn't discount other reasons that he made a mistake: Maybe its been 20 years since he's focused on land mammals and he was doing the best he could. Perhaps he doesn't put a lot of time into certain identifications, because of the nature of them (very difficult to identify). I'm sure we can list more, potential reasons. And yes, they are all maybes.

A mistake is rarely admirable and from the information you've showed us it does look like he made one. But one mistake, I don't believe, is reason to entirely throw Dr. Orr out the window and we should give him the benefit of the doubt.

By the way, I'm definitely not trying to be argumentative, just trying to put a different light on his apparent mis-identification and so people don't shy away from bringing their fossils to universities and museums.

Roddy

[JohnJ]

You have a very interesting jaw fragment. To me, the bulging bone to either side of the teeth is striking. Anyway, HERE is a reference to more sloth info with a good bibliography and general sloth info.

[Harry Pristis]

Harry,

Dr. William N. Orr is held in pretty high regard in Oregon. I have no personal experience with him, but he wrote the best book I can find on Oregon Fossils. Now, I know that doesn't make him a mammalogist or a good paleontologist, but he is the director of this, a rather large fossil collection. But, I believe he may be more of a geologist, than a paleontologist, so you are right in some respect (I could be wrong about that though).

In either case, we shouldn't discount other reasons that he made a mistake: Maybe its been 20 years since he's focused on land mammals and he was doing the best he could. Perhaps he doesn't put a lot of time into certain identifications, because of the nature of them (very difficult to identify). I'm sure we can list more, potential reasons. And yes, they are all maybes.

A mistake is rarely admirable and from the information you've showed us it does look like he made one. But one mistake, I don't believe, is reason to entirely throw Dr. Orr out the window and we should give him the benefit of the doubt.

By the way, I'm definitely not trying to be argumentative, just trying to put a different light on his apparent mis-identification and so people don't shy away from bringing their fossils to universities and museums.

Roddy

The benefit of what doubt, Roddy? The doubt about his competence to identify mammal fossils? I don't think so.

I looked at his publications in a Google scholar search -- it's a very modest list. He must be young. He is no vertebrate paleontologist; geology and a few invert papers seem to represent his expertise.

No one can know everything. What we should expect is humility enough to say "I don't know." What is the opposite of humility?

Perhaps W.N. Orr didn't know that he didn't know. Is that something other than incompetence?

Perhaps he knew he didn't know what the jaw represented and decided to "dust-off" the amateur collector who couldn't tell the difference anyway. What would you call that behavior?

Professional paleontologists are like automobile mechanics. Because of the complexity of their field, they tend to specialize. Granted, some, because of aptitude and opportunity, have broader knowledge than others. However, detailed knowledge in one specialty - say in Volvo transmissions - doesn't mean that the mechanic can diagnose a problem with a Ford transmission. Such a diagnosis may be worse than worthless. We should expect, even demand that the Volvo mechanic defer to the Ford mechanic down the street.

Perhaps I set too high a value on knowledge and have too much disdain for ballshot. Each of us has to set his or her own standards. But this is a good argument to have because is puts focus on such notions as "expertise" and critical observation or critical thinking.

Edited April 10, 2010 by Harry Pristis

[TourmalineGuy]

You're right, Harry. It is definitely some level of incompetence that puts the wrong words into someones mouth. There is no doubts there. But, I'm sure you've misidentified fossils and I know I've misidentified fossils.

If he knew he didn't know or was very unsure, we can only hope he would defer the identification onto someone else. I am in no way saying that any of the cases you listed are warranted in any way. It would be deplorable to knowingly give incorrect or unjustified identifications. However, the benefit of doubt that I'd be willing to give him is that potentially he made an honest mistake. The very best of us do. Perfection is a great standard, but it is never met. Which is why we should cross-check and have skepticism for all information.

Perhaps he didn't make an honest mistake and perhaps he did.

There is clearly nothing wrong with putting a high value on knowledge. However, we have to keep our knowledge in context: we got a second hand account of a identification from a man who we don't know from a woman that we have only begun to know via text only. There are a tremendous amounts of subtleties to the whole process that we lose and we simply don't know what he was thinking when he identified it. So, as people, we have to provide some benefit of doubt.

Although, I give permission for that benefit of doubt to be very limited, given the situation .

[Straus]

Okay guys, I feel like a complete ######, and I don't want to get scared off from this site, soooo let me just say that Dr. Orr was most gracious and lovely. He spent 45 minutes with us and I don't believe he muffed the ID just to get rid of us. If he misidentified this fossil, and it does seem probable, it was just that. A misidentification which was shared with you by one very excited and over revved, novice, fossil hunter. Do any of you have a guess as to what it IS?

[Harry Pristis]

Okay guys, I feel like a complete ######, and I don't want to get scared off from this site, soooo let me just say that Dr. Orr was most gracious and lovely. He spent 45 minutes with us and I don't believe he muffed the ID just to get rid of us. If he misidentified this fossil, and it does seem probable, it was just that. A misidentification which was shared with you by one very excited and over revved, novice, fossil hunter. Do any of you have a guess as to what it IS?

Goodness! Don't be scared off, 'Straus'! I think that your experience with this jaw is quite instructive in a number of ways. You are not the only newbie reading this thread, nor are the lessons restricted to newbies. Thank you for bringing the fossil to our attention.

Professional paleontologists are just human . . . no more and no less. They feel the pressure of our expectations. We expect them to know the answers to our questions, and they want to meet those expectations. Maybe Bill Orr didn't want to disappoint you, 'Straus', with a more-appropriate "I don't know."

Whatever happened, it's been interesting to search for the facts in this case. That great western hero (or is it hero of great westerns?), Ronald Reagan had it about right: "Trust, but verify!" There is no substitute for your own critical observations.

The identification of your jaw may never be more than tentative or probable. You can approach the challenge from a biostratigraphical angle. Determine the age of the stratum from which it was eroded (someone said Late Miocene, I think). Once you know the age, find out what animals have already been identified from that age/stratum in Oregon. (The probability is that this jaw does not represent a first record of the taxon.) I think you should pay special attention to the artiodactyls.

Bill Orr may have access to a comparative collection which would be useful. No small part of your challenge is that no one puts much value on toothless jaws. It's unlikely you'll find a scientific illustration of a jaw with all its teeth broken away. Use a caliper to note some dimensions -- length of tooth row, length and width of m2, width and depth of the mandible under m2 -- so that you can compare these with any prospective match.

If you take on this challenge, you'll be amazed at how much you can learn and at how quickly you can learn it. Let us know how the research is going. Good luck!

-------Harry Pristis

[Straus]

Thank you Harry, Your directions are really helpful. I truly did not even know how to start the process. I will follow your advice, perhaps ask for more of it, and let you know what I learn. Thing is, I'm ignorant but not stupid, so the way you've spelled this out will be a lot of fun.

Thanks again