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Early Miocene Astragalus From Nj


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This comes from a mixed Mid-Eocene/ early Miocene lag deposit site in the Kirkwood fm. of NJ. My best efforts have led to me to assigning it to the order perissodactyl, probably rhino or tapir, but I am not too familiar with Miocene land mammals. Harry Pristis has already chimed in on this topic and believes it is Equus, however. There has only been one report of Miocene Equus from NJ and that belongs to a tooth of the genus Anchitherium. Miocene Entelodonts, rhinos, tapirs, peccaries, and deer-like protoceratids have been reported from the same deposits.

Any other opinions would be helpful!

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---Wie Wasser schleift den Stein, wir steigen und fallen---

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It certainly is a Perissodactyl astragalus, though I suspect that Harry Pristis identified it as an 'Equid' rather than as the genus Equus because there are no Miocene (and certainly not Eocene) Equus. How sure are you of the age of the deposit you found this fossil in? It could be an Equus astragalus if it is in a 'remixed' deposit where Pleistocene deposits have been interspersed with older deposits.

I reserve a more definitive identification until I can see a better picture of the fossil from directly in front and a picture of the lower articulating surfaces (the opposite end of the 'pulley' articulation). That being said...I will say that you can probably rule out a rhinoceros because the general proportions of the astragalus pictured really don't fit any of the rhinos I've ever seen or collected.

-Joe

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It certainly is a Perissodactyl astragalus, though I suspect that Harry Pristis identified it as an 'Equid' rather than as the genus Equus because there are no Miocene (and certainly not Eocene) Equus. How sure are you of the age of the deposit you found this fossil in? It could[/i] be an Equus astragalus if it is in a 'remixed' deposit where Pleistocene deposits have been interspersed with older deposits.

I reserve a more definitive identification until I can see a better picture of the fossil from directly in front and a picture of the lower articulating surfaces (the opposite end of the 'pulley' articulation). That being said...I will say that you can probably rule out a rhinoceros because the general proportions of the astragalus pictured really don't fit any of the rhinos I've ever seen or collected.

-Joe

Thanks for the help Joe. I will try to get you some better pictures tonight. The bone came directly out of a marine lag deposit at the Miocene-Eocene disconformity, so it definitely can't be Pleistocene. It could possibly be Eocene, but most(if not all) of the land mammal remains recovered from this layer have been early Miocene. The layer dates at 21mya, but it has been speculated that it could contain a mix of slightly earlier land mammal forms as well.

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sorry for flooding your post toothpuller, but i found a ton of these in the micro pleistocene material from harry, i suspect they are bird? or would some of the larger ones be skunk? hoping someone can tell me if there are any structural difference between mammals and birds in these bones?

thanks :)

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toothpuller...

The more I look at your pictures, the more I'm leaning toward a tapir rather than a horse. Still not definitive and I need to do some comparative work with the horse astragali that I have available.

Here's an interesting teaser picture of a tapir astragalus from a web site. There are some similarities between it and the astragalus you found.

gallery_330_106_2051.jpg

-Joe

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Thanks for the help Joe. I will try to get you some better pictures tonight. The bone came directly out of a marine lag deposit at the Miocene-Eocene disconformity, so it definitely can't be Pleistocene. It could possibly be Eocene, but most(if not all) of the land mammal remains recovered from this layer have been early Miocene. The layer dates at 21mya, but it has been speculated that it could contain a mix of slightly earlier land mammal forms as well.

Why can't it be Pleistocene, Steve? A "lag deposit" or a "channel lag deposit" is just what it says: It is earlier sediments eroded free, then laid down in the inside of a bend in a river. These channel lag deposits become the final resting place for whatever falls or is thrown into the river.

When we discover these channel lag deposits, we may be surprised to find giant armadillo remains mixed with Miocene bear-dog remains. That doesn't mean that the giant armadillo was contemporaneous with the bear-dogs. It only means that the deposit is contaminated with earlier or later fossils, depending on which you are examining. The actual lag deposit may have been laid down a hundred, or a thousand, or a million years ago.

Channel lag deposits are being laid down now at the moment I'm writing this. Such deposits are composed of whatever sediments are eroded from the bank or bottom, then are mixed together, then are dropped out of suspension (they "lag" behind) in the slower current on the inside of a river-bend. These channel lag deposits become the final resting place for whatever falls or is thrown into the river. (Repetition for emphasis.)

The common suspicion in channel lag deposits is contamination. We are skeptical of anything described as an age-exclusive channel lag deposit.

So, Steve, try to free your mind from the notion that the astragalus MUST be Miocene in age. Fruitbat and Auriculatus have the good instincts. But, you should decide for yourself.

Here is another comparison image of Equus and Tapirus; what do you think?

------Harry Pristis

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In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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OK....I've done a little bit of research and comparative study and have the following to offer:

gallery_330_106_2051.jpg

Confirmed tapir astragalus

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Toothpuller's unidentified astragalus (cropped and rotated for comparative purposes)

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Late Miocene/Early Pliocene (Clarendonian) equid astragalus

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Pleistocene Equus astragalus

Regardless of the actual age of the fossil that toothpuller has presented, it appears to me that the astragalus in question more closely resembles that of a tapir rather than a horse. I base this on:

1) the fact that the facets on the 'pulley' articulation of toothpuller's astragalus do not extend as far distally as those on either of the horse astragali (toothpuller's astragalus has more of a 'neck' at the base)

2) a distinct 'shelf' or 'lip' is present at the base of toothpuller's astragalus and the confirmed tapir astragalus but is absent from both examples of equid (horse) astragali.

No equid astragalus that I've ever collected has both a long 'neck' and a distinct 'shelf' at the base. I therefore suggest that toothpuller's astragalus is more representative of a tapir than of a horse.

-Joe

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OK....I've done a little bit of research and comparative study and have the following to offer:

Regardless of the actual age of the fossil that toothpuller has presented, it appears to me that the astragalus in question more closely resembles that of a tapir rather than a horse. I base this on:

1) the fact that the facets on the 'pulley' articulation of toothpuller's astragalus do not extend as far distally as those on either of the horse astragali (toothpuller's astragalus has more of a 'neck' at the base)

2) a distinct 'shelf' or 'lip' is present at the base of toothpuller's astragalus and the confirmed tapir astragalus but is absent from both examples of equid (horse) astragali.

No equid astragalus that I've ever collected has both a long 'neck' and a distinct 'shelf' at the base. I therefore suggest that toothpuller's astragalus is more representative of a tapir than of a horse.

-Joe

Well, we may never agree on just what this bone represents -- some fossils just have to be held in hand for a reliable ID.

(I think, unless there's been some major revision recently, that Late Miocene/Early Pliocene would fall into the Hemphillian NALMA, not the Clarendonian.)

The best we can do with these bones, I guess, is to put the images side-by-side. Here's another contribution.

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http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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Harry....

Guess we'll once again have to agree to disagree but I do think that the features I pointed out in my earlier post are relatively diagnostic. If you can show me an equid astragalus with the long 'neck' and the presence of a 'shelf' at the base then I'll happily change my diagnosis. I looked at over 20 Miocene/Pliocene/Pleistocene equid astragali in my possession before posting and couldn't find either of those characters on any of them. In addition, tapir astragali seem to have a relatively broader articulation facet for the tibia than do those of horses (though that is a subjective evaluation since I don't personally have any tapir astragali to measure).

I have pointed out the features I'm referring to on toothpuller's astragalus in the picture below. They do most closely resemble the tapir astragalus rather than the equid one.

gallery_330_106_10406.jpg

As to the age of the Clarendonian and its assignment to the Late Miocene or Early Pliocene, I tend to see the Clarendonian as Late Miocene in age, as you suggest. This conforms to Tedford, et al. in their 2004 article Mammalian biochronology of the Arikareean through Hemphillian interval (Late Oligocene through Early Pliocene epochs) . The GeoWhen database ( http://www.stratigraphy.org/geowhen/stages/Clarendonian.html ) shows the Clarendonian as overlapping the Middle to Late Miocene. Carrasco, M.A., B.P. Kraatz, E.B. Davis, and A.D. Barnosky. 2005. Miocene Mammal Mapping Project (MIOMAP). University of California Museum of Paleontology ( http://www.ucmp.berkeley.edu/miomap/ ) also list the Clarendonian as Miocene. Most recent authorities do list the Hemphillian NAMLA (North American Land Mammal Age) as belonging to the Early Pliocene. Some earlier authorities, however, did list the Clarendonian as Early Pliocene and there are still a few holdouts who keep it in the Pliocene.

-Joe

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Harry....

Guess we'll once again have to agree to disagree but I do think that the features I pointed out in my earlier post are relatively diagnostic. If you can show me an equid astragalus with the long 'neck' and the presence of a 'shelf' at the base then I'll happily change my diagnosis. I looked at over 20 Miocene/Pliocene/Pleistocene equid astragali in my possession before posting and couldn't find either of those characters on any of them. In addition, tapir astragali seem to have a relatively broader articulation facet for the tibia than do those of horses (though that is a subjective evaluation since I don't personally have any tapir astragali to measure).

I have pointed out the features I'm referring to on toothpuller's astragalus in the picture below. They do most closely resemble the tapir astragalus rather than the equid one.

As to the age of the Clarendonian and its assignment to the Late Miocene or Early Pliocene <snip> Some earlier authorities, however, did list the Clarendonian as Early Pliocene and there are still a few holdouts who keep it in the Pliocene.

-Joe

Are you having a difficult time admitting you made a mistake about the NALMA, Joe? It would have been so much simpler to say, "Ooops, I mis-spoke!" Now, I have to ask you to show me any reference to the Clarendonian NALMA which includes any part of the Pliocene. There are no such "holdouts," I venture.

As for the astragalus, you have selected characteristics of the bone which are vulnerable to wear, and Steve's bone is worn. I don't think your analysis is reliable. Better to look at some features that are NOT so vulnerable to abrasion.

Here are a couple of images comparing Steve's bone with Equus and with Tapirus. Pay careful attention to the numbered features. Note the size, shape and gap between the articular facets #1 and #2 when comparing the bones. Then note the "shoulder" at #3. These are features that are not vulnerable or are less vulnerable than the features you were comparing.

Still, Steve will have to make up his own mind, as will other viewers.

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What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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Let's not get testy, Harry. The articular facets you have selected are subject to individual variation within members of the same species...let alone the same genus. While there is certainly evidence of wear on the astragalus in question...there is NO doubt about the overall shape of the astragalus nor about the proportions of the bone itself. Interestingly, the 'shelf' near the base of the astragalus that toothpuller presented is NOT worn enough to remove the evidence of its existence and I still maintain that I've never seen such a structure on any equid astragalus. I've done my best to present reasonable evidence to support my contention that the astragalus in question is from a tapir and not a horse. You seem to have made up your mind quite some time ago so it really isn't in anybody's best interest to drag this out any longer. As I said...we will just have to agree to disagree.

As for referring the Clarendonian to the Late Miocene/Early Pliocene...I will simply say that the original assignment of both the Clarendonian and Hemphillian was to the Pliocene and it wasn't until the 1970 with new data from work on the European Land Mammal Ages that they were pushed into the Middle/Late Miocene and Late Miocene/Early Pliocene respectively.

From the definition of the Clarendonian from the on-line version of Encyclopedia Brittanica:

...lowermost and oldest major division of continental rocks and time of the Pliocene in North America (the Pliocene Epoch began about 7,000,000 years ago and lasted about 4,500,000 years). The Clarendonian Stage, which follows the Barstovian Stage of the preceding Miocene Epoch and precedes the Hemphillian Stage, was named for exposures studied near Clarendon, Texas, and is characterized…

And as for references to the Clarendonian as Pliocene:

From a 1970 article in the Bulletin of the Southern California Paleontological Society:

Pliohippus has also been collected from the Tick Canyon Formation of the eastern Ventura basin which has been dated as Clarendonian age (early Pliocene) (Savage and others, 1954). However, because of the age of the molluscan fauna, the tooth from CSCLA 624 probably represents Hemphillian age.

From the 1971 article Pliocene-Pleistocene History of the Perris Block, Southern California :

it is partially filled with alluvium which has yielded a lower Pliocene (Clarendonian) mammalian fauna.

From the 1973 article The Protoceratinae (Mammalia, Tylopoda, Protoceratidae) and the systematics of the Protoceratidae. in The Bulletin of the American Museum of Natural History:

The stratigraphic range of the subfamily extends from the Chadronian (early Oligocene) to the Clarendonian (middle Pliocene);

Another example (among many) is the following title: Herpetofauna of the Wakeeney local fauna (lower Pliocene; Clarendonian) of Trego County, Kansas.

So I wasn't completely without any logic when I mentioned it in my earlier post.

By the way, the original intent of using provincial names (like Rancholabrean, Clarendonian, Hemphillian, etc.) was NOT to provide boundary-defining units at all but simply to bring some semblance of uniformity to the naming of fossil assemblages. I direct your attention to Stephen L. Walsh's article, The Role of Stratotypes in Stratigraphy Part 3. The Wood Committee, the Berkeley school of North American Mammalian Stratigraphic Paleontology, and the Status of Provincial Golden Spikes. in Earth Science Reviews (2005) for an interesting reading regarding some of the ideas currently being debated regarding the concept of biochronological units versus age-determining boundaries.

-Joe

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Why can't it be Pleistocene, Steve? A "lag deposit" or a "channel lag deposit" is just what it says: It is earlier sediments eroded free, then laid down in the inside of a bend in a river. These channel lag deposits become the final resting place for whatever falls or is thrown into the river.

When we discover these channel lag deposits, we may be surprised to find giant armadillo remains mixed with Miocene bear-dog remains. That doesn't mean that the giant armadillo was contemporaneous with the bear-dogs. It only means that the deposit is contaminated with earlier or later fossils, depending on which you are examining. The actual lag deposit may have been laid down a hundred, or a thousand, or a million years ago.

Channel lag deposits are being laid down now at the moment I'm writing this. Such deposits are composed of whatever sediments are eroded from the bank or bottom, then are mixed together, then are dropped out of suspension (they "lag" behind) in the slower current on the inside of a river-bend. These channel lag deposits become the final resting place for whatever falls or is thrown into the river. (Repetition for emphasis.)

The common suspicion in channel lag deposits is contamination. We are skeptical of anything described as an age-exclusive channel lag deposit.

So, Steve, try to free your mind from the notion that the astragalus MUST be Miocene in age. Fruitbat and Auriculatus have the good instincts. But, you should decide for yourself.

Here is another comparison image of Equus and Tapirus; what do you think?

------Harry Pristis

Harry, I think we may use the term lag deposit a little differently up here. That may have added to some confusion. I do fully understand the concept of channel lags in Florida and general (recent) geology of extreme reworkings due to low land elevations down South even though I have never collected there. This is from a reworked layer sandwiched in between Eocene and Miocene sediments which contains fossils from both the Eocene (Shark River) and Miocene (Kirkwood) formations. The depositional environment is considered estaurine or lagoonal for the "lag" and overlying Kirkwood, but the underlying Eocene formation was probably deposited in deeper water. I dug the bone right out of a section of undisturbed formation, so there is no chance of contamination with Pleistocene sediments.

I just remembered that I sort of previously eliminated Miocene 3-toed horse based on size. Maybe I was wrong to do that in the first place??? My specimen is about 1.75" x 1.75" which seemed much larger than 3 toed horse astragali.

For the record, this is definitely not more recent than early Miocene, ~21mya. Theres a slim chance it may be Oligocene or Eocene but was redeposited in the lag in the early Miocene. But most if not all the land mammal material recovered from this deposit in NJ has been early Miocene.

I haven't had a chance to really weigh both of your opinions yet, but I wanted to clear the debate about the age asap. Thanks for the efforts though guys!

-steve

---Wie Wasser schleift den Stein, wir steigen und fallen---

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Let's not get testy, Harry. The articular facets you have selected are subject to individual variation within members of the same species...let alone the same genus. While there is certainly evidence of wear on the astragalus in question...there is NO doubt about the overall shape of the astragalus nor about the proportions of the bone itself. Interestingly, the 'shelf' near the base of the astragalus that toothpuller presented is NOT worn enough to remove the evidence of its existence and I still maintain that I've never seen such a structure on any equid astragalus. I've done my best to present reasonable evidence to support my contention that the astragalus in question is from a tapir and not a horse. You seem to have made up your mind quite some time ago so it really isn't in anybody's best interest to drag this out any longer. As I said...we will just have to agree to disagree.

As for referring the Clarendonian to the Late Miocene/Early Pliocene...I will simply say that the original assignment of both the Clarendonian and Hemphillian was to the Pliocene and it wasn't until the 1970 with new data from work on the European Land Mammal Ages that they were pushed into the Middle/Late Miocene and Late Miocene/Early Pliocene respectively.

<snip>

-Joe

Testy? Moi? Not at all. I am having fun. :P

You spin a good yarn, Joe. Do you really imagine that there is no individual variation in ALL of the diagnostic features we're examining? We're looking for consistent, marked differences here. All of my horses (of whatever species) have a "shelf" on the astragalus.

For someone who doesn't have a tapir astragalus, you seem mighty convinced by a single, dark image. I just ask you to remain open to convincing, 'cause I have more of these bones yet to photograph. Here (below) are astragali from three individual three-toed horses. Notice the consistency and note the "shelves."

___________________

Sooo, Joe . . . It appears that YOU are the sole "holdout" since 1975 who thinks that the Clarendonian NALMA includes part of the Pliocene. If you want a thorough discussion of the history and recent development of NALMAs, I recommend CENOZOIC MAMMALS OF NORTH AMERICA, GEOCHRONOLOGY AND BIOSTRATIGRAPHY by Michael O. Woodburne (Editor).

"European Land Mammal Ages"?! You just made that up, right? That's a good'un! LOL

Here is a chart from THE FOSSIL VERTEBRATES OF FLORIDA by Richard C. Hulbert, Jr. (Editor). I posted this chart on March 30 of this year in another thread.

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post-42-1209400768_thumb.jpg

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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Unfortunately, this has degenerated into a nit-picking event that I'm not going to engage in. Harry...if you want to discuss what I actually wrote regarding the Miocene and Pliocene then please start another thread specifically aimed toward that and I'll be glad to attempt to explain myself in a framework you can understand.

As regards the astragalus in question, the pictures you posted of the three horse astragali are taken with the bones tilted back at a slight angle that makes them appear to have the 'shelf' structure that I've referred to. Perhaps I wasn't clear enough as to what I was referring to when I mentioned a 'shelf'.

For clarification:

gallery_330_106_28539.jpg

The center image is the astragalus that toothpuller asked about. The one on the left is a confirmed tapir astragalus and the one on the right is a confirmed Equus astragalus.

I've stated my case and will let toothpuller and any other interested parties make up their own minds.

-Joe

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Unfortunately, this has degenerated into a nit-picking event that I'm not going to engage in. Harry...if you want to discuss what I actually wrote regarding the Miocene and Pliocene then please start another thread specifically aimed toward that and I'll be glad to attempt to explain myself in a framework you can understand.

As regards the astragalus in question, the pictures you posted of the three horse astragali are taken with the bones tilted back at a slight angle that makes them appear to have the 'shelf' structure that I've referred to. Perhaps I wasn't clear enough as to what I was referring to when I mentioned a 'shelf'.

For clarification:

The center image is the astragalus that toothpuller asked about. The one on the left is a confirmed tapir astragalus and the one on the right is a confirmed Equus astragalus.

I've stated my case and will let toothpuller and any other interested parties make up their own minds.

-Joe

Joe, I'm sorry that you are not happy with the way the conversation is going. I promise, I am not using trick photography to win a point! LOL All these astragali have a lip at the margin of that articular facet. You are seeing something in Toothpuller's image that I don't see.

I'll try not to laugh at peculiar references like "European Land Mammal Ages." I thought you were joking. You're joking or you're winging it -- which is it? Oh! Never mind.

_______________

Here's another image of two tapir astragali from Florida, Toothpuller.

The largest horse in the Early Miocene is likely to be an anchithere -- we have Anchitherium clarencei here in Florida. I probably have one or two Anchithere astragali back there somewhere, but they are just slightly larger than Parahippus which is much too small to match your astragalus.

There is a good-size Miocene tapir, Tapirus simpsoni here. I don't have an astragalus from this tapir; but, there is an illustration of one in THE FOSSIL VERTEBRATES OF FLORIDA. The neck on the process where Joe sees a "shelf" seems to be considerably longer than anything we have talked about so far. Certainly, it seems longer than in your astragalus. The scale indicates that it is about 63mm x 57mm (using the 2-dimensional image).

It's always possible that your bone is from a chalicothere, but I can't help you there.

Your astragalus does not resemble the larger, later Miocene rhinos found here, not Teleoceras (my collection) nor Aphelops (book illustration).

You can see why I'm thinkin' "Equus"!

Tell us more about the lag deposit. Long-shore currents leave lag deposits also. You said you excavated the bone yourself. Are all the bones found in that deposit black?

You dug this bone from a layer of material that was underlain by Eocene sediment and was capped by Miocene sediment. Was this in a riverbank or quarry?

Gotta love the mysteries!

--------Harry Pristis

post-42-1209360037_thumb.jpg

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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Harry...

Just so you don't ascribe too much inner meaning or ironic wit to my use of a term like "European Land Mammal Age" and at the risk of depriving you of your well-deserved laughter, let me assure you that such a term is in published usage. Indeed, just like NALMAs are established for North America, there are also ALMAs for Asia and ELMAs for Europe. While not in as common useage nor well-established as the NALMAs, the ALMA and ELMA concepts are available. So, for example, the Villafranchian stage is sometimes referred to in published accounts as the Villafranchian land mammal age. You can certainly verify this statement on your own with a simple Google search. Whether you personally choose to accept those published accounts will have to remain up to you.

In addition, I did not accuse you of doing anything untoward in your photographs. I simply made a valid statement that the perspective of those pictures can be misleading when compared to the published tapir photo that I presented as well as those from toothpuller's and my own collections. As for your not being able to recognize the feature I'm referring to as a 'lip', I've done everything I can to point the feature out. I'll have to trust in your innate talent and observational skills to eventually see what I'm talking about.

Thanks for your interest,

-Joe

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Harry...

Just so you don't ascribe too much inner meaning or ironic wit to my use of a term like "European Land Mammal Age" and at the risk of depriving you of your well-deserved laughter, let me assure you that such a term is in published usage. Indeed, just like NALMAs are established for North America, there are also ALMAs for Asia and ELMAs for Europe. While not in as common useage nor well-established as the NALMAs, the ALMA and ELMA concepts are available. So, for example, the Villafranchian stage is sometimes referred to in published accounts as the Villafranchian land mammal age. You can certainly verify this statement on your own with a simple Google search. Whether you personally choose to accept those published accounts will have to remain up to you.

<snip>

Thanks for your interest,

-Joe

Yes, Joe, I agree that there are European mammal stages. They have never been well-correlated with North American Land Mammal Ages, nor are they internally consistent within Europe. Two different mammalian age systems are used in Europe, one commonly used for microvertebrates, the other used for macrovertebrates. They are not the equivalent of NALMAs.

For example, Villafranchian may include only the Triversa and Rebielice; OR, the Villafranchian may include, besides the first two sub-stages, also the Villanyian and the Biharian, depending on which group of mammals you're discussing. This unsettled state is why these European mammal stages should not be conflated with the NALMAs.

European mammal stages do not drive our understanding of North American Land Mammal Ages which are more internally consistent and better correlated chronostratigraphically. This is one reason why we don't have a unified international time scale.

-------Harry Pristis

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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Harry...

I never said anything to infer that European Land Mammal Ages (ELMAs) were in any way equivalent to or should be categorized the same way as North American Land Mammal Ages (NALMAs). You picked up on the mention of European Land Mammal Ages from a comment I posted regarding the Clarendonian and made an issue out of it. You basically implied that the idea of European land mammal ages was some sort of figment of my imagination...

I'll try not to laugh at peculiar references like "European Land Mammal Ages." I thought you were joking. You're joking or you're winging it -- which is it?

Now you are implying (not so subtly) that the term European Land Mammal Stages is the only correct one. This is simply wrong. You are welcomed to refer to any of the many publications in which the term European Land Mammal Age is used for confirmation. I'm hardly joking nor am I in the habit of "winging it". Perhaps you need to broaden your reading list a little bit so that you don't make an issue out of something that you're not overly familiar with.

Now...my apologies to those who have managed to muddle through the juvenile tripe in these posts thus far. I have no personal axe to grind with Harry Pristis, who seems to have more than a passing familiarity with mammal fossils. I do, however, reserve the right to disagree with him whenever and however I so choose...as long as I'm willing to back up my arguments with evidence. I will not respond to any additional posts in this thread that are not directly related to the astragalus that toothpuller presented in the first place. In that regard, I have given my opinion and posted my evidence so I'll let that stand as stated.

Thanks for everybody's indulgence,

-Joe

Illigitimati non carborundum

Fruitbat's PDF Library

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Toothpuller,

You have some beautiful mammal fossils posted in the gallery and in this thread. The discussion in this thread has been

very informative. A difference of opinion can be a positive force broadening the discussion and enlightening the members

of the Forum, if respect and civility is kept. I think it was in this case and I hope it will remain so. This board is a true

treasure!

-greel

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Harry...

I never said anything to infer that European Land Mammal Ages (ELMAs) were in any way equivalent to or should be categorized the same way as North American Land Mammal Ages (NALMAs). <snip>

-Joe

Indeed, just like NALMAs are established for North America, there are also ALMAs for Asia and ELMAs for Europe.

Don't be slippery, Joe. I gave you a serious response to your clearly mis-leading assertion.

______________________

Thanks for the feedback, Greel. One seldom knows how these arguments are perceived by those who are observing.

I think I agree with you. This thread has forced me to review and clarify a number of things which hadn't gotten much attention for years. Perhaps other subscribers have had a similar experience. :)

--------Harry Pristis

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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Wow, guys. I am having a hard time keeping up and learning about astragali at the same time!! I have two more images with notes that may or may not be of significance. I've weighed your arguments and pictures and I really can't say which way I am leaning right now without consideration of size. But Harry's last image of Plio-Pleistocene tapir seem to look the closest so far to me. The shoulder Harry pointed out isn't as pronounced as on the one in a previous post (mine vs equus & mine vs tapir) but still larger than the "shoulder" on mine. Harry, your Neohipparion doesn't really seem to do it for me, but it may or may not show the "lip" of the shelf that you were referencing. Not having any other astragalus to compare with (only pictures) I can't really make any judgment in regards to a "lip". Indeed my specimen is somewhat worn at places, but on close inspection I do not think it has been significantly abraded other than causing some "rounding". For one, the lateral extent of the "pulley" articulation is not worn, although the bottom is somewhat worn, but not enough to alter the general shape too much I think.

I do have Hulbert's book. Referring to page 283 of the images you mentioned and noting the scale: The Tapirus is 25-30% larger than mine, the rhino ~50% larger than mine, but mine is ~50% larger than the Nannippus.

I also think it looks more like Hulbert's rhino Aphelops than his Tapirus simpsoni, but we only have that one anterior view in the book. Why have you both eliminated rhino, if it I may ask? Can you take a pic of the articulating surfaces of a rhino astragalus? I also thought the anterior view of the Menoceras astragalus you posted in the other thread looked closest. But if it is completely different than both tapir and equid you don't have to share an image, I will trust you guys on it.

As for the lag deposit, I don't know what to tell you. I know NJ geology and according to the literature, the base of the Asbury Park member of the Kirkwood fm. which contains the lag deposit in a few small areas in Monmouth County, NJ has been dated at ~21mya. I dug the bone out of an undisturbed section of formation along a stream; the eocene Shark River formation was at the bottom of the layer and above the lag is the Miocene Kirkwood formaton. All the bone and sharks teeth in the lag show extreme abrasion (reworking) and are preserved exactly like this astragalus. Some miocene sharks teeth and marine mammal bones can be recovered from right above the lag deposit and they are pristine "in situ" but probably much less than 1% of the quantity in the lag. Theres just no chance of anything younger than early Miocene age....

As for size of the bone, if you are correct about the size of early Miocene horse astragali, then that would seem to rule horse out. I originally ruled out horse because miocene astragali seemed to not get much larger than Parahippus sized and, therefore, seemed too small compared to mine. (Exactly what you have stated about Anchitherium compared to Parahippus, Harry) But I am not sure about the validity of this since it was mostly based on internet resources available to me.

-steve

post-382-1209426984_thumb.jpg

post-382-1209426998_thumb.jpg

---Wie Wasser schleift den Stein, wir steigen und fallen---

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Wow, guys. <snip>

Why have you both eliminated rhino, if it I may ask? Can you take a pic of the articulating surfaces of a rhino astragalus? I also thought the anterior view of the Menoceras astragalus you posted in the other thread looked closest. But if it is completely different than both tapir and equid you don't have to share an image, I will trust you guys on it.

As for the lag deposit, I don't know what to tell you. I know NJ geology and according to the literature, the base of the Asbury Park member of the Kirkwood fm. which contains the lag deposit in a few small areas in Monmouth County, NJ has been dated at ~21mya. I dug the bone out of an undisturbed section of formation along a stream; the eocene Shark River formation was at the bottom of the layer and above the lag is the Miocene Kirkwood formaton. All the bone and sharks teeth in the lag show extreme abrasion (reworking) and are preserved exactly like this astragalus. Some miocene sharks teeth and marine mammal bones can be recovered from right above the lag deposit and they are pristine "in situ" but probably much less than 1% of the quantity in the lag. Theres just no chance of anything younger than early Miocene age....

As for size of the bone, if you are correct about the size of early Miocene horse astragali, then that would seem to rule horse out. I originally ruled out horse because miocene astragali seemed to not get much larger than Parahippus sized and, therefore, seemed too small compared to mine. (Exactly what you have stated about Anchitherium compared to Parahippus, Harry) But I am not sure about the validity of this since it was mostly based on internet resources available to me.

-steve

Well, Steve, I confess that I eliminated rhino because I perceived your astragalus to be larger than it actually is.

I just posted a comment to your gallery image of the group of fossils. Now that I can see the astragalus with rhino teeth and the image here of the bone in your hand, I think it is likely that you have a Menoceras astragalus. I have more than a few here, and I'll be posting an image or two.

This is just the sort of thing that happens when all you have is an image. :wacko:

I have the original paper describing Ammodon from NJ, no doubt from the formation you're working. I got the paper because I found some entelodont material here in Florida.

---Harry Pristis

http://pristis.wix.com/the-demijohn-page

 

What seest thou else

In the dark backward and abysm of time?

---Shakespeare, The Tempest

 

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