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Request help in ID for Dallas 1968 fossil


mode1charlie

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I'm new to this forum, and would like to request help in identifying a fossil that has been in my possession for about 50 years. When I was a child growing up in Dallas, Texas, my father was a landscape architect who often visited job sites and had excellent relations with various sub-contractors. One day, he brought home a fossil "dinosaur bone" from a private residential swimming pool construction project. It certainly does appear to be a fossil bone from a large animal, and one can even see fossilized marrow in a hole on the specimen - but whether it's from a dinosaur or a mammal, I have no idea and would like some help with here.

The specimen is approximately 90mm long, 60mm wide, and 50mm high. I haven't weighed it.


Although I've worked in museums for much of my professional career (and so I'm motivated both by scientific curiosity as well as a strict adherence to scientific rigor), I've somehow never brought this specimen for any expert to identify. Don't know why - just didn't. My father is still living and a couple of weeks ago I asked him if he remembers any additional information on exactly where, at what depth, etc. this specimen was found. Unfortunately, he does not remember any additional information or context. 
 

I'm including some photos here, but of course would be happy to provide additional ones, or to provide any other information that would prove helpful in identifying this specimen. And thank you very much in advance.

Dallas 1968 fossil - 1.jpg

Dallas 1968 fossil - 2.jpg

Edited by mode1charlie
Correcting cm / mm error
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Just now, Rockwood said:

Astragalus from an artiodactyl.

Thank you. Now that you've given me the term "astragalus", I can see that's indeed what it is. Do you have any idea what kind of artiodactyl, and what period it might be from? (Again, recovered from vicinity of Dallas, Texas.)

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13 minutes ago, mode1charlie said:

Thank you. Now that you've given me the term "astragalus", I can see that's indeed what it is. Do you have any idea what kind of artiodactyl, and what period it might be from? (Again, recovered from vicinity of Dallas, Texas.)

Sorry, but I'm going to pass on that part. There are others who may be able to narrow it further though.

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Yeah, a REALLY large deer - the astragalus is about 90mm long by 60mm wide, so unless I'm missing something it's not any deer species that exists today. And I should have pointed out earlier (but it's probably clear from the photos) that this is definitely a fossil, not a sub-fossil.

Per this site, it seems that there were several enormous prehistoric deer species in North America.

However, that's with the caveat that no one here has definitively concluded that it's a deer - just that it's an artiodactyl. 

Edited by mode1charlie
Correcting cm / mm error
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13 minutes ago, Rockwood said:

I hope you meant mm. I wouldn't want to meet the one measured in cm.

HA! Yes. Duh. My bad. Millimeters, not centimeters. (Need more coffee.)

I've corrected my post. 

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You might consider the possibility it's a stag moose (Cervalces  cf. C. scotti) astragalus.  That species is more common in the central USA, but it has been reported from Arkansas.

 

 

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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31 minutes ago, Harry Pristis said:

 

You might consider the possibility it's a stag moose (Cervalces  cf. C. scotti) astragalus.  That species is more common in the central USA, but it has been reported from Arkansas.

 

 

Interesting, thanks. From this paper, it would seem that the measurements are right in the ballpark, though this would be a range extension for the species.

It looks like the specimens in the paper are sub-fossils, but the one I have is fully fossilized. I come from a non-paleontological science background, so I have no idea about the expected differences in terms of chronology, or even what the proper terms to use are. I suppose what I'm asking is: how much older are fossils compared to sub-fossils (generally speaking; I would guess there are differences arising from different local conditions), and would the fact that mine is fossilized indicate a different species (i.e. not Cervalces, but some other artiodactyl or even another group)? 

Thanks to all for your thoughts and help.    

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I still think this is cervid.

 

There seems to be endless misunderstanding about the term "fossilized."

"Fossilized" (along with "petrified") is a near meaningless term in this specialized forum. The term is often substituted for "mineralized" in describing a bone or tooth. But, fossilized doesn't always equate to mineralized because many fossils are not reinforced or replaced by minerals.

Bone is primarily composed of hydroxyapatite and collagen. Hydroxyapatite is an inorganic compound of calcium, phosphate, and hydroxide which is organized in a crystal latticework that gives bone (and teeth) structural rigidity. It preserves well as a fossil under some conditions.

Collagen is a fiberous protein that serves as connective tissue in bones and muscles. It does not preserve well in a fossil. As collagen decomposes, it may be replaced in the hydroxyapatite latticework by minerals from the depositional environment (e.g. silica dioxide dissolved in groundwater).

Bone reinforced with exogenous minerals is said to be "mineralized." If the bone components (including the hydroxyapatite) are entirely replaced by exogenous minerals such as silica, it is said to be "replaced by -". If a bone is mineralized, it is more likely to be a fossil. If a bone is not mineralized, it is less likely to be a fossil. No absolutes, only likelihoods, because there are exceptions.


In the case of leaves and wood, as with bones, permineralization depends on the circulation of mineral-saturated groundwater. If there is limited or no circulation (or no suitable minerals in solution), then there is no permineralization. BUT, the organic remains - the leaves, or wood, or bone - are still fossils ("fossilized" if you like).

  • I found this Informative 5

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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Thank you, Harry - both for your informed opinion on the specimen as well as your helpful explanation of mineralization. 

Just to throw out another possibility... One paper I looked at showed an early bovine astragalus that also could be a candidate (right size, generally similar structure). Could it be from genus Bos?

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Thank you, Harry. From that diagram, it's hard to say. There are some similarities to Bison (the medial turbicle is even/level with the line) but it appears to lack any excavation whatsoever.

Would that point to a cervid (as you first suspected)?

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