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Beaver (?) Jaw from Big Brook - pleistocene or modern?


TRexEliot

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I found this fragment of jaw from what I believe is a beaver yesterday at Big Brook in New Jersey. Could it be pleistocene or just iron stained modern bone?20240423_103848.thumb.jpg.de92eced8fa1c42c9d1d4b350b1b8e27.jpg20240423_103856.thumb.jpg.424396792e6ada039613deeecb924e1e.jpg20240423_103900.thumb.jpg.c49d61bb41b74c20d56c56dd8fa737b5.jpg20240423_103903.thumb.jpg.620a9a510f8fd37d9085b1a5539cdd57.jpg

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Did you perform a flame test?

    Tim    -  VETERAN SHALE SPLITTER

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Posted (edited)

@Fossildude19 does the flame test distinguish between modern and pleistocene? I always thought it only distinguished between permineralized and not-permineralized, and my understanding was that pleistocene material in the brooks often isn't permineralized (Ralph Johnson once told me a story about the disgusting smell of a large mammoth vertebra someone brought to his house that spilled rotten mammoth water all over his floor)

Edited by TRexEliot
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I have these pictures from a while back, sorry about the poor picture quality, they were from when I first joined the forum, but they appear somewhat similar. This was identified as muskrat, though I believe rabbit was also proposed.IMG_20220221_111428.thumb.jpg.8ed068bdb738d1c184a25c674608f3dd.jpgIMG_20220223_133755.thumb.jpg.19a37e98ab2ca18ffdf60d5f7b65a719.jpg

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I do see some differences such as the "slope" of the jaw along the teeth and the difference in incisors.

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@SawTooth thanks for sharing - definitely see some similarities. Also appears to be a different number of molars, however, besides what you mentioned about the angle.

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25 minutes ago, TRexEliot said:

@Fossildude19 does the flame test distinguish between modern and pleistocene? I always thought it only distinguished between permineralized and not-permineralized, and my understanding was that pleistocene material in the brooks often isn't permineralized (Ralph Johnson once told me a story about the disgusting smell of a large mammoth vertebra someone brought to his house that spilled rotten mammoth water all over his floor)

It distinguishes between collagen/protein present and not present, so without having personal experience with pleistocene bones, I guess under most conditions a strong smell would at least hint at it being more recent.

Best Regards,

J

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Try to learn something about everything and everything about something

Thomas Henry Huxley

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@Mahnmut thanks for the explanation - just tried the flame test. Im not sure exactly how strong the smell is supposed to be, but I wasn't getting anything too strong. I couldn't completely tell if i was smelling anything or if it was just the smell of the lighter fluid burning.

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10 hours ago, SawTooth said:

I do see some differences such as the "slope" of the jaw along the teeth and the difference in incisors.

differences in incisors?... there are no incisors in either specimen.  

It is too small to be a beaver.  Muskrat is a pretty good educated guess based on the shape of the occlusal (chewing ) surfaces of the teeth. 

  

Edited by jpc
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Hi,

I am looking at a rabbit skull right now, no camera to hand though.

The rabbit has a row of parallel molars, not the zig zag we see here. best fit I find online is indeed muskrat. (Or someone from that family...)

Try to learn something about everything and everything about something

Thomas Henry Huxley

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It's muskrat.

Here's the link to a specimen for reference:

 

 

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-Jay

 

 

 

''...science is eminently perfectible, and that each theory has constantly to give way to a fresh one.''

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