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Albertonykus borealis was theropod described by Philip Currie and Nicholas Longrich in 2008 from the lower Maastrichtian of the Horseshoe Canyon Formation in Alberta. Its range also extends into Montana, SD and Wyoming in the Hell Creek and Lance Formation. It is noted for having a single hand claw and is a very small theropod, see photo. Very few folks pay attention to small dinosaurs but this one is very cool and material does come out all of the time so I thought it might be interesting to post. If you collect North American dinosaurs the claws are a must have. Teeth have been found on its Asian cousin Mononykus olecranus but no cranial elements to my knowledge have been found in North America. Maybe one of our forum members can find one :) or has more information to add.  Material found in the Hell Creek and Lance formation should be labeled as  Trierarchuncus prairiensis

 

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I've seen hand and foot claws as well as phalanges sold but few sellers know what they have and label them theropod. I've personally collected some specimens and have purchased others. Published literature and the New York Museum of Natural History Mononykus display help pull the picture together for identification of specimens.

 

Trierarchuncus prairiensis

Was  described has the Alvarezsaurid from the Hell Creek Formation July 10, 2020

https://www.sciencedirect.com/science/article/pii/S0195667120302469

 

Hand Claw : They are typically recurved but can be straight. A shallow vascular groove on either side, ventral foramens are present, see second photo (arrow)

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Carpal : Called the Alular digit and just has one. Photos L to R Medial, Ventral and Dorsal Views

post-10935-0-80120800-1439838427_thumb.jpgpost-10935-0-55289900-1439838442_thumb.jpgpost-10935-0-46146800-1439838467_thumb.jpg

Associated Alular Digit :

post-10935-0-24333700-1439839025_thumb.jpgpost-10935-0-61808900-1439839329_thumb.jpg

Foot digits in the following post.

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The Feet of this dinosaur are no different than other theropods other than size. The initial photo is a composite of a digit

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Identifying phalanges is not difficult since they have diagnostics differences from other theropods

In the first photo, a dorsal view, one can see a pulley shapped proximal surface, a deep depression, see arrow. All digits have this characteristic. Side and Ventral view photos follow and another digit side view.

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The Foot Claws have a typical vascular groove but it dips down to the base of the claw. See arrows.

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Phalanx I Digit 1 :

 

Diagnostic features that help with ID

Dorsal Pit - Pulley shaped dorsal pit

Proximal ventral Notch

 

Digit1B.thumb.jpg.21faf74c84c2068ccf1a6d460593e1e1.jpg

 

 

Digit1.thumb.jpg.05fae476383e05d867507ceb57c1c434.jpg

 

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Cool.. Thanks. Did you see aerodactyl's post about a dino toe bone she needs IDed?

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Cool.. Thanks. Did you see aerodactyl's post about a dino toe bone she needs IDed?

Just got off and need to take a look at some of my comparison specimens. Nice bone.

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LordTrilobite

Great stuff! I love all these informative Dinosaur posts you've been making recently.

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Here are photos from AMNH display of Mononykus olecranus. Structure is the same just that Albertonykus borealis it was a smaller animal.

First image are the arms showing a single digit in each. The foot follows.

post-10935-0-76387300-1439989568_thumb.jpgpost-10935-0-85490700-1439989802_thumb.jpgMonkyHand2b.thumb.jpg.90f9408c11feb64f65dbfc5570af57df.jpg

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  • 1 year later...

Trierarchuncus prairiensis

 

Have not touched this topic for a while and I've see a couple of online sellers offering claws these so I decided to refresh this super cool dinosaur so everyone knows what they should look like.   One seller described it as an Alvarezsaurid which is accurate but at a family level.   The other seller identified it as a raptor and suggested a different species altogether which is not correct.   The photos shown above from their Asian cousin show a match to the digits.

 

A. borealis was described in 2009 from Alberta's Horseshoe Canyon Formation, mid Maastrichtian in age.  I've attached a link to access the paper.   The digits I've seen from the Hell Creek appears to be identical to what has been described in Alberta, Asia and South America.  It appears that not enough associated material has been discovered in the Hell Creek/Lance to it described.  I think its acceptable to call it cf Albertonykus borealis until something is described.  

 

Paper - 

http://www.sciencedirect.com/science/article/pii/S0195667108000943

 

Facts about this interesting dinosaur

https://sites.google.com/site/longrich/albertonykus-borealis

 

A couple of claws I recently acquired are shown in the photo,  the top one is my largest at 1 3/8" long.   I photographed both of them together to show that the tip of the bottom one was restored improperly.   Its not a raptor and should not be prepped like one.  Hand claws from this dinosaur are long and thin.   I obtained that claw because it was from a location that was new to me for this species, North Dakota.   I will have the tip restored correctly.

 

Pair.thumb.jpg.d139984048a0d95192deac2ceda87b6e.jpg

 

 

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Susan from PA

Thanks for sharing, Troodon!  Great additions to your collection! 

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  • 6 months later...

Material from Uzbekistan has been on market recently with bones and teeth available.  So if your interested in Alvarezsaurid dinosaurs a new discovery increases the distribution of these interesting dinos into Uzbekistan's dinosaur rich Bissekty Formation.

 

http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0186254

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Added description to identify Phalanx I - 1 ( page two )

 

Opportunities are out there to own material from a very cool theropod dinosaur.  Its not big, but very rare and since most collectors and dealers have no clue what they have prices are very reasonable.  Just need to keep a sharp eye.

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That's a really cool dinosaur! Thanks for sharing! I really wish we had more dinos here in the East, I only have 1 and a half little hadrosaur teeth.

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17 hours ago, TNCollector said:

That's a really cool dinosaur! Thanks for sharing! I really wish we had more dinos here in the East, I only have 1 and a half little hadrosaur teeth.

Thanks and I agree unfortunately most of the deposits are gone, not exposed or buried under concrete.

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  • 5 months later...
Tidgy's Dad

What a very interesting dinosaur. 

Also very informative and great pics as always. :)

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54 minutes ago, Tidgy's Dad said:

What a very interesting dinosaur. 

Also very informative and great pics as always. :)

Thank you.  A very odd dinosaur

 

 

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