New Allosaurus Species from Morrison

[Troodon]

A very long time coming, over a decade in discussion, Allosaurus jimmadseni has finally been described in the attached OPEN paper

 

The abstract says it best

"Allosaurus is one of the best known theropod dinosaurs from the Jurassic and a crucial taxon in phylogenetic analyses. On the basis of an in-depth, firsthand study of the bulk of Allosaurus specimens housed in North American institutions, we describe here a new theropod dinosaur from the Upper Jurassic Morrison Formation of Western North America, Allosaurus jimmadseni sp. nov., based upon a remarkably complete articulated skeleton and skull and a second specimen with an articulated skull and associated skeleton. "

 

https://peerj.com/articles/7803/

 

 

National Park Service article

https://www.nps.gov/dino/learn/nature/allosaurus-jimmadseni.htm

 

Article

https://phys.org/news/2020-01-species-allosaurus-utah.html

 

 

Collectors 

For those of us that collect teeth I'm sure that these teeth are indistinguishable from other Allosaurus species like Allosaurus fragilis and all teeth should all be identified as Allosaurus sp. including bones.  Also please do not get taken by sellers claiming to offer Allosaurus jimmadseni  teeth.  Unless one comes off an identifiable skull its bogus.

[dinosaur man]

So much new species of Dinosaurs!! 

[Arion]

What? Allosaurus jimmadseni is finally official? I remember the paper was supposedly “in press” for almost ten years before PeerJ even existed. Glad it’s finally official, now we can get those quotation marks off the species name!

[Troodon]

8 minutes ago, Arion said:

What? Allosaurus jimmadseni is finally official? I remember the paper was supposedly “in press” for almost ten years before PeerJ even existed. Glad it’s finally official, now we can get those quotation marks off the species name!

Yep its been a long long wait.   Well it sometimes takes time for species to be recognized, not like the early days of discoveries where just a tooth described a species....and it will not be the last one with a long journey in front of it.  

[Pemphix]

If you think in paleontological periods - what means ten years ?

 

 

[Troodon]

Tom Holt posted this skull comparison between three Allo species

 

 

[Shamalama]

CoooooOOOOOOooooool! *8 year old me* also *45 year old me*  

[Pemphix]

1 hour ago, Troodon said:

Tom Holt posted this skull comparison between three Allo species

 

 

Seems that the species are pretty good distinguishable.....?

[Troodon]

42 minutes ago, Pemphix said:

Seems that the species are pretty good distinguishable.....?

The paper does a good job describing the characters that differentiate it from the others.  But just looking at that illustration you can see the differences.   Not sure why it took so long to describe it.

[Arion]

3 hours ago, Troodon said:

Yep its been a long long wait.   Well it sometimes takes time for species to be recognized, not like the early days of discoveries where just a tooth described a species....and it will not be the last one with a long journey in front of it.  

Well it sounds like they spent a fair amount of time doing comparisons with every Allosaurus specimen known to man (slight exaggeration...but only slight haha), but Dan recognized it as a new species back in the 90s and as I mentioned supposedly had a paper in press about it almost 18 years ago. But projects can be like that at times...there’s always something more that can be done, and sometimes (as here) you don’t get it finished until you retire. 

[Pemphix]

2 hours ago, Troodon said:

The paper does a good job describing the characters that differentiate it from the others.  But just looking at that illustration you can see the differences.   Not sure why it took so long to describe it.

That's exact what i thought.....

[Scylla]

Wow, Wikipedia is already updated!

[Megalodoodle]

I was just about to post this exact same thing, when I realized you beat me to it!

[trilo]

Very nice new species! and the paper too!

 

[Troodon]

MOR tweeted this out

"A Big Al,  Paper by Chure & Loewen shows Big Al & other allosaur specimens belong to new species, Allosaurus jimmadseni. Big Al was excavated in Wyoming (1991) from Jurassic Morrison Frm (150 MA). 1st BA Pic- jaws in field 2nd- quarry 3rd-mounting 4th-skeleton at MOR"

[Troodon]

Replica Skulls of Allosaurus jimmadseni at NHMU courtesy R Black

[Scylla]

3 hours ago, Troodon said:

Replica Skulls of Allosaurus jimmadseni at NHMU courtesy R Black

I want one

[DD1991]

Since 2006, I had been aware of the name Allosaurus jimmadseni, and the second edition of the Dinosauria mentioned an in-press paper by Dan Chure, but the reason Chure waited so long to have his paper published was due to possible pushback from some Allosaurus specialists who had to be convinced that morphological variation within Allosaurus is of taxonomic significance. The description of A. jimmadseni also happens to come on the centennial of Charles Gilmore's 1920 monograph on Allosaurus.

[dinosaur man]

7 hours ago, Troodon said:

MOR tweeted this out

"A Big Al,  Paper by Chure & Loewen shows Big Al & other allosaur specimens belong to new species, Allosaurus jimmadseni. Big Al was excavated in Wyoming (1991) from Jurassic Morrison Frm (150 MA). 1st BA Pic- jaws in field 2nd- quarry 3rd-mounting 4th-skeleton at MOR"

A lot of the Allosaurus fragilis specimens are now being labeled as Allosaurus jimmadseni!

[Abstraktum]

Thinking about this as well.

 

This skull is at our local Palaeobiology Museum in Munich. It's there for decades now. Labeled as Allosaurus fragilis from Cleveland-Lloyd Quarry, Utah, Morrison Formation. 

 

Just wondering if the ID is still correct. If I use the skull comparison it looks to me more like A. jimmadseni. But I dont know if locality fits.   (dont mind Sarah sitting at the jaw, it was a picture for her world tour ) 

 

[Troodon]

26 minutes ago, Abstraktum said:

his skull is at our local Palaeobiology Museum in Munich. It's there for decades now. Labeled as Allosaurus fragilis from Cleveland-Lloyd Quarry, Utah, Morrison Formation. 

 

Just wondering if the ID is still correct. If I use the skull comparison it looks to me more like A. jimmadseni. But I dont know if locality fits.

Guess all museums will have to take a look at what they have.  Locality is just fine.   Does have some feature of A. jimmadseni.  If its a replica I'm sure the original might have been part of the initial.