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Isaberrysaura

By cisiopurple
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anonymous's avatar
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Carnoferox's avatar
I think you should have gone for a more huayangosaur-like bodyplan.
cisiopurple's avatar
Maybe you are right, but no plates are found and it is reported as a bipedal animal. After all there will have been a primitive stegosaurus that appeared as a transition between an ornithischian and a true stegosaurus...
After new future descriptions about it , I can revise it.
Carnoferox's avatar
The bipedal posture was based on the original description as a basal neornithischian (Salgado et al. 2017), but a more recent phylogenetic analysis placed it as a stegosaur and the sister taxon of Huayangosaurus (Han et al. 2017). Considering that it is a huayangosaurid, a quadrupedal bodyplan with plates and spikes is most likely.
cisiopurple's avatar
Interesting! I will do a new version
AndreOF-Gallery's avatar
I think you should reconsider the quadrupedal posture, the analysis that found it as a stegosaur only had it, huayango, stego and another one (Kentro?).

When more stegosaurs are included it turns to me more basal them huayango, it may be quadrupedal and it may be bipedal soi if you draw a quadrupedal one please don't exclude the bipedal one.
Carnoferox's avatar
The placement of Isaberrysaurua and Huayangosaurus as sister taxa isn't due to the relatively small number of stegosaur taxa used in the analysis. Isaberrysaura shares synapomorphies with Huayangosaurus that make a close relationship, and thus a similar bodyplan, likely. 

From Han et al. (2017):
The taxa within Thyreophora are quite stable as in previous phylogenetic analyses. Here, a new basal neornithischian, Isaberrysaura mollensis from the Jurassic of South America, was included in the new phylogenetic analysis (Salgado et al. 2017). Isaberrysaura was found to be a basal ornithopod previously (Salgado et al. 2017) although it preserved some stegosaur features. Here it was recovered as a basal stegosaur for the first time. Thirteen synapomorphies (80:1, 91:1, 100:0, 147:0, 191:1, 240:1, 250:1, 252:1, 260:1, 281:1, 307:1, 341:1, 346:1) support its assignment to Stegosauria. Two synapomorphies support Isaberrysaura and Huayangosaurus as sister taxa: fossa-like depression positioned on the premaxillary (15:1) and deep elliptical fossa present along sutural line of the nasals (26:1).
AndreOF-Gallery's avatar
I still maintain my point there is a lack of stegosaurids in the matrice, reasonable since it was made to test neornithischians.

The 2 are the basalmost stegos (together with the C one that I can't pronounce) so they may be plesiomorphic rather them apomorphic.

When more stegosaurids where included, like in Dennonyx analysis, berrys was recovered as the basalmost setegosaur.

It may or may not be bipedal we need to find more of its skeleton, I personally think it was both like scelidosaurids.
Dennonyx's avatar
Sorry I was zapping and incidentally read these comments I just had to specify something:

Chungkingosaurus has a premaxillary fossa that flows into the lower edge of the external nares just as in Isaberrysaura and Huayangosaurus.
The elliptical fossa present along nasals midline is not very deep in Huayangosaurus, just a tad sketched.
Emausaurus remains include different and specialized kinds of osteoderms, among which a stegosaurid-like wedge-shaped plate. IF Emausaurus is outside Eurypoda, that might suggest such plates are a symplesiomorphy shared by early ankylosaurs and stegosaurs, so Isaberrysaura actually might have had primitive dorsal plates. 

More skull remains from stegosaur taxa are needed in order to understand Isaberrysaura's placement in the group.
Carnoferox's avatar
Isaberrysaura also has a similarly high maxillary tooth count to Huayangosaurus, unlike more primitive thyreophorans like scelidosaurs.

From Salgado et al. (2017):
The maxilla has at least 30 tooth positions. In Scelidosaurus (BMNH R1111) there are 19; in Thescelosaurus 20; in Agilisaurus 14; in Emausaurus21; in Stegosaurus 24, and 27–28 in Huayangosaurus.
Side-by-side comparison of the skulls makes it easy to see them as sister taxa. Figures from Salgado et al. (2017) and Sereno & Dong (1992):
Isaberrysaura and Huayangosaurus skull comparison by Carnoferox  
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cisiopurple's avatar
of course, I will do a new, and mantain the old ;) (Wink) 
Carnoferox's avatar
I look forward to seeing it!
cisiopurple's avatar
ok, thank for suggestion and references :) (Smile) :) (Smile) :) (Smile) 
y87arrow's avatar
Is that really a basal and biped stegosaur? Can't believe it, I never heard of this dinosaur! I hope this is true that would be wonderful discovery.
cisiopurple's avatar
I hope too :) (Smile) :) (Smile) 
anonymous's avatar
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