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Re: [dinosaur] Ubirajara, new compsognathid theropod with a filament "mane" from Lower Cretaceous of Brazil



I have no reason to doubt that BMFIs (broad monofilamentous
integuments) sprouted from the shoulders of _ Ubirajara_,
epaulette-style.  However, I'm skeptical of the reasoning for why
these BMFIs were unlikely to be attached to the forelimbs:

"It is also conceivable that the BMFIs have become displaced from a
position on the forelimb, however such elongate structures emanating
from the forelimb of a small raptorial predator would surely have
greatly inhibited the use of those limbs."

I'm not sure usefulness of the forelimbs in predation was a major
consideration.  Compsognathid forelimbs were very small compared to
the rest of the animal, and unlikely to be of much use for prey
acquisition.  So it wouldn't surprise me if these BMFIs sprang from
the forelimbs, just like the elaborate pennaceous structures of
certain pennaraptorans.


On Mon, Dec 14, 2020 at 4:06 AM Ben Creisler <bcreisler@gmail.com> wrote:
>
>
> Ben Creisler
> bcreisler@gmail.com
>
> A new paper:
>
> Ubirajara jubatus gen. et sp. nov.
>
> Robert S.H. Smyth, David M.Martill, Eberhard Frey, HÃctor E. Rivera-Sylva & 
> Norbert Lenz (2020)
> A maned theropod dinosaur from Gondwana with elaborate integumentary 
> structures.
> Cretaceous Research 104686 (advance online publication)
> doi: 
> https://urldefense.com/v3/__https://doi.org/10.1016/j.cretres.2020.104686__;!!LIr3w8kk_Xxm!6Y2cLybiD9-ta2gjFcxqDnAIwEgx0tLf0Y45TW97h24A8Em4r9b-sx4Ct90YuuLG$
>  
> https://urldefense.com/v3/__https://www.sciencedirect.com/science/article/abs/pii/S0195667120303736__;!!LIr3w8kk_Xxm!6Y2cLybiD9-ta2gjFcxqDnAIwEgx0tLf0Y45TW97h24A8Em4r9b-sx4Ct7ev7k3u$
>  
>
>
>
> Discoveries of dinosaurs with integumentary structures over the last few 
> decades have revolutionised our understanding of the phylogenetic 
> relationships between birds and dinosaurs as well as the origin and evolution 
> of feathers. A remarkable number of dinosaurs have been discovered with a 
> diverse range of preserved integumentary structures. Several of these 
> dinosaurs are adorned with elaborate integumentary structures that have been 
> linked to behaviours including thermoregulation, egg incubation, and sexual 
> display. Among Theropoda, such elaborate structures have only been previously 
> recorded within Maniraptoriformes. However, elaborate monofilamentous 
> structures are also present in some small ornithischians. The majority of 
> theropods preserving integumental structures come from the Upper Jurassic and 
> Lower Cretaceous of China or the Upper Jurassic of southern Germany, and all 
> are of Laurasian origin. Herein, we describe a new genus and species of 
> compsognathid theropod from the Lower Cretaceous (Aptian) Crato Formation of 
> Northeast Brazil, representing the first Gondwanan non-avian theropod with 
> preserved filamentous integumentary structures. It is also the first 
> non-maniraptoran possessing elaborate integumentary structures that were most 
> likely used for display. These include slender monofilaments associated with 
> the base of the neck, increasing in length along the dorsal thoracic region 
> where they form an impressive mane, as well as a pair of elongate, 
> ribbon-like structures likely emerging from the shoulder. Such elaborate 
> integumentary structures are hitherto unknown in any other dinosaur, although 
> superficially similar elongate display feathers emerge from the carpal region 
> of the male standardwing bird-of-paradise (Semioptera wallacii).
>
>
> Virus-free. 
> https://urldefense.com/v3/__http://www.avg.com__;!!LIr3w8kk_Xxm!6Y2cLybiD9-ta2gjFcxqDnAIwEgx0tLf0Y45TW97h24A8Em4r9b-sx4Cty1Rq4Ee$
>