Re: [dinosaur] Vespersaurus, new desert-dwelling noasaurine theropod from Brazil (free pdf)

[Tim Williams <tijawi@gmail.com>]

The feet of _Vespersaurus_ are weird, even aside from the putative
functional monodactyly (for locomotion).  Irrespective of whether they
had roles in locomotion or not, the two outer toes were quite robust
and equipped with narrow "slicing/scratching" claws - when retracted,
these outer toes apparently converged behind the major/central
weight-bearing toe.

The most famous example of monodactyl cursorial vertebrates is of
course the clade that includes modern horses (Equini).  In horses, the
evolution of monodactyly has been proposed to be an adaptation to an
arid environment, specifically "speed and efficiency for daily travel
between patchy resources of food", not cursoriality per se (Janis &
Bernor, 2019).  I don't know if this has any relevance to
_Vespersaurus_, though it's noteworthy that this theropod lived in a
desert environment.

The small proterotheriid litoptern _Thoatherium_ was also a monodactyl
quadruped, but I haven't come across an ecomorphological explanation
for this adaptation.

As Langer et al. note, when it comes to monodactyl bipedalism, this is
also seen in the extinct sthenurine macropods, which are cited as
being saltatorial.  However, hopping locomotion has been disputed for
certain sthenurines (especially the larger forms) in favor of bipedal
walking (Janis et al., 2014).


On Thu, Jun 27, 2019 at 1:40 AM Ben Creisler <bcreisler@gmail.com> wrote:
>
>
> Ben Creisler
> bcreisler@gmail.com
>
>
> A new paper in open access:
>
> Vespersaurus paranaensis gen. et sp. nov.
>
> Max Cardoso Langer, Neurides de Oliveira Martins, Paulo CÃsar Manzig, 
> Gabriel de Souza Ferreira, JÃlio CÃsar de Almeida Marsola, Edison Fortes, 
> Rosana Lima, Lucas Cesar Frediani Santâana, Luciano da Silva Vidal, 
> Rosangela HonÃrio da Silva LorenÃato & MartÃn Daniel Ezcurra (2019)
> A new desert-dwelling dinosaur (Theropoda, Noasaurinae) from the Cretaceous 
> of south Brazil.
> Scientific Reports 9, Article number: 9379
> DOI: 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__doi.org_10.1038_s41598-2D019-2D45306-2D9&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=baweBiTWdoibBAnX8pTPVaY6YvG6RkJpcBmCtBte0ug&s=J-u3dwbcP_zHiXtS1IzU6RWbGdh7esr9ir7maxC_-wc&e=
>  
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41598-2D019-2D45306-2D9&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=baweBiTWdoibBAnX8pTPVaY6YvG6RkJpcBmCtBte0ug&s=dlqajfZzMLWcIFt_IZ7y9jVes9pInDeh8W-qsJaLzDg&e=
>  
>
> Free pdf:
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41598-2D019-2D45306-2D9.pdf&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=baweBiTWdoibBAnX8pTPVaY6YvG6RkJpcBmCtBte0ug&s=baO1pIae07zK988VdiTW65HoVSi6_NefDgnB8C3PH9U&e=
>  
>
> Noasaurines form an enigmatic group of small-bodied predatory theropod 
> dinosaurs known from the Late Cretaceous of Gondwana. They are relatively 
> rare, with notable records in Argentina and Madagascar, and possible remains 
> reported for Brazil, India, and continental Africa. In south-central Brazil, 
> the deposits of the Bauru Basin have yielded a rich tetrapod fauna, which is 
> concentrated in the Bauru Group. The mainly aeolian deposits of the Caiuà 
> Group, on the contrary, bear a scarce fossil record composed only of lizards, 
> turtles, and pterosaurs. Here, we describe the first dinosaur of the Caiuà 
> Group, which also represents the best-preserved theropod of the entire Bauru 
> Basin known to date. The recovered skeletal parts (vertebrae, girdles, limbs, 
> and scarce cranial elements) show that the new taxon was just over 1âm 
> long, with a unique anatomy among theropods. The shafts of its metatarsals II 
> and IV are very lateromedially compressed, as are the blade-like ungual 
> phalanges of the respective digits. This implies that the new taxon could 
> have been functionally monodactyl, with a main central weight-bearing digit, 
> flanked by neighbouring elements positioned very close to digit III or even 
> held free of the ground. Such anatomical adaptation is formerly unrecorded 
> among archosaurs, but has been previously inferred from footprints of the 
> same stratigraphic unit that yielded the new dinosaur. A phylogenetic 
> analysis nests the new taxon within the Noasaurinae clade, which is 
> unresolved because of the multiple alternative positions that Noasaurus leali 
> can acquire in the optimal trees. The exclusion of the latter form results in 
> positioning the new dinosaur as the sister-taxon of the Argentinean 
> Velocisaurus unicus.
>
> ==
>
> News:
>
> (in Portuguese)
>
> https://urldefense.proofpoint.com/v2/url?u=http-3A__scienceblogs.com.br_colecionadores_2019_06_um-2Dnovo-2Ddino-2Dbrasileiro_&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=baweBiTWdoibBAnX8pTPVaY6YvG6RkJpcBmCtBte0ug&s=51jr3qrEqXtM10HO41jnqJPQ24eiGlUTPnk0r55_3Yc&e=
>  
>
> https://urldefense.proofpoint.com/v2/url?u=https-3A__www.gmconline.com.br_noticias_cidade_vespersauros-2Dparanaensis-2Dnovo-2Ddinossauro-2De-2Dapresentado-2Dem-2Dmaringa&d=DwIFaQ&c=clK7kQUTWtAVEOVIgvi0NU5BOUHhpN0H8p7CSfnc_gI&r=Ry_mO4IFaUmGof_Yl9MyZgecRCKHn5g4z1CYJgFW9SI&m=baweBiTWdoibBAnX8pTPVaY6YvG6RkJpcBmCtBte0ug&s=3I5bCu03uyHnu7g67eLOwup9pdt5AYJOzP53rbZDKVk&e=
>  
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> Video:
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>  
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