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New early sauropodomorph specimen from Upper Triassic of Brazil



Ben Creisler
bcreisler@gmail.com

A new paper (text not seen--apparently taxon is not named?):


Rodrigo Temp Müller, Max Cardoso Langer & Sérgio Dias-da-Silva
Biostratigraphic significance of a new early sauropodomorph specimen
from the Upper Triassic of southern Brazil.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2016.1144749
http: // www.tandfonline.com/doi/full/10.1080/08912963.2016.1144749


The Wachholz site (Caturrita Formation, Late Triassic), in Agudo, Rio
Grande do Sul (RS), southern Brazil, has yielded several
sauropodomorphs. This includes CAPPA/UFSM 0002, described here based
on associated elements from the basalmost portion of the site. The
specimen possesses a set of traits shared with typical 'prosauropods':
a concave caudal margin of the trunk neural spines and a broadly
convex proximal end of metacarpal V. However, it also retains some
plesiomorphic features, for instance, the slender pedal digit I. Some
bones closely resemble those of Unaysaurus tolentinoi, the other
definitive sauropodomorph from the Caturrita Formation, an affinity
corroborated by a new phylogenetic analysis. An updated
biostratigraphic framework correlates the Wachholz, Água Negra (São
Martinho da Serra/RS) and Botucaraí Hill (Candelária/RS) sites based
on their sample of sauropodomorphs. In addition, the record of
Jachaleria in the Botucaraí Hill site, a dicynodont also known from
early Norian deposits of Argentina, indicates an equivalent age to
deposits bearing U. tolentioni. Accordingly, a more constrained age is
proposed for the Água Negra site. This is important as the early
Norian marks the transition from an epoch of low sauropodomorphs
representativeness to a period of extreme abundance of the group in
Early-to-Middle Mesozoic ecosystems.