Macrocollum itaquii (Müller et al. 2018; CAPPA/UFSM 0001b; early Norian, Triassic, 225 myap; 3m in length) was originally considered a member of the “Unaysauridae [which] differs from all other sauropodomorphs by a substantial cranial expansion of the medial condyle of the astragalus. In addition, a promaxillary fenestra is also unique for the group of sauropodomorphs.” Here, in the LRT, Macrocollum nests with Efraasia, but shares many traits with Massospondylus. That matches the original phylogenetic analysis.
The species is known
from three closely associated specimens demonstrating gregarious behavior. The skull is quite small relative to the neck and rest of the body, even by sauropodomorphi standards. Atypically manual digit 3 is about as long as digit 2.
Müller RT, Langer MC and Dias-da-Silva S 2018. An exceptionally preserved association of complete dinosaur skeletons reveals the oldest long-necked sauropodomorphs. Biol. Lett. 14: 20180633. http://dx.doi.org/10.1098/rsbl.2018.0633