In 2010, Martin Ezcurra defined the subfamily Saturnaliinae for the clade containing Saturnalia and Chromogisaurus, which were found to be close relatives in several studies.[1] While they are sometimes found to be a subgroup within the Guaibasauridae,[1] all recent studies have found the saturnaliines to form an independent lineage at the very base of the sauropodomorph family tree.[3][4][5][6][7][8][9] At one point, Agnosphitys was recovered as a possible saturnaliine until it was recovered as a member of Silesauridae in 2017.[10] Langer and colleagues (2019) recovered Pampadromaeus and Panphagia as relatives of Saturnalia and Chromogisaurus, elevating Saturnaliinae to family rank as Saturnaliidae. In that particular paper, they recovered Guaibasaurus as a basal theropod.[11]
Additionally, Eoraptor, Buriolestes, Bagualosaurus and especially Nhandumirim are also possible members of this clade following their position in many recent phylogenetic analyses[4][5][6][7][8][9] and the new definition given by Langer et al. (2019), as "the maximal sauropodomorph clade to encompass Saturnalia but not Plateosaurus."[11] In several of these analyses, Guaibasaurus is recovered as distantly related to Saturnalia, sometimes as a more basal sauropodomorph or saurischian, and in some cases specifically related to more derived taxa such as Macrocollum and Unaysaurus. This way a Guaibasauridae including Saturnalia and kin is no longer being supported.
References
^ abcEzcurra, Martin D. (2010). "A new early dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Argentina: a reassessment of dinosaur origin and phylogeny". Journal of Systematic Palaeontology. 8 (3): 371–425. Bibcode:2010JSPal...8..371E. doi:10.1080/14772019.2010.484650. S2CID129244872.
^Baron, M.G., Norman, D.B., and Barrett, P.M. (2017). A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature, 543: 501–506. doi:10.1038/nature21700
^ abLanger MC, McPhee BW, Marsola JCdA, Roberto-da-Silva L, Cabreira SF (2019) Anatomy of the dinosaur Pampadromaeus barberenai (Saurischia—Sauropodomorpha) from the Late Triassic Santa Maria Formation of southern Brazil. PLoS ONE 14(2): e0212543. https://doi.org/10.1371/journal.pone.0212543