In 2010,Martin Ezcurra defined the subfamily Saturnaliinae for the clade containingSaturnalia andChromogisaurus, which were found to be close relatives in several studies.[1] While they are sometimes found to be a subgroup within theGuaibasauridae,[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 ofSilesauridae in 2017.[10] Langer and colleagues (2019) recoveredPampadromaeus andPanphagia as relatives ofSaturnalia andChromogisaurus, elevating Saturnaliinae to family rank asSaturnaliidae. In that particular paper, they recoveredGuaibasaurus as a basal theropod.[11]
Additionally,Eoraptor,Buriolestes,Bagualosaurus and especiallyNhandumirim 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 encompassSaturnalia but notPlateosaurus."[11] In several of these analyses,Guaibasaurus is recovered as distantly related toSaturnalia, sometimes as a more basal sauropodomorph or saurischian, and in some cases specifically related to more derived taxa such asMacrocollum andUnaysaurus. This way a Guaibasauridae includingSaturnalia and kin is no longer being supported.
^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 dinosaurPampadromaeus 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
