IS DZHARATITANIS KINGI THE YOUNGEST REBBACHISAURIDAE AND THE FIRST RECORD OF A REBBACHISAURID SAUROPOD IN ASIA?

LERZO LUCAS; CARBALLIDO, JOSÉ; PABLO GALLINA

Jornada; 34º JORNADAS ARGENTINAS DE PALEONTOLOGÍA DE VERTEBRADOS; 2021

34º JORNADAS ARGENTINAS DE PALEONTOLOGÍA DE VERTEBRADOS

Dzharatitanis comprises an isolated vertebra from the Late Cretaceous (Turonian) of Uzbekistan, Asia. It was originally attributed to titanosaurian sauropods, but recently, in a redescription of this material, it was interpreted as the first caudal vertebra of a new species of Rebbachisauridae. This record would drastically impact in both biogeographical and chronological aspects of the group, as could represent the first record of the clade outside Gondwana and Europe and the youngest one worldwide. Nevertheless, some ?rebbachisaurid? characters recognized in it seems to have been incorrectly interpreted or having a more widespread distribution amongst Neosauropoda. The transverse process was incorrectly recognized as wing-like, a widespread character amongst diplodocoids, but is actually similar to the high transverse process present in some lognkosaurian titanosaurs (e.g., Patagotitan), whereas the neural spine is short and does not present the triangular expansion that characterize Rebbachisaurinae; instead, it is dorsally expanded as in the lognkosaurs Futalognkosaurus and Patagotitan. Dzharatitanis has a well-developed and anterolaterally placed spinoprezygapophyseal lamina that reaches the dorsal edge of the neural spine like several titanosaurs, instead of being laterally projected as is in most diplodocoids. The presence of a marked spinodiapophyseal lamina in the anterior caudal vertebrae is widespread amongst Lognkosauria and Rebbachisauridae, whereas the prespinal lamina is dorsally expanded, a character shared within Lognkosauria. The phylogenetic analysis carried out recovered Dzharatitanis as a lognkosaurian titanosaur. So, there is no reliable evidence to assume that rebbachisaurid sauropods have inhabited Asia. Additionally, these results suggest a wider distribution of Lognkosauria during the Cretaceous.