An isolated vertebra from the Late Cretaceous of Uzbekistan (Asia), previously interpreted as a titanosaur anterior caudal, was recently assigned as the holotype and unique specimen of a new rebbachisaurid taxon, Dzharatitanis kingi. This record would drastically impact both biogeographical and chronological aspects of the group. As some of the characters identified for such systematic assignment seem to have been incorrectly scored and/or have a more widespread distribution amongst Neosauropoda, we revised and discussed them in depth to verify the putative rebbachisaurid affinities of this taxon. The phylogenetic analyses carried out recovered Dzharatitanis as a titanosaur sauropod, most probably related to Lognkosauria. The extra steps needed to force Dzharatitanis within Rebbachisauridae confirms that its titanosaur affinity is not solely the most parsimonious hypothesis but also is well supported when the incompleteness of the material is considered. Given this new phylogenetic position, a new modified diagnosis is provided here. Although more complete evidence is needed, the reinterpretation of Dzharatitanis as a titanosaur with lognkosaurian affinities suggests a wider biogeographic distribution of this group of colossosaurs during the Cretaceous. At present, there is no reliable evidence to assume that rebbachisaurid sauropods have inhabited Asia.

El objetivo del presente estudio es caracterizar la fauna de anfibios y reptiles de los partidos de Avellaneda y Quilmes, un sector suburbano de la costa nordeste de la provincia de Buenos Aires, Argentina. El área se visitó esporádicamente entre 2005 y 2014, y con visitas sistematizadas entre este año y 2017. Se dividió el área de estudio en cuatro unidades ambientales mayores (1-playa; 2-bosque y bañados; 3-barranca; y 4-terraza alta) anotando en cuál de ellos fue hallada cada especie. Se encontró un total de 32 especies (12 son anfibios y 20 reptiles), la mayoría de ellos en los bosques y bañados. La totalidad de las especies de anfibios son nativas, mientras que entre los reptiles se cuenta con dos especies exóticas. Los anfibios y reptiles del área costera de Quilmes y Avellaneda exponen la vinculación faunística entre las selvas y humedales de la provincia Paranaense con el Río de la Plata. Los bosques y humedales de Avellaneda y Quilmes funcionan como “stepping stone” en esta ruta de dispersión biogeográfica. Finalmente, se destaca la poca representación de especies de pastizal que se han registrado en áreas cercanas, pero no en el área de estudio. Probablemente, esto se deba a que las actividades antrópicas en la región afectaron irreversiblemente a los pastizales originales.

No abstract

An isolated vertebra from the Late Cretaceous of Uzbekistan (Asia), previously interpreted as a titanosaur anterior caudal, was recently assigned as the holotype and unique specimen of a new rebbachisaurid taxon, Dzharatitanis kingi. This record would drastically impact both biogeographical and chronological aspects of the group. As some of the characters identified for such systematic assignment seem to have been incorrectly scored and/or have a more widespread distribution amongst Neosauropoda, we revised and discussed them in depth to verify the putative rebbachisaurid affinities of this taxon. The phylogenetic analyses carried out recovered Dzharatitanis as a titanosaur sauropod, most probably related to Lognkosauria. The extra steps needed to force Dzharatitanis within Rebbachisauridae confirms that its titanosaur affinity is not solely the most parsimonious hypothesis but also is well supported when the incompleteness of the material is considered. Given this new phylogenetic position, a new modified diagnosis is provided here. Although more complete evidence is needed, the reinterpretation of Dzharatitanis as a titanosaur with lognkosaurian affinities suggests a wider biogeographic distribution of this group of colossosaurs during the Cretaceous. At present, there is no reliable evidence to assume that rebbachisaurid sauropods have inhabited Asia.