A new titanosaur closely related to Lognkosauria from Bajo de la Carpa Formation (Santonian, Upper Cretaceous) of northern Patagonia, Argentina

LEONARDO FILIPPI; CARBALLIDO, JOSÉ L.; RUBEN JUAREZ VALIERI; AGUSTÍN PÉREZ MORENO

Encuentro; I Reunión de Paleovertebrados de la Cuenca Neuquina; 2017

Upper Cretaceous) at La Invernada, Rincón de los Sauces (Neuquén). Recovered material of this specimen (MAU-Pv-LI-626)is composed by three posterior cervical vertebrae; two anterior, and one posterior dorsal vertebra; an anterior caudal verte-brae and a middle caudal centrum. Posterior cervical vertebrae of MAU-Pv-LI-626 share with Lognkosauria titanosaursMendozasaurus neguyelapGonzález Riga and FutalognkosaurusdukeiCalvo et al., three of the five synapomorphies previouslyproposed for this clade: laterodorsally expanded cervical neural spines originated by lateral laminae that reach or surpass thewide of the centra, deep and extended spinodiapophyseal fossa in posterior cervical vertebrae and anteriormost caudal ver-tebrae with neural spines transversely elongated. The preserved anterior dorsal vertebra is similar to that of Mendozasaurusand Futalognkosaurus, with a well-developed prespinal lamina, from the base to nearly the top of neural spine, and withouta spinoprezygapophyseal lamina. Anterior dorsals differs from Mendozasaurusand Futalognkosaurusin having a laterodor-sally oriented transverse processes.Anterior dorsal vertebrae of MAU-Pv-LI-626 can be differentiated from Mendozasaurusdue to the absence of infrapostzygapophyseal fossae and that the spinopostzygapophyseal lamina are straight, forming atriangular contour, that differ to the concave contour present in Mendozasaurus.According to a preliminary cladistic analy-sis MAU-Pv-LI-626 is recovered as a sister group of Lognkosauria (Mendozasaurus+Futalognkosaurus). Nevertheless, digof the rest of the specimen, is necessary to confirm its phylogenetic relationships