Increasing the titanosaurian diversity of the Ibero-Armorican Island: a new titanosaurian dinosaur from Spain (at last!). Nowadays we all know about the impressive fossil-site of Lo Hueco in Cuenca, dated as upper Campanian-lower Maastrichtian. We also know that more than 10000 vertebrate remains were recovered, being more than the 80% of titanosaurian sauropods. And in this percentage several partial titanosaurian skeletons in anatomical connection or with a low disperssion are included, as for example the specimen we want to present for the first time at the Society of Vertebrate Paleontology 74th Annual Meeting: the EC1 specimen.
The EC1 skeleton includes cervical, dorsal, sacral and caudal vertebrae, and several appendicular elements. This specimen presents several titanosaurian features such as the presence of deep eye-shaped dorsal pleurocoels, procoelous caudals up to the most posterior middle ones, a pneumatized ilium, subhorizontal and perpendicular directed pre-acetabular process to the sagittal plan, the general morphology of the ischium, and pronounced femoral trochanteric shelf. EC1 also presents some interesting diagnostic characters, such as the presence of a dorsally and ventrally bifurcated pcdl in the dorsal vertebrae, some features in the lamination of the proximal caudal vertebrae, chevrons with double articular heads, or an accessory trochanter in the fibula.
Some features – as the shallow lateral depressions in the cervical centra, a ridge-like hyposphene in the dorsal vertebrae, procoelous mid-caudal vertebrae, or a subhorizontal preacetabular process – suggest a phylogenetic basal position within Lithostrotia. In addition, a preliminary phylogenetical analysis places EC1 together with the French taxa Ampelosaurus and Atsinganosaurus.
Thanks to all the discoveries that are taking place in the Iberian Peninsula and France these last years the Ibero-Armorican Island (southwestern Europe in the Upper Cretaceous) is acquiring a high importance in the assessment of the diversity of non-avian dinosaurs before the end of the Mesozoic. With the discovery and study of the EC1 specimen we can finally corroborate what we have been hypothesizing: the Iberian Peninsula had a higher titanosaurian diversity at the end of the Cretaceous, not only Lirainosaurus was present. As a future general outcome, the relatively complete titanosaurian skeletons found in Lo Hueco will shed light in the knowledge of the systematics and diversity of the titanosaurs from the European Upper Cretaceous, testing the hypothesis of the presence of at least four different titanosaurian taxa in southwestern Europe at the end of the Cretaceous.