A new theropod dinosaur from the Early Cretaceous (Barremian) of Cabo Espichel, Portugal: implications for spinosaurid evolution
Project
ID: 000396486
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Spinosaurids are some of the most enigmatic of the Mesozoic theropod dinosaurs due to their unique adaptations to aquatic environments and their relative scarcity. Their taxonomy has proven to be especially problematic. Western Europe in general and Iberia in particular has recently shown to provide some the best specimens for the understanding of their phylogeny, leading to the description of the spinosaurid Vallibonavenatrix cani and the recognition of the Iberian dinosaur Camarillasaurus cirugedae as one them. Portuguese associated spinosaurid remains (ML1190) from the Papo Seco Formation (Early Barremian) were previously assigned to Baryonyx walkeri, but new material recovered in 2020 and new phylogenetic analyses suggested a different phylogenetic placement, making their revision necessary. Here we show that these remains are not attributable to Baryonyx walkeri, but to a new genus and species, Iberospinus natarioi, gen. et sp. nov.. The new taxon is characterized by the presence of a single meckelian foramen in the meckelian sulcus (a unique condition in megalosauroid theropods), a straight profile of the ventral surface of the dentary, a distal thickening of the acromion process of the pubis and other characters. Iberospinus natarioi is recovered as a sister taxon of the clade formed by Baryonyx and Suchomimus, and outside Spinosaurinae when Vallibonaventrix cani is excluded from the analysis. The description of this taxon reinforces Iberia as a hotspot for spinosaurian biodiversity, with endemic taxa for the region. The dentary showed a highly vascularized neurovascular network, part of a vascularization trend expected in the group. The metrical analysis of parts of the skeleton (pedal phalanx and caudal vertebrae, among others) show an intermediate condition between basal tetanurans and spinosaurines.