A New Carcharodontosaurian Theropod from the Lusitanian Basin: Evidence of Allosauroid Sympatry in the European Late Jurassic

• Published in: Journal of Vertebrate Paleontology
• Main Authors: Elisabete Malafaia, Pedro Mocho, Fernando Escaso, Francisco Ortega
• Format: Text
• Language: English
• Published: The Society of Vertebrate Paleontology 2020
• Subjects: Morrison; Antarc*; Antarctica
• Online Access: https://doi.org/10.1080/02724634.2020.1768106

Carcharodontosaurian allosauroids were temporally restricted to the Cretaceous, being known from all land masses with the exception of Antarctica. In addition to Veterupristisaurus from Tanzania, exceptions to this distribution have been reported recently, consisting on fragmentary materials from Upper Jurassic strata of China, Germany, and Portugal. Here, we propose a new Late Jurassic carcharodontosaurian taxon, Lusovenator santosi, gen. et sp. nov. based on the reevaluation of previously described specimens from the Lusitanian Basin, Portugal. The performed phylogenetic analysis recovered Lusovenator santosi as an early branching carcharodontosaurian allosauroid diagnosed by an exclusive combination of characters, including three autapomorphic features: (1) large recesses in neural arch of anterior dorsal vertebrae; (2) well-developed and continuous longitudinal laminae extending from the tip of the prezygapophyses to the distal end of the postzygapophyses in mid-caudal vertebrae; and (3) supraacetabular crest of ilium forming a prominent ventrolaterally projecting shelf. Lusovenator santosi is the oldest carcharodontosaurian allosauroid yet discovered from Laurasia and supports unequivocally the hypothesis of a pre-Cretaceous scenario for the radiation of the clade. The identification of this taxon highlights the high diversity of medium- to large-bodied theropods in the later part of the Late Jurassic of the Iberian Peninsula. Carcharodontosauria is not yet known in correlative levels of the North American Morrison Formation, and the existence of contacts after the late Tithonian between these landmasses could explain the distribution of this clade and other dinosaur groups present in the Iberian Jurassic and in the North American Lower Cretaceous.