Carcharodontosaurian remains (Dinosauria, Theropoda) from the Upper Jurassic of Portugal

Abstract

A new specimen of a theropod dinosaur found in the Upper Jurassic (Freixial Formation, late Tithonian) of the Lusitanian Basin is described. It corresponds to a single individual and includes a sequence of articulated caudal vertebrae, an almost complete right pes, and other fragments of the appendicular skeleton. The specimen includes the most complete pes of a theropod dinosaur currently known in the Lusitanian Basin and represents one of the youngest skeletal records of theropod dinosaurs currently known in the Portuguese Upper Jurassic.A systematic analysis of this specimen is performed and it shows a combination of characters that allows us to interpret it as belonging to an allosauroid taxon. Within this clade, the material from Cambelas shares a few features with some carcharodontosaurids, including the presence of a lateral lamina extending along the anterior end of the centrum in the caudal vertebra and of a low vertical crest on the lateral surface of the femoral lesser trochanter. The set of remains described here shares some unusual features with another specimen previously described in the Portuguese fossil record, which also presents some synapomorphies of Carcharodontosauria. However, no autapomorphy or exclusive character combination can be recognized in the specimen here described in order to describe it as a new form. The presence of this specimen suggests a greater diversity in the allosauroid theropod fauna from the Late Jurassic of the Lusitanian Basin than currently known and probably expands the temporal record of Carcharodontosauria up to upper Tithonian of south-western Europe.

A new carcharodontosaurian theropod from the Lusitanian Basin: evidence of allosauroid sympatry in the European Late Jurassic

“…nov., related to Carcharodontosauria, is defined, and the phylogenetic position of the type and referred specimens is presented. The new taxon supports the previously referred evidence for the presence of carcharodontosaurian theropods in Portugal (Malafaia et al, 2019). It is the first taxon of the group defined in the Jurassic of Laurasia and extends the fossil record of this clade already represented in the Lower Cretaceous of Europe (e.g., Brusatte et al, 2008;Ortega et al, 2010).…”

“…Referred Material-SHN.019, a partial skeleton represented by a series of articulated caudal vertebrae and an almost complete right pes collected from another locality and horizon. See Malafaia et al (2019) for a full description of the specimen. Although SHN.019 was found in a different locality and formation (around 8 Ma younger than SHN.036), this specimen is tentatively referred to Lusovenator santosi based on the presence of a shared feature proposed as diagnostic of this taxon: the presence of longitudinal laminae extending from the tip of the prezypapophyses to the distal end of the postzygapophyses in mid-caudal vertebrae.…”

“…It has been assumed that Carcharodontosauria has a ghost lineage extending back to the Late Jurassic (Brusatte et al, 2008). More recently, some isolated elements from Upper Jurassic strata in different localities have been identified to this clade, including a specimen from the Upper Jurassic of the Lusitanian Basin (Malafaia et al, 2019), some isolated teeth, caudal vertebrae, and an ilium from the Tendaguru Formation (Rauhut, 2011;Carrano et al, 2012), some teeth from the Middle-Upper Jurassic Shishugou Formation of China (Han et al, 2011), and possibly some teeth from the Lower Saxony Basin of Germany (Gerke and Wings, 2016). Here, a new taxon, Lusovenator santosi, gen. et sp.…”

“…The Portuguese Upper Jurassic record of theropod dinosaurs comprises members of deeply nested clades that are abundant and diverse in Cretaceous faunas. It includes Carcharodontosauria (Malafaia et al, 2019), Tyrannosauroidea (Rauhut, 2003a), and a great diversity of maniraptorans (Zinke and Rauhut, 1994;Zinke, 1998;Hendrickx and Mateus, 2014a;Malafaia et al, 2017b). The Portuguese specimens represent some of the earliest evidence of these clades in Laurasia and have significant implications for understanding the paleobiogeographic context and dynamics of Late Jurassic theropod fauna in the peri-Atlantic realm.…”

“…The Upper Jurassic theropod record in the Lusitanian Basin is mostly composed of medium-to large-sized taxa with a trans-Atlantic distribution, such as the genera Ceratosaurus (e.g., Malafaia et al, 2015), Torvosaurus (e.g., Hendrickx and Mateus, 2014b), and Allosaurus (e.g., Pérez-Moreno et al, 1999;Mateus et al, 2006). However, this record also includes some exclusive taxa interpreted as related to Jurassic forms from both Laurasian (e.g., Lourinhanosaurus antunesi; Mateus, 1998) and Gondwanan (e.g., Carcharodontosauria;Malafaia et al, 2019) landmasses. The combination of shared and endemic forms is compatible with a model of incipient vicariance pattern for the Late Jurassic dinosaur faunas of North American and Iberian domains (e.g., Ortega et al, 2017).…”