Animalia Royo-Torres, Cobos & Alcalá 2006

Turiasauria indet.

(Figs 24 A-X; 25B, C; 26; 27)

DESCRIPTION

Sauropod remains are especially abundant in the Early Cretaceous of Angeac-Charente. The locality has yielded many teeth (N = 146), bones (N = 784), and track casts of this group of dinosaurs (Néraudeau et al. 2012; Rozada et al. 2021). All parts of the skeleton are represented including the braincase, some skull bones, teeth, cervical, dorsal and caudal vertebrae, chevrons, pelvic girdle and all the limb bones (Figs 24-27). Based on the number of femurs and their size, as well as the teeth, there are at least seven different individuals preserved in the site. With the exception of two teeth (see below), all this material belongs to a single taxon. All remaining teeth are reminiscent of the Turiasauria clade (Allain et al. 2013, 2017). We can classify them based on a small number of diagnostic characters.Teeth are heart-shaped in labial and lingual views, with an asymmetric shape induced by a concave distal margin towards the apex (Royo-Torres et al. 2006, 2017; Royo-Torres & Upchurch 2012; Mocho et al. 2016). This feature has been observed in most of the sauropod teeth that have been collected from Angeac-Charente (Figs 24; 25B, C). A second character permits referral of these teeth to Turiasauria. When the root is well preserved, several long longitudinal grooves are visible in Turiasaurus, Losillasaurus (Royo-Torres et al. 2021) and Moabosaurus (Britt et al. 2017 and RRT personal observation). These grooves are also present in the Angeac-Charente taxon (Fig. 24 I-P, U-X) and may be diagnostic for Turiasauria (Royo-Torres et al. 2021). Moreover, the teeth of Angeac-Charente show a range of crown morphotypes and this variability of forms has also been described in turiasaur teeth from Portugal (Mocho et al. 2016) and in Mierasaurus (Royo-Torres et al. 2017) and Losillasaurus (Royo-Torres et al. 2021). Teeth, in private collections, identical in every way to those of Angeac-Charente, are also present in the Berriasian of Cherves-de-Cognac (RA, TL pers. obs.).

The caudal vertebrae are also useful in determining the systematic position of the Angeac-Charente sauropod (Fig. 26). The anterior caudal vertebrae are procoelous with a slightly convex posterior articulation (Fig. 26 A-I) whereas the middle become amphicoelous or amphyplatyan (Fig. 26 J-L). The presence of a convex posterior articulation on sauropod caudal vertebrae was acquired several times during sauropod evolution (Wilson 2002; Upchurch et al. 2004; D’Emic 2012; Mannion et al. 2017, 2019) and can be seen in diplodocids, titanosaurs and mamenchisaurids. The procoelous condition was also acquired in Turiasauria, as described for the Late Jurassic Turiasaurus and Losillasaurus (Casanovas et al. 2001; Royo-Torres et al. 2006, 2021). It has also been reported in the posterior series of Early Cretaceous Mierasaurus and Moabosaurus (Royo-Torres et al. 2017; Britt et al. 2017). This feature is considered to be synapomorphic for Turiasauria in some phylogenetic analyses (Carballido & Sander 2014). The neural arch of anterior caudal vertebrae is restricted to the anterior half of the centrum. This character is shared with Turiasaurus, Losillasaurus, Moabosaurus, Mierasaurus, Cetiosaurus and the Titanosauriformes(Upchurch et al. 2004; D’Emic 2012; Britt et al. 2017; Royo-Torres et al. 2017). The presence in the Angeac-Charente taxon of caudal vertebrae with short lateral processes (‘caudal ribs’) that do not extend beyond the posterior end of the centrum suggests affinities with Titanosauriformes (Mannion et al. 2019; Royo-Torres et al. 2021).

Two additional possible synapomorphic characters for Turiasauria seen in specimens from Angeac-Charente include slightly opisthocoelous posterior dorsal centra, as well as a high neural arch below the postzygapophyses of the posterior dorsal vertebrae (Carballido & Sander 2014).