The diversity of sauropod dinosaurs and their first taxonomic succession from the latest Cretaceous of southwestern Europe: Clues to demise and extinction

Diversity and faunal changes in the latest Cretaceous dinosaur communities of southwestern Europe

“…The authors described the "lower" assemblages as those composed by titanosaurids alongside rhabdodontids and nodosaurids whereas the "upper" assemblages were dominated by hadrosauroids. The hypothesis was supported by many subsequent findings (Buffetaut, 2005;Buffetaut et al, 1997;Casanovas, PeredaSuberbiola, Santaf e, & Weishampel, 1999;Casanovas et al, 1995;Laurent et al, 2002;L opez-Martínez et al, 1999L opez-Martínez et al, , 2001Vila et al, 2006) and two decades later, with the profusion of new discoveries, correlations of some of the most important localities and successions with the magnetostratigraphic time scale and advances in chronostratigraphy (Oms et al, 2007;Pereda-Suberbiola et al, 2009;Riera et al, 2009;Vila et al, 2012Vila et al, , 2013, we are able to refine the timing and the nature of this turnover (Fig. 2).…”

“…The setting of the turnover is constrained by various important faunal events occurring around the C31r-C31n reversal: a) the first appearance of new titanosaurid faunas; b) the first appearance of hadrosauroids; and c) the last appearance of nodosaurids (and probably of rhabdodontids). The FAD of new titanosaurids, clearly distinct from those from the late Campanian-early Maastrichtian interval, is supported by the occurrence of new taxa based on skeletal remains in the uppermost part of C31n (Vila et al, 2012) and by the replacement observed in oospecies of the Megaloolithidae oofamily (an oofamily assigned to titanosaurids; Chiappe, Salgado, & Coria, 2001) around the C31r-C31n reversal. Thus, the transition between oozones 2 and 3 (Megaloolithus siruguei oospecies is replaced by M. mamillare oospecies) coincides with the magnetochron reversal (Garcia & VianeyLiaud, 2001;Sell es et al, 2013;Vila et al, 2011).…”

“…This faunal turnover hypothesis was based on analysis of the fossil record from restricted areas of the Ibero-Armorican domain, mainly from the French Pyrenees. Later works from other regions supported this hypothesis but pointed out that titanosaurid sauropods persisted until the end of the Maastrichtian alongside an abundant population of hadrosauroids (Canudo, 2001;Laurent, Bilotte, & Le Loeuff, 2002;L opez-Martínez et al, 2001;Riera et al, 2009;Vila et al, 2012Vila et al, , 2013. Apart from the clear patterns characterizing these two major groups of herbivorous dinosaurs, the turnover pattern seems to be more complex since it involves two additional herbivore groups (nodosaurid ankylosaurs and rhabdodontids ornithopods) as well a distinct fauna of carnivorous theropods (mainly abelisaurid and dromaeosaurid taxa) which is still poorly known (Canudo & Ruiz-Omeñaca, 2003;Csiki-Sava et al, 2015;Riera et al, 2009;Sell es, Vila, & Galobart, 2014a;Torices, Currie, Canudo, & Pereda-Suberbiola, in press;Tortosa et al, 2014).…”

Appendicular osteology ofDreadnoughtus schrani, a giant titanosaurian (Sauropoda, Titanosauria) from the Upper Cretaceous of Patagonia, Argentina

“…Vila et al (2012) studied several femora assigned to titanosaurs from upper Campanian to uppermost Maastrichtian fossil-sites of Spain and Southern France, referring them to different types according to a set of anatomical features. One of the types comprises two specimens from Fox-Amphoux and probably three more femora from Bellevue (Campagne-surAude).…”

“…However, these French femora do not share with Lirainosaurus astibiae the following features: Lirainosaurus presents an RI of about 0.2, whereas the French femora exhibit an RI of almost 0.16; in the French femora the lateral bulge is anteriorly projected in anterior and lateral views, whereas in Lirainosaurus it is straight; Lirainosaurus presents a trochanteric shelf in posterior view; and the intercondylar sulcus is much more developed in Lirainosaurus than in the French specimens. Also, Vila et al (2012) noted that the femora assigned to cf. Lirainosaurus astibiae are morphologically similar to those they had assigned to Ampelosaurus atacis, differentiating them only in the proximodistal development of the lateral bulge and the position of its distalmost edge.…”