Putative latest Cretaceous carcharodontosaurs

                                          Carch tooth replica

Carcharodontosaurs reached their acme in the middle Cretaceous, from Aptian to Cenomanian. In recent years, some researchers have claimed they survived in South America well past that time. On the basis of discoveries in Campanian and Maastrichtian strata, carchs are said to have survived to the latest Cretaceous or K-Pg. I don't believe the evidence is sufficient, however. Even if the material is undoubtedly carcharodontosaurid, it is extremely limited and fragmentary, which suggests reworking.

Based on just a single isolated tooth, Martinelli et al. (2004) conclude carcharodontosaurs are present in the Campanian-Maastrichtian Allen formation. How can they be sure the tooth isn't from a Giganotosaurus or Mapusaurus, later reworked into the geologically younger Allen?

Simbras et. al. (2013) are equally incautious. They note the discovery of a partial carch maxilla (below) in the Presidente Prudente formation, also of Campanian-Maastrichtian age. It is considered to indicate the presence of carchs in that unit and time. But again there is just a single isolated element, a mere fragment. If carcharodontosaurs were really present in the latest Cretaceous, why isn't there better material, comparable to that of Carnotaurus?

Perhaps the authors are right and better material will be found, confirming their view. But until it is found I'll consider Schaochilong, of Turonian age, the last of the carchs.

References

Martinelli et al. Late Cretaceous Vertebrates from the Bajo de Santa Rosa (Allen formation) Negro province, Argentina with the description of a new sauropod dinosaur. Revista del Museo Argentino Ciencias Naturales n.s. 6(2) 2004


Simbras et al. First Brazilian carcharodontosaurid and other new therapy finds from theCampanian-Maastrichtian Presidente Prudente formation from Sao Paulo state southeastern Brazil. Cretaceous Research 2013