Temporal range: Late Cretaceous, 93.5–83.5 Ma
Calvo, Porfiri, González-Riga, & Kellner, 2007
They were more derived than Andesauridae (primitive titanosaurs such as Argentinosaurus) but more basal than lithostrotians (such as Antarctosaurus and Saltasaurus). Lognkosaurians can be distinguished from other titanosaurs by the wide and unusually thick cervical rib loops on their neck vertebrae, their extremely robust neck neural spines, the relatively narrow neural canal, and their huge vaulted neural arches. They also had very wide dorsal vertebrae with wing-like side processes, and extremely wide rib cages. Their dorsal side processes are also fairly in-line with the level of the neural canal, instead of being attached further up the neural arch as in lithostrotians.
They became dominant in the Turonian and Coniacian epochs, replacing the Andesauridae as the top giant herbivores. Skull material from Malawisaurus, the sister group to Lognkosauria, indicates that lognkosaurians at least began with the big-nosed, rounded head shape of earlier titanosaurs and more basal macronarians.
Lognkosauria was defined as the node clade encompassing the most recent common ancestor of Futalognkosaurus dukei and Mendozasaurus neguyelap and all its descendants. Malawisaurus was the sister group to this clade. Lognkosauria probably also includes another giant sauropod, Puertasaurus, as well as Traukutitan and Drusilasaura.
- Calvo, J. O., Porfiri, J. D., González-Riga, B. J., and Kellner, A. W. (2007) "A new Cretaceous terrestrial ecosystem from Gondwana with the description of a new sauropod dinosaur". Anais Academia Brasileira Ciencia, 79(3): 529-41.
- Calvo, J. O.; Porfiri, J. D.; González Riga, B. J.; Kellner, A. W. A. (2007). "Anatomy of Futalognkosaurus dukei Calvo, Porfiri, González Riga, & Kellner, 2007 (Dinosauria, Titanosauridae) from the Neuquen Group, Late Cretaceous, Patagonia, Argentina" (PDF). Arquivos do Museu Nacional. 65 (4): 511–526.
- Juárez Valieri, Rubén D.; Calvo, Jorge O. (2011). "Revision of MUCPv 204, a Senonian Basal Titanosaur from Northern Patagonia" (PDF). Paleontología y dinosarios desde América Latina: 143–152.
- Navarrete, César; Casal, Gabriel; Martínez, Rubén (2011). "Drusilasaura deseadensis gen. et sp. nov., a new titanosaur (Dinosauria-Sauropoda), of the Bajo Barreal Formation, Upper Cretaceous of north of Santa Cruz, Argentina". Revista Brasileira de Paleontologia. 14 (1): 1–14. doi:10.4072/rbp.2011.1.01.