Titanomachya gimenezi. Image credit: Gabriel Díaz Yantén.

Titanosaurian sauropods exhibit a remarkable body size disparity in the Late Cretaceous ecosystems of South America. Some of them, were the largest animals ever to walk the Earth. In central Patagonia, there was a coexistence of small bodied saltasauroids, aeolosaurines, and larger bodied titanosaurs of uncertain affinities. A new specimen, Titanomachya gimenezi, shed light on the poorly sampled sauropod fauna from central Patagonia.

The evolution of body mass in this clade is a key element to understand sauropod evolution. Discovered in the late Cretaceous sediments of the La Colonia Formation, at Norte de Cerro Bayo in Chubut Province of Patagonia, Argentina, Titanomachya gimenezi is a small bodied saltasauroid, and the first to be recognised from Central Patagonia for the end-Cretaceous.

Titanomachya gimenezi, holotype. MPEF Pv 11547/1, right femur in A, anterior; B, proximal; C, medial; D, posterior and E, distal views. Scale bar = 20 cm. From Pérez-Moreno et al, 2024.

The holotype (MPEF Pv 11547) is a partial skeleton including a posterior caudal vertebra, several incomplete ribs, the left humerus, fragments of the pelvic girdle, part of both femora, and parts of both astragali. Body mass estimated suggests that Titanomachya gimenezi  weighted 5.79 to 9.79 tons.

The generic name is derived from the battle in which the Olympians defeat the Titans in ancient Greek mythology. The specific name, honours the late Dr. Olga Giménez, the first female palaeontologist that studied the dinosaurs from Chubut Province.

Among the unique combination of features exhibits by Titanomachya are: a prominent development of the humeral deltopectoral attachment, a straight or slightly curved humeral lateral margin, extremely reduced cnemial crests on the tibiae, a symmetrical development of the articular surfaces on the astragalus and a strong posterior bulge on the astragalus.

References:

Pérez-Moreno, A., Salgado, L., Carballido, J. L., Otero, A., & Pol, D. (2024). A new titanosaur from the La Colonia Formation (Campanian-Maastrichtian), Chubut Province, Argentina. Historical Biology, 1–20. https://doi.org/10.1080/08912963.2024.2332997

Mazzetta, G. V., Christiansen, P., & Fariña, R. a. (2004). Giants and Bizarres: Body Size of Some Southern South American Cretaceous Dinosaurs. Historical Biology: A Journal of Paleobiology, 16(2–4), 71–83. http://dx.doi.org/10.1080/08912960410001715132