Futalognkosaurus

Phylogeny: Dinosauria > Saurischia > Sauropodomorpha > Plateosauria > Massopoda > Sauropodiformes > Sauropoda > Gravisauria > Eusauropoda > Neosauropoda > Macronaria > Titanosauriformes > Somphospondyli > Titanosauria > Lithostrotia > Colossosauria > Lognkosauria

Overview: Futalognkosaurus is the namesake of the titanosaurian clade Lognkosauria; considered to be one of the most derived lineages within the Titanosauria. Despite their name, not all of the titanosaurs were gigantic, but quite a few were, many of which belonged to the Lognkosauria. As for Futalognkosaurus itself, it’s a good example of such an animal. Length estimates put it at twenty-eight meters long, with mass estimations usually exceeding fifty standard tons (weight estimates are notoriously difficult from fossils alone). Its relatives Patagotitan and Argentinosaurus appear to have been larger, but Futalognkosaurus was still among the largest known sauropods. Recovered fossils from this animal include most of the neck, spine, rib cage, pelvis, and some of its leg bones. The tail and skull have yet to be described, however. Missing skulls are fairly normal for sauropods, particularly titanosaurs, considering they were so small and fragile relative to the main skeleton. Only a small handful of titanosaur skulls have been discovered and described in detail.

In its general appearance, Futalognkosaurus was quite similar to other titanosaurs, possessing an elongated neck, presumably tiny head, and robust, pillar-like legs. Most of its food was found in the canopies of tall conifers and other such trees. Some titanosaurs possessed simple dermal armor on their backs, which could’ve been present on this genus, though we can’t say for certain. Members of the Lognkosauria, in addition to their size, are also famous for the massive neural spines on their neck vertebrae. These spines were wide and triangular, often compared in shape to the dorsal fin of a shark. This, along with the long cervical ribs that projected behind the vertebrae, were likely adaptations that allowed for such enormous, muscular necks. Futalognkosaurus was officially described as a genus in 2007, its name meaning “giant chieftain lizard”, derived in part from the Mapudungun language, spoken in the part of Argentina where it was found. Fossils are known from the Portezuelo Formation, so it likely lived alongside other dinosaurs such as Megaraptor and Unenlagia.