Open Paleo

Eutitanosauria

Sanz et al., 1999

Its genera lived 132.6–66.0 million years ago Early Cretaceous–Late Cretaceous
Early Cretaceous and Late Cretaceous stages

Eutitanosauria is a clade of titanosaurs that gathers together the more derived members of the group. Under its current node-based definition it spans the smallest grouping that contains both Patagotitan and Saltasaurus, making it the immediate parent of two major branches: Colossosauria, which includes the enormous lognkosaurs and the comparatively small-bodied rinconsaurs, and Saltasauroidea, which includes the smaller, heavily armored saltasaurids. Members are distinguished by the loss of the hyposphene-hypantrum articulation between the vertebrae, and many bore bony osteoderms embedded in the skin. Because the definition has shifted repeatedly and often overlaps with the broader Lithostrotia, the label is frequently left unused or unlabeled on phylogenetic trees.

Under dispute

The content and rank of Eutitanosauria, and its position relative to Lithostrotia, vary among analyses. Sanz and colleagues (1999) introduced the name for a clade of advanced titanosaurs, and Carballido and colleagues (2022) redefined it as the node of Patagotitan and Saltasaurus, whose two stems are Colossosauria and Saltasauroidea. Whether that node lies within Lithostrotia depends on the position of Malawisaurus: in most analyses Lithostrotia includes nearly all titanosaurs, but in others it is the sister of Colossosauria and so falls within Eutitanosauria (Carballido and colleagues, 2022). Its content is highly labile among analyses, and many studies neither define nor label it (Carballido and colleagues, 2022). It is placed within Lithostrotia, following the majority topology.

Diagnosis

  1. Loss of the hyposphene-hypantrum articulation in the posterior dorsal vertebrae
  2. Reduced fourth trochanter of the femur
  3. Dermal osteoderms present

Clades within Eutitanosauria

Genera placed directly in Eutitanosauria

  • Menucocelsior Aranciaga Rolando et al., 2021 Maastrichtian (72.2–66.0 Ma)Argentina
  • Petrustitan Díez Díaz et al., 2025 Maastrichtian (72.2–66.0 Ma)Romania

References

  1. Sanz, J. L.; Powell, J. E.; Le Loeuff, J.; Martínez, R.; Pereda-Suberbiola, X. (1999). Sauropod remains from the Upper Cretaceous of Laño (northcentral Spain). Titanosaur phylogenetic relationships. Estudios del Museo de Ciencias Naturales de Alava 14(especial 1): 235-255.

    Introduced the name Eutitanosauria.

    sanz1999a
  2. Carballido, J. L.; Otero, A.; Mannion, P. D.; Salgado, L.; Pérez Moreno, A. P. (2022). Titanosauria: a critical reappraisal of its systematics and the relevance of the South American record. South American Sauropodomorph Dinosaurs: Record, Diversity and Evolution 269-298. Springer International Publishing. doi:10.1007/978-3-030-95959-3_8

    Redefined Eutitanosauria as the node of Patagotitan and Saltasaurus, with Colossosauria and Saltasauroidea as its two stems.

    carballido2022a