Sauropod undertracks in damp interdunes from Cretaceous of Brazil

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

A new paper:

Diego Luciano Nascimento, Patrícia Colombo Mescolotti, Filipe Giovanini Varejão, Francisco Sérgio Bernardes Ladeira & Mario Luis Assine (2026)
Aptian sauropod undertracks in damp interdunes: indicators of water table fluctuations in Southeast Brazil
Cretaceous Research 106345
doi: https://doi.org/10.1016/j.cretres.2026.106345
https://www.sciencedirect.com/science/article/abs/pii/S0195667126000340


Highlights

Tracks reveal dinosaurs walked on water-saturated, semi-liquid interdune sediment
Results indicate that sauropods inhabited or traveled across wet aeolian systems
Access to freshwater was a critical factor for sauropod foraging behavior
Sauropod habitat preference may be independent of specific environmental setting

ABSTRACT

The Early Cretaceous sauropod track record in South America is scarce and largely restricted to fluvial and lacustrine environments. In contrast to this pattern, we document recurrent sauropod tracks and trackway in aeolian deposits of the Aptian Três Barras Formation in southeastern Brazil. The tracks are preserved in cross-sections of interdune deposits and record the activity of large-bodied dinosaurs, probably sauropods based on their size, morphology, and marked heteropody between pes and manus. The tracks and trackway reveal detailed evidence of interactions between producers and a soft and water-saturated substrate. The foot penetrated and deformed multiple layers, generating undertracks up to more consolidated beds and resulting in liquefied soft-sediment deformation structures. Well-developed marginal folds directed to the track center, massive and deformed sand infill, collapsed walls, and underlying dish and pillar structures suggest that the trackmakers walked on semi-liquid sediment, with the tracks being filled during and immediately after foot withdrawal (syn-track infilling). These features point to substrate saturation with the water table at or near the surface, suggesting that dinosaurs walk in damp interdunes during brief preservation windows with elevated water tables. Therefore, the occurrence of sauropod tracks and trackway in the Sanfranciscana Basin may indicate that these dinosaurs inhabited, or at least travelled in, a wet aeolian environment while moving toward more favorable habitats with greater resource availability. Moreover, this study reinforces that access to freshwater was a critical factor in sauropod foraging behavior, a requirement that appears to have been independent of the specific environmental settings, whether fluvial, aeolian, or coastal wetlands.

[Gregory Paul]

I and Ken Carpenter once walked the Great Sand Dunes of central Colorado. On the flats which were somewhat wet it was real slog, took much more work than when walking on firm substrate, or for that matter beach sand which is usually well packed. Made me suspect that a lot of fossil trackways were made by animals working a lot harder than the usual dimensional and speed calculations indicate. 

GSPaul

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