It's no secret that we like titanosaurs here at Equatorial Minnesota, and another favorite topic is potential gut contents in herbivorous dinosaurs (albeit we don't see a lot of papers on it). When Poropat et al. (2025)'s paper on the potential gut contents of a specimen of Diamantinasaurus matildae came out a couple of weeks ago, it was an obvious paper to cover here. True, diamantinasaurus may not be titanosaurs by phylogeny, but they're close, and they're still titanosaurs in our hearts.
What we're dealing with in this case is AODF 0888 (Australian Age of Dinosaurs Museum, Winton, Queensland, Australia). All good Australian sauropod specimens also have a nickname, and this one's is "Judy". AODF 0888 is a subadult individual perhaps 11 m (36 ft) long represented by an associated to articulated partial skeleton including a bit of dentary, some teeth, the vertebrae from Cervical 3 to the end of the sacrum, the shoulder girdles and sternal bones, the ilia and one pubis, ribs, a humerus, an ulna, a metacarpal, a phalanx bone, the left leg minus the foot, and skin impressions. Most of the impressions are with the possible gut contents, but there are a few patches associated with the limb bones as well. The skeleton is likely to have been more complete before exposure at the surface. It was found in coarse siltstone deposited in a floodplain, possibly in an oxbow lake. Other animal fossils are limited to a couple of bivalves and three megaraptoran teeth; although there are no tooth marks, some of the disarticulation of the specimen may be attributable to scavengers (Poropat et al. 2025). It's not a major part of the publication, but Table S1 in the supplementary table comparing seven specimens of D. matildae illustrates that this species is now not only one of the most completely known titanosaur-type sauropods, but one of the most completely known sauropods in general.
The potential gut contents are a roughly L-shaped blob between the shoulder girdles and the fused sacrum and ilia, represented by a consolidated layer about 2 m x 1 m (7 ft by 3 ft) and 50 to 100 mm (2 to 4 in) thick (a volume estimated about 100 L or 26 gal). This consolidated layer has as many as five sublayers, in ascending order: 1) orange matrix with some plants, 2) mineralized skin impressions, 3) a lower plant-rich layer, 4) an interval of iron-rich precipitates (goethite) likely replacing some other material, and 5) and an upper plant-rich layer. The skin layer, if you were curious, includes polygonal scales 7 to 13 mm (0.3 to 0.5 in) in diameter. Some ribs were embedded in the layer as well. No stones that could be interpreted as gastroliths were found (Poropat et al. 2025).
The plant fossils in the consolidated layer are mostly preserved as molds or voids. Some are identifiable as bracts, leaves or stems, particularly in the lower plant-rich layer. The largest fragments are up to about 100 mm (4 in) long with cross-sections of less than 10 mm (0.4 in). Some are identifiable as conifer bracts with scale-like leaves, larger broad strap-like Araucaria-type leaves, fruiting bodies resembling those of seed ferns, and thin angiosperm leaves up to 80 mm (3.1 in) across). The pieces are not intact, but have frayed edges or show signs of being bent or crushed. Plant fossils are uncommon elsewhere at the site, except for minor accumulations a few meters away. These fossils are preserved as compressions and include a wider variety of plants (Poropat et al. 2025).
The identification of gut contents in herbivorous dinosaurs is limited by the small sample size, but we've got enough to work up some criteria, as established in Brown et al. (2020). Poropat et al. ran AODF 0888 through a battery of tests to characterize the specimen and potential gut contents, practically anything that can be done to a sauropod in the early 2020s. (I'm not kidding; the list includes surface scanning, neutron tomography scanning, synchrotron μCT scanning, μCT scanning, a palynological analysis [no palynomorphs found], X-ray diffraction, microscopy and ToF-SIMS of thin sections, Tescan Integrated Mineral Analyzer, ToF-SIMS, and biomarker analyses. Refer to the paper to find out about these various ways of querying sauropods.) With their thoroughly analyzed material, the authors turned to the Brown et al. criteria. (It would sound snappier without the "et al", but you don't want to forget about the other authors, do you?) Three of the 16 criteria were not applicable or could not be analyzed. Of the rest, two were negative (the body and possible gut contents were not together in a setting other than where the animal would have lived, and the possible gut contents were not enclosed in a three-dimensional body cavity). The other 11 were considered positive, giving AODF 0888 a grade of 11 out of 13 that could be scored, which Poropat et al. regarded as strong evidence for the material being gut contents. (Looking at Table S2, I think Leonardo could score positive on a couple of things it's listed as negative or questionable for, although another look might be necessary.)
I think that's a reasonable interpretation. If so, what does it tell us about AODF 0888, D. matildae, and sauropods in general? The condition of the plant material shows that the animal was not doing a lot of processing in the mouth, and the presence of conifer, seed fern, and angiosperm material indicates it wasn't picky (in type of plant or vertical range), which are both consistent with dietary interpretations of generalized sauropods (Poropat et al. 2025). Anatomically, as we saw before D. matildae had a bluntly pointed snout with relatively long tooth rows, and the teeth are of the robust broad form rather than the slender pencil form. The arms were relatively long and the neck vertebrae, though short, were backed up by long cervical ribs, a setup thought to be conducive to medium to high browsing. However, angiosperms in the gut contents indicate lower browsing as well (granted, Poropat et al. point out that the gut contents may not represent a typical diet, just what the animal was eating near the time of death). The authors, noting the subadult age of the specimen, suggested that AODF 0888 was at a transition from the lower feeding range of a juvenile to the higher range of an adult. In broader evolutionary terms, Poropat et al. note the decline of the broad-toothed generalist sauropods like D. matildae in the Late Cretaceous. If this is the case, what would have made a strategy that had been successful since the Early Jurassic go out of style? (Something else to blame on angiosperms?)
References
Brown, C. M., D. R. Greenwood, J. E. Kalyniuk, D. R. Braman, D. M. Henderson, C. L. Greenwood, and J. F. Basinger. 2020. Dietary palaeoecology of an Early Cretaceous armoured dinosaur (Ornithischia; Nodosauridae) based on floral analysis of stomach contents. Royal Society Open Science 7(6): 200305.doi:10.1098/rsos.200305.
Poropat, S. F., A.-M. P. Tosolini, S. L. Beeston, M. J. Enchelmaier, A. H. Pentland, P. D. Mannion, P. Upchurch, K. Chin, V. A. Korasidis, P. R. Bell, N. J. Enriquez, A. I. Holman, L. M. Brosnan, A. L. Elson, M. Tripp, A. G. Scarlett, B. Godel, R. H. C. Madden, W. D. A. Rickard, J. J. Bevitt, T. R. Tischler, T. L. M. Croxford, T. Sloan, D. A. Elliott, and K. Grice. 2025. Fossilized gut contents elucidate the feeding habits of sauropod dinosaurs. Current Biology 35(11): 2597–2613. doi: https://doi.org/10.1016/j.cub.2025.04.053
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