Phytoliths and herbivore diet
Phytolith assemblages preserved in fossilized feces (coprolites) preserve information about the diet of the animal that produced it. The lab uses this relationship to elucidate the
paleoecology of large Gondwanan herbivores and associated grasses. For example, with Indian colleagues we study phytoliths extracted from coprolites attributed to sauropod dinosaurs from the Late Cretaceous Intertrappean beds in central India. The phytolith data have so far shown that, contrary to what was previously thought, these herbivorous dinosaurs fed on a mixed diet that included grasses; additionally, the enigmatic gondwanatherian mammals may

Titanosaur sauropods (Isisaurus colberti) from the Late Cretaceous of India may have fed in part on grass.

have been early grazers (Prasad et al. 2005).

Another project with U.S. and Argentine colleagues seeks to analyze the shells of Eocene-Miocene scarab (dung beetle) brood balls from Gran Barranca, Argentina.


Generally, the brood balls contain no
original dung, but phytoliths in the shell reveal details about the paleoenvironment in which the dung producers lived. Preliminary results indicate that early Oligocene herds of medium-to-large sized herbivores that produced the dung studied so far frequented an environment with very little grass (Strömberg and Stidham 2001). These results question the link between hypsodonty and grass-dominated habitats and, furthermore, challenge the

Palm phytolith from Oligocene brood ball.

traditional notion that dung beetle behavior evolved in the context of grasslands (e.g., Retallack 1990). New, NSF-sponsored vegetation reconstruction using phytoliths at Gran Barranca has supported these conclusions.

Collaborators: e.g., Vandana Prasad (Birbal Sahni Institute of Palaeobotany, Lucknow), Ashok Sahni (Panjab University, Chandigarh), Greg Wilson (University of Washington), Matt Kohn (Boise State University), Rick Madden (Duke University), Alfredo Carlini (Universided Nacional de La Plata), Eduardo Bellosi (Museo Argentino de Ciencias Naturales).


Dense accumulations of scarab brood balls characterize several levels in the Sarmiento Formation, Argentina.