Physorg.Com has an interesting report on new research by Nate Dominy on underground storage units:
In the new paper, entitled “Mechanical Properties of Plant Underground Storage Organs and Implications for Dietary Models of Early Hominins,” Dominy tested USOs, which plants use to store water and carbohydrates. His data establish rhizomes as the toughest, followed by tubers, corms, and bulbs (familiar examples of which include Bermuda grass, potatoes, iris, and onions, respectively). Corms and bulbs emerged as the most plausible hominin foods, according to Dominy, because their physical qualities match up with dietary inferences based on dental morphology and modern chemical isotopic analysis.
The new data also allowed Dominy to correlate plant characteristics with the dental morphology of different species of hominins. The teeth of Australopithecus, for example, appear well-suited to process bulbs, while the teeth of Paranthropus appear well-adapted to process hard and brittle corms.
The paper is supposed to be published in Evolutionary Biology but I haven’t been able to track it down.