Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae)
and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to
investigate their dietary ecology, using several complementary methods—orientation
patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear,
and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus
and Mochlodon , and traditional and DMTA microwear features suggest low-browsing habits
for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon
possesses a novel adaptation for increasing dental durability: the dentine on the
working side of the crown is double the thickness of that on the balancing side. Moreover,
crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly
between the two taxa. Consequently, these sympatric herbivores probably exploited
plants of different toughness, implying dietary selectivity and niche partitioning.
Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely
fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus ,
the bipedal Mochlodon wore down more than twice as much of its crown volume during
the functional life of the tooth. This heavy tooth wear might correlate with more
intensive food processing and, in turn, could reflect differences in the metabolic
requirements of these animals.
