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Theropod ziphodont serrated teeth, development and evolution (free pdf)

Ben Creisler

A new open access paper:

K. S. Brink, R. R. Reisz, A. R. H. LeBlanc, R. S. Chang, Y. C. Lee, C.
C. Chiang, T. Huang & D. C. Evans (2015)
Developmental and evolutionary novelty in the serrated teeth of
theropod dinosaurs.
Scientific Reports 5, Article number: 12338

Tooth morphology and development can provide valuable insights into
the feeding behaviour and evolution of extinct organisms. The teeth of
Theropoda, the only clade of predominantly predatory dinosaurs, are
characterized by ziphodonty, the presence of serrations (denticles) on
their cutting edges. Known today only in varanid lizards, ziphodonty
is much more pervasive in the fossil record. Here we present the first
model for the development of ziphodont teeth in theropods through
histological, SEM, and SR-FTIR analyses, revealing that structures
previously hypothesized to prevent tooth breakage instead first
evolved to shape and maintain the characteristic denticles through the
life of the tooth. We show that this novel complex of dental
morphology and tissues characterizes Theropoda, with the exception of
species with modified feeding behaviours, suggesting that these
characters are important for facilitating the hypercarnivorous diet of
most theropods. This adaptation may have played an important role in
the initial radiation and subsequent success of theropods as
terrestrial apex predators.