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Brain growth in Dysalotosaurus

From: Ben Creisler

A new online article:

S. Lautenschlager & T. Hübner (2013)
Ontogenetic trajectories in the ornithischian endocranium.
Journal of Evolutionary Biology (advance online publication)
DOI: 10.1111/jeb.12181

Understanding ontogenetic and developmental patterns is critical for
reconstructing the life history of fossil vertebrates. In dinosaurs,
ontogenetic studies have nearly exclusively focused on changes in the
cranial and post-cranial skeleton, whereas ontogenetic changes in the
endocranium have received little attention. Here, we present digital
reconstructions of the brain and inner ear anatomy of two ontogenetic
stages of the Jurassic ornithischian dinosaur Dysalotosaurus
lettowvorbecki. Results show that the endocranial anatomy underwent
considerable changes during growth, including a rostrocaudal
elongation of the olfactory apparatus, a reduction in the cephalic and
pontine flexure and an increase in cerebellum size. Functional
elements, such as the cerebral hemispheres and the inner ear, were
already well developed in early ontogenetic stages, indicating a large
degree of precociality. The anisotropic pattern of size and shape
changes in the endocranium further indicates that ontogenetic
trajectories may be controlled by functional and environmental demands
in the different growth stages in Dysalotosaurus lettowvorbecki. The
occurrence of similar ontogenetic patterns in the endocranial anatomy
of derived ornithopod dinosaurs suggests a more widespread
distribution of this growth trajectory.

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