Yamada wonders what would have driven the evolution of the different skull morphologies seen on this species.
Although much attention has been directed toward the origin of the shell, the enigmatic evolution of the turtle skull and its anapsid temporal region has long clouded our understanding of reptile phylogeny.
From this analysis, hypotheses concerning the evolution of the allosauroid skull and body size are evaluated, a revised cranial diagnosis of the species Acrocanthosaurus atokensis is proposed, and consistencies with the stratigraphic record and biogeographical distribution of Allosauroidea are considered.
For example, to address how the cranial modules that have been identified in placentals influence the evolution of the entire skull, one would need to compare other large clades with different patterns of cranial modularity, including different numbers of modules.
These results support the hypothesis of developmental constraint limiting the evolution of the marsupial skull, and further suggest that the marsupial viscerocranium as a whole, rather than just the early-ossifying oral region, is developmentally constrained.
In the course of evolution, the skull has been modified in most diapsids from the original version evident in the fossil record.
Understanding the evolution of skull shape by examining skull growth trajectories of related species helps to understand the modifications of cranial structures that arise in relation to diet, size, and phylogeny.
Strikingly, this "one-to-many mapping" pattern of evolution between morphology and ecology in hind limb bones is in complete contrast to the "many-to-one mapping" pattern found in the evolution of carnivoran skull shape.
Questions regarding the evolution of damselfish skull biomechanics must therefore be directed at two different aspects of this process: rate and direction.
Still, Zollikofer, an expert on the evolution of skull size and shape who has remained neutral in the hobbit wars, says this study's six measurements are too simple to capture the complexities of skull shape, a concern shared by others.
