Rectilinear evolution in arvicoline rodents and numerical dating of Iberian Early Pleistocene sites
Abstract Lozano-Fernandez et al. (2013a) have recently published a method intended for numerical dating of Early Pleistocene sites, which is based on the assumption of uniform, constant rate increase through time of mean lower molar tooth length of water voles ( Mimomys savini ) in a number of levels sampled in the stratigraphic sequence of Atapuerca TD site. They suggest that the regression equation obtained in this local section for site chronology on tooth size could be useful for estimating the numerical age of other localities from southwestern Europe. However, in our opinion this biostratigraphic approach has severe conceptual and methodological problems, which discourage its use as a…
Constraint and adaptation in the evolution of carnivoran skull shape
The evolutionary history of the Order Carnivora is marked by episodes of iterative evolution. Although this pattern is widely reported in different carnivoran families, the mechanisms driving the evolution of carnivoran skull morphology remain largely unexplored. In this study we use coordinate-point extended eigenshape analysis (CP-EES) to summarize aspects of skull shape in large fissiped carnivores. Results of these comparisons enable the evaluation of the role of different factors constraining the evolution of carnivoran skull design. Empirical morphospaces derived from mandible anatomy show that all hypercarnivores (i.e., those species with a diet that consists almost entirely of verte…
The giant hyena Pachycrocuta brevirostris: Modelling the bone-cracking behavior of an extinct carnivore
Abstract The giant hyena Pachycrocuta brevirostris was the largest bone-cracking carnivore that ever existed. With the mass of a lioness, it had massive limbs with shortened distal bones and a heavy, powerfully built mandible with robust, well-developed premolars. All these features reflect its adaptation for dismembering ungulate carcasses, transporting large pieces of them without dragging to the denning site and fracturing bones. This paper estimates the relative contribution of hunting and scavenging to the diet of this extinct hyena, using a combined biomechanical and taphonomic approach. Analysis of the bone-cracking behavior of P. brevirostris was based on the abundance of skeletal e…