The latter will be less heterogenous (with less force peaks) with an increasing proportion of low-angle enamel ridges. While the validity of these explanations will have to be tested in further studies,
the enamel ridge alignment represents a clear signal that deviates from an arbitrary distribution and hence most likely represents a functional adaptation. “
“Between the Middle Jurassic and Holocene, birds evolved an enormous diversity of behaviours. The distribution and antiquity of these behaviours is difficult to establish given a relatively poor fossil record. Rare crop, stomach and gut contents typically reveal diets consistent with morphology but stem-members of some lineages (including Cariamae and Coraciiformes) seem to have been different in ecology from their extant relatives. Most of our ideas about the behaviour Microtubule Associated inhibitor of fossil birds are based on analogy Navitoclax solubility dmso (with skull form, limb proportions and claw curvature being used to guide hypotheses). However, this has limitations given that some extinct taxa lack extant analogues and that some extant taxa do not behave as predicted by osteology. Reductionist methods have been used to test predation style and running ability in fossil taxa including moa, Gastornis and phorusrhacids. Virtually nothing is
known of nesting and nest-building behaviour but colonial nesting is known from the Cretaceous onwards. Rare vegetative nests demonstrate
modern nest-building from the Eocene onwards. Ornamental rectrices indicate that sexually driven display drove some aspects of feather evolution and evidence for loud vocal behaviour and intraspecific combat is known for some taxa. Our knowledge of fossil bird behaviour indicates that ‘modern’ behaviours are at least as old as crown birds. Stem-members of extant lineages, however, may sometimes or often have differed from extant taxa. “
“This paper presents an analysis of molar occlusal morphology and its relation to diet in modern bovids. The work develops previous research by analysing samples from 86 species from all major subfamilies and medchemexpress from across their geographical distribution. Molar surfaces are characterized by the length, thickness and shape of enamel formations. Discriminant function analysis (DFA) is used to characterize the dental anatomy of each group and permits interpretations as to the selective pressures governing occlusal form. Grazers and most browsers are very different and distinguishable, the former possessing long and thickened enamel with a bimodal distribution of central ridge enamel alignment. Frugivorous duikers possess thickened enamel and large surface areas, traits interpreted as adaptations for hard-object feeding.