Description and taxonomic assessment of fossil Cercopithecidae from the Pliocene Galili Formation (Ethiopia).

The Mount Galili Formation in the Afar region, Ethiopia, samples a critical time in hominin evolution, 4.4 to 3.8 Ma, documenting the last appearance of Ardipithecus and the origin of Australopithecus.

Examination of magnitudes of integration in the catarrhine vertebral column.

The evolution of novel vertebral morphologies observed in humans and other extant hominoids may be related to changes in the magnitudes and/or patterns of covariation among traits. To examine this, we tested magnitudes of integration in the vertebral column of cercopithecoids and hominoids, including humans. Three-dimensional surface scans of 14 vertebral elements from 30 Cercopithecus, 32 Chlorocebus, 39 Macaca, 45 Hylobates, 31 Pan, and 86 Homo specimens were used.

Testing the Giles hypothesis using geometric morphometrics.

Objectives: The Giles hypothesis posits that differences in the cranial morphology of Pan troglodytes and Gorilla gorilla are largely the result of allometric scaling. However, previous support for the Giles hypothesis was based on bivariate plots of linear measurements. This investigation uses geometric morphometric methods to retest this hypothesis and its prediction that extending the ontogenetic trajectory of a chimpanzee would produce an adult gorilla-like cranial morphology.

Ontogenetic allometry and scaling in catarrhine crania.

In studies of ontogenetic allometry, ontogenetic scaling has often been invoked to explain cranial morphological differences between smaller and larger forms of closely related taxa. These scaled variants in shape have been hypothesized to be the result of the extension or truncation of common growth allometries. In this scenario, change in size is the determining factor, perhaps under direct selection, and changes in cranial shapes are byproducts, not under direct selection themselves.

Phylogenetic Perspectives on Catarrhine Talo-Crural Joint Phenotypic Plasticity.

Previous investigations of the primate talo-crural joint (TCJ; specifically on the talus and distal tibia) have demonstrated that substrate preference significantly influences morphology, but this association is not necessarily found in subadults. This has been interpreted as the result of a plastic, behaviorally induced response of bone due to substrate use. In this investigation, we use geometric morphometric and phylogenetic comparative methods to investigate ontogenetic phenotypic plasticity in the catarrhine TCJ.

Ontogeny and phylogeny of the cercopithecine cranium: A geometric morphometric approach to comparing shape change trajectories.

While the analysis of ontogenetic trajectories is common in geometric morphometrics (GM), the simultaneous comparison of several trajectories can be unwieldy and is, in some cases, unable to make use of one of the main advantages of GM, visualization. Furthermore, due to the paucity of the paleontological record, analyses of trajectories are often limited to extant taxa. We address these issues by presenting a method for visualizing the similarities and differences of cranial ontogenetic trajectories among taxa and a method for reconstructing ancestral ontogenetic trajectories, so that these differences can be investigated in a phylogenetic context.

Trajectory analysis among African hominoids can provide insights into genetic and epigenetic influences during ontogeny.

Objectives: Prior examination of the ontogeny of Hominoid talo-crural joint morphology using Singular Warp analysis suggested both a genetic and epigenetic signal during development. This question is examined using trajectory analysis and its implications for the Hominin fossil record explored.

Materials And Methods: Trajectory analysis was used to examine talo-crural joint shape at different molar eruption stages during development among a cohort of 221 specimens of Homo sapiens, Gorilla gorilla, Pan troglodytes, and Pan paniscus.

Constructing cranial ontogenetic trajectories: A comparison of growth, development, and chronological age proxies using a known-age sample of Macaca mulatta.

Recent morphometric research has generated opposing conclusions regarding the ontogenetic trajectories of catarrhine crania, possibly due to the ontogenetic proxies used to calculate them. Therefore, we used three surrogates: size, molar eruption, and chronological age to generate trajectories in a known-age sample to produce ontogenetic trajectories and determine the similarities and differences between them. Forty-three landmarks from an ontogenetic series of 160 Macaca mulatta crania, with associated ages at death, were used to produce ontogenetic trajectories of cranial shape change.