image: This image shows the lower thoracic block of MH2: Right lateral (left), anterior (middle), and left lateral (right) views of the antepenultimate (top, off-set vertebra), penultimate (middle), and ultimate (bottom) ribbearing vertebrae. Arrows identify costal facets (note that the ultimate vertebra is obscured by an unassociated rib on its left side; however, computed tomography (CT) slices confirm the presence of costal facets on both sides). Notice that the penultimate rib-bearing vertebra bears flat, posteriorly oriented superior articular facets and curved, sagittally oriented inferior articular facets—it is the transitional vertebra; thus, the ultimate rib-bearing vertebra is posttransitional. For more information, please see figure 2 in the manuscript. This image relates to a paper that appeared in the April 12, 2013, issue of Science, published by AAAS. The paper, by Scott A. Williams at New York University in New York, N.Y., and colleagues was titled, "The Vertebral Column of Australopithecus sediba." view more
Credit: [Image courtesy of <i>Science</i>/AAAS]