An early 17th-century temporary reduction in global atmospheric carbon dioxide (CO2) levels has now been attributed to reforestation in Amazonia after the catastrophic loss of life of the indigenous population caused by diseases brought by European invaders. Using fossil pollen data from Amazonian lake sediments with temporal resolution over the past millennium, Bush et al. found that forest…

Human brains are larger than and structurally different from the brains of the great apes. Ponce de León et al. explored the timing of the origins of the structurally modern human brain (see the Perspective by Beaudet). By comparing endocasts, representations of the inner surface of fossil brain cases, from early Homo from Africa, Georgia, and Southeast Asia, they show that these structural…

Extant amphibians are represented by three fairly simple morphologies: the mostly hopping frogs and toads, the low-crawling salamanders, and the limbless caecilians. Until the early Pleistocene—and for more than 165 million years—there was another group, the albanerpetontids. We know little about this group because amphibian fossils are poorly preserved, and previous specimens from this group are…