Background Extant sloths present an evolutionary conundrum in that the two living genera
are superficially similar (small-bodied, folivorous, arboreal) but diverged from one another …

Long-held ideas regarding the evolutionary relationships among animals have recently
been upended by sometimes controversial hypotheses based largely on insights from …

Since the late eighteenth century, fossils of bizarre extinct creatures have been described
from the Americas, revealing a previously unimagined chapter in the history of mammals …

Madagascar is well known for its diverse fauna and flora, being home to many species not
found anywhere else in the world. However, its biodiversity in the recent past included a …

Abundant skeletal remains demonstrate that lambeosaurine hadrosaurid, tyrannosaurid,
and troodontid dinosaurs lived on the Alaskan North Slope during late Campanian—early …

The determination of nuclear DNA sequences from ancient remains would open many novel
opportunities such as the resolution of phylogenies, the sexing of hominid and animal …

The earliest insect for which there is significant structural data, a bristletail (Archaeognatha)
from the Early Devonian (Emsian Stage) of the Gaspé Peninsula of Québec, Canada, is …

—Megalonychid sloths are well known from the Quaternary of many West Indian islands,
and some isolated remains date back as far as the early Oligocene. Phylogenetic …

Mandibular teeth and dentitions are features of jawed vertebrates that were first acquired by
the Palaeozoic ancestors,–of living chondrichthyans and osteichthyans. The fossil record …

Resolving difficult nodes for any part of the vertebrate tree of life often requires analyzing a
large number of loci. Developing molecular markers that are workable for the groups of …