Consistent trends towards decreasing body size in the aftermath of mass extinctions--Lilliput effects--imply a predictable response among unitary animals to these events. The occurrence of Lilliput effects has yet to be widely tested in colonial organisms, which are of particular interest as size change may potentially occur at the two hierarchical levels of the colony and the individual zooids...

Teeth of primate-like mammals from the Paleogene (“plesiadapiforms”) have been known for at least 130 years (Gervais, 1877). These fossil taxa are generally recognized as being closely related, but not monophyletic (e.g., Gingerich, 1976; Szalay et al., 1987; Beard, 1993a; Silcox, 2001; Bloch and Boyer, 2002a; Bloch et al., 2007) and we maintain that view here. Thus “plesiadapiforms” are referr...

How did evolution generate the extraordinary diversity of vertebrates on land? Zero species are known prior to ~380 million years ago, and more than 30,000 are present today. An expansionist model suggests this was achieved by large and unbounded increases, leading to substantially greater diversity in the present than at any time in the geological past. This model contrasts starkly with empiri...

The northwestern Gulf of Mexico basin has emerged as an archetype example of a robust, progradational passive margin system that induces substantial translation over underlying detachments due to gravitational loading. Despite this recognition, the difficulties in deep imaging of seismic data have continued to obscure key features of this deformation. Megaregional, 2D, long-offset PSDM data hel...

A new species of Apatemyidae, Sinclairella simplicidens, is based on four isolated teeth that were screenwashed from fissure fillings at the late Oligocene Buda locality, Alachua County, Florida. Compared to its only congener Sinclairella dakotensis, the new species is characterized by upper molars with more simplified crowns, with the near absence of labial shelves and stylar cusps except for ...