Exceptionally large teeth attributable to the theropod genus Troodon are abundant in Upper Cretaceous rocks (Campanian–Maastrichtian) of northern Alaska. The dominance of low-angle light in this Cretaceous high-latitude environment seems to have selected for an abundance of Troodon. The population of these Alaskan specimens— morphologically the same as teeth attributable to this taxon in other regions—show a mean a ... Read more »

Allosauroidea, a clade of large-bodied theropod dinosaurs that ranged from the Middle
Jurassic until the Late Cretaceous, has been the subject of extensive phylogenetic study. However, despite the publication of 12 cladistic analyses little phylogenetic consensus has emerged, frustrating attempts to use these dinosaurs to study character evolution, biogeography and the quality of the fossil record. Here we analy ... Read more »

This field trip covers sedimentological and paleontological research being conducted
on the Jurassic Aztec Sandstone and Lower Cretaceous Willow Tank Formation in Valley of Fire State Park. Valley of Fire State Park is located in southern Nevada, just outside of the town of Overton. The Jurassic Aztec Sandstone is equivalent to the Navajo and Nugget Sandstones; these formations ... Read more »

Many of the best preserved teeth and bones of archosaurian reptiles found in 1834 in an Upper Triassic Rhaetian fissure fill on Durdham Down in Clifton (now in Bristol), southwest England were destroyed in 1940. Based on an 1875 map, the site is positively identified as within Quarry Steps Quarry. This paper includes an annotated catalogue, copies of most of the illustrations from 1840 to 1908, and photos of import ... Read more »

Georgenthalia clavinasica, a new genus and species of amphibamid dissorophoid temnospondyl, is represented by a small, complete, postmetamorphic skull from the Lower Permian Bromacker locality, Germany. It is only the third non-amniote of an assemblage of 12 terrestrial tetrapod taxa known from this locality. It is characterized by a broadly rounded skull with large orbits, a short postorbital length, and a unique ... Read more »