Previous studies have suggested a variety of causes for the end-Permian extinction event including a bolide impact, flood basalt volcanism, methane clathrate dissociation, or some combination of catastrophic processes. One common feature of these hypotheses is the prediction of an enhanced earliest Triassic greenhouse. New high-resolution geochemical results from Graphite Peak, Antarctica suppo...

Tanytrachelos ahynis (n.gen., n. sp.) is a lepidosaur from the Late Triassic Dan River Group (Newark Supergroup) of North Carolina and Virginia. The new reptile has gracile proportions similar to Tanystropheus (Middle Triassic) and is referred to the family Tanystropheidae of the suborder Prolacertiformes. Unlike Tanystropheus, Tanytrachelos has relatively short cervical vertebrae bearing splin...

Ichthyosaurs were important marine predators in the Early Jurassic, and an abundant and diverse component of Mesozoic marine ecosystems. Despite their ecological importance, however, the Early Jurassic species represent a reduced remnant of their former significance in the Triassic. Ichthyosaurs passed through an evolutionary bottleneck at, or close to, the Triassic-Jurassic boundary, which red...

In addition to their devastating effects on global biodiversity, mass extinctions have had a long-term influence on the history of life by eliminating dominant lineages that suppressed ecological change. Here, we test whether the end-Permian mass extinction (252.3 Ma) affected the distribution of tetrapod faunas within the southern hemisphere and apply quantitative methods to analyze four compo...

Orbitally controlled, sedimentary cycles of the Newark Supergroup permit palyniferous Late Triassic sections to be calibrated in time. Carnian palynofloras from · the Richmond basin exhibit 2-m.y. fluctuations in the spore/pollen ratio, but taxonomic composition remains stable. Diversity of Norian and Rhaetian palynofloras increases prior to a 60% reduction at the Triassic/Jurassic boundary. Th...

Based primarily on two previously undescribed skulls, this paper presents a detailed description of the skull and mandible of the latest Triassic procolophonid reptile Hypsognathus fenneri Gilmore, 1928. One of the new skulls, belonging to a presumed juvenile, clearly establishes for the first time the sutural pattern, which differs significantly from that in Procolophon and more basal procolop...

Tanytrachelos ahynis (n.gen., n. sp.) is a lepidosaur from the Late Triassic Dan River Group (Newark Supergroup) of North Carolina and Virginia. The new reptile has gracile proportions similar to Tanystropheus (Middle Triassic) and is referred to the family Tanystropheidae of the suborder Prolacertiformes. Unlike Tanystropheus, Tanytrachelos has relatively short cervical vertebrae bearing splin...

The end-Permian biotic crisis (~252.5 Ma) represents the most severe extinction event in Earth's history. This paper investigates diversity patterns in Anomodontia, an extinct group of therapsid synapsids ('mammal-like reptiles'), through time and in particular across this event. As herbivores and the dominant terrestrial tetrapods of their time, anomodonts play a central role in assessing the ...

Traditional wisdom holds that biotic recovery from the end-Permian extinction was slow and gradual, and was not complete until the Middle Triassic. Here, we report that the evolution of marine predator feeding guilds, and their trophic structure, proceeded faster. Marine reptile lineages with unique feeding adaptations emerged during the Early Triassic (about 248 million years ago), including t...

BACKGROUND Several clades of bivalve molluscs have invaded freshwaters at various times throughout Phanerozoic history. The most successful freshwater clade in the modern world is the Unionoida. Unionoids arose in the Triassic Period, sometime after the major extinction event at the End-Permian boundary and are now widely distributed across all continents except Antarctica. Until now, no freshw...