This research work introduces the Early Triassic, Late Triassic-Early Jurassic, and Early Cretaceous silica-rich sand levels at east and central Alborz, Kopeh-Dagh, and Central Iran, and compares them with the Permian silica-rich sand level in the Chirouk mine at east Iran. Ghoznavi and Gheshlaq loose sand in Alborz (Early Triassic-Early Jurassic), Soh quartzite in Central Iran (Early Triassic...

—A global database of gastropod sizes from the Permian through the Middle Triassic documents trends in gastropod shell size and permits tests of the suggestion that Early Triassic gastropods were everywhere unusually small. Analysis of the database shows that no specimens of unambiguous Early Triassic age larger than 2.6 cm have been reported, in contrast to common 5– 10-cm specimens of both Pe...

Triassic tetrapod tracks have long been studied, including classic ichnofaunas such as those of the lower Newark Supergroup of eastern North America and the Bundsandstein of central Europe. They are known from all seven continents and encompass five archetypal vertebrate ichnofacies for nonmarine environments (Chelichnus, Grallator, Batrachichnus, Brontopodus, Characichnos), all of which are pr...

The rise of archosaurs during the Triassic and Early Jurassic has been treated as a classic example of an evolutionary radiation in the fossil record. This paper reviews published studies and provides new data on archosaur lineage origination, diversity and lineage evolution, morphological disparity, rates of morphological character change, and faunal abundance during the Triassic–Early Jurassi...

Ornithischian dinosaurs are one of the most taxonomically diverse dinosaur clades during the Mesozoic, yet their origin and early diversification remain virtually unknown. In recent years, several new Triassic ornithischian taxa have been proposed, mostly based upon isolated teeth. New discoveries of skeletal material of some of these tooth taxa indicate that these teeth can no longer be assign...

Carbon cycle disturbance associated with mass extinction at the end of the Permian Period continued through the Early Triassic, an interval of approximately 5 million years. Coincidence of carbon cycle stabilization with accelerated Middle Triassic biotic recovery suggests a link between carbon cycling and biodiversity, but the cause of Early Triassic carbon isotope excursions remains poorly un...

The presence of gigantic apex predators in the eastern Panthalassic and western Tethyan oceans suggests that complex ecosystems in the sea had become re-established in these regions at least by the early Middle Triassic, after the Permian-Triassic mass extinction (PTME). However, it is not clear whether oceanic ecosystem recovery from the PTME was globally synchronous because of the apparent la...

We report a new ichthyopterygian assemblage from Lower Triassic horizons of the Prida Formation at Fossil Hill in central Nevada. Although fragmentary, the specimens collected so far document a diverse fauna. One partial jaw exhibits isodont dentition with blunt tipped, mesiodistally compressed crowns and striated enamel. These features are shared with the Early Triassic genus Utatsusaurus know...

—The small size of Early Triassic marine organisms has important implications for the ecological and environmental pressures operating during and after the end-Permian mass extinction. However, this “Lilliput Effect” has only been documented quantitatively in a few invertebrate clades. Moreover, the discovery of Early Triassic gastropod specimens larger than any previously known has called the ...

The Permian-Triassic bottleneck has long been thought to have drastically altered the course of echinoid evolution, with the extinction of the entire echinoid stem group having taken place during the end-Permian mass extinction. The Early Triassic fossil record of echinoids is, however, sparse, and new fossils are paving the way for a revised interpretation of the evolutionary history of echino...