—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 ...

Triassic tetrapods are of key importance in understanding their evolutionary history, because several tetrapod clades, including most of their modern lineages, first appeared or experienced their initial evolutionary radiation during this Period. In order to test previous palaeobiogeographical hypotheses of Triassic tetrapod faunas, tree reconciliation analyses (TRA) were performed with the aim...

Coprolites are the least studied and most under-sampled vertebrate trace fossils. They are very common in some Triassic localities. We recognize six new coprolite ichnotaxa: Alococopros triassicus, A. indicus, Saurocopros bucklandi, Liassococopros hawkinsi, Malericopros matleyi and Falcatocopros oxfordensis. The distribution of coprolite ichnotaxa is: Permian Hyronocopros amphipolar and Heterop...

SYNOPSIS TheNorth American Triassic dinosaur record has been repeatedly cited as oneof themost complete early dinosaur assemblages. The discovery of Silesaurus from Poland and the recognition that Herrerasaurus and Eoraptor may not be theropods have forced a re-evaluation of saurischian and theropod synapomorphies. Here, we re-evaluate each purported Triassic dinosaur from North Americaonaspeci...

The current Triassic chronostratigraphic scale is a hierarchy of three series divided into seven stages, divided further into 15 substages. Ammonoid and conodont biostratigraphies provide the primary basis for chronostratigraphic definition based on global stratotype sections and points (GSSP). I propose that Triassic chronostratigraphic definition should rely entirely on ammonoid biochronologi...

Similarities in body plan evolution, such as wings in pterosaurs, birds, and bats or limblessness in snakes and amphisbaenians, can be recognized as classical examples of convergence among animals [1-3]. We introduce a new Triassic stem archosaur that is unexpectedly and remarkably convergent with the "dome-headed" pachycephalosaur dinosaurs that lived over 100 million years later. Surprisingly...

This issue of Palaeogeography Palaeoclimatology Palaeoecology is devoted to papers on the Permian– Triassic boundary crisis and Early Triassic biotic recovery. It is an outgrowth of the Symposium on Early Triassic Chronostratigraphy and Biotic Recovery that was held in Chaohu, China, on May 21st–23rd, 2005 under the auspices of IGCP Project 467 and attended by about 200 Earth scientists with a ...

The Moenkopi Formation has yielded partial and isolated remains of important archosaurs including rauisuchian skull fragments and isolated poposaur centra and pelvic girdle elements. A recently discovered skeleton referable to Arizonasaurus babbitti shows that most of these archosaurian remains belong to one taxon. Characteristics of the skeleton of Arizonasaurus show that it belongs to a poorl...

Nonmarine fluvial, eolian and lacustrine strata of the Chinle and Glen Canyon groups on the southern Colorado Plateau preserve tetrapod body fossils and footprints that are one of the world's most extensive tetrapod fossil records across the Triassic– Jurassic boundary. We organize these tetrapod fossils into five, time-successive biostratigraphic assemblages (in ascending order, Owl Rock, Rock...