Early Permian fossil localities, including numerous tracksites, in the southern Robledo Mountains of Dona Ana County, New Mexico, cover an area of approximately 20 km2 . Lower Permian strata exposed here belong to four formations of the Hueco Group (ascend ing order): Shalem Colony, Community Pit, Robledo Mountains and Apache Da m Formations. With the exception of the Robledo Mountains Formatio...

Echinoids, or sea urchins, are rare in the Palaeozoic fossil record, and thus the details regarding the early diversification of crown group echinoids are unclear. Here we report on the earliest probable crown group echinoid from the fossil record, recovered from Permian (Roadian-Capitanian) rocks of west Texas, which has important implications for the timing of the divergence of crown group ec...

Coral reefs form the most diverse of all marine ecosystems on the Earth. Corals are among their main components and owe their bioconstructing abilities to a symbiosis with algae (Symbiodinium). The coral-algae symbiosis had been traced back to the Triassic (ca 240 Ma). Modern reef-building corals (Scleractinia) appeared after the Permian-Triassic crisis; in the Palaeozoic, some of the main reef...

Based on specimens previously identified as Tropidostoma, a new taxon of dicynodont (Bulbasaurus phylloxyron gen. et sp. nov.) from the Karoo Basin of South Africa is described. Bulbasaurus is a medium-sized dicynodont (maximum dorsal skull length 16.0 cm) restricted to the Tropidostoma Assemblage Zone (early Lopingian) of the Beaufort Group. Bulbasaurus can be distinguished from Tropidostoma b...

The Permian-Triassic boundary records the most severe mass extinctions in Earth's history. Siberian flood volcanism, the most profuse known such subaerial event, produced 2 million to 3 million cubic kilometers of volcanic ejecta in approximately 1 million years or less. Analysis of (40)Ar/(39)Ar data from two tuffs in southern China yielded a date of 250.0 +/- 0.2 million years ago for the Per...

Terrestrial ecosystems during the Pennsylvanian (late Carboniferous) and Cisuralian (early Permian) are usually described in literature as being dominated by synapsids, mammal-line amniotes. The pelycosaurs (a paraphyletic grouping of synapsid families) have been considered more speciose, abundant, ecologically diverse than contemporary reptile-line However, this dominance has never subjected t...

The first and last occurrences of hexapod families in the fossil record are compiled from publications up to end-2009. The major features of these data are compared with those of previous datasets (1993 and 1994). About a third of families (>400) are new to the fossil record since 1994, over half of the earlier, existing families have experienced changes in their known stratigraphic range and o...

Megaloptera are a basal holometabolous insect order with larvae exclusively predacious and aquatic. The evolutionary history of Megaloptera attracts great interest because of its antiquity and important systematic status in Holometabola. However, due to the difficulties identifying morphological apomorphies for the group, controversial hypotheses on the monophyly and higher phylogeny of Megalop...

A new ichnogenus and ichnospecies of burrow, Katbergia carltonichnus, are described from Upper Permian and Lower Triassic rocks of the Karoo Basin, South Africa, where they are preserved in pedogenically modified overbank deposits that are interpreted as inceptisols subsequently gleysol overprinted. Sigmoidal burrows consist of a long (‡0.5 m) cylindrical tube, ranging from 1–2 cm in diameter, ...

The end-Permian mass extinction, 251 million years (Myr) ago, was the most devastating ecological event of all time, and it was exacerbated by two earlier events at the beginning and end of the Guadalupian, 270 and 260 Myr ago. Ecosystems were destroyed worldwide, communities were restructured and organisms were left struggling to recover. Disaster taxa, such as Lystrosaurus, insinuated themsel...