instead took under 1.5 million years. The Induan age followed the mass extinction event at the end of the Permian period. Both global biodiversity and community-level (alpha) diversity remained low through much of this stage of the Triassic. Marine black shale deposits are common especially in the Dienerian substage of the Induan. These point to low oxygenation in the ocean. Much of the supercontinent Pangea remained almost lifeless, deserted, hot, and dry. In higher latitudes, the flora during the Griesbachian was gymnosperm dominated but became lycopod dominated (e.g. Pleuromeia) in the Dienerian. This change reflects a shift in global climate from cool and dry in the Griesbachian to hot and humid in the Dienerian and points to an extinction event during the Induan, 500,000 years after the end-Permian mass extinction event. It led to the extinction of the Permian Glossopteris flora. The lystrosaurids and the proterosuchids were the only groups of land animals to dominate during the Induan Stage. Other animals, such as the ammonoids, insects, and the tetrapods (cynodonts, amphibians, reptiles, etc.) remained rare and terrestrial ecosystems did not recover for some 30 million years. Both the seas and much of the freshwater during the Induan were anoxic, predominantly during the Dienerian subage. Microbial reefs were common, possibly due to lack of competition with metazoan reef builders as a result of the extinction. Ray-finned fishes largely remained unaffected by the Permian-Triassic extinction event. Many genera show a cosmopolitan (worldwide) distribution during the Induan and Olenekian (e.g. Australosomus, Birgeria, Parasemionotidae, Pteronisculus, Ptycholepidae, Saurichthys). This is well exemplified in the Griesbachian aged fish assemblages of the Wordie Creek Formation (East Greenland), the Dienerian aged assemblages of the Sakamena Formation (Madagascar), Candelaria Formation (Nevada, United States), and Mikin Formation (Himachal Pradesh, India), and the Smithian (Olenekian) aged assemblages of the Vikinghøgda Formation (Spitsbergen, Norway), Thaynes Formation (western United States), and Helongshan Formation (Anhui, China). Induan Chondrichthyans include hybodonts, neoselachians and a few surviving lineages of eugeneodontid holocephalians, a mainly Palaeozoic group. Cartilaginous fishes were seemingly rare during the Induan. Crocodile-shaped, marine temnospondyl amphibians (e.g. Aphaneramma, Wantzosaurus) were geographically widespread during the Induan and Olenekian ages. Their fossils are found in Greenland, Spitsbergen, Pakistan and Madagascar. The bivalve Claraia was widespread and common in the Panthalassa and Tethys oceans. The geologically oldest oysters (Liostrea) are known from the Induan. They grew on the shells of living ammonoids. Notable formations Arcadia Formation* (Queensland, Australia)