<P> No coal deposits are known from the Early Triassic, and those in the Middle Triassic are thin and low - grade . This "coal gap" has been explained in many ways . It has been suggested that new, more aggressive fungi, insects and vertebrates evolved, and killed vast numbers of trees . These decomposers themselves suffered heavy losses of species during the extinction, and are not considered a likely cause of the coal gap . It could simply be that all coal forming plants were rendered extinct by the P--Tr extinction, and that it took 10 million years for a new suite of plants to adapt to the moist, acid conditions of peat bogs . Abiotic factors (factors not caused by organisms), such as decreased rainfall or increased input of clastic sediments, may also be to blame . </P> <P> On the other hand, the lack of coal may simply reflect the scarcity of all known sediments from the Early Triassic . Coal - producing ecosystems, rather than disappearing, may have moved to areas where we have no sedimentary record for the Early Triassic . For example, in eastern Australia a cold climate had been the norm for a long period, with a peat mire ecosystem adapted to these conditions . Approximately 95% of these peat - producing plants went locally extinct at the P--Tr boundary; Interestingly, coal deposits in Australia and Antarctica disappear significantly before the P--Tr boundary . </P> <P> There is enough evidence to indicate that over two - thirds of terrestrial labyrinthodont amphibians, sauropsid ("reptile") and therapsid ("proto - mammal") families became extinct . Large herbivores suffered the heaviest losses . </P> <P> All Permian anapsid reptiles died out except the procolophonids (although testudines have morphologically anapsid skulls, they are now thought to have separately evolved from diapsid ancestors). Pelycosaurs died out before the end of the Permian . Too few Permian diapsid fossils have been found to support any conclusion about the effect of the Permian extinction on diapsids (the "reptile" group from which lizards, snakes, crocodilians, and dinosaurs (including birds) evolved). </P>

Which of these have been associated with and may have contributed to the end-permian mass extinction