difficult to date absolutely, ostracod and brachiopod extinctions were separated by around 670,000 to 1.17 million years. In a well-preserved sequence in east Greenland, the decline of animal life is concentrated in a period approximately 10,000 to 60,000 years long, with plants taking an additional several hundred thousand years to show the full impact of the event. Palaeoenvironmental analysis of Lopingian strata in the Bowen Basin of Queensland indicates numerous intermittent periods of marine environmental stress from the middle to late Lopingian leading up to the end-Permian extinction proper. The terrestrial mass extinction is believed by some scientists to have begun between 60 and 370 thousand years before the onset of the marine mass extinction. An older theory, still supported in some recent papers, is that there were two major extinction pulses 9.4 million years apart, separated by a period of extinctions well above the background level, and that the final extinction killed off only about 80% of marine species alive at that time while the other losses occurred during the first pulse or the interval between pulses. According to this theory one of these extinction pulses occurred at the end of the Guadalupian epoch of the Permian. For example, all dinocephalian genera died out at the end of the Guadalupian, as did the Verbeekinidae, a family of large-size fusuline foraminifera. The impact of the end-Guadalupian extinction on marine organisms appears to have varied between locations and between taxonomic groups – brachiopods and corals had severe losses. Studies of the timing and causes of the Permian-Triassic extinction are complicated by the often-overlooked Capitanian extinction (also called the Guadalupian extinction), just one of perhaps two mass extinctions in the late Permian that closely preceded the Permian-Triassic event. In short, when the Permian-Triassic starts it is difficult to know whether the end-Capitanian had finished, depending on the factor considered. Some of the extinctions dated to the Permian-Triassic boundary have recently been redated to the end-Capitanian. Further, it is unclear whether some species who survived the prior extinction(s) had recovered well enough for their final demise in the Permian-Triassic event to be considered separate from Capitanian event. A minority point of view considers the sequence of environmental disasters to have effectively constituted a single, prolonged extinction event, perhaps depending on which species is considered. Extinction patterns Marine organisms Marine invertebrates suffered the greatest losses during the P–Tr extinction. Evidence of this was found