Other fossil beds discovered since 1980 – some rather small and others rivalling the Burgess Shale – have also produced similar collections of fossils, and show that the types of animals they represent lived in seas all over the world.[82] It appears that most of the major animal lineages had arisen before the time of the Burgess Shale, and before that of the Chengjiang and Sirius Passet lagerstätten about 15 million years earlier, in which very similar fossils are found,[2] and that the Cambrian explosion was complete by then.[83] In the 1990s it was suggested that some Ediacaran fossils from 555 to 542 million years ago, just before the start of the Cambrian, may have been primitive bilaterians, and one, Kimberella, may have been a primitive mollusc.[83][84] By 1996, with new fossil discoveries filling in some of the gaps in the "family tree", some Burgess Shale "weird wonders" such as Hallucinogenia and Opabinia were seen as stem members of a total group that included arthropods and some other living phyla.[5][81]