The family Emuellidae Pocock, 1970 was established for Emuella Pocock, 1970 and Balcoracania Pocock, 1970 from the Lower Cambrian of South Australia. Based on their peculiar trunk tagmosis, emuellids have been interpreted as the sister group of all other trilobites with dorsal facial sutures, and classified as high as the ordinal level. Cladistic analysis with a range of exemplar taxa of the Olenellina and Redlichiina instead resolves the emuellids within the Redlichiina, with tagmosis into a prothorax and opisthothorax ("telosoma") nonhomologous in olenellines and emuellids. A taxonomic revision of Australian species identifies Balcoracania flindersi as a junior subjective synonym of B. dailyi, whereas the two named species of Emuella are considered to be distinct. Balcoracania dailyi possesses up to 103 thoracic segments, the maximum number recorded in any trilobite

The lower Cambrian Emu Bay Shale on Kangaroo Island, South Australia, contains the only known Cambrian Burgess Shale-type biota in Australia. Two new lamellipedian arthropods, 'Emucaris fava' gen. et sp. nov. and Kangacaris zhangi gen. et sp. nov., from the Emu Bay Shale Lagerstätte are described as monotypic genera that are resolved cladistically as a monophyletic group that is sister to Naraoiidae + Liwiidae and classified within the Nektaspida as a new family Emucarididae. Shared derived characters of Emucarididae involve a bipartite, elongate hypostome and elongation of the pygidium relative to the cephalic shield and very short thorax. A monophyletic Liwiidae is composed of 'Liwia' and the Ordovician 'Tariccoia' + 'Soomaspis' but excludes 'Buenaspis', and even the membership of 'Buenaspis' in Nektaspida is contradicted amongst the shortest cladograms. New morphological interpretations favour affinities of 'Kwanyinaspis' with Conciliterga rather than with Aglaspidida, and 'Phytophilaspis' with Petalopleura.

A distinctive group of lobopodians known from Cambrian Stage 5 in western Laurentia includes 'Acinocricus' Conway Morris & Robison, 1988, from the Spence Shale in Utah, and an unnamed species from the Burgess Shale, British Columbia, popularly known as 'Collins' monster'. The temporal gap from their closest relative, the Chengjiang lobopodian 'Luolishania', is bridged by a single, incomplete specimen of a Collins' monster-type lobopodian from the Emu Bay Shale (Cambrian Series 2, Stage 4), Kangaroo Island, South Australia, the first lobopodian discovered in this Konservat-Lagerstätte. Pending formal description of the Burgess Shale species, the Australian specimen is left unassigned to a genus.

Background: Vetulicolians are one of the most problematic and controversial Cambrian fossil groups, having been considered as arthropods, chordates, kinorhynchs, or their own phylum. Mounting evidence suggests that vetulicolians are deuterostomes, but affinities to crown-group phyla are unresolved. Results: A new vetulicolian from the Emu Bay Shale Konservat-Lagerstätte, South Australia, 'Nesonektris aldridgei' gen. et sp. nov., preserves an axial, rod-like structure in the posterior body region that resembles a notochord in its morphology and taphonomy, with notable similarity to early decay stages of the notochord of extant cephalochordates and vertebrates. Some of its features are also consistent with other structures, such as a gut or a coelomic cavity. Conclusions: Phylogenetic analyses resolve a monophyletic Vetulicolia as sister-group to tunicates (Urochordata) within crown Chordata, and this holds even if they are scored as unknown for all notochord characters. The hypothesis that the free-swimming vetulicolians are the nearest relatives of tunicates suggests that a perpetual free-living life cycle was primitive for tunicates. Characters of the common ancestor of Vetulicolia + Tunicata include distinct anterior and posterior body regions - the former being non-fusiform and used for filter feeding and the latter originally segmented - plus a terminal mouth, absence of pharyngeal bars, the notochord restricted to the posterior body region, and the gut extending to the end of the tail.