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The Emu Bay Shale Lagerstätte ( Cambrian Series 2, Stage 4) occurs on the north coast of Kangaroo Island, South Australia. Over 50 species are known from here, including trilobites and non-biomineralized arthropods, palaeoscolecids, a lobopodian, a polychaete, vetulicolians, nectocaridids, hyoliths, brachiopods, sponges and chancelloriids. A new chelicerate, Wisangocaris barbarahardyae gen. et sp. nov., is described herein, based on a collection of some 270 specimens. It is up to 60 mm long, with the length of the cephalic shield comprising about 30% that of the exoskeleton. The cephalic margin has three pairs of bilaterally-symmetrical small triangular spines. A pair of small eyes is placed well forwards on the ventral margin of the cephalic shield. The trunk comprises 11 segments that increase in length while narrowing posteriorly, each possibly bearing a pair of biramous appendages; the most posterior segment is almost square whereas the others are transversely elongated. The spatulate telson is proportionately longer than in taxa such as Sanctacaris, Utahcaris and Leanchoilia. Up to eight (?four pairs) of 3 mm-long elements bearing alternating inward-curving short and long spines beneath the cephalic shield are interpreted as basipodal gnathobases, part of a complex feeding apparatus. A well-developed gut includes a stomach within the cephalic shield; it extends to the base of the telson. In a few specimens there are shell fragments within the gut, including those of the trilobite Estaingia bilobata (the most common species in the biota); these fragments have sharp margins and extend across the gut lumen. The species may have been a predator or a scavenger, ingesting material already broken up by a larger predator/scavenger. The morphology of this taxon shares many overall body features with Sanctacaris, and some with Sidneyia, particularly its gnathobasic complex. These chelicerate affinities are corroborated by phylogenetic analyses. [ABSTRACT FROM AUTHOR]

Two species of Anomalocaris co-occur in the Emu Bay Shale ( Cambrian Series 2, Stage 4) at Big Gully, Kangaroo Island. Frontal appendages of Anomalocaris briggsi Nedin, 1995, are more common than those of Anomalocaris cf. canadensis Whiteaves, 1892, at a quarry inland of the wave-cut platform site from which these species were originally described. An oral cone has the three large, node-bearing plates recently documented for Anomalocaris canadensis, confirming that Anomalocaris lacks a tetraradial ' Peytoia' oral cone and strengthening the case for the identity of the Australian specimens as Anomalocaris. Disarticulated anomalocaridid body flaps are more numerous in the Emu Bay Shale than in other localities, and they preserve anatomical details not recognized elsewhere. Transverse lines on the anterior part of the flaps, interpreted as strengthening rays or veins in previous descriptions of anomalocaridids, are associated with internal structures consisting of a series of well-bounded, striated blocks or bars. Their structure is consistent with a structural function imparting strength to the body flaps. Setal structures consisting of a series of lanceolate blades are similar to those of other anomalocaridids and are found in isolation or associated with body flaps. A single specimen also preserves putative gut diverticula. The morphology of the appendages, oral cone, gut diverticula and compound eyes of Anomalocaris, along with its large size, suggests that it was an active predator, and specimens of coprolites containing trilobite fragments and trilobites with prominent injuries have been cited as evidence of anomalocaridid predation on trilobites. Based on frontal appendage morphology, Anomalocaris briggsi is inferred to have been a predator of soft-bodied animals exclusively and only Anomalocaris cf. canadensis may have been capable of durophagous predation on trilobites, although predation (including possible cannibalism) by Redlichia could also explain the coprolites and damage to trilobite exoskeletons found in the Emu Bay Shale. [ABSTRACT FROM AUTHOR]

Abundant material from a new quarry excavated in the lower Cambrian Emu Bay Shale (Kangaroo Island, South Australia) and, particularly, the preservation of soft-bodied features previously unknown from this Burgess Shale-type locality, permit the revision of two bivalved arthropod taxa described in the late 1970s, Isoxys communis and Tuzoia australis. The collections have also produced fossils belonging to two new species: Isoxys glaessneri and Tuzoia sp. Among the soft parts preserved in these taxa are stalked eyes, digestive structures and cephalic and trunk appendages, rivalling in quality and quantity those described from better-known Lagerstätten, notably the lower Cambrian Chengjiang fauna of China and the middle Cambrian Burgess Shale of Canada. [ABSTRACT FROM AUTHOR]