palmate ones ranged from to in length, and the cultrates from to . The siculates fall into two groups: those with a shallow S-curve at the base, which range from to in length, and often have a slight twist at the base; and those with a 45° and 90° bend at the base and are to long. Scleritomes of Early Cambrian halkieriids have many more palmate and cultrate than siculate sclerites. On the other hand, siculate sclerites of A. superstes are more abundant than either cultrate or palmate sclerites; in fact palmate sclerites are rare. Possibly some process after death removed many of the palmates and some of the cultrates, but it is more likely that in A. superstes the part of the scleritome, or "coat of mail", closest to the sea-bed was larger relative to the lateral and dorsal zones further up and towards the center. A. superstes sclerites are also about one-third the size of Early Cambrian halkieriid sclerites. Since the Georgina assemblage includes larger fossils and most Early Cambrian halkieriids are preserved by the same method, phosphatization, it is unlikely that preservational bias has produced an unrepresentative sample. Possible explanations for the small size of A. superstes sclerites include: the individual(s) represented in the Georgina assemblage were juveniles; their scleritomes were composed of many more sclerites than those of Early Cambrian halkieriids; or the species itself was relatively small. No shells that might be assigned to halkieriids have been found in the Georgina Basin. This does not prove that Australohalkieria lacked shells, as shells of Halkieria are rarely found. Australohalkieria parva This species, whose name means "Small Southern Halkieria", was first described in 1990. Like A. superstes, its sclerites have undivided longitudinal canals and a very similar structure to their walls wall, but A. parva has sclerites whose central canals are not flattened. Other halkieriid fossils from Australia The other sclerites from the Georgina Basin are different enough to be excluded from Australohalkieria superstes, but are not sufficiently abundant to provide enough detail for them to be classified. One type is very similar to those of A.superstes, even having a two-pronged tip, but the middle canal is not flattened. The other has a flattened central canal and no longitudinal canals, and may represent an additional Middle Cambrian halkieriid genus, distinct from Australohalkieria and from the Early Cambrian Halkieria. Siphogonuchitids Siphogonuchitids have two sclerite morphs as well as