Earliest known pelecypod on Earth — a new Early Cambrian genus from South Australia

A new genus and species of fordilloid pelecypod, Pojetaia runnegari gen. et sp. nov., is described from the lower part of the Parara Limestone, Yorke Peninsula, South Australia. Establishing the age of the sample on an international scale is difficult, as with almost all Early Cambrian formations, but evidence tends to suggest that this is the oldest pelecypod so far recorded. Clearly defined hinge teeth and sockets on both valves and on internal moulds help to confirm the pelecypod placement of fordilloids.     

The micromammalian fauna from Border Cave,Kwazulu, South Africa

The micromammalian fauna from Border Cave is analysed in terms of community composition and structure. Changes in these aspects are interpreted as indicative of changes in vegetation and climate in the vicinity of the cave during the period of deposition. It would appear that vegetation comprised relatively extensive forest or thick bush and dense grass during wetter phases and fairly open savanna woodland, even open grassland, during drier periods. Variation through time in mean mandibular size in two species of Crocidura (musk shrew) was different both in the two species and from what was expected. It now seems likely that the size change constitutes a response to complex phenomena and not simply to changes in temperature. Comparison with the Boomplaas A sequence indicates that the same general pattern of change is reflected at both sites but that there was a greater amplitude of change at Boomplaas A and that ¹⁸O stage 4 was dry at this site but wet at Border Cave. Evidence for periodic changes in the distribution of various species, and in some cases the mutually exclusive occurrence of ecologically equivalent species, has implications for the zoogeography of the species involved. In particular, the occurrence of Pelomys fallax (creek rat) in the lower half of the sequence is of interest in view of its present distribution 600 + km north of Border Cave.